Ice sheets, heat expansion factor in sea level rise

In the Feb. 15/16 weekend edition of Maui News was a letter that talked about how warming cannot raise sea levels because glaciers act like ice cubes. I wanted to comment on that.

Glaciers are ice sheets, on land, that flow between geologic features such as alpine valleys. Ice sheets are masses of ice, on land, that are mostly stationary, and icebergs are pieces of ice unattached to land that float in the ocean. The author of the letter was really talking about icebergs, not glaciers.

But in the context of sea level rise it is neither icebergs nor glaciers that are the concern. It is the massive ice sheets of Antarctica and Greenland, both of which are thousands of feet thick and well above ground, so they do not fit the simple example in the letter of ice in the ocean.

But another problem is that some of the sea level rise will be simply due to the thermal expansion of the sea. For instance, a one degree rise in temperature of the ocean will result in about seven feet of rise in the level. That will be on top of the rise due to the melting of the Antarctic and Greenland ice sheets, which will be about 200 feet added to the ocean.

The scientists working on this are pretty smart people. We should all trust their training and dedication to this problem.

Scott Werden



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