Greenland's Ice

One of the concerns with global warming is the rise in sea levels due to the melting of the Greenland ice sheet. In an article at the Wall Street Journal (paywall), New York University theoretical physicist Steven Koonin argues that the situation is not nearly as dire as many make it out to be.

Here's his lede:

One of the most sacred tenets of climate alarmism is that Greenland’s vast ice sheet is shrinking ever more rapidly because of human-induced climate change. The media and politicians warn constantly of rising sea levels that would swamp coastlines from Florida to Bangladesh. A typical headline: “Greenland ice sheet on course to lose ice at fastest rate in 12,000 years.”

With an area of 660,000 square miles and a thickness up to 1.9 miles, Greenland’s ice sheet certainly deserves attention. Its shrinking has been a major cause of recent sea-level rise, but as is often the case in climate science, the data tell quite a different story from the media coverage and the political laments.

Referring to the following chart, Koonin declares that the amount of ice Greenland has lost since 1900 averages about 110 billion tons per year, which sounds like a lot but which has resulted in a rise in sea level of about one fifth the thickness of a dime.

On the other hand, the IPCC projects a more dramatic rise over the next 80 years:

In contrast, the United Nations’ Intergovernmental Panel on Climate Change projects that for the most likely course of greenhouse-gas emissions in the 21st century, the average annual ice loss would be somewhat larger than the peak values shown in the graph.

That would cause sea level to rise by 3 inches by the end of this century, and if losses were to continue at that rate, it would take about 10,000 years for all the ice to disappear, causing sea level to rise more than 20 feet.

However, according to Koonin, the ice melt is not increasing steadily each year. The graph shows that it's fluctuating, and in fact the ice loss today is not significantly larger than it was in the 1930s when human influences made much less of an impact.

"Moreover," he notes, "the annual loss of ice has been decreasing in the past decade even as the globe continues to warm."

His takeaway is this:

While a warming globe might eventually be the dominant cause of Greenland’s shrinking ice, natural cycles in temperatures and currents in the North Atlantic that extend for decades have been a much more important influence since 1900.

Those cycles, together with the recent slowdown, make it plausible that the next few decades will see a further, perhaps dramatic slowing of ice loss.

That would be inconsistent with the IPCC’s projection and wouldn’t at all support the media’s exaggerations.

For my part, I wonder why a gradual loss of ice in Greenland would be catastrophic. To be sure some coastal areas and islands may be rendered uninhabitable by a rise in sea levels of three inches, but if the rise was gradual enough many areas would be able to adjust.

Just as importantly, vast tracts of land in Greenland (and Siberia) would become available for human and wildlife habitation and resource mining. The loss of ice cover could well be a boon to humanity, so why do we assume that it would necessarily be a disaster?