Methane Isotope Variations Covering the Holocene from the WAIS Divide Core

Sowers 0944584该奖项支持一个项目，以更好地预测自然CH 4排放将如何响应和推动未来的气候变化，通过对过去11，000年（11 kyr）控制大气CH 4的全球地球化学循环的详细研究，当时地球气候保持相对接近其当前状态。在此期间，甲烷浓度发生了显著变化。 该项目涉及使用WAIS分水岭冰芯的核心材料生成大气CH 4的13 C/12 C同位素记录。WAIS的13 CH 4数据将用于建立第一个覆盖全新世的南极大气记录。这一记录将与我们最近从格陵兰岛GISP 2冰芯获得的全新世记录进行比较。新的南极记录将提供对GISP 2记录的重要验证，以及我们第一次看到覆盖全新世的半球间ä13 CH 4梯度。 这些记录一起提供了重要的边界条件，测试各种排放情景（时间，空间和源），应该提供一个定量的基础，评估整个全新世甲烷排放的性质。 这项工作的知识价值与地球气候直接受到微量“温室”气体（二氧化碳，甲烷，一氧化二氮，CFC's等）水平的影响有关，这些气体在大气中的现代积累是人类社会的基本关注。 在更广泛的影响方面，拟议的工作将提高我们对整个全新世甲烷变化的模式和原因的理解。这对于理解自然气候系统，特别是气候和温室气体地球化学之间的反馈非常重要。全新世甲烷记录表明，全球甲烷循环受到各种反馈的深刻影响，这些反馈并不涉及大的温度波动。这意味着强反馈到一个相对较小的（目前未知的）强迫。 这项拟议中的工作将有助于更好地理解为什么甲烷水平在整个全新世发生变化，为完善和测试全球模型提供基本信息。它还将有助于检验一个有争议但重要的假设，即人类从大约5000年前开始对大气层产生重大影响。本科生和研究生将参与研究的各个阶段，并特别强调通过我们的学院教育公平办公室招募代表性不足的少数族裔学生。所有数据将按照安全性政策存档在适当的数据库中。

Sowers 0944584This award supports a project to better predict how natural CH4 emissions will respond to and force future climate change through a detailed study of the global biogeochemical cycles that control atmospheric CH4 over the past 11,000 years (11kyr), when the Earth's climate has remained relatively close to its current state. During that time, methane concentrations changed significantly. The project involves generating 13C/12C isotopic records of atmospheric CH4 using the core material from the WAIS Divide ice core. The ä13CH4 data from WAIS will be used to construct the first Antarctic atmospheric record covering the Holocene. This record will be compared to our recent Holocene record from the GISP2 ice core from Greenland. The new Antarctic record will provide an important verification of the GISP2 record as well as our first glimpse of the inter-hemispheric ä13CH4 gradient covering the Holocene. Together these records provide important boundary conditions for testing various emission scenarios (time, space and source) that should provide a quantitative basis for assessing the nature of CH4 emissions throughout the Holocene. The intellectual merit of this work relates to the fact that the earth's climate is directly influenced by levels of trace, "greenhouse" gases (carbon dioxide, methane, nitrous oxide, CFC's, and others), and the modern build up of these gases in the atmosphere is a fundamental concern for human society. In terms of broader impacts the proposed work will enhance our understanding of the patterns and causes of methane change throughout the Holocene. This is important for understanding the natural climate system, and in particular, feedbacks between climate and greenhouse gas biogeochemistry. The Holocene CH4 record suggests that the global methane cycle was profoundly influenced by various feedbacks that do not involve large temperature swings. This implies strong feedbacks to a relatively small (and presently unknown) forcing. The proposed work will lead to improved understanding of why methane levels changed throughout the Holocene, providing fundamental information to refine and test global models. It will also contribute to testing the controversial, but important, hypothesis, that humans impacted the atmosphere significantly starting about 5000 years ago. Undergraduate and graduate students will participate in all phases of the research and a special emphasis will be placed on recruiting under represented minority students thru our college based office of educational equity. All data will be archived on appropriate databases per OPP policies.