I have been traveling around Europe since late October. Alaska greeted me with bone chilling cold as I exited the airport terminal on Sunday. As I write this blog, the temperature at my house sits at a balmy -7 F (-21 C for everybody but the USA). It has been cold most of the time I was gone.
This got me wondering about the Arctic Ice Sheet. So I wondered over to the National Snow and Ice Data Center and took a look. The Ice sheet is growing at a surprisingly rapid rate. The site has lots of information about the Polar Ice Cap.
When looking at this data it is helpful if you ignore the 1979-2000 average data presented in grey. Virtually all summer data in recent years is outside the grey area which is supposed to cover 95% of all data. The grey data set is an object lessen of poor statistical analysis. The aforementioned website has an interactive chart with better data that displays averages and standard deviations for the entire data set, but it doesn’t transfer well, so I used this one.
2012 was a big year for summer melt….and so far it has been a big winter for ice building. Summer data appears to vary wildly, while the winter data is much more stable. This is likely to continue due the the nature of sea ice. First year sea ice has a higher salt content than ice that has been in the Arctic for a while. This higher salt content makes it melt more rapidly than ice that is older. And there’s been lots of first year ice in the data set since 2007.
People searching for benefits of global warming talk about the shorter shipping routes the Arctic represents. Environmentalist worry about Polar Bear habitat and excess rain and snow in Europe. Yep, they are going to happen….but you better be quick. Summer is an extremely short season and winter seems to last forever.
So far at least, the changes seen for most of the year have been relatively small when compared to the wild variation seen in summer. If and when the Arctic gets a cold summer following a cold winter, then we will have more second year ice…and the ice will become more stable. But until then the ice will continue to show wild swings in summer. It really is more a measurement of past warming, and less so a warning flag of future warming.
But is it? Recent studies argue that yes the ice melts faster when it is warm, but it also is impacted by pollution. Air pollution discolors the ice, making is slightly less white, which helps it absorb sunlight in summer. So maybe it’s a marker for air pollution. Either way first year sea ice is more a marker of past woes and less a predictor of future woes.
If the trend of a warmer more polluted world continues then the summer ice free area will probably expand. This is not a new experience for the Arctic. 130,000 years ago the Arctic was much warmer than it is today and it is widely believed that there was less ice then than we have now. And 20,000 years later it was much colder.
But this analysis is probably too simplistic too. If the ice free period expands, then snowfall in the Arctic will likely increase too, which could bring on a new ice age cold period. Or maybe not.
The current climate cycle for the earth is 2.5 million years old. Any effort to predict long term trends using a 35 year data base is more than a bit speculative. Talk about wild extrapolation. It is virtually impossible to identify a trend in a 2.5 million year system using a 35 year data base that is more reactive than predictive.
Well. What happens next? I don’t know. Time will tell.