Holocene climate change, ecosystem response and human impacts

全新世气候变化、生态系统响应和人类影响

• 批准号: RGPIN-2021-02713
• 负责人: Gajewski, Konrad
• 金额: $ 2.19万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754765
• 关键词: Holocene; climate; change; ecosystem; response

This research program studies the evolution of the earth ecosystem during the transition from the glacial to interglacial period. It has as goal understanding how the climate system has changed in the past, in response to various forcing factors including human impacts. We reconstruct past climates and vegetation using the fossil record, and develop and use archives of past climate and environmental changes such as lake sediment, ocean and ice cores. The main focus of this research program is the mapping and statistical analysis of databases of paleoclimates, paleo-vegetation and past human populations to understand the ecosystem evolution of North America, and, in the longer term, globally. The time scale is the past 20,000 years; the transition from a glacial period to an interglacial and into the Anthropocene. We will use a global database of past climates, derived from many different proxies (microfossils, geochemical parameters, isotopes, biomarkers, etc,) collected from lake sediments, ice cores, ocean sediments, tree-rings and other sources to understand how the climate has changed over the past 20,000 years. Using mapping and statistical analysis, we will study if the climate system changes slowly or abruptly, when were the maximum and minimum temperatures by region, how precipitation changed in time and space and when were major transitions in global and regional climates. We will explore new data-analytic methods, such as machine learning, in addition to classical methods of multivariate, time series and spatial statistics to summarize and map these data. Then we will use pollen databases, which are available from many parts of the world, to reconstruct past vegetation dynamics. Vegetation changes will be associated with the climate changes determined independently to see if terrestrial ecosystems respond rapidly to climate changes, or if there are thresholds or lags in vegetation change to climate variability of several timescales. An innovative part of the proposal is to quantify human impacts on the vegetation and climate over the Holocene. We use a global archaeological radiocarbon database to map and analyze human population density though time. These paleodemography results are interpreted as proportional to human impact on the environment, and are statistically associated with vegetation and climate changes to study (a) did past climate changes affect human population numbers, and/or (b) are vegetation composition and climate associated with changes in human numbers (early Anthropocene hypothesis). We also study human impact on natural fire regimes using a charcoal database. These studies are done at regional to continental scale, as appropriate, and the overall goal is a global analysis of how past climate changes drove vegetation responses, which in turn helped determine human population changes.

该研究计划研究从冰期到间冰期过渡期间地球生态系统的演变。它的目标是了解气候系统在过去是如何变化的，以应对包括人类影响在内的各种强迫因素。我们利用化石记录重建过去的气候和植被，并开发和利用过去气候和环境变化的档案，如湖泊沉积物，海洋和冰芯。该研究计划的主要重点是对古气候，古植被和过去人口的数据库进行绘图和统计分析，以了解北美的生态系统演变，并从长远来看，全球。时间尺度是过去的20,000年;从冰期到间冰期再到人类世的过渡。我们将使用过去气候的全球数据库，这些数据库来自于从湖泊沉积物，冰芯，海洋沉积物，树木年轮和其他来源收集的许多不同的代理（微体化石，地球化学参数，同位素，生物标志物等），以了解气候在过去20，000年中是如何变化的。利用绘图和统计分析，我们将研究气候系统是否缓慢或突然变化，何时是最高和最低温度的区域，降水如何在时间和空间上变化，以及何时是全球和区域气候的主要转变。我们将探索新的数据分析方法，如机器学习，除了多变量，时间序列和空间统计的经典方法来总结和映射这些数据。然后，我们将使用花粉数据库，这是从世界许多地方，重建过去的植被动态。植被变化将与独立确定的气候变化相关联，以了解陆地生态系统是否对气候变化迅速作出反应，或者植被变化对几个时间尺度的气候变率是否存在阈值或滞后。该提案的一个创新部分是量化人类对全新世植被和气候的影响。我们使用全球考古放射性碳数据库来绘制和分析人类人口密度。这些古人口学结果被解释为与人类对环境的影响成正比，并与植被和气候变化统计相关，以研究（a）过去的气候变化是否影响人口数量，和/或（B）与人类数量变化相关的植被组成和气候（早期人类世假设）。我们还研究了人类对自然火制度使用木炭数据库的影响。这些研究是在区域到大陆的范围内进行的，总体目标是对过去的气候变化如何驱动植被反应进行全球分析，这反过来又有助于确定人口变化。