More on Antarctic sea ice

I wrote a post recently on Antarctic sea ice where I only included sea ice extent at minimum month, mostly because it was a nice figure.

Anyway, I just noticed this nicer figure from a new paper in the International Journal of Climatology (Tareghian and Rasmussen, 2013):

Quantile regressions (20th, 50th, and 80th percentiles) and standard linear regression of monthly sea ice extent (1979–2010) for (a) the Northern Hemisphere and (b) the Southern Hemisphere from Tareghian and Rasmussen (2013)

This shows the difference in the annual trends as well as the seasonal ones.

Reference

Tareghian, R. and Rasmussen, P. (2013), Analysis of Arctic and Antarctic sea ice extent using quantile regression. Int. J. Climatol., 33: 1079–1086.

Climate quick fix! (But please sign this disclaimer first.)

Geoengineering sometimes looks like a good option: international agreements on greenhouse gas emission reductions don’t seem to be going anywhere so having a back-up plan to deal with global temperatures would be useful.

However, there are potentially big problems with tinkering with the climate system more than we already have.

Haywood et al. outline one of these problems in a new Nature Climate Change paper that was published this week.

They look at the response of the climate in models when you add aerosol particles to the stratosphere – this will reduce the amount of energy entering the climate system by reflecting some of it away.

The unintended consequences, however, are not good: global rainfall patterns change as a result of the intervention and could lead to droughts in some areas e.g. the Sahel. (These outcomes are sensitive to where the aerosol is added and, of course, are subject to all the usual model uncertainties.)

So it would seem that geoengineering might only be useful if there are international agreements on who takes responsibility for the outcomes. Best get those negotiations started ASAP then!

There’s some more comment in The Gaurdian.