I wrote this post for Skeptical Science as part of an ongoing series looking at the arguments made by Christopher Monckton against climate science.
This post examines Monckton’s arguments about global sea ice. Monckton claims:
[T]he global sea ice record shows virtually no change throughout the past 30 years, because the quite rapid loss of Arctic sea ice since the satellites were watching has been matched by a near-equally rapid gain of Antarctic sea ice.
Global Sea Ice Is Decreasing
Have Arctic ice losses truly been balanced by Antarctic gains? The first point to clarify is that we are talking about floating sea ice, not to be confused with land ice. Land ice at both poles and in glaciers around the world is sliding into the ocean at an accelerating rate. This net loss of land ice is contributing to sea level rise.
However, Monckton is clearly referring to sea ice. The rapid decline of Arctic sea ice has indeed coincided with an increase in Antarctic sea ice. But do these two opposite trends cancel out as Monckton suggests? In reality, the upward Antarctic trend is only slight compared to the plummeting Arctic trend. Tamino has crunched the numbers and found the Arctic trend is in fact more than three times faster than the Antarctic one. The net result is a statistically significant global decrease of more than a million km2 – would you agree with Monckton that this is “virtually no change”?