Human activities continuously change land coverage and the atmosphere; they directly and indirectly influence the global energy balance, and cause climate change [1
]. Humans are slowly coming to understand that the issue of climate change must be considered with an eye to establishing a consensus around sustainable development. This awareness arises mainly from disasters that are caused by extreme climate events worldwide. The issue forces people to reflect on the relationship between social development and the environment. The IPCC has also noted that island states are particularly vulnerable to global warming [2
]. Bueno et al.
] found that various investigations of the effect of climate change on small Caribbean islands emphasize the loss of tourism and damage to infrastructure, which will reduce the economies of these islands by 10%.
The 2011 edition of National Footprint Accounts (NFA), published by the Global Footprint Network (GFN) suggests that humankind consumed ecological resources and services that are equivalent to 1.5 planets in 2008; the corresponding value in 1960 was only 0.7 planets. While North Americans had an ecological footprint of 8.7 global hectares (gha) per person, Africans had a footprint of 1.4 gha per person. Given a global average biocapacity of only 1.8 gha per person, human beings are over-exploiting the ecological resources of the planet.
In the latest NFA of the GFN [4
], the six major categories of footprint are cropland, grazing land, fishing grounds, forest land, carbon uptake land and built-up land. The size of an ecological footprint is positively related to environmental impact but negatively related to the area of available bioproductive land per person; a larger footprint corresponds to less bioproductive land per person. Table 1
presents global ecological footprint data before 2009 [5
Global ecological footprint.
Global ecological footprint.
The global ecological footprint in 1961 represented only 62% of the total resources of the biosphere. In the 1980s, total human demand exceeded the biocapacity of the earth, meaning that the demand of some people exceeded an amount that, if demanded by everyone, the earth’s resources could satisfy. The global ecological footprint became about 1.5 times the earth’s biocapacity in 2007. Accordingly, the global ecological deficit has increased rapidly over recent years, suggesting that overexploitation by human beings has overloaded the environment. Humans must address this issue and act to improve the sustainability of urban and rural development.
Lee and Chen [9
] examined Taiwan’s ecological footprint and attempted to calculate the ecological footprint in 1997. However, since they did not take into account the equivalence factor [8
], the ecological footprint that they estimated was inaccurate. In 2005, to capture accurately Taiwan’s ecological footprint and its long-term variation, the Council of Agriculture (COA) began a series of scientific projects to determine the country’s ecological footprint from 1994–2003. Through data collection and measurement, an ecological footprint database for Taiwan was thus established. To increase accuracy, the 2005 study used the equivalence factors proposed by the GFN. The results thus obtained revealed an increase in the ecological footprint from 1994–2003 [10
]. A follow-up study in 2006 included the contribution of CO2
emissions to the footprint [11
]. Wang et al.
] calculated Taiwan’s ecological footprint from 1994–2007 and found that it was 6.54 gha per person in 2007. The total ecological footprint of Taiwan was 42 times the area of Taiwan. An analysis of ecological footprints can yield insight into the seriousness of the problem of global warming, and the ecological footprint is a useful tool for measuring sustainability [11
]. This study extends the important results of studies of Taiwan’s ecological footprint in 1994–2007 and updates the national ecological footprint accounts to enable the trend in the ecological footprint from 2008–2011 to be analyzed.
5. Conclusions and Suggestions
In the early 21st century, natural resources began significantly to limit economic development. As domestic demand increases, a country inevitably obtains various resources from other countries by international trade to maintain economic development and quality of life. However, as global resources are consumed, dependency on trade may stimulate a crisis of geopolitical competition. Successful economic development then no longer depends on active management and increasing availability of natural capital, requiring each country to focus on the sustainable use of resources [8
]. The ecological footprint is a tool for estimating environmental sustainability. However, various methods for evaluating ecological footprints yield divergent results. To ensure confidence in, and consistency among, ecological footprint accounts and their use as a basis for setting sustainable development policies, the GFN [4
] developed a standard method for calculating ecological footprints. In this study, the GFN’s latest method was used to calculate the ecological footprint and ecological deficit of Taiwan from 2004–2011. This study contributes by presenting the calculating changes in footprints in order to understand whether Taiwan appropriates resources from other countries. In fact, Taiwan did appropriate resources from other countries. In achieving its economic development, Taiwan induces impacts on the resources and environment of other countries. Taiwan’s case studies could become a reference for those countries which have been targeted for economic growth, especially the island states with few resources.
Research has revealed that the ecological footprint of Taiwan is slowly increasing. Based on data for 2011, the ecological footprint of Taiwan in that year was 219,010,920 gha, or 61 times the area of the country. The ecological deficit was approximately 50 times of the area of Taiwan. Both results reveal that the ecological footprint and the ecological deficit of Taiwan have increased annually, further suggesting that consumption by Taiwanese have far exceeded Taiwan’s carrying capacity. The increasing ecological deficit of Taiwan indicates that the Taiwanese are overusing global resources and placing tremendous pressures on the earth. The rising trend should remind Taiwanese to act immediately to reduce their ecological deficit.
Comparing with the data in 2007, which was based on the report of GFN [8
], Taiwan’s ecological footprint was 5.86 gha per person which was the 12th ranking and lower than the United Arab Emirates (10.7), Qatar (10.5), Denmark (8.3), Belgium (8.0), USA (8.0), Estonia (7.9), Australia (6.8), Ireland (6.3), Kuwait (6.3), Finland (6.2) and the Netherlands (6.2). As for Asian countries, Taiwan was higher than Singapore (5.3), South Korea (4.9), Japan (4.7) and China (2.2). These results manifest the importance of comparing the ecological footprints of Taiwan with other countries.
Comparing the ecological footprint of Taiwan with that of Asian countries, the reasons for high ecological footprint and ecological deficit lead to examine specific land use systems and ecological footprints in consumption-based approaches. For example, the calculation of specific impact accounts in the ecological footprint drawn from Life Cycle Assessment (LCA) method will be possible to elaborate the recent debate about the needs for improving ecological footprint method [48
]. Castellani and Sala [49
] highlighted the methodology for a joint use of the two methods and found the relevance of energy and fossil fuel consumption as main drivers of impact. However, the process-flow LCA studies may suffer from truncation errors, a lack of full coverage of indirect upstream flows [50
]. The joint approach between the two methods associated with the iterative nature of LCA process may make it difficult to standardize boundary setting principles for calculation. Using the Consumption Land Use Matrix [51
] including food, mobility, shelter, goods and services is a more detailed method of sub-national calculation of human activities but is often limited by a lack of available personnel and financial resources for ecological footprint accounting practices [48
]. Although this study is insufficient to generate improvements in analytical methodology, this study includes a carbon footprint from the Footprint Family which is an indicator emphasizing the expenditure analysis from the perspective of consumers rather than that of producers. As a consumption-based approach, these indicators have led to the establishment of a quantifiable and acceptable framework [48
] and a basis for further detailed assessment.
Any theoretical framework necessarily imposes limitations on empirical work. Consequently, this study presents a case study of Taiwan, and is hindered by the following limitations.
5.1.1. The Use of Different Sub-Items of Land Uses Yields Conservative Results
To ensure comparability of the results herein with those of international research, the categorization herein was based on the structure that was used by the FAO and the IEA. However, some of the statistical items in various domestic statistical yearbooks differ from those used by the FAO and the IEA, preventing the categorization of some sub-items, which were therefore omitted in the calculations, yielding excessively conservative results for the ecological footprint of Taiwan.
5.1.2. The Mixed Use of Land as Cropland and for Grazing May Result in the Double Counting of Some Land Areas
In Taiwan, most pasture is cropland. One piece of cropland may be rotated between crops or economic plants and pasture. For consistency with the GFN framework, the grazing lands are separated from croplands herein. This method may result in double counting in some calculations of land areas.
5.1.3. Lack of Bioproductivity and Equivalence Factor for Taiwan
This study uses data on global bioproductivity and the global equivalence factor from the GFN to determine the yield factors and land use adjustments in the accounting of the ecological footprint of Taiwan. However, to support ecological footprint accounting for the purposes of policy-making in Taiwan, a bank of long-term data on land bioproductivity and equivalence factors is required.
5.2.1. Evaluating Equivalence Factors and Yield Factors for Taiwan
Owing to Taiwan’s geographical characteristics, land use patterns and high population density, the yield factors and the equivalence factors that are used by the GFN may result in some errors in the ecological footprint accounts that are obtained herein. Accordingly, regular environmental surveys and thorough statistical data would provide more reliable ecological footprint accounting.