West Antarctic Ice Sheet collapse? Not yet
The West Antarctic Ice Sheet (WAIS) is a huge concern for glaciologists and climate scientists. With almost 4m of sea level rise locked up in the ice and warming climate, melting could cause big problems. Several authors (e.g. James Hansen or the 2006 British Antactic Survey) theorise that WAIS like Greenland is very close to a tipping point, whereby feedbacks such melt water fracturing can cause rapid and unstoppable melt.
A new study released this week in Geology though could offer hope. Rose et al (2014) used a combination of radio-echo sounding and satellite images to analyse potential sub-glacial channels. The location of these channels well below current sea level, and their current frozen state indicates previous melting on a scale large enough to erode the bedrock. The authors suggest the most recent time when this could’ve occurred was in the Mid-Pliocene, an era 2°C warmer than today. The important point here is that despite melting the WAIS was still there and relatively stable, acting similar to a temperature ice sheet like Greenland. Global warming will continue to reduce the size, and change the behaviour of WAIS but it looks as though catastrophic collapse may still be some way off.