Follow the trend

With the blizzard of climate-change data and research constantly swirling around, it’s easy to become disoriented. As my op-ed column in today’s Business Report points out, Keith Bryer became seriously muddled by a single data point in his July 29 opinion column. If anyone tells you that the planet is not warming because they read in Business Report that Arctic ice in increasing, show them the chart above.

As Bryer correctly pointed out, research from the European Cryosat satellite shows that the volume of ice in the Arctic increased from 2010, the year that the satellite was launched — which I have noted with a green circle on the chart — until 2013 — noted with a red circle. Bryer got lost in the blizzard when he leapt to the conclusion that this single data point from a three-year time span somehow debunks decades of science on global climate change.

As the chart shows, Arctic ice is highly variable from year to year, including a recent, three-year growth spurt, evident from the steep upward line between the two circles. But the long-term trend is clear. Anyone looking at this chart as a whole, instead of just the years 2010 to 2013, can see very clearly that the Arctic ice sheet is indeed melting. (The chart uses data from the National Snow and Ice Data Center that show the extent of Arctic sea ice, not its volume; no data on volume existed before Cryosat. But volume and area are related, and the 2010-2013 uptick is also evident in this measurement.)

In a coincidence, Cryosat was launched just after the end of an El Niño cycle that exacerbated ice loss. Then the first two years of Cryosat data collection coinciding with La Niña, which is associated with ice accumulation. So nothing about the short-term increase overturns the existing consensus.

Bryer reveals his ignorance of basic climate science by writing: “Instead of shrinking, raising sea levels, flooding coastal cities, and reversing the Gulf Stream, the Arctic ice cap has grown.” But climate scientists don’t claim that sea levels rise when sea ice melts. Bryer does not seem to understand that basic science rules out a connection between sea ice melting and sea levels.

Anyone who has watched the ice melt in their drink on a hot day knows that the level of the drink does not rise as the ice melts. Since water expands when it freezes and contracts when it melts, and since most of the ice is below the surface level, melting ice does not affect the level of your drink or the sea. Sea levels are rising by about 3 mm a year because ice on land is melting and flowing into the sea — especially mountain glaciers and the ice cap on Greenland — and because warming water expands. Those are the real threats to coastal cities.

Yes, the volume of Arctic ice grew from 2010 to 2013. Rational minds will take that as an interesting data point, not an excuse for a meltdown in logic.