(UNEDITED)I am mildly skeptical of claims of human caused global warming. The author of the March 13th letter, "Melted Sea Ice Won't Increase Sea Level", appears to be even more so. But the bad science used by the author does not abet the cause of skepticism. It detracts from it.
The author is correct in his assertion that ice floating in water, when it melts, will not raise the water level - but only if the water is pure. Ocean water is much heavier than pure water because of its salt content. Seawater is about 17 percent heavier than fresh water. So melting ice, which has no salt, will add 17 percent to the volume of the water it displaces. The melted ice water has more volume than the equivalent mass of seawater.
The real kicker, however, is that 90 percent of the earth's ice is located in Greenland and Antarctica, and a large portion of that sits atop land masses. This portion is not submerged in seawater, and if it melted it would add all of its fresh water volume to the oceans, not just 17 percent. If you go online, you can find estimates varying from 20 feet to 200 feet for a rise in sea level if all of the polar ice on earth were to melt. I tend to go with the 20-foot estimate. My own calculations indicate an upper limit of 30 feet, if all the polar ice were high and dry, which it's not. Global warming is certainly real. The data indicate that the rise in earth's mean temperature is closely correlated to the rise in solar activity. The extent to which human activity is influencing global warming is, in my mind, still problematic.
Chuck Lear
Ogden
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