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the oceans. This heat will slowly pass downward to the lower 

 and cooler layers. In this way, the oceans will act as heat 

 "sinks", somewhat delaying the full atmospheric warming. 



EXPECTED TEMPERATURE INCREASES WILL BE SIGNIFICANT 



The expected global warming will be large compared to 

 historical temperature changes, and even more significant 

 compared to historical rates of temperature change. In the last 

 two million years, the earth nas never been more than 2 to 3°C 

 warmer than it is today . 14/ In the last hundred thousand years, 

 it has been at most 1°C warmer, and in the last thousand years, 

 at most 0.5°C warmer. Since the Wisconsin Ice Age (18,000 years 

 ago), the eartn has warmed about 4°C , 15/ anc i i n the last century, 

 about . 4°C. 16/ The projected warming for the next century would 

 be ten times as rapid as the nistorical warming trend. 



The expected warming will also be large compared to geo- 

 graphical temperature differences. A 3°C warming would leave 

 San Francisco as warm as San Diego is today. A 9°C warming 

 would raise New York City's average temperature to the current 

 temperature of Daytona Beach, Florida. 



THERMAL EXPANSION AND GLACIAL DISCHARGES COULD RAISE SEA LEVEL 

 As global temperature rises, the sea level can be raised 



in two ways: 



o Thermal expansion 



Warming will decrease the density of ocean water, and 

 thus increase its volume. Because the same water will 

 take up more space, the levels of the oceans will 

 rise. The rate of this rise directly depends on the 

 amount of heat the oceans absorb. 



