工业化以来全球平均温度上升了1℃北大核心CSCD

全球变暖已经得到了公众、政府机构和科学家的广泛认知[1-3].但是,对于全球是否变暖以及这个变暖是否由人类活动造成,却依然不断受到质疑.这种质疑在2009年达到巅峰,同年出版的非政府间国际气候变化专门委员会(NIPCC)报告[4],对政府间气候变化专门委员会(IPCC)的观点[5]提出全面的质疑.最新的一轮质疑是2012年1月27日《华尔街日报》刊登了Allegre等16位科学家的署名文章[6],认为近10年地球气候没有变暖,呼吁不要压制气候变暖怀疑论者的声音.这说明尽管全球变暖的证据日益增加、全球变暖的观点得到越来越多的承认,但是对全球变暖这个事实的论证却绝不是多余的.     

全球气候变暖原因的争议

综合分析了政府间气候变化专门委员会(IPCC)与非政府间国际气候变化专门委员会(NIPCC)针锋相对的观点:是人类活动还是自然因素主导了过去近百年的气候变化.指出20世纪中期以来温度变化的事实支持人类活动影响的观点,但是在近百年中自然因素如太阳活动、火山活动或大洋热盐环流的变化,对温度的年代际变化有重要影响.有充分的古...     

IPCC AR5气候变化影响、适应和脆弱性评估报告展望

继2007年IPCC第四次评估报告发布以来,人类活动所引起的全球变暖问题已引起国际社会更多关注,特别是对气候变化的影响有了更深的了解和认知。近日,IPCC第五次评估报告(AR5)第二工作组在日本筑波召开了第一次主要作者会议.     

气候变暖的归因研究

气候变暖的成因是目前国际上的一个争议焦点,代表国际主流思想的4次IPCC评估报告[1-4]认为是人类活动的影响造成了变暖,其中包括温室效应加剧使气候变暖,而气溶胶的直接和间接影响则抵消了一部分变暖.但是,从20世纪末至今对气候变暖持怀疑观点的科学家,仍然不断对气候变暖的原因提出质疑[5 7].所以气候变暧的归因研究仍然是国际上的热门问题.     

气候模式

气候模式建立在物理、化学、生物学等基础上,用数学方程式表现地球气候系统各个圈层相互作用和反馈的主要过程以及与外强迫的关联,广泛应用在气候与气候变化研究中,因此气候模式是气候变暖研究的核心技术。气候变暖的预估几乎完全依赖模式的模拟。历届IPCC第一工作组的评估报告,均     

全球气候变暖:浅谈从AR5到AR6的认知进展

自政府间气候变化专门委员会（IPCC）第五次评估报告（AR5）发布以来,国际科学界在气候系统变化领域取得显著进展,有关气候变化的科学认识不断深入。IPCC第六次评估报告（AR6）第一工作组（WGI）报告对这些科学进展和最新认识作了综合评估。温度是全球变化最直接的指示器。本文从温度变化视角,对从AR5到AR6的科学进展进行了梳理和简要评述,主要聚焦观测的变化、归因以及未来预估三个方面。与AR5相比,AR6以更强有力的证据进一步确证了近百年全球气候变暖的客观事实,人类活动对气候变暖影响的信号更为清晰,未来变暖幅度取决于温室气体减排力度。     

气候变化科学的最新认知

 政府间气候变化专门委员会（IPCC）第一工作组于2007年2月2日发布的第四次评估报告明确指出,近100 a（1906-2005年）地球表面平均温度上升了0.74℃,近50 a的线性增温速率为0.13℃/10 a,1850年以来最暖的12个年份中有11个出现在近期的1995-2006年。全球变暖已经是不争的科学事实,报告认为人类活动是近50 a全球气候系统变暖的主要原因。 IPCC评估报告是国际科学界对气候变化问题最权威、最全面的认识,代表了目前全球气候变化研究的科学认识水平,是国际上制定相关政策的重要依据。     

IPCC气候变化自然科学认知的发展

过去20年来,随着观测手段的改善、气候模式的进步以及分析方法的提升,人类对气候变化事实、原因和未来趋势的认识水平不断深化,进一步确认全球气候系统变暖是毋庸置疑的,人类活动是20世纪中叶以来气候变暖的主要原因,未来气候系统仍将继续变暖。IPCC评估报告极大地促进了气候变化自然科学的进展,并为适应和减缓气候变化奠定了坚实的科学基础。     

全球增暖1.5℃的再思考——写在SR15发表之后

<正>2018年秋季IPCC发布了《IPCC全球升温1.5℃特别报告》(简称SR15),报告中指出:将全球变暖限制在1.5℃需要社会各方进行快速、深远和前所未有的变革。并且说明:与将全球变暖限制在2℃相比,限制在1.5℃对人类和自然生态系统有明显的益处,同时还可确保社会更加可持续和公平。本文将进一步再思考以下几点:(1)升温1.5℃特别报告与AR5人类排放的设计的对比,即对比全球增暖1.5℃与人类排放的设计以及可能     

海洋环流的长期变化和预估

IPCC第六次评估报告(AR6)于2021年8月在IPCC第一工作组第14次联合大会上得到审议通过,并得到了IPCC第54届全会接受和批准.文中主要对该报告第九章"海洋、冰冻圈和海平面"中与海洋环流的相关评估内容进行解读.与以前的IPCC报告相比,AR6进一步确认人类活动对海洋环流的影响,并基于最新的数值模式给出对未来...     

Progress and evaluation of international climate change cooperation北大核心CSCD

气候变化是当前世界面临的巨大挑战,应对气候变化需要国际间合作已成为普遍共识。IPCC第六次评估报告(AR6)第三工作组(WGⅢ)报告第十四章回顾了IPCC第五次评估报告(AR5)以来气候变化国际合作的进展,基于所提出的评价体系对进展进行了系统评估。报告认为,AR5以来气候变化国际合作最重要的进展是基于《巴黎协定》建立的以国家自主贡献为核心的全球行动模式;除《巴黎协定》外,国际上也形成了多种形式的合作机制,其中,气候俱乐部是国际气候合作研究的新热点。对于《巴黎协定》的有效性,目前国际社会存在正反两种观点,并认为《巴黎协定》能否达成既定目标取决于是否有能力强化全球下一步的集体气候行动目标和实施。     

Key themes in the Working Group II contribution to the Intergovernmental Panel on Climate Change 5th assessment report

Assessments conducted by the Intergovernmental Panel on Climate Change (IPCC) are significant undertakings that require input from experts and practitioners in multiple scientific disciplines, integrating local to international information across spatial and temporal scales. An IPCC report is a unique collaboration between the scientific community and policymakers, with governments (through their Focal Points) providing guidance and input to the scientists conducting an assessment at several stages during the process. This commentary reviews the IPCC mandate and process; summarizes key themes to be addressed in the Working Group II contribution to the 5th assessment report; discusses challenges for the WGII report when assessing qualitative literature, incorporating local knowledge, and identifying particularly vulnerable groups; and touches on the expertise and commitment of the WGII authors. Active engagement of the wider scientific community in IPCC assessments through publication and review will enhance their relevance to decision- and policy-makers.     

Constraining anthropogenic CH4 emissions in Nanjing and the Yangtze River Delta,China, using atmospheric CO2 and CH4 mixing ratios

Methane （CH4） emissions estimated with the Intergovernmental Panel on Climate Change （IPCC） inventory method at the city and regional scale are subject to large uncertainties.In this study,we determined the CH4：CO2 emissions ratio for both Nanjing and the Yangtze River Delta （YRD）,using the atmospheric CH4 and CO2 concentrations measured at a suburban site in Nanjing in the winter.The atmospheric estimate of the CH4：CO2 emissions ratio was in reasonable agreement with that calculated using the IPCC method for the YRD （within 20％）,but was 200％ greater for the municipality of Nanjing.The most likely reason for the discrepancy is that emissions from unmanaged landfills are omitted from the official statistics on garbage production.     

Understanding the latest progress in mitigating climate change and facilitating carbon neutrality北大核心CSCD

The Intergovernmental Panel on Climate Change (IPCC) released the report of Working Group III of the Sixth Assessment Report "climate change 2022: mitigating climate change". The report accessed and summarized the latest research progress on climate change mitigation since the release of the Fifth Assessment Report, which will provide an important reference for the international community to further understand climate change mitigation actions, system transformation, and the pursuit of sustainable development. The report pointed out that human activities had cumulatively emitted about 2.4 trillion tons of CO2 from 1850 to 2019, of which 58% was emitted before 1990. In order to control the level of global temperature rise in the future, deep and immediate mitigation actions are required. In both low and minimum emission scenarios, fossil energy needs to be greatly reduced; renewable energy will be the mainstay of future energy supply; achieving carbon neutrality requires relying on negative emission technologies and increasing carbon sinks. Technological progress is one of the key conditions for helping the world combat climate change. Accelerated and equitable climate action is critical to sustainable development. The report's conclusions once again show that China's carbon neutrality target is in line with the mitigation path of the Paris Agreement's temperature rise target of less than 2 °C and striving to achieve 1.5°C. In the future, China should strengthen special research programs on the national concerns and key contents covered in the report. While strengthening scientific interpretation and effective use of the report's conclusions, it is also necessary to actively participate in the IPCC scientific assessment process, actively contribute Chinese wisdom, and contribute to the international dissemination of Chinese climate governance concepts. © 2022 Chinese Journal of Digestive Endoscopy All rights reserved.     

Stories from the IPCC: An essay on climate science in fourteen questions

Women’s experiences as Intergovernmental Panel on Climate Change (IPCC) authors, have been explored showing how gender, race, nationality, etc. increase barriers to participate in the production of climate science even for the best scientists. Recently, the IPCC Gender Task Force, conducted another survey exploring barriers to participation in the IPCC that included men as well as women. The Gender Task Force released a report on gendered barriers mostly focusing on quantitative responses. This paper presents a qualitative analysis of the fourteen open-ended questions in the survey. In addition to qualitative analysis, storytelling and the concept of feminist objectivity are useful approaches to convey the complicated web of responses of over 500 scientists about their experiences participating in the IPCC and in climate science more broadly. Gender, race and nationality continue to be barriers. I stress the connection between exclusions of underrepresented scientists in the IPCC with the persistent western belief that science is an objective and impartial practice. The paper brings attention to exclusionary structures that prevent participation in the IPCC and in science more broadly, but also provides stories of how these are resisted. These stories go beyond recognizing people as disadvantaged toward addressing the intersecting structures that exclude people from participating in science. As climate science becomes more diverse, and evidence points toward the benefit of diversity for superior science, understanding barriers and opportunities for scientists participating in multidisciplinary and international reports such as the IPCC becomes increasingly important. The stories provide a theoretical and methodological catalyst for international science institutions who seek to increase the influence and presence of underrepresented groups in science and produce superior science.     

对IPCC第六次评估报告中有关干旱变化的解读

政府间气候变化专门委员会（IPCC）于2021年8月发布了第六次评估报告（AR6）自然科学基础卷的决策者摘要,主要对自2013年第五次评估报告（AR5）以来的气候变化科学研究进展进行了系统的评估,并使用新一代气候模式在新的共享社会经济路径情景下对未来气候变化进行了预估。本文基于AR5和AR6相关章节素材,解读了干旱变化的评估结论。     

气候反馈对温度空间模态的依赖性:IPCC AR6解读

依据政府间气候变化专门委员会(IPCC)第六次评估报告(AR6)第一工作组(WGI)报告第七章的内容,详细解读了气候反馈对温度空间模态的依赖性。与第五次评估报告(AR5)相比,AR6对于地表温度空间模态演变在驱动气候反馈变化中作用的理解已有了较大提升。AR6认为,在温室气体强迫下,北极在21世纪的增温幅度很可能大于全球平均水平,南极在百年时间尺度上的增温要强于热带地区;同时,在百年时间尺度上热带太平洋东部的变暖幅度大于西部,即热带太平洋东-西向海表温度梯度减弱。极地放大效应(尤其是南半球)和热带太平洋东-西向海表温度梯度随时间的变化是影响未来气候反馈如何演变的关键因素。随着地表增温空间模态的演变,气候反馈(尤其云反馈)预计将在未来几十年的时间尺度上逐渐增加,对气候变化更多是起放大作用。     

Stratospheric Temperature Changes and Ozone Recovery in the 21st Century

Increasing greenhouse gases and likely ozone recovery will be the two most important factors influencing changes in stratospheric temperatures in the 21st century. The radiative effect of increasing greenhouse gases will cause cooling in the stratosphere, while ozone recovery will lead to stratospheric warming. To investigate how stratospheric temperatures change under the two opposite forcings in the 21st century, we use observed ozone and reanalysis data as well as simulation results from four coupled oceanic and atmo- spheric general circulation models （GISS-ER, GFDL-CM20, NCAR-CCSM3, and UKMO-HadCM3） used in the IPCC （Intergovernment Panel for Climate Change） Fourth Assessment Report （AR4）. Observational analysis shows that total column ozone and lower stratospheric temperatures all show increasing in the past 10 years, while middle stratospheric temperatures demonstrate cooling. IPCC AR4 simulations show that greenhouse forcing alone will lead to stratospheric cooling. However, with forcing of both increasing greenhouse gases and ozone recovery, the middle stratosphere will be cooled, while the lower stratosphere will be warmed. Warming magnitudes vary from one model to another. UKMO-HadCM3 generates relatively strong warming for all three greenhouse scenarios, and warming extends to 40 hPa. GFDL-CM20 and NCAR-CCSM3 produce weak warming, and warming mainly exists at lower levels, below about 60 hPa. In addition, we also discuss the effect of temperature changes on ozone recovery.     

Who participates in the Intergovernmental Panel on Climate Change and why: A quantitative assessment of the national representation of authors in the Intergovernmental Panel on Climate Change

This paper presents a quantitative analysis of international representation in the activities of the Intergovernmental Panel on Climate Change using expert authorship counts by country in each of the four IPCC assessment reports (1990, 1995, 2001 and 2007). Overall, we find that 45% of countries, all Non-Annex 1, have never had authors participate in the IPCC process; on the other hand, European and North American experts are make up more than 75% of all authors (N = 4394). Generalized linear models using negative binomial regression were used to quantitatively estimate the effect of a number of socio-economic, environmental and procedural factors influencing country-level participation in the IPCC. Per capita gross domestic product, population, English-speaking status, and levels of tertiary education were all found to be statistically significant drivers of authorship counts. In particular, participation by authors from English-speaking Non-Annex 1 countries is 2.5 times greater than those that are non-English speaking. Regionally small island nations of Oceania were the most severely under-represented group. South American and Asian countries had fewer authors, and African countries had more authors than what might be expected on the basis of demographic and socio-economic data. These differences across nations partly reflect existing scientific capacity that will be slow to change. However, the on-going under-representation of developing country scientists in the IPCC, particularly in the assessment of climate science (WGI) and climate mitigation (WGIII) warrants greater efforts to close the capacity gap.     

The use of PPP or MER in the construction of emission scenarios is more than a question of ‘metrics’

Abstract

The Intergovernmental Panel on Climate Change (IPCC)'s Special Report on Emissions Scenarios (SRES, IPCC, 2000) has been a matter of debate since Ian Castles and David Henderson claimed that the scenarios were based on unsound economics, giving rise to improbably high emission growth. A main point in their critique was that the scenario-makers converted national gross domestic product (GDP) data to a common measure using market exchange rates (MER) rather than purchasing power parity (PPP) rates. The IPCC responded to the critique by claiming that the use of PPP- or MER-based measures is just a question of ‘metrics’, as important as the ‘switch from degrees Celsius to Fahrenheit’. This paper addresses both the critique from Castles and Henderson and the response from the IPCC. It builds on our earlier argument that the use of MER-based measures, although misleading in some respects, probably has not given rise to seriously exaggerated emission forecasts because comparing regional income levels by the use of MER has two types of implications that draw in different directions and effectively neutralize one another. Nevertheless, we argue that the choice between MER and PPP in the construction of emission scenarios is far more than just a question of metrics. Finally, we discuss whether the SRES scenario with the lowest cumulative emissions is a reasonable lower limit with respect to global emission growth.