Current Estimates on Greenhouse Gas Emissions in China Between 1970 and 2023

Abstract

Between 1970 and 2023, China’s yearly anthropogenic CO₂ emissions increased from 0.96 to 13.58 Pg. Yearly non-CO₂ greenhouse gases (GHGs) in China increased from 1133.7 Tg CO₂eq in 1970 to 3095.3 Tg CO₂eq in 2023. In terms of weight of the global warming potential over a horizon of 100 years, China’s anthropogenic non-CO₂ GHG emissions, approximately 56.8%, 13.5%, 10.1%, 10.4%, 5.2%, and 3.9% of which were from methane, nitrous oxide, hydrochlorofluorocarbons, hydrofluorocarbons, perfluorinated compounds, and chlorofluorocarbons, respectively, were equal to 23.3% of its anthropogenic CO₂ emissions in 2023. Despite efforts for mitigation, China’s non-CO₂ emissions are projected to keep growing in the foreseeable future due to unreported emissions, continuous industrialization, and global warming. This result shows that merely controlling anthropogenic CO₂ emissions and achieving carbon neutrality are not enough; non-CO₂ GHG emissions also need to be curbed.

1. Introduction

Due to anthropogenic climate change, the number of neonates facing climate extremes (e.g., heatwaves, floods, droughts, wildfires, typhoons, and food insecurity) has remarkably increased [1], showing the existence of intergenerational inequities in experiencing extreme weather events [2]. Equally important, climate change may cause the extinction of as many as a third of the Earth’s species, lowering biodiversity [3]. Sea levels have reached a record high since 1993 and surged at an accelerating speed, imperiling coastal economies [4]. The pH of the global mean ocean surface decreased from 8.11 in 1985 to less than 8.05 in 2023 [5].

Anthropogenic emissions of greenhouse gases (GHGs) are primarily responsible for global warming, and the global average surface temperature between 2011 and 2020 was 1.1 °C above that between 1850 and 1900 [6]. Emitting GHGs has led to an increase in radiative forcing (RF), which has caused a rise in temperature. Between 1990 and 2023, RF increased, which was caused by long-lived GHGs increasing by 51.5% from approximately 2.3 to 3.5 W·m⁻², with carbon dioxide (CO₂) accounting for 81% of this increase; from the preindustrial era to 2023, the global mean surface CO₂ abundance increased from 278.3 to 420.0 ± 0.1 ppm [7].

Between the preindustrial era of 1750 and 2023, anthropogenic emissions of non-CO₂ GHGs, including methane (CH₄), nitrous oxide (N₂O), and halocarbons, accounted for around 34% of the global mean temperature rise [7]. Halocarbons include chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), fluorinated compounds (e.g., perfluorocarbons (PFCs), fluorinated ethers, perfluoropolyethers, and Halon-1201), and other types of GHGs (e.g., chloroform, carbon tetrachloride, methyl bromide); specifically, from the preindustrial era to 2023, the contributions of CO₂, CH₄, N₂O, CFCs, HCFCs, and HFCs to the increase in global RF were 66%, 16%, 6%, 9%, 2%, and 1%, respectively [7]. CFCs and HCFCs are ozone-depleting substances (ODSs). Between 1960 and 2020, the increase in RF caused by ODS was around 0.3 W·m⁻², greater than that caused by CH₄ [8]. Stratospheric ozone depletion is a driving force of changes in weather, ocean surface temperature, sea currents, and the frequency of wildfires via altering atmospheric circulations [9].

To curtail climate change, the central Chinese government has crafted a detailed scheme to achieve peak carbon emissions by 2030 and realize carbon neutrality by 2060. China has planned to reduce anthropogenic CO₂ emissions per unit of gross domestic product (GDP) by 65% from the 2005 level, enhance non-fossil energy production to more than 25% of total energy consumption, augment forest storage volume by 6 billion cubic meters compared to the 2005 level, and increase total installed capacity of wind and solar power to over 1.2 billion kilowatts by 2030.

In recent years, China has begun to focus on mitigating human-induced emissions of non-CO₂ GHGs. China did not sign the global CH₄ pledge in 2021 [10], but eleven pivotal departments of the central government, including the Ministry of Foreign Affairs, the Ministry of Finance, and the Ministry of Agriculture and Rural Affairs, jointly issued China’s first plan to curtail anthropogenic CH₄ emissions [11], which was announced by Chinese President Xi and former President Biden of the United States in November 2023 as a watershed event [12]. The climate topic has been raised to a head-of-state level.

In China’s CH₄ emission control scheme announced on 7 November 2023, four main objectives and plans are given: (a) To strengthen overall planning and coordination, the Ministry of Ecology and Environment will set up a coordinated working mechanism to organize implementation, and enterprises are urged to consciously fulfill their social responsibilities. (b) To strengthen the fulfillment of responsibilities, key industries and enterprises should fully recognize the importance of CH₄ emission control. (c) To strengthen publicity and training, local governments should popularize and publicize the benefits of CH₄ emissions control. (d) To improve evaluation and supervision, the Ministry of Ecology and Environment will regularly monitor the progress of the implementation of CH₄ reduction plans [11,12].

Moreover, China has implemented the Clean Development Mechanism (CDM) project under the framework of the 1997 Kyoto Protocol to abate CO₂ and non-CO₂ GHG emissions through saving energy usage. However, as the largest anthropogenic CH₄ and N₂O emitter around the world in the early 2020s [13,14], China has paid less attention to reducing non-CO₂ GHGs than CO₂ emissions. In this study, long-term non-CO₂ GHG emissions in China are thoroughly reviewed.

This study aims to thoroughly recapitulate human-induced GHG emissions in China, depict their long-term emission trends, and analyze their sources.

2. Materials and Methods

We reviewed the most cited peer-reviewed research articles to holistically analyze China’s GHG emissions. These research articles were found through the most widely used databases around the world, including Web of Science and SCOPUS. We survey China’s official database for Patent Search and Analysis on the China National Intellectual Property Administration’s website (https://www.cnipa.gov.cn/). In the database of Web of Science, when we searched for “China anthropogenic CH₄ emission”, a total of 554 documents were displayed; when we searched for “China anthropogenic N₂O emission”, a total of 368 items were listed; when we searched for “China CFC emission”, “China HCFC emission”, and “China HFC emission”, a total of 151, 110, and 182 documents were shown, respectively. In the database of SCOPUS, when we searched for “China anthropogenic CH₄ emission”, a total of 309 documents were displayed; when we searched for “China anthropogenic N₂O emission”, a total of 173 items were listed; when we searched for “China CFC emission”, “China HCFC emission”, and “China HFC emission”, a total of 111, 70, and 89 documents were shown, respectively. By reviewing the literature, we have selected over 100 of the most representative and authoritative ones and summarized them in detail. We covered all emission data for anthropogenic CH₄, N₂O, and halocarbon sources in China over the last five decades.

Also, we consulted the latest files published by the Chinese government to list the latest emission reduction policies in China. According to the Ministry of Ecology and Environment, China fully, accurately, and comprehensively implements the new development concept; adheres to the people-centered approach; accelerates the formation of a new pattern of building a beautiful China guided by the goal of achieving harmonious coexistence between humans and nature; collaborates to promote carbon reduction, pollution reduction, green expansion, and growth; firmly implements the goal of carbon peak and carbon neutrality; regards green and low-carbon development as the fundamental solution to ecological and environmental problems; and makes new arrangements and requirements for addressing climate change. A systematic deployment has been made around building a green, low-carbon, and high-quality development spatial pattern; accelerating green transformation in key areas, implementing comprehensive conservation strategies; promoting green transformation of consumption patterns; and leveraging the support of technological innovation. Scientists propose establishing and improving policies, systems, and management mechanisms for local carbon assessment, industry carbon control, enterprise carbon management, project carbon evaluation, product carbon footprint, etc., and effectively connecting them with the national carbon emission trading market to build a comprehensive carbon emission dual control system. China will implement a carbon emission dual control system with intensity control as the main focus and total amount control as a supplement after reaching peak carbon emissions. By 2035, China’s net GHG emissions across the entire economy spectrum will decrease by 7% to 10% compared to the peak levels; the proportion of non-fossil energy consumption in total energy consumption will be over 30%; the total installed capacity of wind and solar power combined will reach 3.6 billion kilowatts; the forest storage volume will reach more than 24 billion cubic meters; the national carbon emission trading market will cover all major high emission industries. Thus, a climate-adaptive society will be built by 2035.

3. Results

3.1. Anthropogenic CH₄ Emissions

From the preindustrial era of 1750 to 2023, the global average atmospheric mole fraction of CH₄ had increased from around 729.2 parts per billion (ppb) to 1934 ± 2 ppb as 153 atmospheric monitoring stations around the world showed, reaching a level unparalleled in the last 800 thousand years [7]. Estimates of global CH₄ emissions include the Emissions Database for Global Atmospheric Research (EDGAR) [15], the Greenhouse Gas and Air Pollutant Interactions and Synergies (GAINS) [16], the Global Carbon Project (GCP) [17,18,19], the United States Environmental Protection Agency (USEPA), Netherland’s Environmental Assessment Agency (PBL), and the Community Emissions Data System (CEDS) for the Food and Agriculture Organization (FAO). Since the lifetime of CH₄ is 9.1 ± 0.9 years in 2010 [20], which was much shorter than that of other GHGs, a reduction in CH₄ emissions can effectively curb global warming in the short term.

The global warming potential values for the time horizon of 100 years (GWP₁₀₀) can be used to assess the impact of different kinds of GHG emissions on global warming. According to the GCP (https://www.globalcarbonproject.org/), the results of top-down atmospheric inversions showed that between 2008 and 2017, the annual average global CH₄ emissions were 576 Teragram (Tg) (16.1 Picogram (Pg) CO₂eq), approximately 62% and 38% of which were attributed to anthropogenic and natural sources, respectively [21]. Agricultural activities, fossil fuel utilization, and waste management accounted for approximately 40%, 35%, and 20% of total global anthropogenic CH₄ emissions, respectively [22]. According to EDGARv8.0 (https://edgar.jrc.ec.europa.eu/, accessed on 5 September 2025) [23], between 1970 and 2023, yearly anthropogenic CH₄ emissions around the world increased from 233.1 to 349.6 Tg (6.5 to 9.8 Pg CO₂eq); China’s annual anthropogenic CH₄ emissions increased from 35.8 to 62.8 Tg (1.0 to 1.8 Pg CO₂eq), accounting for 15.4% and 18.0% of global emissions in 1970 and 2023, respectively. China’s yearly natural CH₄ emissions were estimated to range from 4.0 [24] to 8.0 Tg [25]. Figure 1 illustrates the annual anthropogenic CH₄ emissions in China between 1970 and 2023 [14,15,23]. Emission reduction approaches of anthropogenic CH₄ emissions have been detailed [26,27,28,29].

Table 1. Estimates of annual anthropogenic CH₄ emissions in China.

Yearly Average Anthropogenic CH4 Emissions	Periods	Method	Reference
24.4 Tg in 1980; 44.9 Tg in 2010	1980 and 2010	Bottom-up inventory	[30]
48.4 ± 13.8 Tg (including natural emissions)	2000–2021	Top-down inversion	[31]
50 Tg	2010–2017	Top-down inversion	[24]
47 Tg	2010–2018	Top-down inversion	[32]
45 Tg	2008–2017	Top-down inversion	[33]
58 Tg	2009–2018	Top-down inversion	[34]
46 Tg	2010–2012	Top-down inversion	[35]
55 Tg	2010–2017	Top-down inversion	[36]
56 Tg	2019	Top-down inversion	[37]
43 Tg	2010–2017	Top-down inversion	[38]
45 Tg	2000–2017	Top-down inversion	[21]
46 Tg	2011–2017	Top-down inversion	[39]
59 Tg	2010–2015	Top-down inversion	[40]
54 Tg	2000–2011	Top-down inversion	[41]
45 Tg	2000–2010	Top-down inversion	[42]
72.6 Tg (including natural sources)	2023	Emission factor methods, process-based models, atmospheric inversions, and data-driven models combined	[43]
60.8 ± 5.9 Tg (including natural sources)	2015–2024	Top-down inversion	[44]
56 Tg	2022	Bottom-up inventory	[11]
39 Tg (16 Tg from agriculture, 16 Tg from energy, and 7 Tg from wastes)	2008	Bottom-up inventory	[45]
62 Tg	2022	Bottom-up inventory	[23]

shows the estimates of China’s anthropogenic CH₄ emissions [11,21,23,24,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45].

3.2. Anthropogenic N₂O Emissions

From the preindustrial era of 1750 to 2023, the global average atmospheric mole fraction of N₂O had increased from about 270.1 ppb to 336.9 ± 0.1 ppb, as indicated by 112 atmospheric monitoring stations around the world [7]. N₂O has been the most prominent ODS throughout this century [46,47]. N₂O and CH₄ have complex coupling interrelations, which have indirect impacts on climate change and stratospheric ozone. In the atmosphere, an increase in 1 mole fraction of N₂O would result in a reduction of 0.36 mole fraction of CH₄ through depleting stratospheric ozone, changing solar ultraviolet radiation, altering stratosphere-to-troposphere O₃ flux, and elevating tropospheric hydroxyl radical concentrations [48]. In addition, due to the emissions of GHGs, mainly including CO₂, CH₄, and N₂O, global mid and upper stratosphere has cooled at a rate of −0.6 K per decade since the late 1990s [49], leading to an increase in the ratio of N atoms to nitric oxide (NO) and thus a reduction in stratospheric ozone destruction [50].

Top-down atmospheric inversions showed that, in 2020, annual global natural and anthropogenic N₂O emissions were 26.7 (26.1–27.3) Tg (7.1 Pg CO₂eq) [51]; between 2007 and 2016, yearly average global N₂O emissions were estimated to be 26.6 (25.0–27.8) Tg (7.0 Pg CO₂eq), approximately 43% and 57% of which were ascribed to anthropogenic and natural sources, respectively [52]; between 2011 and 2020, annually average global N₂O emissions were estimated to be 27.0 (26.2–27.8) Tg (7.2 Pg CO₂eq), approximately 70% and 30% of which were from the land and ocean, respectively [53].

A bottom-up inventory showed that, between 1970 and 2023, annual global anthropogenic N₂O emissions increased by three-fourths from 5.4 to 9.4 Tg (1.4 to 2.5 Pg CO₂eq); China’s anthropogenic N₂O emissions increased by more than two times from 496.7 to 1581.2 Gigagram (Gg) (131.6 to 419.0 Tg CO₂eq) [23], accounting for 9.1% and 16.8% of global emissions in 1970 and 2023, respectively. In 2008, China’s annual anthropogenic N₂O emissions were 2150 (1174 to 2787) Gg (596.8 Tg CO₂eq), approximately 64%, 17%, 12%, 5%, 2.8%, and 0.2% of which were attributable to agriculture, energy, indirect sources, wastes, the chemical industry, and wildfires [54]. From 1978 to 2015, China’s annual anthropogenic N₂O emissions increased by 140% from 1.6 to 3.8 Tg [55]. Figure 2 illustrates the annual anthropogenic N₂O emissions in China between 1970 and 2023 [23]. The emission reduction avenues of anthropogenic N₂O emissions have been elaborated [28,56].

3.3. Halocarbons

The Chinese government terminated the production of all CFCs in 2007, which was completed three years ahead of the 1987 Montreal Protocol’s 2010 phase-out deadline for developing countries. The Montreal Protocol focused on CFC emissions, but it did not cover CFCs from obsolete cooling units. At present, only a small amount of CFCs for medical purposes is allowed to be used. China has implemented a quota license system for the import and export of CFCs, and import or export is not allowed without permission [57]. Estimates of China’s CFC-11 and CFC-12 emissions under strict governmental regulations between 1978 and 2037 [58], indicating that peak CFC-11 emissions occurred in 2004, reaching 17.5 Gg; the peak CFC-12 emissions occurred in 1995, reaching 33.7 Gg; in 2010, CFC-11 and CFC-12 emissions were supposed to be slashed to 14.4 Gg and 2.7 Gg, respectively.

High-precision measurements of atmospheric halogenated compounds can be used to assess emissions using inversion models [59,60]. The rate of decline of atmospheric CFC-11 abundance decreased by 50% during 2012–2016 compared to that during 2002–2012, showing an annual increase of 13 ± 5 Gg with respect to CFC-11 emissions globally [61]. Rogue CFC-11 emissions were found in the Chinese provinces of Shandong and Hebei, indicating new production and use; yearly average CFC-11 emissions from eastern mainland China were 7.0 ± 3.0 Gg during 2014–2017, higher than during 2008–2012, accounting for approximately half of the global increase in CFC-11 emissions [62]. Southwestern and central China and the Pearl River Delta metropolitan region contributed CFC-11 emissions in 2017 [63].

China has crafted a plan to establish a national monitoring network [64] to track rogue CFC-11 emissions and has seized illicit CFC-11 production since 2012 [65]. In carrying this out, an accelerated decline in the global average atmospheric CFC-11 abundance during 2019–2020 was achieved; in 2019, annual global CFC-11 emissions were estimated to be 52 ± 10 Gg, which decreased by 18 ± 6 Gg compared to previous years [66]. The annual mean CFC-11 emissions in eastern China were 19 ± 5 Gg during 2014–2018 [67]; the yearly average CFC-11 emissions in eastern China were estimated to be 7.2 ± 1.5 Gg during 2008–2012 and 5.0 ± 1.0 Gg in 2019 [68], showing that China has successfully curtailed CFC-11 production [69]. The annual mean CFC-11 emissions from southeastern China were estimated to range from 1.23 ± 0.25 to 1.58 ± 0.21 Gg using top-down inversions and 1.50 Gg using the bottom-up inventory during 2022–2023, which returned to the levels prior to 2010 [70].

Atmospheric observations at the top of Mount Tai in Shandong indicated that there were several types of unreported CFC emissions, including not only CFC-11 but also CFC-12, CFC-113, and CFC-114 in China between 2017 and 2018 [71]. Annually average CFC-12 emissions in China from 2010 to 2020 were estimated to be 11.0 ± 0.6 Gg [72]. In 2021, CFC-113 emissions in eastern China were estimated to be 0.88 ± 0.19 Gg [73]. Globally, yearly combined emissions of five CFCs (CFC-13, CFC-112a, CFC-113a, CFC-114a, and CFC-115) were equivalent to 4.2 ± 0.4 Gg CFC-11eq and 47 ± 5 Tg CO₂eq in 2020 [74], and emissions of CFC-113, CFC-114, and CFC-115 have not been reduced as expected [75]. However, China’s CFC emissions other than CFC-11 and CFC-12 have not been fully investigated. The interspecies relevance of CFC-11 with CHCl₃, CCl₄, HCFC-141b, HCFC-142b, CH₂Cl₂, and HCFC-22 implied the co-location of the emissions [67], showing that CFC-11 may be used as an indicator for estimating the emissions of other types of halocarbons. For more accurate estimations of rogue productions, ground-level observation is of importance [76]. Developing low-cost alternatives is a feasible way to curb rogue productions [77]. Because CFC emissions have not only contributed to stratospheric ozone depletion but also led to global warming, their emission reductions have triggered widespread concerns for decades [78,79,80,81,82,83,84,85,86].

China’s annual production and usage of HCFCs were estimated to be 29.1 Gg and 18.1 Gg CFC-11eq, respectively, in the early 2020s; the Chinese government plans to cut down 97.5% of baseline production and reserve only 2.5% for meeting the needs of refrigeration and air conditioning maintenance by 2030 [57]. During 2009–2019, among all released ODSs in China, HCFC emissions accounted for 58.6% in terms of CO₂eq [87]. China’s HCFC banks in foam products accounted for more than 91% of the national total in 2019 [88]. Like CFCs, unexpected emissions of HCFCs, including HCFC-31, HCFC-132b, and HCFC-133a, which have no known end uses, were detected, and East Asian countries, including China, were identified as the dominant source region for HCFC-132b and HCFC-133a [89].

Annual global HCHC-22 emissions decreased from 17.3 ± 0.8 Gg in 2019 to 14.0 ± 0.9 Gg in 2023; China has been the world’s largest HCFC-22 producer [90], accounting for around 80% of the national total HCFC production [87]. Between 1990 and 2014, China’s annual HCFC-22 emissions increased from 0.2 to 127.2 Gg [91]. Between 2018 and 2021, China’s annual average HCFC-22 emissions were estimated to be 160 ± 33 Gg [92]. The production of HCFC-141b will be completely prohibited by the Chinese government by January 2030 [57]. However, used as a substitute for CFC-11, China’s yearly HCFC-141b emissions increased from 0.8 Gg in 2000 to 15.8 Gg in 2013 [93]. Annual HCFC-141b emissions in eastern China increased from 3.7 Gg in 2008 to 6.8 Gg in 2020 [94]. Yearly HCFC-141b emissions in eastern China increased from 0.4 Gg in 2000 to 7.1 Gg in 2019, with a bank of 253.6 Gg in polyurethane foam products [95]. China’s HCFC-141b emissions were estimated to be 19.4 (17.3–21.6) Gg per year on average from 2018 to 2020 and 15.5 Gg in 2017 [96]. Between 2018 and 2021, China’s annual average HCFC-142b emissions were estimated to be 7.9 ± 1.7 Gg [92]. Except for HCFC-22, HCFC-141b, and HCFC-142b, emissions of other types of HCFCs in China have not been fully investigated. Moreover, using the default emission factors for fluorochemical production recommended by IPCC 2006 to estimate the emissions of HCFCs and HFCs from fluorochemical plants in China may lead to underestimation [97]. Atmospheric concentrations of HCFC-22 and HCFC-142b in China were reported by a previous study [98], indicating China’s high emissions.

With the gradual phase-out of CFCs and HCFCs, China’s HFC production has tremendously scaled up [97]. HFC-23 is a byproduct of HCFC-22 synthesis [90]. An increase in global HFC-23 emissions was found despite near-total expected reductions [99,100]. According to EDGARv8.0 [23], the annual combined average HFC emissions, including HFC-23, HFC-32, HFC-125, HFC-134a, and HFC-227ea, in China increased more than 64 thousand times from 5.0 Gg CO₂eq in 1991 to 322.22 Tg CO₂eq in 2023. China’s annual production and usage of HFCs were estimated to be 1853 Tg and 905 Tg CO₂eq, respectively, in the early 2020s; the Chinese government plans to cut down 10% of baseline HFC production by 2029 [57]. During 2011–2017, HFC-32, HFC-125, HFC-134a, HFC-227ea, and HFC-245fa emissions increased rapidly, and HFC-143a, HFC-152a, HFC-236fa, and HFC-365mfc emissions remained stable [101]. For 2010–2012, China’s yearly average emissions of HFC-32, HFC-125, HFC-134a, HFC-143a, and HFC-152a were 7.03 (4.92–9.24), 5.72 (4.02–7.73), 12.25 (4.87–20.90), 2.15 (1.33–3.15), and 5.33 (1.64–9.42) Gg, respectively [102]. The economically powerful Chinese provinces such as Jiangsu, Zhejiang, and Guangdong were the major contributors of HFC (HFC-32, HFC-125, HFC-134a, and HFC-143a) emissions [103]. Between 2011 and 2020, China’s yearly HFC-134a emissions increased from 19.5 ± 2.5 Gg to 33.1 ± 7.5 Gg [104]. Over the period of 2018–2020, China’s annual average HFC-152a emissions were estimated to be 9.9 ± 1.7 Gg [105]. Figure 3 shows HFC emissions in China from 1990 to 2023 [14]. Even though HFC emissions have not been regulated yet in China, emission reduction pathways have proven to be feasible [106].

According to EDGARv8.0 [23], annual average perfluorinated compound emissions, including PFCs, sulfur hexafluoride (SF₆), and nitrogen trifluoride (NF₃), in China increased more than 64 thousand times from 5.1 Tg CO₂eq in 1990 to 168.8 Tg CO₂eq in 2023. Several types of F-gases emissions, including PFC (CF₄, C₂F₆, C₃F₈, and c-C₄F₈), NF₃, and SF₆ combined, in China increased from 5.5 Tg CO₂eq in 1990 to 221 Tg CO₂eq in 2019 [107]. China’s yearly PFC-318 (c-C₄F₈) emissions, a byproduct of the pyrolysis of HCFC-22, increased from 0.65 Gg in 2011 to 1.12 Gg [108]. Yearly NF₃ emissions in China increased from 0.93 ± 0.15 Gg in 2015 to 1.53 ± 0.20 Gg in 2021 [109]. Figure 4 shows China’s annual emissions of HFC and perfluorinated compounds from 1990 to 2023 [14]. Figure 5 indicates the distribution of HFC emissions in China in 2023 [14]. Abating perfluorinated compounds in China has proven to be viable [110].

HFO-1336mzz(Z) has been produced in China since 2014 [111]. From 2011 to 2019, yearly CH₂Cl₂ emissions in China increased from 231 (213–245) to 628 (599–658) Gg [112]. During 2010–2015, China’s yearly chloroform emissions increased by 49 Gg [113].

3.4. Emissions of Overall Non-CO₂ GHGs

According to EDGARv8.0, between 1970 and 2023, China’s yearly non-CO₂ GHG emissions increased from 1.5 to 2.7 Pg CO₂eq; in terms of GWP₁₀₀-weight, the proportion of non-CO₂ GHG emissions from China compared to global total emissions increased from 14.6% to 19.3% [23]. According to previous studies [14,15,23,58,62,67,72,91,92,96,104,107], evidently, China’s total anthropogenic non-CO₂ GHG emissions increased from 1.1 Pg CO₂eq in 1970 to 1.6 Pg CO₂eq in 1990 to 3.1 Pg CO₂eq in 2023, as shown in Figure 6.

3.5. Anthropogenic CO₂ Emissions

China has become the largest anthropogenic CO₂ emitter around the world since 2006, and it exceeded the European Union (EU) with respect to per capita anthropogenic CO₂ emission in 2014 [114]. In 2023, global total net CO₂ emissions were estimated to be 40.6 ± 3.2 Pg; global fossil CO₂ emissions were estimated to be 37.8 ± 1.8 Pg, approximately 31% of which were from fossil fuel utilization in China [115]. As Figure 7 indicates, from 1970 to 2023, China’s yearly anthropogenic CO₂ emissions increased from 0.96 to 13.58 Pg [23]. China’s overall GHG emissions by sector from 1990 to 2023 [23]. The Multi-Resolution Emission Inventory Model for Climate and Air Pollution Research (MEIC; http://meicmodel.org.cn) provides detailed anthropogenic CO₂ emissions in China [116].

4. Discussion

4.1. Improving Estimation Accuracy

To limit global warming below 1.5 °C, more than 90% of anthropogenic GHG emissions need to be reduced by 2040 compared to 2015 levels [117]. In January 2024, as a follow-up to China’s first CH₄ control plan, the Ministry of Ecology and Environment of China crafted and published an official handbook called “Technical guidelines for compiling integrated emission inventories of atmospheric pollutants and GHGs”. This 123-page guidebook comprises the most detailed report introducing a bottom-up approach, and the methods for calculating anthropogenic CH₄ and N₂O emissions in each Chinese province are stated [118], showing China’s determination to construct a clean, beautiful, and sustainable world.

This guidebook, to our knowledge, introduces a more comprehensive estimate method for assessing non-CO₂ emissions in China than EDGARv8.0 does. However, according to newly discovered climate science, the calculation method for China’s assessment of anthropogenic CH₄ and N₂O emissions in this guidebook can be improved with respect to certain aspects. First, the guidebook may underestimate soil CH₄ and N₂O emissions in China. In the guidebook, anthropogenic CH₄ and N₂O emissions are estimated by multiplying activity-level data with emission factors (EFs), which were based on field observations in 2005, nearly two decades ago. Global warming has regulated soil CH₄ and N₂O emissions. Climate change has led to the thickening of active layers of methanogens [119], changes in vertical substrate availability [120], and an increase in large-scale inundation that resulted in the enhanced activity of methanogens [121], causing increased global soil CH₄ emissions. However, other reports showed that, due to soil drying and enrichment in nutrient supply, global warming has also increased microbial CH₄ oxidation by methanotrophs, leading to an increase in CH₄ sinks [122,123]. As temperature rises, soil N₂O emissions increase [124]; soil N₂O emissions also increase as moisture increases when monthly precipitation is less than 79 mm [125]. Some EFs used in the guidebook may be out of date and cannot reflect real emissions in a warming climate. Second, in the guidebook, the relationship between soil N₂O emissions and active nitrogen input is assumed to be strictly linear. However, an increasing number of studies have reported the nonlinearity of response between these two [126]. Due to the overuse of chemical fertilizers in Chinese smallholders [127], the guideline may underestimate agricultural N₂O emissions. Third, the point sources from energy utilization in the guidebook are omitted. In recent years, super-emitters of CH₄ have been found in North America by geostationary satellites [128,129]. However, extreme and transient CH₄ emissions from energy utilization were not included in the guideline. Moreover, CH₄ emissions from small-scale wildfires were discovered [130,131], which were not included as well. Moreover, the concepts of the social cost of CH₄ and N₂O emissions (SC-CH₄ and SC-N₂O) [132,133] are not fully understood and accepted by local technocrats. In a changing climate, personal behavior may lead to loss of social welfare [134]. The benefits of clean development mechanism projects in China were assessed [135].

To fulfill the four goals listed above, formulating a more comprehensive and up-to-date inventory based on newly discovered climate sciences to make the estimation of human-induced sources more accurate is imperative. Process-based models, atmospheric inversions, and data-driven models are needed to validate the accuracy of bottom-up approaches. Also, to fill the gap of the mismatch between nation-level emission reduction plans and emission reduction technologies, thoroughly exploring viable emission reduction technologies presently mastered by each province and the local costs required to implement these technologies is necessary. Finally, climate scientists should guide enterprises, colleges, universities, and scientific research institutions to comprehend the concept of SC-CH₄ and SC-N₂O. In doing so, policymakers can more persuasively price and manage anthropogenic emissions, and locals would have more forward-looking motivation to follow emission reduction plans.

4.2. Limitations and Recommendations

Out of around 1500 climate policies carried out from 1998 to 2022 in 41 countries across six continents, 63 have been identified as successful policies with an overall reduction of around 1.2 Pg CO₂ [136]. Reportedly, to achieve the ambitious goals of the 2016 Paris Agreement, the economic costs may be as much as 3 to 6% of China’s gross domestic product by 2050 [137]. Equally important, different versions of international climate agreements tend to ignore the mismatch between the world’s intention and the ability to reduce non-CO2 GHG emissions. Technologies for mitigating CH₄ and N₂O have been reported [22,132]. However, for developing countries, both technical capacity and reserve for reducing CH₄ and N₂O emissions are inadequate [138]; advanced N₂O abatement technology [139] has not been used in China yet. The economic cost of reducing one Pg of CO₂eq was estimated to be around USD 2.4 trillion [140]. To better implement abatement schemes, an investigation into the economic costs and monetized social benefits of emission reduction is imperative; an authoritative cost–benefit analysis must be formulated and widely accepted. At last, shared socioeconomic pathways [141,142,143] can be used to predict future non-CO₂ GHG emissions in China. One limitation is that China does not possess many reduction options. The largest challenge in abating CH₄ and N₂O emissions is that China has substantially fewer technical options than developed countries. Reportedly, the number of GHG emission reduction inventions was associated with the slowdown of GHG emission growth [138]. To develop feasible reduction schemes, the first two questions are what CH₄ and N₂O emission reduction technologies China currently possesses and whether they have been applied for formulating realistic emission reduction policies. We find that, presently, China only holds around 100 patents related to CH₄ and N₂O emission reduction technologies (see

Table 2. The patents related to CH₄ emission reductions currently owned by China.

Number	Date of Application	Brief Introduction of Invention	Category
1. CN120158469A	19 May 2025	A method of reducing methane emissions in cattle by delivering targeted, edited Methanococcus through gastric lavage	Agriculture
2. CN120140772A	11 April 2025	Mixed combustion air exhaust gas oxidation device to reduce methane emissions	Energy
3. CN120114554A	13 March 2025	Application of ginger leaf extract in the preparation of drugs or products for reducing rumen methane emissions in ruminants	Agriculture
4. CN120097781A	5 March 2025	A method for reducing methane emissions in paddy soil based on the mixed application of biochar and kitchen manure	Agriculture
5. CN119896280A	23 January 2025	A composite seaweed, feed additive, application, and method for reducing rumen methane emissions in ruminants	Agriculture
6. CN119870134A	16 January 2025	Technology for methane emission reduction using biochar in flooded soils	Agriculture
7. CN119736348A	15 January 2025	A method to accelerate the anaerobic biological oxidation rate of methane	Waste
8. CN119776189A	12 December 2024	Methylomonas strain RSM1 for reducing methane emissions	Agriculture
9. CN119100514A	19 October 2024	Preparation and application of a slow-release oxidant for reducing methane emissions	Agriculture and waste
10. CN119214043A	29 September 2024	A method of full straw returning and sowing for high-yielding rice and reducing emissions in paddy fields	Agriculture
11. CN118985248A	9 September 2024	A method to promote methane absorption in sheep grass grassland	Agriculture
12. CN118628278A	9 August 2024	A prediction method for methane weekly emission flux in paddy fields based on real-time sensor monitoring data	Agriculture
13. CN118773066A	29 July 2024	A greenhouse gas emission reduction inhibitor and its application in livestock and poultry breeding bedding	Agriculture
14. CN118773064A	25 July 2024	Bacterial strains (Bacillus velezensis) for methane oxidation and their applications	Agriculture and waste
15. CN118703589A	12 July 2024	A screening method for methanol-producing and methane-oxidizing bacteria	Agriculture and waste
16. CN118863416A	8 July 2024	A reservoir scheduling optimization method for reducing methane emissions	Natural
17. CN118964777A	2 July 2024	A method for calculating methane emissions from sealing points of natural gas station equipment	Energy
18. CN118834692A	25 June 2024	A manganese ion-modified biochar, its preparation method, and its application in reducing methane emissions in rice cultivation	Agriculture
19. CN118460434A	17 June 2024	Bacterial strains (Bacillus velezensis) for methane oxidation and their applications	Agriculture and waste
20. CN118598353A	31 May 2024	A nitrate wastewater treatment and resource utilization method based on denitrification anaerobic methane oxidation process	Waste
21. CN118460669A	28 May 2024	A method for cultivating in situ enrichment of sulfate-dependent anaerobic methane-oxidizing archaea	Waste
22. CN118303283A	15 May 2024	A synergistic method for reducing methane emissions in paddy fields while increasing yield of rice	Agriculture
23. CN118086114A	21 February 2024	An aerobic methane-oxidizing bacterium (Methylomonas sp.C1-2) with phosphorus-solubilizing abilities and its application	Agriculture and waste
24. CN118088161A	2 February 2024	A monitoring and measurement method for methane emissions in underground coal mines	Energy
25. CN117882621A	10 January 2024	A soil nutrient activation technology for improving rice light energy utilization efficiency while reducing methane emissions	Agriculture
26. CN117461732A	22 November 2023	Application of guanylacetic acid as a feed additive for reducing methane emissions by cattle	Agriculture
27. CN117358748A	22 November 2023	A synergistic method for reducing methane emissions in organic chlorine-contaminated soil through microbial remediation	Agriculture
28. CN117530124A	8 November 2023	A cultivation method that synergistically reduces methane emissions and cadmium emissions in paddy fields	Agriculture
29. CN117423405A	3 November 2023	A bottom-up accounting method for methane emissions during shale gas extraction process	Energy
30. CN117487839A	3 November 2023	A method for cultivating Phenazine-1-carboxylic Acid-producing methanophilic bacteria	Agriculture and waste
31. CN117413892A	31 October 2023	A fermented feed for reducing methane productions from ruminants during rumen fermentation	Agriculture
32. CN117296764A	27 October 2023	Raising crayfish in rice fields, increasing the utilization of organic materials such as straw feed for crayfish, reducing anaerobic decomposition by methanogens, and lowering methane emissions	Agriculture
33. CN117362097A	28 September 2023	Method and application of functional carbon-based organic fertilizer for enhancing ammonia and greenhouse gas emission reduction	Agriculture and waste
34. CN117223563A	19 September 2023	Methods for reducing methane emissions during the tillering stage of rice	Agriculture
35. CN116508887A	10 May 2023	A split pot algae powder additive and feed for reducing methane production in dairy cows	Agriculture
36. CN116286554A	28 April 2023	Adding Clostridium difficile to the feeds to reduce methane emissions from ruminants	Agriculture
37. CN117158148A	7 April 2023	A method for reducing methane emissions and promoting hexavalent chromium reduction in paddy soil using nitrification inhibitors	Agriculture
38. CN116286367A	24 March 2023	A microbial method suitable for efficient denitrification and simultaneous methane reduction through niche differentiation screening	Agriculture
39. CN116399527A	22 March 2023	A monitoring method for methane emission reduction in natural gas pipelines	Energy
40. CN116268190A	7 March 2023	Application of seaweed or seaweed hydrolysate in reducing methane emissions in the gastrointestinal tract	Agriculture
41. CN115975903A	28 January 2023	Enrichment, domestication, and application methods of methane-oxidizing bacterial communities	Agriculture and waste
42. CN116081818A	27 December 2022	A method for synergistic denitrification and methane emission reduction from aged garbage leachate	Waste
43. CN116011861A	26 December 2022	A methane emission estimate method for landfill leachate treatment station	Waste
44. CN116004236A	23 December 2022	Application of biochar in simultaneously reducing cadmium content and methane emissions in paddy fields	Agriculture
45. CN116078777A	9 December 2022	A cover layer for enhancing methane oxidation in municipal solid waste landfill sites	Waste
46. CN115991543A	11 November 2022	Methane reduction method in wetland using artificial ventilation	Natural
47. CN115481790A	2 September 2022	Catalytic materials for fixing cadmium and synergistically reducing methane emissions	Agriculture
48. CN218011924U	14 June 2022	A cattle breeding house for methane reduction and reuse	Agriculture
49. CN115028492A	7 June 2022	An aerobic composting methane emission reduction device	Waste
50. CN114713625A	18 April 2022	Methionine and organic acid salts combined for reducing methane emissions during soil remediation	Agriculture
51. CN114456816A	18 February 2022	Using graphite rods, magnetite, and biochar to construct a biochar magnetite graphite rod electron transfer network; providing a continuous source of electron acceptors for soil electrogenic bacteria; forming electrogenic bacteria and functional bacteria that cooperate with them to compete with methanogenic bacteria for substrates; reducing the available carbon source for methanogenic bacteria, thereby inhibiting the pathways of carbon dioxide reduction and methyl compound reduction during methane production; and ultimately achieving soil methane reduction	Agriculture
52. CN116411894A	30 December 2021	Quantitative detection device for methane emissions from beam pumping units	Energy
53. CN115005036A	30 November 2021	Microbial additional fertilizer for methane reduction in rice fields	Agriculture
54. CN114080960A	30 November 2021	Microbial powder for methane emission reduction in rice fields	Agriculture
55. CN113736717A	3 November 2021	Cultivating a methane-oxidizing bacterium with denitrification function and hypoxia stress resistance	Agriculture
56. CN115612497A	14 July 2021	A method of using nitric acid-modified biochar to reduce methane emissions in rice soil	Agriculture
57. CN112264422A	27 August 2020	A method for enhancing methane emission reduction by modifying soil cover layer with hydrophobic biochar	Agriculture and waste
58. CN212236724U	21 August 2020	A methane oxidation device used in municipal solid waste landfill	Waste
59. CN110605290A	2 August 2019	A methane emission reduction structure used in solid waste landfill	Waste
60. CN110037178A	12 April 2019	A feed for reducing rumen methane emissions in cows	Agriculture
61. CN109022481A	10 September 2018	Cultivating rice with frameshift mutation of the susiba-like gene to decrease methane emissions from rice fields	Agriculture
62. CN109293447A	5 September 2018	Adding nitrogen fertilizer-containing sulfate and nitrate ions to biochar powder made from crushed crop straw to achieve methane emission reductions	Agriculture
63. CN109092879A	18 July 2018	A device utilizing biochar to enhance methane emission reduction in landfill plants	Waste
64. CN108703264A	27 April 2018	A feed containing aloe powder for reducing methane emissions from cattle intestines	Agriculture
65. CN108014634A	15 November 2017	Crystalline iron oxides for improving the anaerobic oxidation rate of methane	Waste
66. CN105995061A	8 June 2016	Adding lactobacillus plantarum to feeds for ruminants to reduce methane emissions	Agriculture
67. CN106036080A	8 June 2016	Adding tropical Candida, calcium chloride, ammonium sulfate, and lactose to feeds for ruminants to reduce methane emissions	Agriculture
68. CN104671923A	7 January 2015	Using lime nitrogen, ammonium chloride, ammonium dihydrogen phosphate, calcium superphosphate, and potassium chloride to reduce methane emissions from paddy fields	Agriculture
69. CN104000052A	14 May 2014	Licking bricks for methane emission reductions from ruminants	Agriculture
70. CN103497921A	29 October 2013	Cultivating methane oxidizing bacterial solution for methane reduction in landfills	Waste
71. CN102627507A	25 April 2012	Rice compound granular fertilizer with methane emission reduction function	Agriculture
72. CN102216229A	30 October 2009	A processing unit and system for collecting methane-containing biogas from wastes	Waste
73. CN101412033A	1 December 2008	Biological soil-covering materials for methane emission reduction in landfill sites	Waste

and

Table 3. The patents related to N₂O emission reductions currently owned by China.

Number	Date of Application	Brief Introduction of Invention	Category
1. CN120041210A	24 February 2025	A hydroquinone biochar for reducing soil N2O emissions	Agriculture
2. CN119993297A	8 January 2025	Real-time adjustment of aeration rate in sewage treatment plants to effectively ensure residual dissolved oxygen and reduce the release concentration of nitrous oxide	Waste
3. CN119425377A	10 December 2024	A control system for reducing nitrous oxide emissions in SCR denitrification devices	Energy
4. CN119431082A	20 September 2024	An iron-based fertilizer with nitrous oxide emission reduction ability	Agriculture
5. CN118773066A	29 July 2024	Using calcium superphosphate, n-butyl thiophosphoryl triamide, and dicyandiamide as livestock and poultry breeding bedding to reduce nitrous oxide emissions	Agriculture
6. CN118525648A	1 April 2024	A fertilizing method for reducing nitrous oxide emissions by inserting liquid ammonia into deep soil	Agriculture
7. CN117830059A	29 February 2024	A method for generating strategies for reducing nitrous oxide emissions in wastewater treatment plants	Waste
8. CN117362130A	8 December 2023	Using Vicia sativa L with concave–convex rod, zeolite, kaolin, sepiolite, or diatomaceous earth to reduce nitrous oxide emissions	Agriculture
9. CN117362097A	28 September 2023	Using sulfide zero valent iron, magnesium-modified biochar, and microbial agents to reduce nitrous oxide emissions	Agriculture
10. CN117186899A	8 September 2023	Using biochar and root exudates of switchgrass to reduce nitrous oxide emissions	Agriculture
11. CN117023796A	28 April 2023	Using modified basalt fiber filler to reduce nitrous oxide emissions from wastewater	Waste
12. CN116333937A	3 April 2023	Using Bacillusvelezensis to reduce soil nitrous oxide emissions	Agriculture
13. CN114806924A	14 March 2022	Using Achromobacter denitrificans to reduce soil nitrous oxide emissions	Agriculture
14. CN113926846A	14 October 2021	Using hydroxyapatite to reduce soil nitrous oxide emissions	Agriculture
15. CN113046261A	1 March 2021	Using Bacillus albus to reduce soil nitrous oxide emissions	Agriculture
16. CN112284853A	27 October 2020	Using biochar to increase the abundance of nosZ genes in soil microorganisms, thereby reducing soil nitrous oxide emissions	Agriculture
17. CN111302502A	24 February 2020	Enriching nitrous oxide-reducing microbial abundance by adjusting nutrient conditions and oxygen content using lakeside substrates as raw materials to reduce N2O emissions in wetland sediments	Natural
18. CN110495275A	26 August 2019	Using camphor tree leaves to reduce soil nitrous oxide emissions	Agriculture
19. CN109499357A	12 December 2018	Using catalysts to convert N2O into N2, O2, NO2, and NO	Industry
20. CN103936233A	4 May 2014	A control system for reducing mitrous oxide emissions in wastewater treatment denitrification process	Waste
21. CN102919026A	12 November 2012	Using trichoderma and cultivating trifolium repens to reduce soil nitrous oxide emissions	Agriculture

), substantially fewer than developed countries [3]. Approximately seven-tenths of high-quality CH₄ emission reduction inventions are possessed by developed countries; however, populous developing countries such as China are playing an increasingly important role in reducing CH₄ waste emissions, and the international diffusion rate of these technologies is slow.

Another limitation is that atmospheric inversions cannot reflect emission hotspots well. Figure 8 and Figure 9 show China’s anthropogenic CH₄ and N₂O emissions in 2023, respectively, at high resolutions [14,23]. However, the resolution of atmospheric inversions is much lower. The lack of observational data is the main obstacle to accurately assessing China’s non-CO₂ GHG emissions.

Due to the relatively small number of patented technologies in China [138,144], Chinese scientists develop more technologies with independent intellectual property rights. Equally important, it is imperative to establish more ground-based GHG observation stations to more accurately assess their emissions via atmospheric inversion models.

5. Conclusions

Anthropogenic GHG emissions, including not only CO₂ but also potent non-CO₂ GHGs, should be cut down to prevent global warming from pushing the ecosystem towards the edge of the precipice. China’s annual non-CO₂ GHG emissions increased by more than 1.7 times from 1970 to 2023. With the enforcement of China’s carbon neutrality scheme, non-CO₂ GHGs are playing an increasingly critical role in contributing to climate change. However, most non-CO₂ GHGs are not under control. We suggest that scientists pay more attention to the management of non-CO₂ GHG emissions in China. An across-the-board assessment on future emission trends is also imperative. China has taken a series of targeted measures to control the anthropogenic emissions of non-CO₂ GHGs and has made clear progress. In the Action Plan for Methane Emission Control, released by the end of 2023, China has planned to improve the utilization rate of coal mine gas, promote the resource utilization of livestock and poultry manure, and scientifically control CH₄ emissions from rice fields. In the Action Plan for Controlling Nitrous Oxide Emissions in the Industrial Sector, released in August 2025, China has planned to continuously decrease industrial N₂O emissions per unit of product. China has also crafted detailed policies to reduce the emissions of CFCs, HCFCs, and HFCs. The national voluntary GHG emission reduction trading market was launched, indicating that enterprises can obtain economic gains by developing emission reduction projects and trading verified emission reductions in the market. As of the end of October 2025, the total trading volume of the market has reached 3.25 million tons in CO₂eq. China’s control over non-CO₂ GHG emissions will continue to deepen and has been incorporated into the national top-level design. For the first time, in China’s announced 2035 Nationally Determined Contributions (NDCs), non-CO₂ GHGs were explicitly included in the overall economic GHG emission reduction target, which means that future emission reduction schemes will be a systematic project covering all types of GHGs. In the future, China will continuously expand the scope of the voluntary emission reduction market to support and construct a methodological system with high standards in order to encourage more social forces to participate in all kinds of GHG emission reductions.