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Int. J. Environ. Res. Public Health 2010, 7(6), 2559-2606; doi:10.3390/ijerph7062559

Article
Public Perceptions of Climate Change as a Human Health Risk: Surveys of the United States, Canada and Malta
Karen Akerlof 1,*, Roberto DeBono 2, Peter Berry 3, Anthony Leiserowitz 4, Connie Roser-Renouf 1, Kaila-Lea Clarke 3, Anastasia Rogaeva 3, Matthew C. Nisbet 5, Melinda R. Weathers 1 and Edward W. Maibach 1
1
Center for Climate Change Communication, George Mason University, Fairfax, VA 22030, USA; E-Mails: croserre@gmu.edu (C.R.R); mweathe1@gmu.edu (M.R.W.); emaibach@gmu.edu (E.W.M.)
2
Department of Public Health, Ministry for Health, the Elderly and Community Care, Valletta, VLT 2000, Malta; E-Mail: roberto.debono@gov.mt
3
Health Canada, Ottawa, K1A 0K9, Canada; E-Mails: Peter.Berry@hc-sc.gc.ca (P.B.); kaila-lea.clarke@hc-sc.gc.ca (K.L.C.); anastasia.rogaeva@hc-sc.gc.ca (A.R.)
4
Yale Project on Climate Change Communication, Yale University, New Haven, CT 06511, USA; E-Mail: anthony.leiserowitz@yale.edu
5
School of Communication, American University, Washington, DC, USA; E-Mail: nisbet@American.edu
*
Author to whom correspondence should be addressed; E-Mail: kakerlof@gmu.edu; Tel.: +1-703-282-1289.
Received: 4 May 2010; in revised form: 3 June 2010 / Accepted: 9 June 2010 /
Published: 14 June 2010

Abstract

: We used data from nationally representative surveys conducted in the United States, Canada and Malta between 2008 and 2009 to answer three questions: Does the public believe that climate change poses human health risks, and if so, are they seen as current or future risks? Whose health does the public think will be harmed? In what specific ways does the public believe climate change will harm human health? When asked directly about the potential impacts of climate change on health and well-being, a majority of people in all three nations said that it poses significant risks; moreover, about one third of Americans, one half of Canadians, and two-thirds of Maltese said that people are already being harmed. About a third or more of people in the United States and Canada saw themselves (United States, 32%; Canada, 67%), their family (United States, 35%; Canada, 46%), and people in their community (United States, 39%; Canada, 76%) as being vulnerable to at least moderate harm from climate change. About one third of Maltese (31%) said they were most concerned about the risk to themselves and their families. Many Canadians said that the elderly (45%) and children (33%) are at heightened risk of harm, while Americans were more likely to see people in developing countries as being at risk than people in their own nation. When prompted, large numbers of Canadians and Maltese said that climate change can cause respiratory problems (78–91%), heat-related problems (75–84%), cancer (61–90%), and infectious diseases (49–62%). Canadians also named sunburn (79%) and injuries from extreme weather events (73%), and Maltese cited allergies (84%). However, climate change appears to lack salience as a health issue in all three countries: relatively few people answered open-ended questions in a manner that indicated clear top-of-mind associations between climate change and human health risks. We recommend mounting public health communication initiatives that increase the salience of the human health consequences associated with climate change.
Keywords:
climate change; global warming; public health; opinion poll; survey; United States; Canada; Malta

1. Introduction

Little evidence of the human health impacts of climate change existed in 2001 [1] when the Intergovernmental Panel on Climate Change’s third assessment report was released, but by 2007, the international panel of research scientists announced with very high confidence that “climate change currently contributes to the global burden of disease and premature deaths” [2]. Epidemiological research that until recently had only linked climate change to human injuries, deaths and illnesses resulting from heat waves and infectious diseases is beginning to be augmented by studies that address other potential stressors that may also impact population health, such as refugee migrations and increased vulnerability to poverty [3,4] among others.

Public health officials, at least in some nations, are aware of the growing human health risks associated with climate change. A 2008 survey of Ministries of Health in the British Commonwealth—including Malta’s—found that of the 31 health ministries that responded from 53 member states, all were concerned about climate change’s current or future public health impacts, particularly on children, the elderly and those in poverty, from flooding and sea level rise, changes in temperature and precipitation, and food insecurity [5]. In the United States, a 2008 survey of local public health department directors found that almost 70% believed that their jurisdiction (a county or city) would experience serious negative health effects associated with climate change over the next two decades [6]. Public health officials at all levels—from local to international—are calling for more attention to the issue [79].

There has been relatively little research on public awareness and understanding of the human health impacts and risks associated with climate change, and almost none of the research has been published or synthesized in the academic literature. A 2001 survey of the public in 30 countries found that when respondents were provided with a list of potential climate change impacts almost a third of respondents named human health as their greatest concern, the most of any category and higher than droughts and water shortages, extreme weather, and sea level rise [10]. People in developing nations were more likely to cite health impacts as a concern than people in developed nations. Recent polls in Canada also found high rates of identification of climate change as a human health threat when closed-ended questions were used. A survey in 2006 found that 65% of Canadians thought that greenhouse gases would negatively affect health [11], and another in 2007 found 81% were concerned about risks to health associated with climate change [12]. Although not focused primarily on this research question, surveys in the United States have indicated that Americans are less likely to identify climate change as a potential risk to their own health and that of others [1315]. Therefore, it appears there may be large differences in the ways in which people across different countries respond to survey questions about the risks of climate change to human health, even when prompted.

There have been few cross-national studies on climate change public opinion [16], but even less research is available that compares international perceptions of climate change health impacts. Three national surveys that solely or substantially focused on public perceptions about the health impacts of climate change were conducted recently over a one-year period—February 2008 to 2009—in the United States [17], Canada [18,19] and Malta [20]. While these studies were conducted independently, there was some overlap in the research questions and survey measures due to correspondence between the investigators. The lead investigators in the Canadian (PB) and the American survey (AL and EM) exchanged ideas prior to those surveys being fielded, and one of the American investigators (AL) served as an academic advisor to the Maltese investigator (RD). In this paper, we draw from the data collected in these surveys to answer three broad research questions among members of three developed Western nations:

  • RQ1: Does the public believe that climate change poses human health risks? And if so, are they seen as current or future risks?

  • RQ2: Whose health does the public think will be harmed?

  • RQ3: In what specific ways does the public believe climate change will harm human health?

2. Methodology

The three surveys were conducted in 2008 and early 2009 with nationally representative samples of adults in the United States, Canada and Malta. The population samples reflect similar gender divisions and age distributions, but somewhat different proportions of educational attainment (46% of the Canadian sample had a university degree or higher compared to 27% in the U.S. and 17% in Malta) (Table S1, Appendix). All the studies asked questions about respondents’ beliefs, attitudes and behaviors regarding global warming/climate change. The Canadian and Maltese studies specifically addressed the extent of public knowledge and concern about the human health consequences of climate change; the American study addressed this as one of many topics covered in the survey. The American survey employed the term “global warming,” while the Canadian and Maltese studies used “climate change.” Additional crosstabular analysis of the response measures by age, income and education is provided in tables in the Appendix. Further details of study methodology follow below.

2.1. United States

This survey was conducted by the Yale Project on Climate Change Communication and George Mason University’s Center for Climate Change Communication using Knowledge Networks’ nationally representative online panel of adults in the United States. Panel members are initially recruited using random digit dialing from a sampling frame of all U.S. phone numbers. Participants are provided hardware and Internet access to enable them to access Web-based questionnaires. The recruitment success rate is approximately 56%. A random sample of these panel members was drawn for the U.S. survey.

To accommodate a large number of survey measures, the U.S. instrument was divided into two questionnaires that were administered between October 7 and November 12, 2008. Of the original 3,997 invited respondents, 2,164 completed both questionnaires, a 54% response rate. The online panel tracks the U.S. Census Bureau’s Current Population Survey (CPS) on demographic variables such as age, race, Hispanic ethnicity, geographic region and employment. In order to adjust for non-coverage or non-response biases, the data was weighted to reflect CPS distributions of age, race, gender and education. The margin for error for the weighted data is ±2% within a 95% probability. Yale and George Mason University’s Human Subjects Review Boards approved the study protocol.

2.2. Canada

This survey was conducted by Environics Research Group between February 12 and March 3, 2008, using telephone interviews of 1,600 respondents. The sample of households was chosen using random-digit dialing. Household members 18 years of age or older with the most recent birthday were interviewed, either in English or French. The response rate was 10%. The data was weighted based on the Canadian 2006 Census to reflect regional population demographic characteristics for the country’s 10 provinces and three territories, and by age and gender in line with national population percentages. The final weighted sample under-represented those with lower education levels (25% high school education or less compared to 45% in the 2006 Census). The margin of error for the entire sample is ±2.4% with a 95% probability. Health Canada, which commissioned the research, does not require human subjects approval for public opinion research.

2.3. Malta

Using a list-based telephone survey method, this survey was conducted by one of the authors (RD) between January 12 and February 28, 2009. The March 2008 Electoral Register provided the sample frame for the study; phone numbers were identified through the online directories of the two main telephone providers. Interviews were conducted primarily in Maltese (97.4%), with the remaining in English. The sample—stratified by gender, age group, and regional district representative of distributions found within the Maltese adult population—yielded 543 completed questionnaires, a 92.7% completion rate. The final respondent sample was compared to the characteristics of the initial sample of 800 and found to be statistically indistinguishable by age, gender and region. In comparing the sample to the 2005 Census across the categories of labor status, occupation and education, the respondents were slightly more likely to be employed, professionals, and more highly educated. The margin of error is ±5% with a 95% probability. The University Research Ethics Committee provided prior approval of the study protocol.

3. Results

3.1. Does the Public Believe that Climate Change Poses Human Health Risks? And if so, Are They Seen as Current or Future Risks?

Fifty percent or more of Canadians and Maltese said that climate change is already harming people’s health, while only slightly more than a third of Americans said the same. A majority in all three countries said that in the future climate change will likely cause poverty/reduced standards of living, water shortages, and disease (United States and Malta), and more severe/frequent hurricanes and heat waves (United States and Canada), all of which either directly or indirectly undermine public health.

3.1.1. United States

A majority of Americans said that global warming will cause a range of environmental and societal impacts over the next 20 years (Figure 1). They were more likely to believe global warming will cause more frequent droughts and water shortages (65%), severe heat waves (66%), famines and food shortages (63%), and intense hurricanes (62%) than increases in epidemics (53%), people living in poverty (51%) and refugee migration (51%). About a quarter of respondents said they did not know what the effects of global warming would be (19 to 27%), and slightly fewer said that these events will not increase due to global warming (14 to 22%).

Box 1. U.S. survey questions addressing if and when global warming will cause health risks.

  • Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it? Droughts and water shortages, extinctions of plant and animal species, people living in poverty, refugees, disease epidemics, intense hurricanes, floods, forest fires, expanding deserts, melting ice caps and glaciers, intense rainstorms, severe heat waves, famines and food shortages, abandoning large coastal cities due to rising sea levels [Many more, a few more, no difference, a few less, many less, don’t know]

  • Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think …

    • ○ Currently die each year due to global warming?

    • ○ Are currently injured or become ill each year due to global warming?

    • ○ Will die each year 50 years from now due to global warming?

    • ○ Will be injured or become ill each year 50 years from now due to global warming? [Millions, thousands, hundreds, none, don’t know]

  • When do you think global warming will start to harm people in the United States? [They are being harmed now, in 10 years, in 25 years, in 50 years, in 100 years, never].

Sixty percent of Americans thought that global warming will begin to harm people in the United States within the next quarter century (Figure 2). About a third said that people in the United States are already being harmed, and 38% said this is true of people around the world. Only a small proportion—14 to 15%—believed that people will never be harmed by global warming.

Americans had difficulty estimating the number of people worldwide who are currently—or will be in the future—harmed by global warming. Almost half responded they do not know whether hundreds, thousands or millions of people are currently being injured/becoming ill (46%) or dying (48%) as a result of global warming (Figures 3 and 4), and slightly more indicated “don’t know” regarding these health impacts in the future (50% injuries/illness; 50%, deaths). Of those who were willing to estimate current health impacts, a plurality estimated “none” (21%, injuries/illness; 23%, deaths), followed by thousands (15%, injuries/illness; 14%, deaths), hundreds (13%, injuries/illness; 12%, deaths) and millions (5%, injuries/illness; 3%, deaths). Larger numbers of people estimated there would be injuries and deaths in 50 years as a result of global warming: millions of future injuries (13%), and thousands (17%) or millions (11%) of future deaths. Only 14 to 15% of Americans foresaw no harm to people worldwide by the next half century.

3.1.2. Canada

Box 2. Canada survey questions addressing if and when climate change will cause health risks.

  • Would you say that climate change definitely causes, likely causes, likely does not cause or definitely does not cause each of the following types of environmental impacts in Canada? Heat waves, more frequent storms including hurricanes, drought conditions, flooding of rivers/coastal areas, extreme cold weather, melting permafrost in Arctic, loss of wildlife habitat, coastal erosion, forest fires [Read only 6 of 9 items to reduce burden of response]

  • For each of these potential risks to health, would you say the risks to Canadians have generally increased, have generally decreased, or remained the same over the past ten years or so? Heat waves, more frequent storms including hurricanes, drought conditions, flooding of rivers/coastal areas, extreme cold weather, melting permafrost in Arctic, loss of wildlife habitat, coastal erosion, forest fires [Read only 6 of 9 items to reduce burden of response]

  • (Unprompted) In your view, what environmental problem or hazard would you say poses the greatest risk to the health of Canadians?

  • I will now read you a list of potential risk to the health of Canadians. Please tell me whether you think each of the following poses a major risk, a moderate risk, a minor risk, or no risk at all to the health of Canadians. Second-hand smoke from tobacco, chemical pollution, climate change, air pollution, heat waves, obesity, heart disease, pesticides in food, pandemic flu epidemics, West Nile virus, extreme cold weather, tap water [Read only 8 of 12 items to reduce burden of response]

  • Do you think that climate change already poses a risk to Canadians today, or do you think this is something that will happen in the future?

  • (Asked if respondents answer either “depends” or “in the future” to the above question) Do you think climate change will start affecting the health of Canadians: [in the] next 5 years, next 6–10 years, next 11–25 years, at least 25 years from now, never, depends, don’t know, not applicable.

When asked in an open-ended question what environmental problem or hazard poses the greatest risk to their nation’s public health, only 10% of Canadians named climate change, while 54% cited air pollution/smog and 18% cited water pollution. When specifically prompted, a large majority said that climate change is likely to trigger environmental conditions that are harmful to human health (61–87%, Figure 5). Similar to Americans, sizable numbers of Canadians said that climate change likely or definitely causes more frequent storms/hurricanes (79%), flooding of rivers and coastal areas (79%), heat waves (79%), and drought conditions (78%).

3.1.3. Malta

Box 3. Malta survey questions addressing if and when climate change will cause health risks.

  • How likely do you think it is that each of the following will occur during the next 50 years due to climate change?

    • ○ Worldwide, many people’s standard of living will decrease due to climate change.

    • ○ Worldwide, water shortages will occur due to climate change.

    • ○ Increased rates of serious disease worldwide due to climate change.

    • ○ You or your family’s standard of living will decrease due to climate change.

    • ○ Water shortages will occur in Malta due to climate change.

    • ○ The chance of you or your family getting a serious disease will increase due to climate change.

      [Very unlikely, somewhat unlikely, somewhat likely, very likely, don’t know]

  • Do you think people can die because of climate change? [Yes, no, don’t know]

  • If yes, worldwide, do you think this is happening now or is it something that will happen in the future? [Now, future, don’t know]

  • Do you think people can become ill because of climate change? [Yes, no, don’t know]

  • If yes, worldwide, do you think this is happening now or is it something which will happen in the future? [Now, future, don’t know].

When asked to classify a series of threats posed to the health of Canadians as being major, moderate, minor or no risk, 32% ranked climate change as a major risk, below obesity (70%), heart disease (65%), and air pollution (62%), but above pandemic flu epidemics (29%), heat waves (20%) and West Nile virus (16%).

More than half of Canadians (54%) identified climate change as a current risk to the health of their nation’s citizens as opposed to a future threat (39%). Very few said climate change will never pose health risks (4%) with about the same number (3%) saying that it depends/don’t know/not applicable. Of those who reported health impacts will not be felt until the future or that it depends, 40% said health impacts will begin within the next 10 years, 29% said health impacts will begin in 11–25 years, and 22% said 25 years or more.

Large numbers of Canadians said that health risks to Canadians from climate change (69%) and related problems including air pollution (76%), West Nile virus (50%), and heat waves (48%) have been increasing over the past decade.

About half or more (47–85%) of Maltese said that climate change over the next half century will cause declines in people’s standard of living, and increases in rates of serious disease and water shortages (Figure 6). Increasing rates of serious disease were seen as the most likely consequence of climate change of the options presented (worldwide, 85%; you/your family, 71%), followed by declines in standard of living (worldwide, 63%; you/your family, 50%). Water shortages were least likely to be identified as a climate change impact both worldwide (57%) and in Malta (47%).

Compared to Americans, a much larger proportion of the Maltese said that climate change is already causing death and illness worldwide. Nearly all (89%) Maltese said that climate change can cause illness, with nearly two-thirds (63%) saying that it is happening now. Somewhat fewer said that people can die because of climate change (77%), with half (50%) saying that this is already happening now. Only small percentages said they do not believe climate change can cause people to die (11%) or become ill (6%), and similarly small percentages said they “don’t know” (12% and 5%, respectively).

3.2. Whose Health does the Public Think will be Harmed?

Less than half of Americans said that they believe they themselves, or those people close to them, will be harmed by global warming; they were more likely to cite people in developing countries and future generations as those who are most at risk. Conversely, between about one-half to three-quarters of Canadians said that they themselves, their community, and their family are vulnerable to the human health impacts of climate change, and about equal numbers of Maltese were concerned about climate change’s impacts on people all over the world, and on themselves and their families.

3.2.1. United States

Box 4. U.S. survey questions addressing whose health will be harmed by global warming.

  • How concerned are you about the impact of global warming on … ? All people, all children, your children, people in the United States, you, your health, your lifestyle, your future [Scale from 1=not at all concerned to 7=extremely concerned]

  • How much do you think global warming will harm … ? You personally, your family, your community, people in the United States, people in other modern industrialized countries, people in developing countries, future generations of people [A great deal, a moderate amount, only a little, not at all, don’t know].

Americans were far more likely to see climate change as a problem for people geographically and temporarily distant, rather than for themselves (Figure 7). A majority of respondents said that global warming will harm future generations (61%) and people in developing countries (53%) a great deal or moderate amount. Conversely, far fewer respondents said global warming will harm themselves (32%), their family (35%), or their community (39%) to the same degree.

Americans on average said that they were more concerned about the effects of global warming on human beings than not. On a scale from not at all concerned (1) to extremely concerned (7), they indicated the most concern for all children (M = 5.01), all people (4.79) and their children (4.78) and the least amount of worry about global warming’s impacts on their own lifestyle (4.03).

3.2.2. Canada

Box 5. Canada survey questions addressing whose health will be harmed by climate change.

  • What about your own health? Do you believe that you personally are definitely, likely, likely not, or definitely not vulnerable to the potential health impacts of climate change?

  • Do you believe that people living in your community are definitely vulnerable, likely vulnerable, likely not vulnerable, or definitely not vulnerable to the potential health impacts of climate change?

  • (Open-ended) What types of Canadians, if any, do you think might be most likely to experience the negative effects of climate change?

Canadians said that the elderly (45%), children (33%) and people with illnesses (14%) will be the most likely to experience the negative effects of climate change. Though Canada is an Arctic nation with long coastlines, relatively few said people in the North/Arctic (8%) and those living near oceans/coasts (5%) would be especially vulnerable. Two thirds reported feeling personally vulnerable to the potential health impacts of climate change (67%) and almost one half (46%) said someone in their immediate household is especially vulnerable. Additionally, a large majority of Canadians viewed their community as being definitely or likely vulnerable (76%).

3.2.3. Malta

Box 6. Malta survey questions addressing whose health will be harmed by climate change.

  • Which of the following are you most concerned about? The impacts of climate change on …? You and your family, the Maltese people, people all over the world, non-human nature, not at all concerned.

About a third of Maltese said they were most worried about the impacts of climate change on themselves and their families (31%), another third identified other people around the world (32%), and a quarter indicated that they were most worried about non-human nature (26%). Only a small proportion of respondents said they were most concerned about impacts on the Maltese people (5%) or that they were not at all concerned (6%).

3.3. In What Specific Ways does the Public Believe Climate Change will Harm Human Health?

When presented with a list of potential health risks from climate change, the majority of people in both Canada and Malta said the changing climate will cause increased respiratory and breathing difficulties, cancer and heat-related health problems. No questions addressed this topic in the United States survey.

3.3.1. Canada

Box 7. Canada survey questions addressing types of health conditions affected.

Canada:

  • (Open-ended) I would now like to ask you about how climate change may affect the health of Canadians. In what ways, if any, do you think climate change poses a risk to the health of Canadians?

  • I will now read you a list of health risks that affect many Canadians today. Would you say that climate change definitely, likely, likely not or definitely does not increase the risk of: cancer, heat stroke, respiratory/breathing problems, infectious diseases, injuries from storms/extreme weather events, sunburn.

In the Canadian survey, respondents were first asked without prompting to identify one or more health conditions that are impacted by climate change. Sixty percent could name at least one, but the answers were exceedingly diverse, with low percentages of responses in any one category (<22%). In response to the open-ended question “In what ways, if any, do you think climate change poses a risk to the health of Canadians?” the most common answers were respiratory/breathing problems (22%), infectious diseases (11%), cancer (11%), and air quality impacts (8%). One of the most commonly cited health risks from climate change, respiratory or breathing problems, was mentioned unprompted by less than a quarter of Canadians, but when asked specifically almost 80% said they thought it was a definite or likely consequence (Figure 8). Indeed, when prompted with a list of potential conditions that may be affected, a large majority of Canadians (62–79%, Figure 8) cited multiple health consequences from climate as definitely or likely. This difference in responses between prompted and unprompted questions may be an indication that climate change health risk information is still relatively new for the public and either unknown or less cognitively salient.

3.3.2. Malta

Box 8. Malta survey questions addressing types of health conditions affected.

Malta:

  • The following list contains items, some of which are affected by climate change while others are not. Which of the following is affected by climate change? Heat waves, skin cancer, infections which can cause diarrhea, cardiovascular conditions, allergies, infectious diseases such as malaria, asthma and respiratory conditions.

Large percentages of Maltese identified asthma and respiratory difficulties (91%), skin cancer (90%), heat wave events (84%), and allergies (84%) as being associated with climate change (Figure 9). Only about a third identified cardiovascular problems as a result of climate change, and just less than half said a changing climate will cause more infectious and diarrheal diseases.

4. Discussion

In this paper, we have attempted to synthesize findings from three largely independent representative national surveys conducted in three distinctly different, albeit developed Western nations. That said, we urge appropriate caution in interpreting our findings due to limitations in the methods. While each of the surveys used was methodologically sound, synthesizing their findings to answer a set of overarching research questions is inherently limited by differences in measures, research questions, and foci (e.g., while the Canada survey focused solely on perceived health impacts for Canadians, the U.S. and Malta surveys also assessed perceived impacts on people elsewhere in the world). Research has indicated that even the use of the term global warming as opposed to climate change, as was done in these surveys (global warming in the U.S. survey, and climate change in Malta and Canada’s), may impact survey responses [21,22]. We have presented a range of detailed results, but will limit our discussion to the big picture findings that emerge from the data.

RQ1: Does the public believe that climate change poses human health risks? And if so, are they seen as current or future risks?

Substantial numbers of the American, Canadian and Maltese people appear to believe that climate change poses important risks to human health and well-being now or in decades to come. With regard to timing, about one third of Americans believe that health impacts are already occurring, while about half of Canadians and two thirds of Maltese believe that people are being harmed now.

The most commonly perceived threats to health and well-being, however, differed between countries. For example, Americans saw droughts and water shortages as one of the most “likely” global warming impacts (65%), the Maltese saw it as the least likely (where water shortages in Malta and worldwide were seen as “likely” by 47% and 57%, respectively), and Canadians placed it in the middle of the range of likely impacts, although they were more apt to see it as a likely risk than Americans (drought conditions, 78%). These differences are probably due in part to the array of response options provided in each of the surveys. Cultural differences, local and regional climate conditions, and personal experiences may also have played a role in these differences. Many regions of the United States and Canada have experienced drought conditions over the past decade [23], which may influence perceptions. Malta is unique in this respect as it has the capacity to supply demand for potable water by desalinating sea water.

Even by the early 1990s, concern over climate change was highest internationally in Canada, Europe and South America, and lower in the United States [15]. American concern over global warming has continued to rank lower compared to other nations, in part due to the larger representation of climate change deniers [24]. Standardized questions about health impact should be developed so that future surveys can more meaningfully explore these perceptions within and between regions and nations, and particularly address potential differences between developed and developing countries.

It is important to note, however, that climate change may lack salience as a health issue in the three countries studied. When asked closed-ended questions, many respondents gave answers consistent with beliefs in climate change as a threat to human health. Conversely, when asked open-ended questions, and closed-ended questions of a more specific nature, relatively few respondents gave answers consistent with perceptions of climate change as a serious risk to human health. For example, few Canadians, unprompted, identified climate change as the environmental problem or hazard that poses the greatest health risk to their nation. About half of the American survey respondents were unwilling to venture even a general guess (e.g., hundreds, thousands, millions) as to how many people are being—or will in the future be—harmed worldwide by global warming. A World Health Organization study estimated that by the year 2000 climate change was causing 150,000 deaths across the globe annually, with another 5 million ‘disability-adjusted life years’ per year due to increased illness and malnutrition [25]. Of those in the United States who did guess how many deaths currently are caused by global warming, the majority underestimated by at least a factor of 10, choosing “hundreds” or “none” instead of thousands. Only 5% of Americans said correctly that estimates of current global warming injuries and illnesses are in the millions. These numbers have been publicized by the World Health Organization and in some media reports [26,27]. Yet even in Malta, when asked “What comes to your mind when you hear the terms ‘climate change’ or ‘global warming’?”, only 9.5% of respondents unprompted associated climate change with human health, and even so may be the result of confusion between greenhouse gas impacts and other types of air pollution [20].

The low salience of the human health implications of climate change should not come as a surprise. Climate change receives relatively little news coverage [28], and when it does, the human health consequences are rarely mentioned [29]. Rather, news representations and entertainment programming representations of climate change impacts tend to focus on attributes of the environment such as polar ice and glaciers, and non-human species such as polar bears and pine trees [30]. Moreover, until relatively recently, public health officials have been largely silent about climate change as a health risk [31,32]. Much of the recent public health communication activity about climate change appears to be targeted internally—from leaders in the public health community to members of the public health community at large—rather than aimed at the public. Health Canada recently conducted a study of provincial and local health authority websites and found that while 69% provide information related to health conditions that may be exacerbated by climate change, only 10% mention climate change specifically [18]. The same appears to be true of American and Maltese public health websites, although formal assessments have not been conducted.

RQ2: Whose health does the public think will be harmed?

There were substantial differences among the three surveys with regard to questions used to assess perceptions of who is most susceptible to harm. The U.S. and Maltese questionnaires asked about harm to people both at home and abroad, while the Canadian questionnaire focused exclusively on Canadian communities and people. Furthermore, the U.S. questionnaire asked about harm to “future generations of people,” which proved to be the category of people that Americans were most likely to see as being harmed by global warming. Similarly, the Maltese questionnaire asked respondents to indicate whether they thought climate change impacts are occurring or will happen in the future.

Although the range of responses across the surveys was sizable, about a third or more of people in the United States and Canada saw themselves (United States, 32%; Canada, 67%), their family (United States, 35%; Canada, 46%), and people in their community (United States, 39%; Canada, 76%) as being vulnerable to at least moderate harm from with climate change. About one third of Maltese (31%) said they were most concerned about the risk to themselves and their families. Americans were the least likely to see themselves, their family and their community as being at risk, and viewed distant people elsewhere (in the United States, in other countries, and in future generations) as more likely to be harmed. Canadians, when asked this in an open-ended question, were most likely to see the elderly and children as most susceptible to harm; relatively few respondents pointed to other at-risk groups such as people with low incomes or who live in the Arctic or coastal regions that will be more heavily affected by climate change.

A large literature in the field of health and risk communication points to an individual’s personal sense of risk as the most powerful motivator of behavioral change [33,34]. This theory suggests that the closer to home a threat is, the more likely individuals will be to recognize and act on it. This may be particularly relevant in encouraging public adoption of adaptation measures to avoid increased climate health risks. A competing literature in political science—of perhaps more relevance to campaigns that seek to use public health as a frame for motivating reductions in national greenhouse gas emissions—finds that perceptions of national threat are sufficient drivers of policy support [35], and that the importance of self-interest in motivating behavior is over-estimated [36]. Thus, the importance of perceived personal as opposed to national health consequences of climate change is an important research question remaining to be answered.

The fact that substantial numbers of people in all countries did not view themselves as vulnerable or did not identify at-risk groups identified by scientists to be vulnerable should also not come as a surprise. Public health authorities have only just begun over the last decade to formulate approaches to identify and assess vulnerabilities in specific communities and regions [37,38] with assessments being conducted by many countries as a function of their commitment to the United Nations Framework Convention on Climate Change, including Canada [39] and Malta. Because these assessments are only relatively recent, there has been little communication of this information to the public.

RQ3: In what specific ways does the public believe climate change will harm human health?

Canadian’s responses to an open-ended question about the ways in which climate change can harm the health of Canadians further reinforce our previously stated conclusion that the human health implications of climate change may lack salience. While 60% of Canadian respondents were able, unprompted, to name at least one specific health threat, a wide range of threats were mentioned but even the most commonly mentioned—respiratory diseases—was named by only 22% of respondents.

When specifically prompted, however, Canadians and Maltese in large numbers expressed their belief that climate change can cause respiratory/breathing problems (78–91%), heat-related problems (75–84%), cancer (61–90%), and infectious diseases (49–62%). Large numbers of Canadians also indicated sunburn (79%) and injuries from extreme weather events (73%), and large numbers of Maltese indicated allergies (84%). Some of these beliefs are misperceptions—both sunburn and (skin) cancer are likely tied to the common misperception that climate change is caused by the hole in the earth’s ozone layer [40]—but these findings indicate that the Canadian and Maltese public accept the claim that climate change can harm human health in specific ways, even if they are not based upon an accurate scientific understanding. Future educational efforts may need to focus on increasing knowledge of these specific risks and ensuring that the public is aware of their hazards, symptoms and of preventative measures.

What actions, if any, do these findings suggest for public health officials?

Across all three countries, large numbers of people are already willing to accept that climate change has implications for human health. It is widely recognized by public health officials [8] and research scientists from other disciplines [1,2] that people in all nations need to take actions to reduce greenhouse gas emissions and to adapt to the risks posed by climate change. The willingness of Americans, Canadians and the Maltese to accept climate change as a health issue may indicate an opportunity for public health officials to educate the public not just about climate change’s health risks, but about actions needed to limit climate change and to adapt successfully to its risks.

Krosnick and colleagues [41] demonstrated that Americans who view climate change as being harmful to people are significantly more likely to support climate policy responses. More recently, research has shown that segments of the American public who understand that climate change is harming people here (rather than only in nations far away) and now (rather than at some time in the future, if at all), are more engaged in personal actions and more supportive of climate change policies [42,43]. Other studies that have assessed population behavior changes for climate change and air quality, however, have found that regional and perceptual barriers may exist as well [44,45].

Framing is an important process by which communicators can enhance their impact by linking messages and recommendations to their audience members’ deeply held values and beliefs. By defining or “framing” the relevance of climate change in ways that connect to the core values of specific audience segments—and repeatedly reinforcing that information through a variety of trusted sources and networks of recruitment—purposive communication can foster enhanced public engagement with the issue.

The public health frame—i.e., that climate change is a major threat to people’s health and well-being—has considerable potential to motivate individuals to reduce greenhouse gas emissions and take adaptive actions to reduce their health risks from expected impacts. The health frame connects a complex and poorly understood topic (such as climate change) to risks the public already understand and accept as important (e.g., asthma, respiratory problems, vulnerability to extreme heat, food-borne illness and infectious disease) [30,46,47]. Several of the authors have argued that a public health frame could shift the climate debate in the United States from one based on environmental values to public health values, which are more widely held, cutting across ideology and partisanship [30,31,48]. It would also enable a new and highly respected group of voices—such as doctors, nurses and public health officials—to engage the public in the issue. And finally, it moves the location of impacts closer to home, replacing polar bears with vulnerable people, such as children, the elderly and the poor. These three surveys indicate that people in the United States, Canada and Malta are receptive to the idea that climate change will have human health impacts—and thus this may be an indication that this type of message framing is likely to be effective. People who perceive climate change as a human health threat may be more willing to adopt lifestyles that are lower in greenhouse gas emissions and support mitigation and adaptation policies. At the same time, the surveys revealed that climate change health risks are not necessarily well-known or understood, suggesting that campaigns that impart this knowledge will be viewed as imparting novel and potentially useful information.

Recent research in the United States has found that when global warming is introduced as a health problem and information is provided about how specific mitigation-related policy actions will lead to health benefits such as cleaner air to breath, healthier food to eat, and more pedestrian- and bicycle-friendly communities, a broad cross-section of Americans responded positively to this re-framing of the issue [48].

Many of the policy options to reduce greenhouse gas emissions provide direct societal benefits from improved public health, thereby offsetting some of the often more apparent costs of carbon tax, cap or regulatory mechanisms [46]. Public health officials can assist policymakers responsible for actions to reduce greenhouse gas emissions by heightening their awareness of the health co-benefits of climate policies and their monetary value. Recently, a series of papers in the Lancet quantified health outcomes from increased household energy efficiency, walking and cycling, less consumption of animal products, and cleaner fuels and technologies in order to better integrate health gains, and cost savings, into climate policy decisions [47,4953]. A public health approach to climate change may also have more relevance at local governmental levels. More walkable communities, public transit systems and urban reforestation serve to protect global climate [46], but of perhaps more relevance to local officials, they also directly reduce air pollution levels in their municipalities, and may aid them in achieving other environmental objectives, such as reduced ground level ozone.

In Canada, health promotion programs already exist that attempt to motivate individuals to reduce their personal risks from climate-related hazards such as West Nile virus, smog, extreme heat and food safety [18]; similar programs exist in the United States and Malta. The 2009 Health Canada report found that virtually all materials produced by these programs on climate-related risks do not refer to climate change, and moreover, even with dissemination of the materials, many Canadians still are not adopting health-protective behaviors. There is little evidence on whether the use of a climate change public health frame in engaging the public on adaptation to these risks would be more effective, however. This raises an important issue that should be addressed in additional research.

What, if any, additional research should be undertaken?

Little social science research exists to date on the ways in which people—in any country—are thinking about the health risks from climate change. As posited above, introducing a new frame for people to use in understanding the complex issue of climate change may serve to bring a new dimension to help efforts of public health officials increase public knowledge of climate change health risks and motivate individuals to take adaptive and greenhouse gas reduction actions. Several of the authors on this paper are currently conducting research on the effectiveness of a public health message frame compared to traditional environmental and national security frames, and are analyzing the differences in message appeal across audience segments that have previously been defined by their attitudes, beliefs, actions and policy preferences on global warming [42,43]. We expect that the manner in which various audiences process public health information is likely to be influenced by their deeply held values, attitudes and beliefs, and is also a function of variables that differ across individuals, such as political ideology [54] or socioeconomics, as well as those that vary at broader scales, such as national cultural traits [24]. The development of uniform measures of climate health beliefs, risk perceptions and adaptation actions will provide a yardstick by which comparisons can be more easily made at all levels and by teams of researchers working independently, with the end goal of the development of more effective public health outreach campaigns on climate change at all levels—local, regional, national and international.

However useful surveys may be in broadly understanding the public’s perceptions, more fine-grained information about the mental models they use in processing this information will also need to be obtained using techniques such as those established by Baruch Fischhoff at Carnegie Mellon [55]. In-depth interviews with both members of the scientific community and the public on climate change health risks and adaptation responses will be needed in order to learn what types of information will be most valuable to audiences in affecting behavioral changes to reduce their risks from climate change as individuals and communities. Surveys, such as conducted in Malta, that obtain richer narrative data may also provide a window to greater understanding of the ways that the public intersects with this issue.

5. Conclusion

The public health community has an opportunity to frame the issue of climate change in a manner that promotes the engagement of individuals, governments, and a range of other stakeholders. Doing so will likely build support for policies that will mitigate climate change and help communities successfully adapt to unavoidable changes, and will encourage individuals to take actions to reduce their own contributions to climate change and protect themselves from its impacts. In the face of aggressive counter-claims against climate science, public beliefs in and concerns about climate change have recently declined in the United States [56] and Europe [57]. This opens a window of opportunity for the public health community to draw attention to climate change’s human health consequences using a communication strategy that has proven effective in ameliorating a range of public health problems: simple clear messages, repeated often, by a variety of trusted public health voices within a wider policy environment that supports greenhouse gas reduction behavior and healthy lifestyles.

This research was supported by a RWJF Investigator Award in Health Policy (to Edward Maibach & Matthew Nisbet), and by grants from The Yale Center for Environmental Law and Policy, the Betsy and Jesse Fink Foundation, the 11th Hour Project; and the Pacific Foundation (to Anthony Leiserowitz). The views expressed in this paper are not necessarily endorsed by Health Canada.

Appendix

Table Table S1. National sample demographic characteristics.

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Table S1. National sample demographic characteristics.
U.S.CanadaMalta
Gender
Male48%48%49%
Female52%52%51%
Age group
18–24 yrs11%11%12%
25–34 yrs19%16%16%
35–44 yrs19%20%16%
45–54 yrs18%20%21%
55–64 yrs18%15%18%
65–74 yrs11%65+ yrs: 18%11%
75+ yrs5%6%
Education level
Less than high school: 13%Primary: 17%
High school: 32%High school or less: 25%Secondary: 48%
Some college: 28%College: 28%Post-secondary: 18%
Bachelor’s degree or higher: 27%University +: 46%Tertiary: 17%
Table Table S2. U.S. perceptions of global warming impacts by educational level; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?

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Table S2. U.S. perceptions of global warming impacts by educational level; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?
%National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
Droughts and water shortages
Many more4350384246
A few more2214242025
No difference147131516
A few less13111
Many less11120
Don’t know1925232011
χ2, p < 0.01; n = 2,129
People living in poverty
Many more3334293438
A few more1819211618
No difference2212212427
A few less01100
Many less11021
Don’t know2532282517
χ2, p < 0.01; n = 2,137
Disease epidemics
Many more3140283131
A few more2213232223
No difference209182125
A few less11101
Many less10011
Don’t know2638292519
χ2, p < 0.01; n = 2,131
Intense hurricanes
Many more3938364042
A few more2316242323
No difference158141520
A few less01101
Many less10121
Don’t know2237252014
χ2, p < 0.01; n = 2,141
Intense rainstorms
Many more3942353942
A few more2419272225
No difference158141619
A few less11200
Many less10021
Don’t know2031222112
χ2, p<0.01; n = 2,130
Severe heat waves
Many more4243374245
A few more2418262426
No difference148131418
A few less11101
Many less10020
Don’t know1930221710
χ2, p<0.01; n = 2,136
Famines and food shortages
Many more3944343843
A few more2414252427
No difference159141617
A few less12101
Many less11120
Don’t know2130252012
χ2, p < 0.01; n = 2,140
Table Table S3. U.S. perceptions of global warming impacts by income level; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?

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Table S3. U.S. perceptions of global warming impacts by income level; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?
%National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
Droughts and water shortages
Many more43494441424042
A few more22152221242825
No difference1491213151619
A few less1302121
Many less1130110
Don’t know19241823171313
χ2, p < 0.01; n = 2,112
People living in poverty
Many more33353533343032
A few more19182015172023
No difference23161822243126
A few less0101000
Many less1031110
Don’t know24312328231918
χ2, p < 0.01; n = 2,120
Disease epidemics
Many more31353434292729
A few more22212019242225
No difference20121817212825
A few less1111101
Many less1000110
Don’t know26312630242220
χ2, p < 0.01; n = 2,117
Intense hurricanes
Many more39443739403836
A few more23172023262725
No difference15111414131724
A few less0100011
Many less1030110
Don’t know21272624201714
χ2, p < 0.01; n = 2,123
Intense rainstorms
Many more39453739393438
A few more24172524253125
No difference15101314151822
A few less1100110
Many less1030110
Don’t know20262222191514
χ2, p < 0.01; n = 2,114
Severe heat waves
Many more42473940424139
A few more25172823272728
No difference14101412111921
A few less1200101
Many less1030110
Don’t know18231724181211
χ2, p < 0.01; n = 2,125
Famines and food shortages
Many more39434237393639
A few more24172126262528
No difference15101512152018
A few less1201011
Many less1031110
Don’t know20281823191714
χ2, p < 0.01; n = 2,125
Table Table S4. U.S. perceptions of global warming impacts by age category; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?

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Table S4. U.S. perceptions of global warming impacts by age category; Worldwide over the next 20 years, do you think global warming will cause more or less of the following, if nothing is done to address it?
%National average18–2930–4445–5960+
Droughts and water shortages
Many more4340434742
A few more2222242022
No difference1416141214
A few less11122
Many less12011
Don’t know1920181920
χ2, p = 0.130; n = 2,128
People living in poverty
Many more3327304232
A few more1820211518
No difference2228221823
A few less01100
Many less12010
Don’t know2523262327
χ2, p < 0.01; n = 2,133
Disease epidemics
Many more3128293432
A few more2226222020
No difference2021221719
A few less10110
Many less10011
Don’t know2625252729
χ2, p = 0.098; n = 2,135
Intense hurricanes
Many more3935404337
A few more2325261921
No difference1515141516
A few less00100
Many less12110
Don’t know2223192125
χ2, p < 0.028; n = 2,138
Intense rainstorms
Many more3935384438
A few more2426242225
No difference1516161415
A few less11200
Many less12110
Don’t know2020202021
χ2, p < 0.061; n = 2,133
Severe heat waves
Many more4239444538
A few more2423272126
No difference1415131413
A few less11111
Many less12011
Don’t know1921161821
χ2, p < 0.186; n = 2,140
Famines and food shortages
Many more3932384439
A few more2426272121
No difference1517151315
A few less11111
Many less12121
Don’t know2123192022
χ2, p < 0.034; n = 2,139
Table Table S5. U.S. perceptions of timing of harm to people in the United States by educational level; When do you think global warming will start to harm people in the United States?

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Table S5. U.S. perceptions of timing of harm to people in the United States by educational level; When do you think global warming will start to harm people in the United States?
National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
They are being harmed now3432353434
In 10 years1315141014
In 25 years1315131213
In 50 years1314151311
In 100 years1211111411
Never1513121716
χ2, p = 0.258; n = 2,097
Table Table S6. U.S. perceptions of timing of harm to people in the United States by income level; When do you think global warming will start to harm people in the United States?

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Table S6. U.S. perceptions of timing of harm to people in the United States by income level; When do you think global warming will start to harm people in the United States?
National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
They are being harmed now34404330352828
In 10 years13141213111217
In 25 years13121210191311
In 50 years13131316131114
In 100 years12971591811
Never15111217131820
χ2, p = 0.258; n = 2,082
Table Table S7. U.S. perceptions of timing of harm to people in the United States by age; When do you think global warming will start to harm people in the United States?

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Table S7. U.S. perceptions of timing of harm to people in the United States by age; When do you think global warming will start to harm people in the United States?
National average18–2930–4445–5960+
They are being harmed now3430304133
In 10 years1312161114
In 25 years1317111213
In 50 years1314151015
In 100 years1213141110
Never1514131615
χ2, p < 0.01; n = 2,097
Table Table S8. U.S. perceptions of timing of harm to people worldwide by educational level; When do you think global warming will start to harm other people around the world?

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Table S8. U.S. perceptions of timing of harm to people worldwide by educational level; When do you think global warming will start to harm other people around the world?
National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
They are being harmed now3835413639
In 10 years1315111213
In 25 years1214121212
In 50 years1212131211
In 100 years119121210
Never1415121615
χ2, p = 0.513; n = 2,090
Table Table S9. U.S. perceptions of timing of harm to people worldwide by income level; When do you think global warming will start to harm other people around the world?

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Table S9. U.S. perceptions of timing of harm to people worldwide by income level; When do you think global warming will start to harm other people around the world?
National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
They are being harmed now38464534383233
In 10 years13101312131316
In 25 years12121210161210
In 50 years12101114121212
In 100 years11971491412
Never14121116111717
χ2, p < 0.01; n = 2,073
Table Table S10. U.S. perceptions of timing of harm to people worldwide by age category; When do you think global warming will start to harm other people around the world?

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Table S10. U.S. perceptions of timing of harm to people worldwide by age category; When do you think global warming will start to harm other people around the world?
National average18–2930–4445–5960+
They are being harmed now3830374539
In 10 years1313151012
In 25 years121891113
In 50 years121414813
In 100 years111113119
Never1413131514
χ2, p < 0.01; n = 2,091
Table Table S11. U.S. perceptions of morbidity and mortality rates by educational level; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?

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Table S11. U.S. perceptions of morbidity and mortality rates by educational level; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?
%National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
Currently die each year due to global warming?
Millions33334
Thousands1412121119
Hundreds121391412
None2320202427
Don't Know4852564838
χ2, p<0.01; n = 2,138
Will die each year 50 years from now due to global warming?
Millions111061315
Thousands1714161422
Hundreds86988
None1415111615
Don't Know5056574940
χ2, p<0.01; n = 2,147
Are currently injured or become ill each year due to global warming?
Millions56355
Thousands1515131419
Hundreds1310111515
None2121172324
Don't Know4648564336
χ2, p < 0.01; n = 2,143
Will be injured or become ill each year 50 years from now due to global warming?
Millions131291317
Thousands1513141419
Hundreds78878
None1514121715
Don't Know5053574941
χ2, p<0.01; n = 2,124
Table Table S12. U.S. perceptions of morbidity and mortality rates by income level; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?

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Table S12. U.S. perceptions of morbidity and mortality rates by income level; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?
%National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
Currently die each year due to global warming?
Millions3415324
Thousands14171511131217
Hundreds12810914158
None23172224233017
Don't Know48555251474155
χ2, p<0.01; n = 2,120
Will die each year 50 years from now due to global warming?
Millions1111711121014
Thousands17161912152021
Hundreds874101267
None1591415151819
Don't Know50575553464639
χ2, p < 0.01; n = 2,125
Are currently injured or become ill each year due to global warming?
Millions5545445
Thousands15171614141316
Hundreds139912151615
None22142021212826
Don't Know46545148453838
χ2, p < 0.01; n = 2,120
Will be injured or become ill each year 50 years from now due to global warming?
Millions1314810131516
Thousands15142013131519
Hundreds87381176
None1591416151719
Don't Know50565554474640
χ2, p < 0.01; n = 2,103
Table Table S13. U.S. perceptions of morbidity and mortality rates by age; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?

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Table S13. U.S. perceptions of morbidity and mortality rates by age; Now please think about the human health effects of global warming. (Please choose the answer corresponding to your best estimate.) Worldwide, how many people do you think?
%National average18–2930–4445–5960+
Currently die each year due to global warming?
Millions32243
Thousands1412131712
Hundreds121513109
None2328222122
Don't Know4842504853
χ2, p = 0.001; n = 2,141
Will die each year 50 years from now due to global warming?
Millions111110148
Thousands1717211414
Hundreds811887
None1416141512
Don't Know5045474959
χ2, p < 0.01; n = 2,147
Are currently injured or become ill each year due to global warming?
Millions54474
Thousands1516151713
Hundreds131813129
None2124222021
Don't Know4638474554
χ2, p < 0.01; n = 2,120
Will be injured or become ill each year 50 years from now due to global warming?
Millions1312131610
Thousands1517171413
Hundreds79876
None1517141514
Don't Know5046484857
χ2, p < 0.01; n = 2,103
Table Table S14. Canadian perceptions of environmental impacts resulting from climate change by age; I will now read you a list of potential risks to the health of Canadians. Please tell me whether you think each of the following poses a major risk, a moderate risk, a minor risk, or no risk at all to the health of Canadians. [Read only 8 of 12 items to reduce burden response] (n = 1,600).

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Table S14. Canadian perceptions of environmental impacts resulting from climate change by age; I will now read you a list of potential risks to the health of Canadians. Please tell me whether you think each of the following poses a major risk, a moderate risk, a minor risk, or no risk at all to the health of Canadians. [Read only 8 of 12 items to reduce burden response] (n = 1,600).
National average18–3435–4950–6465+
Obesity (n = 938)7061747371
Heart disease (n = 1,146)6559707273
Air pollution (n = 1,154)6259646562
Chemical pollution (n = 1,145)5846646060
Second-hand smoke (n = 1,139)5756545865
Pesticides in food (n = 919)4632505352
Climate change (n = 902)3235323028
Pandemic flu epidemics (n = 1,159)2923263439
Heat waves (n = 916)2018162326
West Nile virus (n = 1,168)1613151622
Extreme cold weather (n = 1,165)1514101719
Tap water (n = 903)1415141315
Table Table S15. Maltese perceptions of likelihood of health risks resulting from climate change by age; How likely do you think it is that each of the following will occur during the next 50 years due to climate change? [Index: 1 = very unlikely to 4 = very likely]

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Table S15. Maltese perceptions of likelihood of health risks resulting from climate change by age; How likely do you think it is that each of the following will occur during the next 50 years due to climate change? [Index: 1 = very unlikely to 4 = very likely]
National average18–3435–5455+
Worldwide, many people’s standard of living will decrease due to climate change.2.852.822.942.76
Worldwide, water shortages will occur due to climate change.2.852.822.992.73
Increased rates of serious disease worldwide due to climate change.3.283.243.363.22
You or your family’s standard of living will decrease due to climate change.2.652.572.732.64
Water shortages will occur in Malta due to climate change.2.662.522.752.67
The chance of you or your family getting a serious disease will increase due to climate change.3.002.962.993.05
Table Table S16. Maltese perceptions of likelihood of health risks resulting from climate change by educational level; How likely do you think it is that each of the following will occur during the next 50 years due to climate change? [Index: 1 = very unlikely to 4 = very likely]

Click here to display table

Table S16. Maltese perceptions of likelihood of health risks resulting from climate change by educational level; How likely do you think it is that each of the following will occur during the next 50 years due to climate change? [Index: 1 = very unlikely to 4 = very likely]
National averagePrimary / No educationSecondaryPost secondaryTertiary
Worldwide, many people’s standard of living will decrease due to climate change.2.852.752.932.832.72
Worldwide, water shortages will occur due to climate change.2.852.512.852.903.04
Increased rates of serious disease worldwide due to climate change.3.283.253.333.213.26
You or your family’s standard of living will decrease due to climate change.2.652.572.762.652.47
Water shortages will occur in Malta due to climate change.2.662.602.732.542.64
The chance of you or your family getting a serious disease will increase due to climate change.3.003.163.052.852.92
Table Table S17. U.S. perceptions of how much people will be harmed by educational level; How much do you think global warming will harm?

Click here to display table

Table S17. U.S. perceptions of how much people will be harmed by educational level; How much do you think global warming will harm?
National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
You personally
A great deal1019987
A moderate amount2218202225
Only a little2418202729
Not at all2217212324
Don't know2329312015
A great deal1019987
Don't know2218202225
χ2, p < 0.01; n = 2,139
Your family
A great deal1118101010
A moderate amount2419242526
Only a little2321192427
Not at all1914162121
Don't know2328312015
χ2, p < 0.01; n = 2,135
Your community
A great deal1320121312
A moderate amount2621262530
Only a little2014182323
Not at all1713141920
Don't know2332302015
χ2, p < 0.01; n = 2,137
People in the United States
A great deal2128202021
A moderate amount2821262933
Only a little159151716
Not at all1411121516
Don't know2231281914
χ2, p < 0.01; n = 2,145
People in other modern industrialized countries
A great deal2225212223
A moderate amount2819272733
Only a little139121515
Not at all139111515
Don't know2437292215
χ2, p < 0.01; n = 2,137
People in developing countries
A great deal3131243240
A moderate amount2217261921
Only a little106111310
Not at all1310101515
Don't know2436302114
χ2, p < 0.01; n = 2,134
Future generations of people
A great deal4445364551
A moderate amount1712201616
Only a little76877
Not at all10871113
Don't know2228282113
χ2, p < 0.01; n = 2,130
Table Table S18. U.S. perceptions of how much people will be harmed by income level; How much do you think global warming will harm?

Click here to display table

Table S18. U.S. perceptions of how much people will be harmed by income level; How much do you think global warming will harm?
National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
You personally
A great deal1013612898
A moderate amount22192422222124
Only a little24202020253129
Not at all22152424222624
Don't know23342523221314
χ2, p < 0.01; n = 2,123
Your family
A great deal111481311811
A moderate amount24202922262724
Only a little23211722242727
Not at all19102220182522
Don't know23352423221315
χ2, p < 0.01; n = 2,121
Your community
A great deal1317111313914
A moderate amount26243025272725
Only a little21181418222824
Not at all1781918172221
Don't know23332526211415
χ2, p < 0.01; n = 2,124
People in the United States
A great deal22282220202018
A moderate amount28252628312830
Only a little15101114172119
Not at all1471814131817
Don't know22302425191316
χ2, p < 0.01; n = 2,128
People in other modern industrialized countries
A great deal22282122212318
A moderate amount27232525322832
Only a little13111112131817
Not at all1361613131717
Don't know24322728211517
χ2, p < 0.01; n = 2,126
People in developing countries
A great deal32332829293437
A moderate amount22211820242321
Only a little1171011131310
Not at all1371613131616
Don't know24322727221416
χ2, p < 0.01; n = 2,123
Future generations of people
A great deal44444138425051
A moderate amount17141817221514
Only a little76610777
Not at all105121181314
Don't know22312324211413
χ2, p < 0.01; n = 2,111
Table Table S19. U.S. perceptions of how much people will be harmed by age category; How much do you think global warming will harm?

Click here to display table

Table S19. U.S. perceptions of how much people will be harmed by age category; How much do you think global warming will harm?
National average18–2930–4445–5960+
You personally
A great deal10813116
A moderate amount2223212321
Only a little2427262221
Not at all2225201923
Don't know2318202527
χ2, p < 0.01; n = 2,144
Your family
A great deal11813139
A moderate amount2425222525
Only a little2327252021
Not at all1921191718
Don't know2319202528
χ2, p = 0.001; n = 2,139
Your community
A great deal1312141610
A moderate amount2625252628
Only a little2024231719
Not at all1720161616
Don't know2319222527
χ2, p = 0.004; n = 2,136
People in the United States
A great deal2118192720
A moderate amount2830322427
Only a little1517141415
Not at all1417131312
Don't know2218222225
χ2, p = 0.001; n = 2,128
People in other modern industrialized countries
A great deal2219182724
A moderate amount2830332325
Only a little1315121215
Not at all1316131310
Don't know2421242427
χ2, p < 0.01; n = 2,138
People in developing countries
A great deal3131313529
A moderate amount2123221922
Only a little111111912
Not at all1316121310
Don't know2419242427
χ2, p = 0.045; n = 2,136
Future generations of people
A great deal4445444640
A moderate amount1716191517
Only a little787510
Not at all10138117
Don't know2218212326
χ2, p = 0.001; n = 2,130
Table Table S20. U.S. concern about who will be impacted by global warming by educational level; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]

Click here to display table

Table S20. U.S. concern about who will be impacted by global warming by educational level; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]
National averageLess than high schoolHigh schoolSome collegeBachelor's degree or higher
All people
72431252222
61616151717
51914182020
41919231716
388797
256556
19681011
χ2, p = 0.016; n = 2,135
All children
73045312626
61713152118
5179181621
41617181513
378685
253556
1858810
χ2, p<0.01; n=2,129
Your children
73039292926
61514131618
51513161415
41517181512
367676
253546
1148131417
χ2, p < 0.01; n = 2,109
People in the U.S.
72127231918
61617141716
51913192021
42120231921
3814797
264657
19581010
χ2, p < 0.01; n = 2,141
You
72123242117
61419111315
51714182016
42125221920
39771210
274769
1118111013
χ2, p < 0.01; n = 2,117
Your health
72438252218
61514141517
51713152018
41916221917
3988910
264668
1107101013
χ2, p < 0.01; n = 2,134
Your lifestyle
7132413139
6101010811
51717161914
42523282424
3128101414
210810912
11311131315
χ2, p < 0.01; n = 2,126
Your future
72133231916
61519141615
51911162222
41915231718
391091010
267667
1106101013
χ2, p < 0.01; n = 2,131
Table Table S21. U.S. concern about who will be impacted by global warming by income level; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]

Click here to display table

Table S21. U.S. concern about who will be impacted by global warming by income level; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]
National averageLess than $25,000$25,000 to $34,999$35,000 to $49,999$50,000 to $74,999$75,000 to $99,999$100,000 or more
All people
725342521232120
617191218171715
519142018202319
419171820231716
37699768
25374587
19710107914
χ2, p < 0.01; n = 2,113
All children
730442529272625
617151418192016
517132215191819
416141814181614
37689747
25356367
186797913
χ2, p < 0.01; n = 2,113
Your children
730392430272925
615141316171715
515121713181513
415141913171517
37789735
25454476
113111314111519
χ2, p = 0.01; n = 2,095
People in the U.S.
721322120181716
616191014161517
519142022221918
421181919262618
3891010768
26394479
196111061013
χ2, p < 0.01; n = 2,119
You
721341921181614
614131217151512
517151617192217
421192317232022
39711101089
274965810
11181112101115
χ2, p < 0.01; n = 2,095
Your health
724392025191617
616131019151916
517142212201816
418152116212117
39791110610
26566589
1107111191115
χ2, p < 0.01; n = 2,114
Your lifestyle
7132215157810
610128810911
517151815182015
425232025302822
312101614121012
2107138111212
113111214131318
χ2, p < 0.01; n = 2,105
Your future
721332223161416
61617617171815
519162015202320
419152117251917
3971112899
265116578
110781191014
χ2, p < 0.01; n = 2,107
Table Table S22. U.S. concern about who will be impacted by global warming by age category; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]

Click here to display table

Table S22. U.S. concern about who will be impacted by global warming by age category; How concerned are you about the impact of global warming on…. [all people, all children, your children, people in the U.S., you, your health].[not at all concerned = 1, extremely concerned =7]
National average18–2930–4445–5960+
All people
72424182926
61616181615
51819211717
41918201720
388868
254656
19118107
χ2, p = 0.028; n = 2,136
All children
73030263432
61716221516
51717171816
41617161415
376758
255446
189997
χ2, p = 0.072; n = 2,130
Your children
73030273329
61517191115
51514161415
41516151515
377658
254365
11412141611
χ2, p = 0.016; n = 2,111
People in the U.S.
72120172423
61616151716
51919221719
42121232219
3879710
265557
1912897
χ2, p = 0.060; n = 2,142
You
72123182519
61413131514
51718191518
42121232119
3999810
276778
11110111112
χ2, p = 0.343; n = 2,119
Your health
72422202824
61517171414
51719161815
41916201918
39109611
264767
110119911
χ2, p = 0.032; n = 2,136
Your lifestyle
71315101512
610981011
51717171815
42524272525
3129141113
210119911
11313141214
χ2, p = 0.124; n = 2,126
Your future
72124182420
61516161614
51920211716
41918182019
310811811
2646610
1101091010
χ2, p = 0.014; n = 2,133
Table Table S23. Canadian perceptions of likelihood of increased specific risks by education level; (Prompted) I will now read you a list health risks that affect many Canadians today. Would you say that climate change definitely, likely, likely not or definitely does not increase the risk of: (n = 1,600). Percent of definitely responses

Click here to display table

Table S23. Canadian perceptions of likelihood of increased specific risks by education level; (Prompted) I will now read you a list health risks that affect many Canadians today. Would you say that climate change definitely, likely, likely not or definitely does not increase the risk of: (n = 1,600). Percent of definitely responses
National averageLess than high schoolHigh school graduateSome collegeUniversity degree
Respiratory/breathing problems4651474942
Sunburn4655494544
Heat stroke3943424035
Injuries from storms/extreme weather3241303330
Cancer3238343132
Infectious diseases2730312724
n=1,600168257582577
Table Table S24. Canadian perceptions of likelihood of increased specific risks by income level; (Prompted) I will now read you a list health risks that affect many Canadians today. Would you say that climate change definitely, likely, likely not or definitely does not increase the risk of: (n = 1,600). Percent of definitely responses.

Click here to display table

Table S24. Canadian perceptions of likelihood of increased specific risks by income level; (Prompted) I will now read you a list health risks that affect many Canadians today. Would you say that climate change definitely, likely, likely not or definitely does not increase the risk of: (n = 1,600). Percent of definitely responses.
National averageLess than $40,000$40,000–$74,999$75,000 to $99,999$100,000+
Respiratory/breathing problems4651464637
Sunburn4649474636
Heat stroke3940403930
Injuries from storms/extreme weather3236332925
Cancer3235323126
Infectious diseases2729282918
n=1,600392435201299
Ijerph 07 02559f10 1024
Figure S1. Maltese perceptions of risk of death from climate change by educational level.

Click here to enlarge figure

Figure S1. Maltese perceptions of risk of death from climate change by educational level.
Ijerph 07 02559f10 1024

References

  1. Intergovernmental Panel on Climate Change (IPCC). Climate Change 2001: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change; McCarthy, JJ, Canziani, OF, Leary, NA, Dokken, DJ, White, KS, Eds.; Cambridge University Press: Cambridge, UK, 2001. [Google Scholar]
  2. Confalonieri, U; Menne, B; Akhtar, R; Ebi, KL; Hauengue, M; Kovats, RS; Revich, B; Woodward, A. Human Health. In Climate Change 2007: Impacts, Adaptation and Vulnerability, Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change; Parry, ML, Canziani, OF, Palutikof, JP, van der Linden, PJ, Hanson, CE, Eds.; Cambridge University Press: Cambridge, UK, 2007; pp. 391–431. [Google Scholar]
  3. Reuveny, R. Climate Change-Induced Migration and Violent Conflict. Polit. Geogr 2007, 26, 656–673. [Google Scholar]
  4. Ahmed, SA; Diffenbaugh, NS; Hertel, TW. Climate Volatility Deepens Poverty Vulnerability in Developing Countries. Environ. Res. Lett 2009, 4, 1–8. [Google Scholar]
  5. Commonwealth Health Minister’s Update; Commonwealth Secretariat, Pro-Book Publishing: Suffolk, UK, 2009. Available online: http://www.thecommonwealth.org/files/210353/FileName/CHMU2009ebook2.pdf (accessed on 24 May 2010)..
  6. Maibach, EW; Chadwick, A; McBride, D; Chuk, M; Ebi, KL; Balbus, J. Climate Change and Local Public Health in the United States: Preparedness, Programs and Perceptions of Local Public Health Department Directors. PLoS ONE 2008, 3, e283. [Google Scholar]
  7. American Public Health Association. Addressing the Urgent Threat of Global Climate Change to Public Health and the Environment, Policy Number 20078. 2007. American Public Health Association Website. Available online: http://www.apha.org/advocacy/policy/policysearch/default.htm?id=1351 (accessed on 24 May 2010).. [Google Scholar]
  8. World Health Organization. Climate Change and Health: Resolution of the 61st World Health Assembly. 2008. World Health Organization Website. Available online: http://apps.who.int/gb/ebwha/pdf_files/A61/A61_R19-en.pdf (accessed on 24 May 2010).. [Google Scholar]
  9. Canadian Public Health Association. National Public Education and Outreach Strategy on Climate Change. 2001. Canadian Public Health Association Website. Available online: http://www.cpha.ca/uploads/progs/_/ccah/strategy_e.pdf (accessed on 24 May 2010).. [Google Scholar]
  10. Leiserowitz, A. Public Perception, Opinion and Understanding of Climate Change—Current Patterns, Trends and Limitations. Human Development Report 2007/2008. Available online: http://hdr.undp.org/en/reports/global/hdr2007-2008/papers/leiserowitz_anthony.pdf (accessed on 24 May 2010)..
  11. POLLARA Research. Health Care in Canada Survey 2006: A National Survey of Health Care Providers, Managers, and the Public. Health Care in Canada Survey Website. Available online: http://www.hcic-sssc.ca/pdf/2006_hcic.pdf (accessed on 24 May 2010)..
  12. Canadian Medical Association. 7th Annual National Report Card on Health Care. Canadian Medical Association Website. Available online: http://www.cma.ca/multimedia/cma/Content_images/Inside_cma/Annual_Meeting/2007/GC_page/Report_Card_e.pdf (accessed on 24 May 2010)..
  13. Newport, F. Americans’ Global Warming Concerns Continue to Drop. 2010. Gallup. Available online: http://www.gallup.com/poll/126560/americans-global-warming-concerns-continue-drop.aspx (accessed on 24 May 2010).. [Google Scholar]
  14. Leiserowitz, A. Climate Change Risk Perception and Policy Preferences: The Role of Affect, Imagery and Values. Clim. Change 2006, 77, 45–72. [Google Scholar]
  15. Bord, RJ; Fisher, A; O’Connor, RE. Public Perceptions of Global Warming: United States and International Perspectives. Clim. Res 1998, 11, 75–84. [Google Scholar]
  16. Brechin, SR. Comparative Public Opinion and Knowledge on Global Climatic Change and the Kyoto Protocol: The U.S versus the World? Int. J. Soc. Soc. Policy 2003, 23, 106–134. [Google Scholar]
  17. Maibach, EW; Roser-Renouf, C; Leiserowitz, A. Climate Change in the American Mind: Americans’ Climate Change Beliefs, Attitudes, Policy Preferences, and Actions; Yale Project on Climate Change: New Haven, CT, 2009. Available online: http://www.climatechangecommunication.org/images/files/Climate_Change_in_the_American_Mind.pdf (accessed on 24 May 2010)..
  18. Berry, P; Clarke, K; Pajot, M; Hutton, D; Verret, M. The Role of Risk Perception and Health Communication in Adapting to the Health Impacts of Climate Change in Canada; Natural Resources Canada: Ottawa, Canada, 2009. [Google Scholar]
  19. Environics Research Group Ltd. Assessing Perceived Health Risks of Climate Change: Canadian Public Opinion; Health Canada: Ottawa, Canada, 2008. [Google Scholar]
  20. DeBono, R. Maltese Public Perceptions on Climate Change and Health. M.P.H. Thesis, Faculty of Medicine and Surgery, University of Malta, 2009. [Google Scholar]
  21. Kempton, W. How the Public Views Climate Change. Environment 1997, 39, 12–21. [Google Scholar]
  22. Whitmarsh, L. What’s in a Name? Commonalities and Differences in Public Understanding of “Climate Change” and “Global Warming”. Pub. Understand. Sci 2009, 18, 401–420. [Google Scholar]
  23. .
  24. Reiner, DM; Curry, TE; De Figueiredo, MA; Herzog, HJ; Ansolabehere, SD; Itaoka, K; Johnsson, F; Odenberger, M. American Exceptionalism? Similarities and Differences in National Attitudes toward Energy Policy and Global Warming. Environ. Sci. Technol 2006, 40, 2093–2098. [Google Scholar]
  25. Patz, JA; Campbell-Lendrum, D; Holloway, T; Foley, JA. Impact of Regional Climate Change on Human Health. Nature 2005, 438, 310–317. [Google Scholar]
  26. Sample, I. Climate Change Will Hit Least Polluting Countries Hardest.
  27. Eilperin, J. Climate Shift Tied to 150,000 Fatalities. The Washington Post, 17 November 2005. Available online: http://www.washingtonpost.com/wpdyn/content/article/2005/11/16/AR2005111602197.html (accessed on 24 May 2010).. [Google Scholar]
  28. Boykoff, MT. We Speak for the Trees: Media Reporting on the Environment. Annu. Rev. Env. Resour 2009, 34, 431–457. [Google Scholar]
  29. Nisbet, MC; Price, S; Pascual-Ferra, P; Maibach, E. Communicating the Public Health Relevance of Climate Change: A News Agenda-building Analysis. Sci Commun, 2010. in review.. [Google Scholar]
  30. Nisbet, MC. Communicating Climate Change: Why Frames Matter for Public Engagement. Environment 2009, 51, 514–518. [Google Scholar]
  31. Maibach, E; Roser-Renouf, C; Leiserowitz, A. Communication and Marketing as Climate Change Intervention Assets: A Public Health Perspective. Am. J. Prev. Med 2008, 35, 488–500. [Google Scholar]
  32. Campbell-Lendrum, D; Bertollini, R. Science, Media and Public Perception: Implications for Climate and Health Policies. B World Health Organ, 2010, 88, pp. 242–242. Available online: http://www.who.int/bulletin/volumes/88/4/10-077362.pdf (accessed on 24 May 2010).. [Google Scholar]
  33. Witte, K; Allen, M. A Meta-analysis of Fear Appeals: Implications for Effective Public Health Campaigns. Health Educ. Behav 2000, 27, 591–615. [Google Scholar]
  34. Hale, J; Dillard, J. Fear Appeals in Health Promotion Campaigns: Too Much, Too little, or Just Right? In Designing Health Messages: Approaches from Communication Theory and Public Health Practice; Maibach, E, Parrott, R, Eds.; Sage Publications: Thousand Oaks, CA, USA, 1995; pp. 65–80. [Google Scholar]
  35. Sears, D; Funk, C. The Role of Self-interest in Social and Political Attitudes. In Advances in Experimental Social Psychology; Zanna, MP, Ed.; Academic Press: San Diego, CA, USA, 1991; pp. 1–91. [Google Scholar]
  36. Miller, D; Ratner, R. The Disparity between the Actual and Assumed Power of Self-Interest. J. Pers. Soc. Psychol 1998, 74, 53–62. [Google Scholar]
  37. Ebi, KL; Kovtas, RS; Menne, B. An Approach for Assessing Human Health Vulnerability and Public Health Interventions to Adapt to Climate Change. Environ Health Persp, 2006, 114, pp. 1930–1934. Available online: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1764166/ (accessed on 24 May 2010).. [Google Scholar]
  38. Kovats, RS; Ebi, K; Menne, B. .
  39. Human Health in a Changing Climate: A Canadian Assessment of Vulnerabilities and Adaptive Capacity. Health Canada, 2008. Available online: http://www.sindark.com/NonBlog/Articles/hc-cc-report/CCandHealth.pdf (accessed on 24 May 2010)..
  40. Bostrom, A; Lashof, D. Weather or Climate Change? In Creating a Climate for Change: Communicating Climate Change and Facilitating Social Change; Moser, S, Dilling, L, Eds.; Cambridge University Press: Cambridge, UK, 2007; pp. 31–43. [Google Scholar]
  41. Krosnick, JA; Holbrook, AL; Lowe, L; Visser, PS. The Origins and Consequences of Democratic Citizens’ Policy Agendas: A Study of Popular Concern about Global Warming. Climatic Change 2006, 77, 7–43. [Google Scholar]
  42. Leiserowitz, A; Maibach, E; Roser-Renouf, C. Global Warming’s “Six Americas”: An Audience Segmentation; Yale Project on Climate Change: New Haven, CT, 2008. Available online: http://www.climatechangecommunication.org/images/files/SixAmericas-final-v3-Web.pdf (accessed on 24 May 2010)..
  43. Maibach, E; Roser-Renouf, C; Leiserowitz, A. Global Warming’s Six Americas 2009: An Audience Segmentation. Yale Project on Climate Change: New Haven, CT, 2009. Available online: http://environment.yale.edu/uploads/6Americas2009.pdf (accessed on 24 May 2010).. [Google Scholar]
  44. Semenza, JC; Hall, DE; Wilson, DJ; Bontempo, BD; Sailor, DJ; George, LA. Public Perception of Climate Change: Voluntary Mitigation and Barriers to Behavior Change. Am. J. Prev. Med 2008, 35, 479–487. [Google Scholar]
  45. Semenza, JC; Wilson, DJ; Parra, J; Bontempo, BD; Hart, M; Sailor, DJ; George, LA. Public Perception and Behavior Change in Relationship to Hot Weather and Air Pollution. Environ. Res 2008, 107, 401–411. [Google Scholar]
  46. Protecting Health from Climate Change: Connecting Science, Policy and People. World Health Organization, 2009. Available online: http://whqlibdoc.who.int/publications/2009/9789241598880_eng.pdf (accessed on 24 May 2010)..
  47. Haines, A; McMichael, AJ; Smith, KR; Roberts, I; Woodcock, J; Markandya, B; Armstrong, G; Campbell-Lendrum, D; Dangour, AD; Davies, M; Bruce, N; Tonne, C; Barrett, M; Wilkinson, P. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Overview and Implications for Policy Makers. Lancet 2009, 374, 2006–2015. [Google Scholar]
  48. Maibach, EW; Nisbet, MC; Baldwin, PK; Akerlof, K; Diao, G. Reframing Climate Change as a Public Health Issue: An Exploratory Study of Public Reactions. BMC Public Health, 2010. in press. [Google Scholar]
  49. Wilkinson, P; Smith, KR; Davies, M; Adair, H; Armstrong, BG; Barrett, M; Bruce, N; Haines, A; Hamilton, I; Oreszczyn, T; Ridley, I; Tonne, C; Chalabi, Z. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Household Energy. Lancet 2009, 374, 1917–1929. [Google Scholar]
  50. Woodcock, J; Edwards, P; Tonne, C; Armstrong, BG; Ashiru, O; Banister, D; Beevers, S; Chalabi, Z; Chowdhury, Z; Cohen, A; Franco, OH; Haines, A; Hickman, R; Lindsay, G; Mittal, I; Mohan, D; Tiwari, G; Woodward, A; Roberts, I. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Urban Land Transport. Lancet 2009, 374, 1930–1943. [Google Scholar]
  51. Markandya, A; Armstrong, BG; Hales, S; Chiabai, A; Criqui, P; Mima, S; Tonne, C; Wilkinson, P. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Low-Carbon Electricity Generation. Lancet 2009, 374, 2006–2015. [Google Scholar]
  52. Friel, S; Dangour, AD; Garnett, T; Lock, K; Chalabi, Z; Roberts, I; Butler, A; Butler, CD; Waage, J; McMichael, AJ; Haines, A. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Food and Agriculture. Lancet 2009, 374, 2016–2025. [Google Scholar]
  53. Smith, KR; Jerrett, M; Anderson, HR; Burnett, RT; Stone, V; Derwent, R; Atkinson, RW; Cohen, A; Shonkoff, SB; Krewski, D; Pope, CA; Thun, MJ; Thurston, G. Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Health Implications of Short-Lived Greenhouse Pollutants. Lancet 2009, 374, 2091–2103. [Google Scholar]
  54. Malka, A; Krosnick, J; Langer, G. The Association of Knowledge with Concern about Global Warming: Trusted Information Sources Shape Public Thinking. Risk. Anal 2009, 29, 633–647. [Google Scholar]
  55. Morgan, MG; Fischhoff, B; Bostrom, A; Atman, CJ. Risk Communication: A Mental Models Approach; Cambridge University Press: Cambridge, UK, 2002. [Google Scholar]
  56. Leiserowitz, A; Maibach, E; Roser-Renouf, C. Climate Change in the American Mind: Public Support for Climate and Energy policies in January 2010; Yale University and George Mason University: New Haven, CT.
  57. Rosenthal, E. Climate Fears Turn to Doubts Among Britons. The New York Times, 24 May 2010, p. 1. [Google Scholar]
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Figure 1. U.S. public perceptions of impacts from global warming.

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Figure 1. U.S. public perceptions of impacts from global warming.
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Figure 2. U.S. perceptions of timing of harm to people from global warming.

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Figure 2. U.S. perceptions of timing of harm to people from global warming.
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Figure 3. U.S. perceptions of current and future deaths resulting from global warming.

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Figure 3. U.S. perceptions of current and future deaths resulting from global warming.
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Figure 4. U.S. perceptions of current and future illnesses and injuries resulting from global warming.

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Figure 4. U.S. perceptions of current and future illnesses and injuries resulting from global warming.
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Figure 5. Canadian perceptions of environmental impacts resulting from climate change.

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Figure 5. Canadian perceptions of environmental impacts resulting from climate change.
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Figure 6. Maltese perceptions of likelihood of health risks resulting from climate change.

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Figure 6. Maltese perceptions of likelihood of health risks resulting from climate change.
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Figure 7. U.S. perceptions of who will be the most harmed from global warming.

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Figure 7. U.S. perceptions of who will be the most harmed from global warming.
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Figure 8. Canadian perceptions of likelihood of increased specific risks from climate change.

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Figure 8. Canadian perceptions of likelihood of increased specific risks from climate change.
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Figure 9. Maltese public perceptions of types of health risks from climate change.

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Figure 9. Maltese public perceptions of types of health risks from climate change.
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