The Impact of Short-Lived Halocarbons on Ozone and Climate (ISHOC): An International Multi-Model Intercomparison

短期卤化碳对臭氧和气候的影响 (ISHOC)：国际多模型比较

• 批准号: NE/R004927/1
• 负责人: Ryan Hossaini
• 金额: $ 3.53万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FR004927%2F1
• 关键词: Impact; Short; Lived; Halocarbons; Ozone

Depletion of the stratospheric ozone layer has been at the forefront of environmental concern over the last 40 years. The layer shields Earth's surface from certain wavelengths of harmful ultraviolet (UV) radiation that would otherwise be detrimental to human and plant health. Ozone also absorbs terrestrial infra-red (IR) radiation meaning it is a greenhouse gas, and changes in its abundance can therefore impact climate. The primary cause of ozone depletion is the release of halogens (chlorine and bromine) from long-lived anthropogenic compounds, such as chlorofluorocarbons (CFCs) and halons. Production of these ozone-depleting compounds is now controlled by the UN Montreal Protocol, but they were once widely used in refrigeration and fire suppression units, among other applications. Due to the success of the Protocol, the stratospheric abundance of chlorine and bromine is now declining, albeit slowly, and the ozone layer is widely expected to 'recover' to levels observed pre-1980 in the middle to latter half of this century. However, a key uncertainty, highlighted in the WMO/UNEP 2014 Assessment of Stratospheric Ozone Depletion, is the increasing emissions of uncontrolled chlorine-containing Very Short-Lived Substances (Cl-VSLS) which can also reach the stratosphere and cause ozone loss.The most abundant Cl-VSLS is dichloromethane (CH2Cl2), whose tropospheric abundance has increased by >60% over the last decade. CH2Cl2 is human-produced and in the Northern Hemisphere, close to industrial sources, long-term observations show a mean CH2Cl2 growth rate of ~8%/year. The precise cause of these increases is unknown. However, emissions of CH2Cl2 (and other Cl-VSLS) are known to be relatively large over Asia, and in the absence of policy controls on production, atmospheric concentrations are expected to continue to increase in coming years. Our recent modelling work has shown (i) that the contribution of Cl-VSLS to stratospheric chlorine has already doubled in the last decade alone, and (ii) that sustained CH2Cl2 growth could delay the recovery of the Antarctic Ozone Hole by up to several decades. This would significantly offset some of the gains achieved by the Montreal Protocol, and because the Ozone Hole influences surface climate of the Southern Hemisphere in several ways, could affect forward predictions of climate change.This project (ISHOC) establishes a new task force comprised of world-leading chemistry-climate modelling groups. We will perform the first concerted multi-model assessment of the threat posed to stratospheric ozone from CH2Cl2 growth. Lancaster University will lead the model intercomparison in collaboration with the University of Cambridge, and an international consortium of 9 partners. We will develop a series of growth scenarios describing possible future trajectories of CH2Cl2 in the atmosphere. Each of the models in our consortium will perform forward simulations considering these scenarios and the output will be analysed to determine (a) the expected delay to ozone recovery in different regions of the stratosphere due to CH2Cl2 growth and (b) the subsequent implications for climate and surface UV. The results from ISHOC will provide powerful new insight into the role of compounds not controlled by the Montreal Protocol in ozone depletion, which will be highly relevant to future international assessments of ozone and climate change (e.g. WMO/UNEP and IPCC reports). While the focus of ISHOC is on CH2Cl2, the task force will remain active beyond the project to examine future threats to ozone from other uncontrolled Cl-VSLS (e.g. CHCl3, C2H4Cl2) as they emerge. Indeed, our ongoing work suggests that emissions of these Cl-VSLS are also increasing.

在过去40年里，平流层臭氧层的消耗一直是环境问题的首要问题。该层保护地球表面免受某些波长的有害紫外线（UV）辐射，否则这些辐射将对人类和植物健康有害。臭氧还吸收陆地红外线（IR）辐射，这意味着它是一种温室气体，因此其丰度的变化会影响气候。臭氧消耗的主要原因是从长期存在的人为化合物中释放出卤素（氯和溴），如氯氟烃（CFC）和哈龙。这些臭氧消耗化合物的生产现在受到联合国蒙特利尔议定书的控制，但它们曾经广泛用于制冷和灭火装置等应用。由于《议定书》取得了成功，平流层中氯和溴的丰度目前正在下降，尽管速度缓慢，人们普遍预计，臭氧层将在本世纪的中、后半叶“恢复”到1980年以前的水平。然而，WMO/UNEP 2014年平流层臭氧消耗评估中强调的一个关键不确定性是，不受控制的含氯极短寿命物质（Cl-VSLS）的排放量不断增加，这些物质也可以到达平流层并导致臭氧损失。最丰富的Cl-VSLS是二氯甲烷（CH 2Cl 2），其对流层丰度在过去十年中增加了60%以上。CH 2Cl 2是人类产生的，在北方半球，靠近工业源，长期观察显示CH 2Cl 2的平均增长率约为8%/年。这些增加的确切原因尚不清楚。然而，众所周知，在亚洲，CH 2Cl 2（和其他Cl-VSLS）的排放量相对较大，在没有对生产进行政策控制的情况下，预计未来几年大气浓度将继续增加。我们最近的建模工作表明：（i）Cl-VSLS对平流层氯的贡献仅在过去十年中就已经翻了一番，（ii）持续的CH 2Cl 2增长可能会推迟南极臭氧洞的恢复长达几十年。这将大大抵消《蒙特利尔议定书》所取得的一些成果，而且由于臭氧洞以几种方式影响南半球的地表气候，可能会影响对气候变化的预测。我们将对CH 2Cl 2增长对平流层臭氧构成的威胁进行首次协调一致的多模式评估。兰开斯特大学将与剑桥大学和一个由9个合作伙伴组成的国际联盟合作，领导模型的相互比较。我们将开发一系列的增长情景描述可能的未来轨迹的CH 2Cl 2在大气中。我们联合体中的每个模型都将考虑到这些设想方案进行正向模拟，并将对模拟结果进行分析，以确定（a）由于二氯甲烷的增长，平流层不同区域臭氧恢复的预期延迟和（B）随后对气候和地表紫外线的影响。国际职业健康组织的研究结果将为不受《蒙特利尔议定书》管制的化合物在臭氧消耗方面的作用提供有力的新见解，这将与今后对臭氧和气候变化的国际评估（例如气象组织/环境署和气候小组的报告）密切相关。虽然国际固体化学品组织的重点是二氯甲烷，但工作队将在项目之外继续积极开展工作，以审查其他不受控制的氯-挥发性固体物质（如二氯甲烷、C2 H4 Cl 2）对臭氧的未来威胁。事实上，我们正在进行的工作表明，这些Cl-VSLS的排放量也在增加。

项目成果

Rapid increase in dichloromethane emissions from China inferred through atmospheric observations.

• DOI: 10.1038/s41467-021-27592-y
• 发表时间: 2021-12-14
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: An M;Western LM;Say D;Chen L;Claxton T;Ganesan AL;Hossaini R;Krummel PB;Manning AJ;Mühle J;O'Doherty S;Prinn RG;Weiss RF;Young D;Hu J;Yao B;Rigby M
• 通讯作者: Rigby M

Description and evaluation of the new UM-UKCA (vn11.0) Double Extended Stratospheric-Tropospheric (DEST vn1.0) scheme for comprehensive modelling of halogen chemistry in the stratosphere

用于平流层卤素化学综合建模的新 UM-UKCA (vn11.0) 双扩展平流层-对流层 (DEST vn1.0) 方案的描述和评估

• DOI: 10.5194/gmd-2022-215
• 发表时间: 2022
• 作者: Bednarz E

Projecting ozone hole recovery using an ensemble of chemistry-climate models weighted by model performance and independence

使用按模型性能和独立性加权的化学气候模型集合来预测臭氧空洞的恢复

• DOI: 10.5194/acp-20-9961-2020
• 发表时间: 2020
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: Amos M

A Synthesis Inversion to Constrain Global Emissions of Two Very Short Lived Chlorocarbons: Dichloromethane, and Perchloroethylene

• DOI: 10.1029/2019jd031818
• 发表时间: 2020-06-27
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
• 影响因子: 4.4
• 作者: Claxton, Tom;Hossaini, Ryan;Lunder, Chris
• 通讯作者: Lunder, Chris