Post by Vectorman on Sept 12, 2012 20:40:55 GMT 9.5
This terrifying data shows our desperate situation when looking at the potential for positive feedback from the deposits of methane hydrates in the Arctic region that have shown signs of destabilizing since 2010. Plumes of methane entering the atmosphere up to 1 km across have been seen on the East Siberian Shelf.
There have been new record concentrations just this month and anomalous temperature readings of 10-20 degrees above the mean. Bearing in mind a 22 degree sustained increase in mean temperature would lead to a Permian extinction .
Of high import is the geographical distance between these methane events [1-2], Svalbard is over 1000 miles away from Barrow, Alaska where methane releases have been observed. The releases coincide with periods when the sea ice is at it's lowest and sadly the ice volume is decreasing exponentially .
Post by moguitar7 on Sept 17, 2012 0:44:59 GMT 9.5
There were 3 reports of being at the tipping point of a tundra methane self release positive feedback loop. That was from two Russian teams and one Alaskan, in 2009. The same year Norwegians reported the upper 1200 feet of ocean off their continental shelf was warmed 1*F. Methane hydrate sensitivity is +2*F, but was releasing slowly to dissolve. Of course, this year is worse for Arctic air temperature increase from AGW and ocean warming from the resulting ice cap loss. There was an article in 2010 on the possibility of a runaway tundra methane release spreading more slowly to the oceanic methane hydrate deposits at deeper and deeper depths, leading to complete methane turnover within 300 to 1500 years. Too short a time for life to adapt, and an ELE completion of the extant "6th Great Extinction". It is likened to a faster PETM and called by some Anthropocene Epoch Thermal Maximum, AETM. In 2006 Hansen warned that humanity had a decade to reduce HGHGs 90% to avoid CAGW. Other groups gave an 80% decrease by 2020 to have a 50% chance of stopping CAGW, meaning irretrievably crossing the tipping points of open ocean warming and methane self release from the tundras then oceans. Others think that the Arctic warming has already reached this point and there is enough carbon to be released from the tundra to equal over 150% what humans have put in the atmosphere. There is a similar amount or more in the oceans, which are warming non-linearly. People do not want to stop "business as usual" until forced by the crashing population at mid century. By then, the tipping points will be well crossed, and the survivors and their grandchildren will face rapidly warming and changing climate, as ecosystems begin to collapse. The rate of extinction could be at least 85% and as high as 90%, which is more than the KT extinction of 75% of species. The recovery will be longer than PETM's 180K years for carbon resequestation and 2 million years to get diversity of species back. It is unlikely any humans will make it through such a long bottleneck, even in breeder reactor powered subterranean fortresses over the few good aquifers left. People made it through the several thousand year Toba bottleneck 73.6 thousand years ago, but this is much worse.
Last Edit: Sept 17, 2012 0:47:09 GMT 9.5 by moguitar7
With every decision and action, think first of the consequences 7 generations from now.....Ute Rule of Life
Post by David B. Benson on Sept 17, 2012 13:58:08 GMT 9.5
Professor David Archer of the University of Chicago finds this methane release to be much ado about very little. He is an expert on the carbon cycle. I am an amateur student of geology (53 years now) and much more recently climatology. So looking back at the paleoclimate data one notices that much these same methane releases must have occurred during the Eemian interglacial (interglacial 2) about 115,000 years ago.
Note that then there was no monster temperature spike (to be found in the ice core proxies). There were no unusual (mass) extinctions; this from paleontological studies.
This same boring pattern is also true of the earlier interglacials.