-Submitted by David Drumm (Nal), Guest Blogger
A recent article in the Daily Mail, and picked up by other media, claims an increase in Arctic ice foretells a cooling trend. The article boasts of a 60% increase in sea ice over the minimum that occurred in 2012. While the actual numbers from IARC-JAXA Information System (IJIS) show, as of yesterday, only a 50% increase, this is still a significant expansion.
Professor Judith Curry, climatologist and chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, referred to the title as melodramatic and said of the content of the article: “the ‘cooling’ aspect has been overplayed.” Last year, University of Reading climate scientist Ed Hawkins predicted that “there would be MORE Arctic sea-ice in 2013, compared to 2012.”
An important tool used in analyzing random data is the statistical phenomenon known as reversion to the mean, or regression to the mean. The extent of sea ice at the end of the annual melt, mid to late September, set a extreme minimum in 2012. Using reversion to the mean, it is more likely that the the extent in 2013 will be larger. Exactly what happened. The following graph indicates the variability of sea ice extent and the clear downward trend.
Cherry picking short-term results while ignoring long-term trends is a hallmark of misleading climate reporting. Long-term data needs to be analyzed to average out cyclical dependencies. There is a strong natural variability in sea ice extent and separating the natural from the greenhouse gases requires decades long timescales.
Climate science is an undertaking fraught with complex interactions and unknown cycles with unknown effects. It will take time and money to improve our understanding. However, improvement is mandatory if we are to be responsible conservators of our world.
Climate scientists estimate the amount of sea ice loss due to greenhouse gasses is between 50-70%.