- Arctic Sea ice reached a record low in 2012, but it's up 60 percent this year, when levels in August 2012 and August 2013 are compared.
- Some have cited this as a sign of global warming being "paused" or of "global cooling." Others say not so fast, noting 2013 was already predicted to have less melt than the previous record-setting year.
- Ahead of the U.N. Intergovernmental Panel on Climate Change's expected release of its Fifth Assessment Report in October, the debate between "mainstream scientists" and "climate skeptics" continues.
Last year, Arctic Sea ice shrank to a record low, but according recent data it has rebounded, covering 60 percent more in August 2013 than August 2012.
Still, the National Snow and Ice Data Center, points out it still falls below the 1981 through 2010 average for the month:
Sea ice extent for August 2013 averaged 6.09 million square kilometers (2.35 million square miles). This was 1.03 million square kilometers (398,000 square miles) below the 1981 to 2010 average for August, but well above the level recorded last year, which was the lowest September extent in the satellite record. Ice extent this August was similar to the years 2008 to 2010. These contrasts in ice extent from one year to the next highlight the year-to-year variability attending the overall, long-term decline in sea ice extent.
Arctic sea ice extent for August 2013 was 6.09 million square kilometers (2.35 million square miles). The magenta line shows the 1981 to 2010 median extent for that month. The black cross indicates the geographic North Pole. (Image and caption: NSIDC)
This graph shows Arctic Sea ice levels as of Sept. 8. You can see they are well above last year, but still below the average of previous years. (Image and caption: NSIDC)
The U.K.'s Daily Mail took a moment with this latest data to recall a prediction made several years ago by a scientist speaking to the BBC, saying that the Arctic would be ice-free in the summer by 2013. The Daily Mail wrote of this statement:
The BBC’s 2007 report quoted scientist Professor Wieslaw Maslowski, who based his views on super-computer models and the fact that "we use a high-resolution regional model for the Arctic Ocean and sea ice".
He was confident his results were "much more realistic" than other projections, which "underestimate the amount of heat delivered to the sea ice". Also quoted was Cambridge University expert
Professor Peter Wadhams. He backed Professor Maslowski, saying his model was "more efficient" than others because it "takes account of processes that happen internally in the ice".
He added: "This is not a cycle; not just a fluctuation. In the end, it will all just melt away quite suddenly."
But a follow-up column in The Guardian's Climate Consensus -- The 97% by Dana Nuccitelli states that although the 60 percent growth of Arctic ice this year compared to last is true, they say it is "largely irrelevant."
Why? 1) Because Arctic ice generally reaches its minimum in September, and 2) scientists had already predicted less melt for this year compared to last.
"The reason so many climate scientists predicted more ice this year than last is quite simple. There's 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. In other words, we should not often expect to observe records in consecutive years. 2012 shattered the previous record low sea ice extent; hence 'regression towards the mean' told us that 2013 would likely have a higher minimum extent," the Guardian's columnist explained.
As for the Daily Mail's reference to the 2007 remarks, the Guardian pointed out that the scientist said the ice-free summers could come by 2013 plus or minus a few years, but also that other scientists had labeled this prediction as too extreme.
The Daily Mail in its report also took the opportunity to draw attention back to its article last year that cited evidence that global warming had "paused" and could even be trending toward "global cooling":
In its draft report, the IPCC says it is "95 per cent confident" that global warming has been caused by humans – up from 90 per cent in 2007.
This claim is already hotly disputed. US climate expert Professor Judith Curry said last night: "In fact, the uncertainty is getting bigger. It’s now clear the models are way too sensitive to carbon dioxide. I cannot see any basis for the IPCC increasing its confidence level."
She pointed to long-term cycles in ocean temperature, which have a huge influence on climate and suggest the world may be approaching a period similar to that from 1965 to 1975, when there was a clear cooling trend. This led some scientists at the time to forecast an imminent ice age.
Professor Anastasios Tsonis, of the University of Wisconsin, was one of the first to investigate the ocean cycles. He said: "We are already in a cooling trend, which I think will continue for the next 15 years at least. There is no doubt the warming of the 1980s and 1990s has stopped."
Guardian columnist Nuccitelli called it "foolhardy" to think of global warming as pausing or shifting toward cooling.
"In reality, global surface temperatures have warmed over the past 15 years, albeit more slowly than during the previous 15 years," Nuccitelli noted. But he cited the overall planet (including the oceans) as getting warming in the last 15 years compared to the prior 15 years.
Featured image via Shutterstock.com.