Cryo-methane emissions - global consequences of permafrost and hydrate destabilization

低温甲烷排放——永久冻土和水合物不稳定的全球后果

• 批准号: 105389-2007
• 负责人: Whiticar, Michael
• 金额: $ 3.32万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=390852
• 关键词: Cryo; methane; emissions; global; consequences

Earth's largest repositories of methane are in marine and terrestrial gas hydrates and within/beneath permafrost layers. Although estimates are uncertain, marine gas hydrates store ca. 1.5 x10^15 m^3 and terrestrial hydrates up to 0.06-0.7 x10^15 m^3. Combined they double conventional gas resources of ca. 0.4 x10^15 m^3. Our biogeochemical research of marine hydrates offshore Oregon and Vancouver Is. Margins, and onshore Arctic Mallik 2L-38 hydrate well, documented the character, environmental and economic aspects of hydrates. In concert, we investigated the rapid methane changes at Preboreal /Younger Dryas/Preboreal (YD/PB) transition and Late Glacial Maximum using methane stable C- and H-isotope ratios in Greenland ice. Our ice research indicates that marine gas hydrates and tropical wetlands are not responsible for the Late Pleistocene methane changes. My hypothesis for the YD/PB rise is the release of methane stored in near-surface permafrost soils. Warming causes permafrost layers in front of ice sheets to thaw and release trapped methane. Today, we are experiencing a similar retreat in permafrost. If my YD/PB hypothesis is correct, then in the coming decades we shall experience a similar rapid rise in atmospheric methane as the subArctic warms. This may be combined with the release of methane from shelf gas hydrates. The implications are dramatic shifts in present day global greenhouse gas budgets, impacts on current radiative budgets and influences on climate change. In my coming Discovery Grant period, I wish to intensely investigate the controls and rates of soil gas fluxes, especially methane, from changing discontinuous permafrost regions and shelf hydrates of Canada's Arctic. Using biogeochemical field measurements (including eddy flux correlation, gas composition, isotopes, biomarker compounds, and microbiological assays) coupled with modeling, I seek to determine if permafrost-and hydrate-derived methane: 1) is being influenced by changes in subArctic conditions, 2) is or can be released with sufficient quantity and isotope composition to be consistent with our YD/PB Canadian and Greenland ice signals, 3) will be of a magnitude that can significantly affect our future climate.

地球上最大的甲烷储存库是海洋和陆地的天然气水合物以及永久冻土层之内/之下。虽然估计是不确定的，海洋天然气水合物储存约。1.5 x10^15 m^3，陆地水合物高达0.06-0.7 x10^15 m^3。加在一起，它们使加州的常规天然气资源增加了一倍。0.4 x10^15 m^3。我们对俄勒冈州和温哥华近海海洋水合物的地球化学研究。Margins和陆上Arctic Mallik 2L-38水合物井记录了水合物的特征、环境和经济方面。在演唱会上，我们调查了快速甲烷变化在Preboreal /Younger Dryas/Preboreal（YD/PB）过渡和晚冰期最大使用甲烷稳定的C-和H-同位素比在格陵兰岛冰。我们的冰研究表明，海洋天然气水合物和热带湿地是不是负责晚更新世甲烷变化。我对YD/PB上升的假设是储存在近地表永久冻土中的甲烷的释放。气候变暖导致冰盖前的永久冻土层融化并释放出被困的甲烷。今天，我们正在经历一个类似的撤退在永久冻土。如果我的YD/PB假设是正确的，那么在未来几十年里，随着亚北极变暖，我们将经历类似的大气甲烷快速上升。这可能与从大陆架天然气水合物释放甲烷相结合。其影响是当今全球温室气体预算的急剧变化，对当前辐射预算的影响以及对气候变化的影响。 在我即将到来的发现资助期间，我希望深入研究土壤气体通量的控制和速率，特别是甲烷，来自加拿大北极地区不断变化的不连续永久冻土区和陆架水合物。 利用地球化学场测量（包括涡流通量相关性、气体成分、同位素、生物标志物化合物和微生物测定）结合建模，我试图确定永冻土和水合物衍生的甲烷是否：1）受到亚北极条件变化的影响，2）释放或可以释放足够的数量和同位素组成，与我们的YD/PB加拿大和格陵兰冰信号一致，3）将是一个规模，可以显着影响我们未来的气候。