The multi-year impacts of the 2015/2016 El Nino on the carbon cycle of tropical forests

2015/2016厄尔尼诺现象对热带森林碳循环的多年影响

• 批准号: NE/P001092/1
• 负责人: Yadvinder Malhi
• 金额: $ 82.87万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FP001092%2F1
• 关键词: multi; year; impacts; 2015; 2016

A key challenge in Earth System science is to understand the role the biosphere plays in ameliorating or accelerating global atmospheric change. The global carbon cycle is of particular interest: the terrestrial biosphere appears to act normally as a sink for atmospheric carbon dioxide, but under extreme conditions, in particular during El Niño events, appears to switch from being a sink to a net source of carbon dioxide to the atmosphere. The tropical land biosphere in particular dominates the interannual variability of the carbon cycle, and this variability appears to be increasing over recent decades. This suggests that the tropical land biosphere may be approaching some critical transition, that may result in it becoming an accelerator of climate change.While the sensitivity of the tropical carbon cycle to climate perturbations has frequently been modelled and more recently estimated from atmospheric mass budgets and remote sensing, there has been almost no direct field validation of the impact of the El Nino on the tropical carbon cycle. The Earth is currently (2015/2016) experiencing its strongest El Niño event for many decades, with unusually high temperatures across the tropics and drought in many parts of the tropical Americas, Africa and Asia. Unlike the case during previous strong El Niños, we now have established a global network of detailed carbon cycle process studies across the tropics, supported by a patchwork of short-term funding. Such an opportunity may not come again for decades, and we are well-placed to seize it. Our plots monitor forest carbon cycling at seasonal and monthly timescales, and span across the tropics (in Belize, Bolivia, Peru, Brazil, Ghana, Gabom, Ethiopia, and Malaysia). They also span gradients of human modification ranging from old growth through different intensities of logging, fire occurrence, agroforestry and other natural disturbance including hurricanes. This provides a unique opportunity to attain a direct empirical understanding of how carbon cycle processes change over and after an El Nino, including productivity, allocation, autotrophic and heterotrophic respiration. We propose to monitor 80 plots across the tropics through this El Nino and beyond until end 2017, at monthly or seasonal resolution.We are uniquely placed to closely track the carbon cycle of forests through this event and for several years after, potentially providing a definitive answer to how much tropical forest carbon cycle responses contribute to the interannual variation of the biosphere carbon sink, and which component processes determine this interannual variation. This information will be use to validate and improve land biosphere models, including the JULES land surface model that sits within the UK Met Office Earth System Model.In this proposal we see to utilise this network to answer several key questions:1. What are the local immediate and multi-year carbon cycle responses to drought, and how consistent are these across the tropics?2. How does a ~1 degree C rise in temperature affect carbon cycle processes across gradients of drought and disturbance? 3. Which components of productivity and respiration dominate interannual variability, and what can this tell us about the correspondence between short-term variability and long-term resilience?4. Is there evidence that forest productivity (NPP) is maintained through the event via a decline in non-structural carbohydrate reserves?5. How do human-modification (logging, tree crops, past fires) and natural disturbance (hurricanes, elephants) affect carbon cycle sensitivity to the El Niño? 6. What are the impacts of fire on the carbon cycle of our forest plots in Brazil, that have burned in this El Niño?

地球系统科学的一个关键挑战是了解生物圈在改善或加速全球大气变化中所发挥的作用。全球碳循环特别令人感兴趣：陆地生物圈通常充当大气二氧化碳的汇，但在极端条件下，特别是在厄尔尼诺事件期间，似乎从汇转变为大气中二氧化碳的净来源。热带陆地生物圈尤其主导着碳循环的年际变化，而且这种变化在近几十年来似乎在增加。这表明热带陆地生物圈可能正在接近某种关键转变，这可能会导致其成为气候变化的加速器。虽然热带碳循环对气候扰动的敏感性经常被建模，并且最近根据大气质量预算和遥感进行估计，但几乎没有直接实地验证厄尔尼诺对热带碳循环的影响。地球目前（2015/2016）正在经历几十年来最强烈的厄尔尼诺事件，热带地区气温异常高温，热带美洲、非洲和亚洲许多地区出现干旱。与之前强烈厄尔尼诺现象期间的情况不同，我们现在已经建立了一个跨热带地区详细碳循环过程研究的全球网络，并得到了短期资金的支持。这样的机会可能几十年都不会再出现，我们完全有能力抓住它。我们的地块监测季节性和每月时间尺度的森林碳循环，横跨热带地区（伯利兹、玻利维亚、秘鲁、巴西、加纳、加博姆、埃塞俄比亚和马来西亚）。它们还跨越了人类改造的梯度，从古老的生长到不同强度的伐木、火灾、农林业和包括飓风在内的其他自然干扰。这提供了一个独特的机会，可以直接凭经验了解厄尔尼诺现象期间和之后碳循环过程如何变化，包括生产力、分配、自养和异养呼吸。我们建议在 2017 年底之前以月度或季节性分辨率监测整个热带地区的 80 个地块，以月度或季节性分辨率监测厄尔尼诺现象及其后的情况。我们具有独特的优势，可以密切跟踪该事件期间及其后几年的森林碳循环，有可能为以下问题提供明确的答案：热带森林碳循环响应对生物圈碳汇的年际变化有多大影响，以及哪些组成过程决定了这种年际变化。这些信息将用于验证和改进陆地生物圈模型，包括英国气象局地球系统模型中的 JULES 陆地表面模型。在本提案中，我们希望利用该网络来回答几个关键问题：1。当地对干旱的直接和多年碳循环反应是什么？这些反应在整个热带地区的一致性如何？2。温度升高约 1 摄氏度如何影响干旱和干扰梯度下的碳循环过程？ 3. 生产力和呼吸的哪些组成部分主导年际变化，这可以告诉我们关于短期变化和长期恢复力之间的对应关系什么？4。是否有证据表明森林生产力（NPP）在整个事件期间通过非结构性碳水化合物储备的下降得以维持？5。人类改造（伐木、木本作物、过去的火灾）和自然干扰（飓风、大象）如何影响碳循环对厄尔尼诺现象的敏感性？ 6. 在这次厄尔尼诺现象中，火灾对巴西林地的碳循环有何影响？

项目成果

Resistance of African tropical forests to an extreme climate anomaly.

• DOI: 10.1073/pnas.2003169118
• 发表时间: 2021-05-25
• 期刊: Proceedings of the National Academy of Sciences of the United States of America
• 影响因子: 11.1
• 作者: Bennett AC;Dargie GC;Cuni-Sanchez A;Tshibamba Mukendi J;Hubau W;Mukinzi JM;Phillips OL;Malhi Y;Sullivan MJP;Cooper DLM;Adu-Bredu S;Affum-Baffoe K;Amani CA;Banin LF;Beeckman H;Begne SK;Bocko YE;Boeckx P;Bogaert J;Brncic T;Chezeaux E;Clark CJ;Daniels AK;de Haulleville T;Djuikouo Kamdem MN;Doucet JL;Evouna Ondo F;Ewango CEN;Feldpausch TR;Foli EG;Gonmadje C;Hall JS;Hardy OJ;Harris DJ;Ifo SA;Jeffery KJ;Kearsley E;Leal M;Levesley A;Makana JR;Mbayu Lukasu F;Medjibe VP;Mihindu V;Moore S;Nssi Begone N;Pickavance GC;Poulsen JR;Reitsma J;Sonké B;Sunderland TCH;Taedoumg H;Talbot J;Tuagben DS;Umunay PM;Verbeeck H;Vleminckx J;White LJT;Woell H;Woods JT;Zemagho L;Lewis SL
• 通讯作者: Lewis SL

21st Century drought-related fires counteract the decline of Amazon deforestation carbon emissions.

• DOI: 10.1038/s41467-017-02771-y
• 发表时间: 2018-02-13
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Aragão LEOC;Anderson LO;Fonseca MG;Rosan TM;Vedovato LB;Wagner FH;Silva CVJ;Silva Junior CHL;Arai E;Aguiar AP;Barlow J;Berenguer E;Deeter MN;Domingues LG;Gatti L;Gloor M;Malhi Y;Marengo JA;Miller JB;Phillips OL;Saatchi S
• 通讯作者: Saatchi S

Drier tropical forests are susceptible to functional changes in response to a long-term drought

• DOI: 10.1111/ele.13243
• 发表时间: 2019-05-01
• 期刊: ECOLOGY LETTERS
• 影响因子: 8.8
• 作者: Aguirre-Gutierrez, Jesus;Oliveras, Imma;Malhi, Yadvinder
• 通讯作者: Malhi, Yadvinder

Tree growth and stem carbon accumulation in human-modified Amazonian forests following drought and fire

• DOI: 10.1098/rstb.2017.0308
• 发表时间: 2018-11-19
• 期刊: PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
• 影响因子: 6.3
• 作者: Berenguer, Erika;Malhi, Yadvinder;Barlow, Jos
• 通讯作者: Barlow, Jos

Tropical tree growth sensitivity to climate is driven by species intrinsic growth rate and leaf traits

热带树木生长对气候的敏感性是由物种内在生长速率和叶子特征驱动的

• DOI: 10.1101/2021.06.08.447571
• 发表时间: 2021
• 作者: Bauman D