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植被动力学与地球系统

Vegetation Dynamics and the Earth System
课程网址: http://videolectures.net/mitworld_claussen_vdes/  
主讲教师: Martin Claussen
开课单位: 汉堡大学
开课时间: 2013-03-08
课程语种: 英语
中文简介:
气候变化不是渐进的,也不是线性的。回顾11000年前我们自己的全新世时代,马丁·克劳森描绘了一幅生物圈突然而残酷的变化。他的工作包括模拟大气、海洋、海冰和植被之间复杂的相互作用。撒哈拉沙漠曾经是一片绿色的绿洲,但在过去的六千年里,剧烈的破坏导致了它的迅速褐变。克劳森的模型表明,地球轨道的缓慢演化及其向太阳的倾斜引发了一种反应,导致北非的水分和植被迅速丧失。克劳森认为,地球上的气候和植被之间的相互作用被放大了。克劳森说:“如果这个系统受到轻微的冲击,它可以从绿地跳到沙漠。”。由于这一变化,人类可能被迫从饱受破坏的撒哈拉地区迁移到肥沃的底格里斯、幼发拉底河和尼罗河流域,在那里新的文明不断涌现。展望未来,克劳森指出,人类产生的二氧化碳过量或森林砍伐等触发因素可能会在全球热点地区引发类似的剧烈气候变化。
课程简介: Climate change does not unfold gradually or in a linear way. Peering back 11,000 years in our own Holocene era, Martin Claussen sketches a picture of abrupt and brutal shifts in the biosphere. His work involves modeling complex interactions among atmosphere, ocean, sea ice and vegetation. The Sahara Desert was once a green oasis, but dramatic disruptions in the last six thousand years led to its very rapid browning. Claussen’s models demonstrate that a slow evolution in the earth’s orbit and its tilt toward the sun triggered a reaction that led to swift loss of moisture and vegetation in North Africa. Claussen believes that interactions within Earth’s climate system -- specifically between vegetation cover and sea ice -- amplified the impact of the orbital shifts. “If the system gets a slight kick, it can jump from green to desert,” says Claussen. As a result of this change, humans may have been forced to migrate from the devastated Sahara region to the fertile Tigris, Euphrates and Nile River valleys, where new civilizations sprang up. Looking forward, Claussen notes that triggers such as an excess of human-generated carbon dioxide or deforestation might provoke similar dramatic climatic changes in global hotspots.
关 键 词: 植被; 动力学; 地球系统
课程来源: 视频讲座网
数据采集: 2020-11-26:yxd
最后编审: 2020-11-26:yxd
阅读次数: 47