A direct link between human activity and the break-up of the Larsen Ice Shelf in Antarctica has been demonstrated according to Dr Gareth Marshall, the lead author of a recent paper entitled ‘The Impact of a changing Southern Hemisphere Annular Mode on Antarctic Summer Temperatures’ in the Journal of Climate (Vol 19: pg. 5388-5404).
Dr Marshall also said, “Climate change does not impact our planet evenly – it changes weather patterns in a complex way that takes detailed research and computer modelling techniques to unravel. What we’ve observed at one of the planet’s more remote regions is a regional amplifying mechanism that led to the dramatic climate change we see over the Antarctic Peninsula.”
The human impact is thought to be from both global warming and the ozone hole. The paper concludes: Given the modelling studies indicate that the observed change in the summer Southern Hemisphere Annular Mode is predominantly a response to anthropogenic forcing*, then the physical mechanisms outlined in this paper enable this climatic change to be linked directly to the Larsen Ice Shelf disintegration and any consequent sea level rise.
Here’s a link to the media release, from the British Antarctic Survey.
* Strengthened westerly winds force warm air eastward over the natural barrier created by the Antarctic Peninsula’s high mountain chain warming the north-east Peninsula by around 5 degrees C, creating the conditions that allowed the drainage of melt-water into crevasses on the Larsen Ice Shelf, a key process that led to its break-up in 2002.
This blog post is based on an email from Luke.