How fast are Greenland and Antarctica losing ice?
If you trust the National Climate Assessment (NCA), you’ll think, “Very fast!” And that’s intentional. The aim is to provoke fear so the American public will support the Obama administration’s aim to spend $Trillions fighting global warming.
Here’s how the NCA (in Appendix 4, FAQ-L) depicts the rate of loss from the ice sheets covering Greenland and Antarctica:
Pretty steep declines, right? Downright scary.
But if there’s any way to depict trends guaranteed to be misleading, it’s depicting them in raw numbers without the context of proportion. The NCA should either have depicted the ice loss as percent—with graphs showing the whole span from 0 to 100—or as gigatons but spanning from 0 to the highest totals for the two locations.
What would the resulting graphs look like? To know that, you have to know the total mass of ice in both Greenland and Antarctica and the annual rate of loss. Neither is known very precisely, but working from widely accepted figures we ran the calculations. The results?
Greenland is losing about 0.1% of its ice per decade—that is, about 0.01% per year. At that rate, it will take a century for it to lose 1%.
Antarctica is losing about 0.0045% of its ice per decade—about 4.5/10,000ths of a percent per year. At that rate, it will take about 2,200 years for it to lose 1%.
Oh—and what would the graphs look like if drawn proportionally? Here you go:
No, the trend lines aren’t missing. They’re the red lines up at the 100% level of the graphs. Their slopes are so shallow that Greenland’s is barely perceptible—and Antarctica’s, not at all.
And the effect on sea level? Combined, about 1 millimeter per year—or about 3.3 inches by the end of this century.
Not quite so scared now?
But that’s not what the Obama administration intended. Now you know why it used the deceptive graphs.
