Fox Business is claiming that because 2013 Arctic sea ice extent is unlikely to beat the 2012 record low, melting in the region is “slowing,” an idea one climate scientist called “absolutely ridiculous” in the context of a long-term decline.
On Wednesday, Fox Business' Charles Payne launched a segment on the National Oceanic and Atmospheric Administration's (NOAA) State of the Climate report by claiming that the agency “has forgotten to mention ... that 2012 was one of the coolest years of the decade,” thereby “slowing down the melting of Arctic ice this summer.”
This statement was based on a lack of understanding of "regression to the mean" -- or in the case of climate change, regression to the new mean. This and other mathematical concepts seem to give Fox a lot of trouble.
1. Regression To The Mean
Unfortunately for baby harp seals, Payne is wrong about Arctic sea ice melt “slowing” -- it seems he either didn't grasp the aforementioned idea or didn't read NOAA's report very carefully. The State of the Climate found record low Arctic sea ice extent in 2012 and included this chart illustrating monthly trends compared to the 1979-2000 average:
As Skeptical Science explained, it's unsurprising that 2013 will not likely beat that record low if you consider “regression toward the mean” :
[N]ote that neither [of two statistical predictions for 2013 Arctic sea ice extent] predicts that 2013 will break the 2012 record (3.6 million square kilometers). There is a principle in statistics known as "regression toward the mean," which is the phenomenon that if an extreme value of a variable is observed, the next measurement will generally be less extreme, i.e. we should not expect to observe record lows in consecutive years. This is because when extremes are reached and records are broken, a number of different variables generally have to align in the same direction to make this happen.
Sea ice disappeared more quickly last month than in the mean July from 1981-2010, and overall extent is still below the long-term average. Ted Scambos, lead scientist at the National Snow and Ice Data Center, told Media Matters in an email that the melting trend persists:
While it is fair to say that sea ice loss in the Arctic probably won't beat the record 2012 level, it is still among the 6 lowest extents in the 35 years of detailed monitoring. All of those very low years have happened since 2007. Moreover, there is lots of evidence for a very thin ice cover even in the ice-bound areas.
This is unfortunately all too common - using climate variability after a record heat wave or low ice year to claim that we have turned a corner. But if you look at a running average of a few years, the consistent trend towards more warming and less ice is clear.
You can't wish this away. We are faced with a global, man-made problem that is going to require action.
Rutgers University's Jennifer Francis, an expert on Arctic climate change effects, added that it's “absolutely ridiculous to say that the Arctic melt is slowing down” :
It's absolutely ridiculous to say that the Arctic melt is slowing down. The amount of ice in the Arctic this year is well below average, as it has been consistently every year since 2007. Last year it smashed the previous record set only 5 years earlier. Weather conditions in any given year cause some fluctuation about the trend line, but there is no doubt that the trend is on a steady downward slide. The only possible explanation for continued dramatic Arctic ice loss is increasing greenhouse gases that come primarily from burning fossil fuels.
2. Sampling Bias
Payne was also wrong when he claimed vindication for the idea that the planet is “cooling” by pointing out that “2012 was one of the coolest years of the decade.” Partial credit is due, since 2012 was the fourth coldest year in the last ten. However, since each of the last three decades has been hotter than the one before, this still makes 2012 the 9th hottest year on record, as measured by deviation from the long-term global average.
To draw an analogy, it is as if Fox found a single comparatively lightweight offensive lineman, ignored his rotundity in the context of the general populace, and reported “Offensive Linemen Now Getting Skinny.”
This point appeared to draw heavily on a CNSNews.com post that cited blogger Pierre Gosselin, who holds a bachelor's degree in mechanical engineering, claiming a global “cooling trend.” That article displayed a fundamental misunderstanding of climate science, erroneously treating stratospheric cooling as evidence against climate change. The fact that the stratosphere is cooling as the troposphere warms is actually evidence of manmade global warming: this phenomenon can't be explained in the absence of human-generated greenhouse gases.
Fox Business reporter Elizabeth MacDonald, who previously suggested "Mars wobbles" may be behind climate change on Earth, told Payne that scientists “need to come to a consensus” on whether human activity is causing it. But scientists, including 97 percent of climate scientists, already overwhelmingly accept the science behind manmade climate change.
UPDATE (8/15/2013): Skeptical Science has posted a graphic illustrating how ignoring regression to the mean makes it possible to claim that Arctic sea ice is “recovering” even as the long-term melting trend remains clear:
September Arctic sea ice extent data since 1980 from the National Snow and Ice Data Center (blue diamonds). “Recovery” years, meaning years when the sea ice extent is greater than the previous year, are highlighted in red to mock the repeated cynical claims of climate change “skeptics” that global warming has somehow stopped. Many factors affect the annual summer decrease in Arctic sea ice extent, and it is illogical at best to claim any “trend” by cherry-picking only brief periods of data. The obvious true long-term trend in Arctic sea ice extent (red second-order polynomial curve fit) is that it is declining at an accelerating rate.