Individual countries are requested to submit nationally determined contributions(NDCs)to alleviate global warming in the Paris Agreement.However,the global climate effects and regional contributions are not explicitly...Individual countries are requested to submit nationally determined contributions(NDCs)to alleviate global warming in the Paris Agreement.However,the global climate effects and regional contributions are not explicitly considered in the countries’decision-making process.In this study,we evaluate the global temperature slowdown of the NDC scenario(ΔT=0.6°C)and attribute the global temperature slowdown to certain regions of the world with a compact earth system model.Considering reductions in CO_(2),CH_(4),N_(2)O,BC,and SO_(2),the R5OECD(the Organization for Economic Co-operation and Development in 1990)and R5ASIA(Asian countries)are the top two contributors to global warming mitigation,accounting for 39.3%and 36.8%,respectively.R5LAM(Latin America and the Caribbean)and R5MAF(the Middle East and Africa)followed behind,with contributions of 11.5%and 8.9%,respectively.The remaining 3.5%is attributed to R5REF(the Reforming Economies).Carbon Dioxide emission reduction is the decisive factor of regional contributions,but not the only one.Other greenhouse gases are also important,especially for R5MAF.The contribution of short-lived aerosols is small but significant,notably SO_(2)reduction in R5ASIA.We argue that additional species beyond CO_(2)need to be considered,including short-lived pollutants,when planning a route to mitigate climate change.It needs to be emphasized that there is still a gap to achieve the Paris Agreement 2-degree target with current NDC efforts,let alone the ambitious 1.5-degree target.All countries need to pursue stricter reduction policies for a more sustainable world.展开更多
Comparing and evaluating the Nationally Determined Contribution(NDC) is an important element in global stocktake in the post-Paris climate negotiations, aimed at closing the emissions gap with the Paris Agreement goal...Comparing and evaluating the Nationally Determined Contribution(NDC) is an important element in global stocktake in the post-Paris climate negotiations, aimed at closing the emissions gap with the Paris Agreement goals. To date, however, there has still been no explicit guideline or method. By applying emissions allowance allocated by 16 schemes as benchmarks, this paper tries to compare and evaluate the NDCs of the top six emitters, which jointly account for about 70% of the world's CO_2 emissions. Results show that the four developed countries' NDCs lack ambition with respect to most allocations under 2℃ and all under 1.5℃, indicating they need to substantially ratchet up their NDCs and lead elevating mitigation. Evaluating cumulative emissions is more likely to clarify the ambition and fairness of China's NDC. If considering cumulative emissions, China's NDC is aligned with the median of cumulative allowances under 2℃ and within the 1.5℃ range. The Paris Agreement invited the Parties to communicate the mid-century low emissions strategies. This paper also tries to explore the mid-century mitigation in the perspective of allocations, which might provide decision-makers with some useful information when envisaging the post-NDC mitigation.展开更多
Nationally determined contributions raised by Paris Agreement aim to control the temperature rise below 2°C or even 1.5°C at the end of the 21st century,compared to pre-industrial levels.However,the climate ...Nationally determined contributions raised by Paris Agreement aim to control the temperature rise below 2°C or even 1.5°C at the end of the 21st century,compared to pre-industrial levels.However,the climate response of the Nationally Determined Contributions(NDCs)remains uncertain due to unstable policies and their credibility.In this study,we calculated the uncertainty of global temperature rise caused by uncertain NDCs and carbon-neutral policies and discussed the difficulty of policy implementation.The results show that there will be 8 GtC uncertainty in emission at the end of the 21st century,responsible for the temperature rise of 0.37°C(1.73–2.10°C).A delayed policy in emission reduction by major emitters would result in a temperature rise of over 2°C,while under non-delay policy,the 2°C target will be possibly achieved.Besides,low-emission countries would introduce a 30 GtC cumulative emission uncertainty at the end of the 21st century if there are no restrictions,leading to a 0.3°C global warming uncertainty.Developed countries need more substantial reductions in carbon intensity to achieve their climate policies while developing countries are under less pressure.The reduction of carbon intensity requires the strengthening of technical and economic methods.This study provides a reference for the realization of emission policies and temperature rise targets.展开更多
The recent Conference of the Parties of the United Nations Framework Convention on Climate Change has resulted in the submission of the Intended Nationally Determined Contributions (INDCs) of 190 countries. This study...The recent Conference of the Parties of the United Nations Framework Convention on Climate Change has resulted in the submission of the Intended Nationally Determined Contributions (INDCs) of 190 countries. This study aims to provide an analysis of the ambitiousness and fairness of the mitigation components of the INDCs submitted by various parties. We use a unified framework to assess 23 INDCs that cover 50 countries, including European Union (EU)-28 countries as parties to the Convention, which represent 87.45% of the global greenhouse gas emissions in 2012. First, we transform initial INDC files into reported reduction targets. Second, we create four schemes and six scenarios to determine the required reduction effort, which considers each nation's reduction responsibility, capacity, and potential, thereby reflecting their historical and current development status. Finally, we combine the reported reduction target and the required reduction effort to assess INDCs. Evaluation results of the 23 emitters indicate that 2 emitters (i.e., EU and Brazil) are rated as "sufficient," 7 emitters (e.g., China, the United States, and Canada) are rated as "moderate," and 14 emitters (e.g., India, Russia, and Japan) are rated as "insufficient." Most pledges exhibit a considerable distance from representing a fair contribution.展开更多
基金funded by the undergraduate student research training program of the Ministry of Education, the National Natural Science Foundation of China (Grants Nos. 41771495, 41830641, and 41988101)the Second Tibetan Plateau Scientific Expedition and Research Program Grant 2019QZKK0208+1 种基金funded by the European Research Council Synergy project “Imbalance-P ” (Grant No. ERC-2013-Sy G-610028)the European Union’s Horizon 2020 research and innovation project “CONSTRAIN” (Grant No. 820829)
文摘Individual countries are requested to submit nationally determined contributions(NDCs)to alleviate global warming in the Paris Agreement.However,the global climate effects and regional contributions are not explicitly considered in the countries’decision-making process.In this study,we evaluate the global temperature slowdown of the NDC scenario(ΔT=0.6°C)and attribute the global temperature slowdown to certain regions of the world with a compact earth system model.Considering reductions in CO_(2),CH_(4),N_(2)O,BC,and SO_(2),the R5OECD(the Organization for Economic Co-operation and Development in 1990)and R5ASIA(Asian countries)are the top two contributors to global warming mitigation,accounting for 39.3%and 36.8%,respectively.R5LAM(Latin America and the Caribbean)and R5MAF(the Middle East and Africa)followed behind,with contributions of 11.5%and 8.9%,respectively.The remaining 3.5%is attributed to R5REF(the Reforming Economies).Carbon Dioxide emission reduction is the decisive factor of regional contributions,but not the only one.Other greenhouse gases are also important,especially for R5MAF.The contribution of short-lived aerosols is small but significant,notably SO_(2)reduction in R5ASIA.We argue that additional species beyond CO_(2)need to be considered,including short-lived pollutants,when planning a route to mitigate climate change.It needs to be emphasized that there is still a gap to achieve the Paris Agreement 2-degree target with current NDC efforts,let alone the ambitious 1.5-degree target.All countries need to pursue stricter reduction policies for a more sustainable world.
基金supported by the National Natural Science Foundation of China "Assessment,enhancement and impact of the Intended Nationally Determined Contributions in the context of the Paris Agreement"[Grant number:71703167]the National Key Research and Development Program of the Ministry of Science and Technology "Carbon emissions reduction potentials and economic costs of major countries"[Grant number:2017YFA0605302]the Science Foundation of China University of Petroleum,Beijing "China's energy system transformation toward the 2℃goal:a perspective of carbon budgets"[Grant number:2462016YJRC023]
文摘Comparing and evaluating the Nationally Determined Contribution(NDC) is an important element in global stocktake in the post-Paris climate negotiations, aimed at closing the emissions gap with the Paris Agreement goals. To date, however, there has still been no explicit guideline or method. By applying emissions allowance allocated by 16 schemes as benchmarks, this paper tries to compare and evaluate the NDCs of the top six emitters, which jointly account for about 70% of the world's CO_2 emissions. Results show that the four developed countries' NDCs lack ambition with respect to most allocations under 2℃ and all under 1.5℃, indicating they need to substantially ratchet up their NDCs and lead elevating mitigation. Evaluating cumulative emissions is more likely to clarify the ambition and fairness of China's NDC. If considering cumulative emissions, China's NDC is aligned with the median of cumulative allowances under 2℃ and within the 1.5℃ range. The Paris Agreement invited the Parties to communicate the mid-century low emissions strategies. This paper also tries to explore the mid-century mitigation in the perspective of allocations, which might provide decision-makers with some useful information when envisaging the post-NDC mitigation.
基金upported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23100401)the National Key Research and Development Program of China(2017YFA0605303)the Youth Innovation Promotion Association of CAS(2019053).
文摘Nationally determined contributions raised by Paris Agreement aim to control the temperature rise below 2°C or even 1.5°C at the end of the 21st century,compared to pre-industrial levels.However,the climate response of the Nationally Determined Contributions(NDCs)remains uncertain due to unstable policies and their credibility.In this study,we calculated the uncertainty of global temperature rise caused by uncertain NDCs and carbon-neutral policies and discussed the difficulty of policy implementation.The results show that there will be 8 GtC uncertainty in emission at the end of the 21st century,responsible for the temperature rise of 0.37°C(1.73–2.10°C).A delayed policy in emission reduction by major emitters would result in a temperature rise of over 2°C,while under non-delay policy,the 2°C target will be possibly achieved.Besides,low-emission countries would introduce a 30 GtC cumulative emission uncertainty at the end of the 21st century if there are no restrictions,leading to a 0.3°C global warming uncertainty.Developed countries need more substantial reductions in carbon intensity to achieve their climate policies while developing countries are under less pressure.The reduction of carbon intensity requires the strengthening of technical and economic methods.This study provides a reference for the realization of emission policies and temperature rise targets.
文摘The recent Conference of the Parties of the United Nations Framework Convention on Climate Change has resulted in the submission of the Intended Nationally Determined Contributions (INDCs) of 190 countries. This study aims to provide an analysis of the ambitiousness and fairness of the mitigation components of the INDCs submitted by various parties. We use a unified framework to assess 23 INDCs that cover 50 countries, including European Union (EU)-28 countries as parties to the Convention, which represent 87.45% of the global greenhouse gas emissions in 2012. First, we transform initial INDC files into reported reduction targets. Second, we create four schemes and six scenarios to determine the required reduction effort, which considers each nation's reduction responsibility, capacity, and potential, thereby reflecting their historical and current development status. Finally, we combine the reported reduction target and the required reduction effort to assess INDCs. Evaluation results of the 23 emitters indicate that 2 emitters (i.e., EU and Brazil) are rated as "sufficient," 7 emitters (e.g., China, the United States, and Canada) are rated as "moderate," and 14 emitters (e.g., India, Russia, and Japan) are rated as "insufficient." Most pledges exhibit a considerable distance from representing a fair contribution.
