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while only a few articles have discussed thermal expansion. 

 Yet no glaciologist has estimated the potential contributions of 

 ice and snow to sea level in the next century. In this section, 

 we discuss the several methods developed to perform this task. 

 Because the contributions of ice and snow to sea level rise could 

 be more important than thermal expansion, these methods should 

 be improved as soon as possible. 



Size and Potential Source of the Land-Based Contributions 



The amount of water contained in the ice and snow of 



Antarctica, Greenland, Northern Europe, Asia, and North America 



or in alpine glaciers is equivalent to about 70 meters of sea 



level rise (see Table 3-1). The Arctic Ocean consists of sea 



ice; therefore, its melting or breakup would not directly 



raise sea level. 



Global warming can influence the percentage of the earth's 



water resting on land by several means: 



o It can melt ice and snow. Melt water that runs off 

 into the sea will raise sea level. 



o It can increase the rate of flow of land-based ice 

 sheets toward the sea. This deglaciation would add 

 ice to the oceans, thereby raising sea level. 



o It can cause the atmosphere to carry more moisture to 

 cold areas in the form of snow, thereby increasing 

 snowfall accumulation and decreasing sea level. 



Estimates of ice and snow contributions to sea level rise 



can be made for each of these sources separately, or through 



an aggregate estimating method. Both approaches are used 



here. 



