Ice Sheet Collapse: “We used to think it (would take) centuries”
There are two striking reports out in the last week which, when juxtaposed, are sobering.
The first is reported by The Guardian, and talks about ice sheet collapse. A few years ago when I talked about ice sheet collapse and dramatically rising sea levels, the best science had such things happening in the next few hundred years. I disagreed and called for as much as a meter of sea level increase by 2050. I did this on the basis of the accelerating decline in all natural systems, all of which potentiate each other in their decline, accelerating an already exponential decay and decline. Since that time, science has steadily caught up to my time-frame. Now they might have surpassed me. The report in The Guardian talks about sea level increase and ice sheet collapse (in the Antarctic and in Greenland) and concludes that these sheets are far more unstable than previously believed, and their decay and collapse is exponential and tipping points may lead to sudden increases in sea level in as little as a decade. The article projects as much as a 20 foot increase in sea levels (destabilizing most mega-cities in the world) as a result of current warming of the world, regardless of any effort to limit CO2 emissions. The rise is, in essence, “baked in” to our future. But the article also point out that catastrophic collapse of ice sheets could happen in a much, much shorter time frame – as little as a decade. Andrea Dutton, the chief scientist of the study that the article focuses on, spoke about how quickly perceptions were changing and how quickly ice sheets could collapse. She said, “There are some recent modeling efforts that now show you could get a section of the Antarctic ice sheet, several meters worth of sea level rise, to go in a decade. We used to think it was centuries.”
The second study is altogether less certain – only an indication, really, as it is new data without context. What was measured is strong geothermal heating below the Antarctic ice sheets. We already know that slightly warming sea water (and strong upwelling currents) are rapidly eating away at Antarctic ice sheets. We don’t know what role geothermal heating plays in this process, but the fact that strong heating was found likely means that the ice sheets are not as stable at their base as thought, which means that the tipping point referenced above by professor Dutton could be even nearer.
Taken together, the studies paint a picture of an Antarctic in accelerating decline. No surprise there, really. But when contemplating the human suffering that would be engendered by a rapid 1o or 20 feet sea rise, the studies are still quite striking
The final events will be rapid ones.