Collaborative Research: P2C2--Late Holocene Climate: Natural or Anthropogenic?

合作研究：P2C2——全新世晚期气候：自然还是人为？

• 批准号: 1602967
• 负责人: William Ruddiman
• 金额: $ 11.79万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1602967&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Late; Holocene

This collaborative project generally aims to address a fundamental and yet unresolved question about Holocene climate which is: When did humans assume the "driver's seat" of the global climate system? Did it coincide with the advent of the Industrial Era, as traditionally believed, or did it instead occur many millennia ago with the emergence of agriculture? The scientific community remains divided on whether carbon emissions released by early farming activities were large enough to explain the unprecedented rise in atmospheric greenhouse gas (GHG) concentrations during the late Holocene compared with declines in these climatic drivers during recent previous inter-glacial periods. This research will test the "Early Anthropogenic Hypothesis," which posits that anthropogenic global climate change was initiated by agriculture in the middle Holocene, by identifying the "fingerprint" of human influence on global climate during the past 6,000 years.The project will capitalize on state-of-the-art earth system models to distinguish between the actual climatic evolution of the late Holocene and the hypothesized "natural" trajectory that would have been followed in the absence of human land clearance and greenhouse-gas overprints. To achieve this goal, a pair of 6,000-year long transient simulations will be run with the Community Earth System Model (CESM). In one experiment CESM will be driven by historical variations in orbital parameters, GHG concentrations, and regional land clearance, whereas the latter two forcings will differ in the counterpart experiment according to the hypothesized declines in carbon dioxide and methane and the associated global vegetation patterns compatible with "natural" climate evolution.The Broader Impacts involve the potential for a unique and potentially transformative shift in the scientific understanding of human influence on global climate.

这个合作项目总体上旨在解决关于全新世气候的一个基本但尚未解决的问题，即：人类何时占据了全球气候系统的“驾驶座”？它是像传统认为的那样与工业时代的到来同时发生的，还是在几千年前随着农业的出现而发生的？对于早期农业活动释放的碳排放量是否足以解释全新世晚期大气温室气体（GHG）浓度前所未有的上升与最近的冰间期这些气候驱动因素的下降相比，科学界仍然存在分歧。这项研究将通过识别过去 6000 年来人类对全球气候影响的“指纹”来检验“早期人类假说”，该假说认为人类造成的全球气候变化是由全新世中期的农业引发的。该项目将利用最先进的地球系统模型来区分全新世晚期的实际气候演化和假设的全新世时期的“自然”轨迹。 没有人类土地清理和温室气体叠印。 为了实现这一目标，将使用社区地球系统模型 (CESM) 运行一对长达 6,000 年的瞬态模拟。 在一项实验中，CESM 将由轨道参数、温室气体浓度和区域土地清理的历史变化驱动，而根据二氧化碳和甲烷的假设下降以及与“自然”气候演化相容的相关全球植被模式，后两种强迫在对应实验中将有所不同。更广泛的影响涉及对科学理解的独特且潜在的变革性转变的潜力。 人类对全球气候的影响。