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Past and Present Climate

Last Updated: June 29, 2011

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Excerpt from the Southwest Climate Change Network, written by Zack Guido, University of Arizona

At night, illuminated satellites can be faintly seen moving across the sky. Some of them are imaging the Earth, recording data that is used to track weather and climate. On boats, thermometers thrown overboard measure temperatures of the ocean depths. From the tops of buildings, balloons float aloft to measure atmospheric conditions.

For the past 100 years, there has been a widespread scientific effort to monitor and understand the Earth’s climate system. These data have helped document recent climate change and have also enabled scientists to dive deeper into the geologic record to uncover past climatic conditions. Detailed climate records now exist for the last two million years. They combine with modern observations to reveal numerous long periods of glaciations, shorter-lived warmer times, regional temperature swings of 15°F within a decade, and current warming that has made most regions warmer now than at any other time in the past 1,000 years.

A common catchphrase in geology is “knowledge of the present is the key to the past.” However, it is equally important to understand the past to clarify the future. Therefore, a comprehensive understanding of the climate system includes knowledge of:

Adapted for eXtension.org by Michael Crimmins, University of Arizona

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Southwest Climate Change Network


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