Climate Change

Climate Change: How Do We Know?

Scientific evidence for warming of the climate system is unequivocal.

 Global Temperature Rise
    

The planet's average surface temperature has risen about  (0.9 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere. Most of the warming occurred in the past 35 years



 Warming Oceans

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  The oceans have absorbed much of increased heat, with the top 700 meters  of ocean showing warming of more than 0.4 degrees Fahrenheit since 1969.
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• Shrinking Ice Sheets
• The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 286 billion tons of ice per year between 1993 and 2016, while Antarctica lost about 127 billion tons of ice per year during the same time period. The rate of Antarctica ice mass loss has tripled in the last decade.

• Sea Level Rise                                        

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  Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century and is accelerating slightly every year

Extreme Events

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  The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.

Ocean Acidification

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  Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent.This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year