The End of the Amazon Carbon Sink? (AMSINK)

亚马逊碳汇的终结？

• 批准号: NE/X014347/1
• 负责人: Oliver Phillips
• 金额: $ 104万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX014347%2F1
• 关键词: End; Amazon; Carbon; Sink; AMSINK

How forests respond to climate change and the increasing concentration of carbon dioxide in the atmosphere affects the course of climate change itself. The response of these ecosystems thus determine how much humanity needs to reduce greenhouse gas emissions to keep global heating within agreed limits. Understanding these is especially critical for the Amazon due to its huge importance for Earth's climate. While the need to know is urgent, the challenge is enormous. Satellites, planes, experiments and models all help, but long-term, tree-by-tree measurements in many sites are essential to understand how forests are accelerating or slowing the rate of climate change.So far intact Amazon forests have provided a huge 'sink' for carbon, slowing climate change. But a decade ago there were already signs this had weakened with tree death rates increasing, partly as a result of severe droughts. Projections suggest the sink may now be finished. If so we have lost a key ally in stabilising Earth's climate. But with no ground analysis since 2011 a big gap between knowledge and projection has opened up. The forecast is based on old measurements, has large uncertainty, and crucially fails to account for the huge natural variability of forests. AMSINK will resolve this. It uses ambitious new measurements, analysis and integration to discover how and why South American forests are changing, where and why they are able to resist climate change, and what the future holds. In short to understand the dynamics and destiny of this critical system.Our central idea is that the biomass carbon sink depends on the fundamental nature of forests - their climate, nutrients, soil water, species and diversity, and turnover rate - so that in many places net uptake of carbon may persist well beyond simple predictions based on climate-change. For example, while we know that scarce nutrients limit forest growth and droughts kill trees, (1) one third of the Amazon has relatively-rich soils where nutrients may allow long-term growth increases and (2) up to half is prone to waterlogging so some drying could benefit trees by aerating the soil, while (3) tree resistance to drought is likely to vary greatly with species.To know what is happening to S American forests, where and why therefore requires a huge, integrated and ambitious measurement effort. We must look widely at many forests for a long time. We need holistic science.To make this possible AMSINK takes three key steps. First we will unite 15 forest plot networks, each examining different locations and aspects of change across tropical S America, to create a connected 'team-of-teams' spanning 8 million km2 of forest. Second we will enrich these, with comparable nutrient, moisture and species drought-sensitivity measurements across the networks. Third, for the most valuable long-term Amazon plots we will take careful consistent tree-by-tree monitoring into the mid-2020s. In total AMSINK will integrate 1000 plots into a globally standardized framework and track more than half-a-million trees for up to 62 years. It will analyse these to discover the distribution, dynamics and trend of the biomass carbon sink to 2026, determine its drivers, and test our hypotheses of forest resistance to climate change. Our new findings will be applied to forecast future growth, mortality and carbon trends across the region, providing critical insights for national policy-makers, global agreements & fellow scientists.In all AMSINK makes the first continent-scale integrated measurement and analysis of how nature controls the long-term climate-change sensitivity of tropical forests and their carbon balance. It replaces projection with new measures to 2026, novel insight into which sink processes are changing where, critical understanding of why, and new constraints on how their future will unfold. It delivers exceptional scientific value for UK taxpayer support and vital, timely discoveries for policy-makers.

森林如何应对气候变化以及大气中二氧化碳浓度的增加会影响气候变化本身。因此，这些生态系统的反应决定了人类需要多少减少温室气体排放，以使全球供暖保持在商定的范围内。由于其对地球气候的重要性，因此对亚马逊的理解对于亚马逊来说尤其重要。虽然需要知道的需求是紧迫的，但挑战是巨大的。卫星，飞机，实验和模型都有所帮助，但是许多地点的长期，树木的测量对于了解森林如何加速或减缓气候变化速度至关重要。因此，完整的亚马逊森林为碳提供了巨大的“水槽”，以减缓气候变化。但是十年前，已经有迹象表明，由于严重干旱的结果，树木死亡率的升高却有所降低。预测表明水槽现在可能已经完成。如果是这样，我们在稳定地球的气候方面失去了关键盟友。但是，自2011年以来就没有地面分析，知识和投影之间的差距很大。预测基于旧测量，具有较大的不确定性，至关重要的是无法解释森林的巨大自然变异性。 Amsink将解决此问题。它使用雄心勃勃的新测量，分析和整合来发现南美森林如何以及为什么在何处以及为什么能够抵抗气候变化以及未来的影响。简而言之，要理解这个关键系统的动态和命运。我们的主要思想是，生物质碳汇取决于森林的基本性质 - 它们的气候，养分，土壤水，物种和多样性以及周转率 - 因此，在许多地方，碳的吸收可能会超出基于气候变化的简单预测。例如，虽然我们知道稀缺的营养限制了森林的生长和干旱杀死树木，但（1）亚马逊的三分之一具有相对丰富的土壤，在这些土壤中，养分可能会允许长期增长，并且（2）最多一半易于灌水，因此某些干燥可以使树木受益，从而使土壤充气，而（3）对某种境内的境内却可能遇到众多的境地。综合和雄心勃勃的测量工作。我们必须长时间广泛地看许多森林。我们需要整体科学。要使这一可能，Amsink采取了三个关键步骤。首先，我们将团结15个森林情节网络，每个林地网络都研究了热带地区的不同位置和变化的各个方面，以创建一个跨越800万公里森林的“团队”。其次，我们将以可比的养分，水分和物种干旱的敏感性测量值来丰富它们。第三，对于最有价值的长期亚马逊地块，我们将在2020年代中期进行仔细的一致的树木监控。 Amsink总共将1000个地块整合到全球标准化的框架中，并在62年内追踪超过500万棵树。它将分析它们，以发现生物质碳汇到2026年的分布，动态和趋势，确定其驱动因素，并测试我们对森林对气候变化的抗性的假设。我们的新发现将用于预测该地区的未来增长，死亡率和碳趋势，为国家政策制定者，全球协议和科学家提供关键见解。在所有AMSINK中，AMSINK都使第一大陆规模的综合衡量和分析自然控制了长期的气候气候敏感性，使热带森林及其碳纤维平衡。它用新的措施取代了2026年的新措施，新的洞察力在哪些过程中发生了变化，对原因的批判性理解以及对其未来如何展开的新约束。它为英国纳税人支持和对决策者的及时发现提供了卓越的科学价值。