古环境重建(也称为古气候重建)是指结果和调查,以确定过去特定时间和地点的气候和植被。气候,包括植被,温度和相对湿度,在自地球最早的人类居住以来,从自然和文化(人为)的原因开始,变化很大。研究人员依赖现代类比;也就是说,他们将过去的发现与世界各地当前气候中的发现进行了比较。然而,在过去很古老的时期,气候与我们这个星球上目前正在经历的气候完全不同。总的来说,这些情况似乎是气候条件的结果,这些气候条件的季节性差异比我们今天所经历的任何情况都要大。特别重要的是要认识到过去的大气二氧化碳水平低于现在的水平,因此大气中温室气体较少的生态系统可能表现得与现在不同。气候学家主要使用古环境数据来了解我们世界的环境如何变化以及现代社会如何为即将到来的变化做好准备。考古学家使用古环境数据来帮助了解居住在考古遗址的人们的生活条件。气候学家受益于考古学研究,因为他们展示了过去人类如何学习如何适应或不适应环境变化,以及它们如何引起环境变化或通过其行为使其变得更糟或更好。由古气候学家收集和解释的数据被称为代理,是不能直接测量的代表。我们无法及时返回来测量某一天或一年或一个世纪的温度或湿度,也没有气候变化的书面记录可以给我们提供超过几百年的详细信息。相反,古气候研究人员依赖于受气候影响的过去事件的生物,化学和地质痕迹。气候研究人员使用的主要代理是植物和动物遗骸,因为一个地区的动植物类型表明了气候:将北极熊和棕榈树视为当地气候的指标。可识别的植物和动物痕迹的大小从整棵树到微观硅藻和化学特征。最有用的遗骸是那些足以被物种识别的遗骸;现代科学已经能够识别像花粉粒和孢子到植物物种一样微小的物体。代理证据可以是生物,地貌,地球化学或地球物理;他们可以记录每年,每十年,每一个世纪,每一千年甚至几千年的时间范围内的环境数据。树木生长和区域植被变化等事件会在土壤和泥炭沉积物,冰川冰碛,洞穴形成以及湖泊和海洋底部留下痕迹。

美国杜克大学环境学Assignment代写:古环境重建

Paleoenvironmental reconstruction (also known as paleoclimate reconstruction) refers to the results and the investigations undertaken to determine what the climate and vegetation were like at a particular time and place in the past. Climate, including vegetation, temperature, and relative humidity, has varied considerably during the time since the earliest human habitation of planet earth, from both natural and cultural (human-made) causes. Researchers rely on modern analogs; that is to say, they compare the findings from the past to those found in current climates around the world. However, there are periods in the very ancient past when the climate was completely different from what is currently being experienced on our planet. In general, those situations appear to be the result of climate conditions that had more extreme seasonal differences than any we’ve experienced today. It is particularly important to recognize that atmospheric carbon dioxide levels were lower in the past than those present today, so ecosystems with less greenhouse gas in the atmosphere likely behaved differently than they do today. Climatologists primarily use paleoenvironmental data to understand how the environment of our world has changed and how modern societies need to prepare for the changes to come. Archaeologists use paleoenvironmental data to help understand the living conditions for the people who lived at an archaeological site. Climatologists benefit from the archaeological studies because they show how humans in the past learned how to adapt or failed to adapt to environmental change, and how they caused environmental changes or made them worse or better by their actions. The data that are collected and interpreted by paleoclimatologists are known as proxies, stand-ins for what can’t be directly measured. We can’t travel back in time to measure the temperature or humidity of a given day or year or century, and there are no written records of climatic changes that would give us those details older than a couple of hundred years. Instead, paleoclimate researchers rely on biological, chemical, and geological traces of past events that were influenced by the climate. The primary proxies used by climate researchers are plant and animal remains because the type of flora and fauna in a region indicates the climate: think of polar bears and palm trees as indicators of local climates. Identifiable traces of plants and animals range in size from whole trees to microscopic diatoms and chemical signatures. The most useful remains are those that are large enough to be identifiable to species; modern science has been able to identify objects as tiny as pollen grains and spores to plant species. Proxy evidence can be biotic, geomorphic, geochemical, or geophysical; they can record environmental data that range in time from yearly, every ten years, every century, every millennium or even multi-millennia. Events such as tree growth and regional vegetation changes leave traces in soils and peat deposits, glacial ice and moraines, cave formations, and in the bottoms of lakes and oceans.

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