lightblueline

The BBC (February 24, 2008) reports on a scientific expedition to the West Antarctic Ice Shelf: Antarctic glaciers surge to ocean

Excerpt below:
"Throughout the 1990s, according to satellite measurements, the glacier was accelerating by around 1% a year. Julian Scott's sensational finding this season is that it now seems to have accelerated by 7% in a single season, sending more and more ice into the ocean.

Twenty five polar ice experts met at the University of Texas, Austin, in March of 2007 to examine the state of scientific knowledge about the potential contributions of the West Antarctic ice sheet to future sea-level rise.

The report of the West Antarctic links to Sea Level Estimation (WALSE) Workshop states that more attention needs to be paid to this element of the climate system.

Climate Change Corp., August 16, 2007: John Shephard
[Professor John Shepherd FRS conducts research at the National Oceanography Centre, University of Southampton, UK, and is deputy director of the Tyndall Centre for climate change research]

Is the IPCC report too optimistic? Prof. Shephard reports on the work of James Hansen. You can read the whole report here:
Sea special report: NASA's James Hansen on the IPCC forecas

The article is also available below:

May 15, 2007
A team of NASA and university scientists has found clear evidence that extensive areas of snow melted in west Antarctica in January 2005 in response to warm temperatures. This was the first widespread Antarctic melting ever detected with NASA's QuikScat satellite and the most significant melt observed using satellites during the past three decades. Combined, the affected regions encompassed an area as big as California.

The British Antarctic Survey website offers a concise description of the science questions surrounding the West Antarctic ice sheet:

"The West Antarctic ice sheet is unique in that it rests of on rock that is, in places, thousands of metres below sea level, and over large areas, the present ice sheet would not need to thin by much in order of the ice to begin to float. This means that the West Antarctic ice sheet may be uniquely capable of rapid deglaciation, and is the focus of considerable concern. A decade of satellite measurements of the ice sheet surface in West Antarctica have shown that the portion of the ice sheet that drains into the Amundsen Sea is thinning at rates of several centimetres to several metres per year. Several neighbouring glacier basins appear to be behaving in a similar fashion, and thinning is most concentrated on the fast-moving parts of those glaciers, suggesting that this is the result of a dynamic change in the ice sheet itself rather than a change in snowfall. All the glaciers effected drain into the same part of the Amundsen Sea, and so it is likely that the change in the ice sheet across this region has its root cause in those waters. At present, the timescales of the changes in the sea condition, that might be driving the ice sheet, are not clear, and there are too few measurements to establish whether any change is on-going. Since ocean temperature and circulation is linked to atmospheric climate, the oceans provide plausible connection between anthropogenic greenhouse emissions and the changes we are seeing in this part of the Antarctic ice sheet. However there are other, competing theories as to why this change may be taking place; for example, it is possible that this is part of a longer-term retreat of the ice sheet has been going on for millennia.

Low probability, but high impact scenarios: Introducing the backgrounds of a “Dangerous Climate Change”

The balance of scientific evidence now suggests that anthropogenic greenhouse gas emissions are having a significant effect on the earth’s system and especially on the earth’s climate. Since the 1970s, there has been a significant increase of extreme weather events. Tropical and extra-tropical storm frequency and magnitude have considerably increased and so have the flood risks and heatwave occurrences along with very severe socio-economic and ecological impacts all over the globe. Even though the natural science of extreme weather events has progressed over the last decades, modelling climate scenarios still remains pretty speculative. However, it is now scientific consensus that if we continue to follow our “Business as usual”-path and if the greenhouse gas emissions weren’t cut drastically within the next decades, the impacts of a changing climate will intensify throughout the 21st century, with dangerous high impact scenarios becoming more likely to happen. A “dangerous climate change” with raising temperatures especially above 2°C (above pre-industrial levels) could tip certain ecological thresholds and trigger non-linear processes and feedback loops within the earth’s system, forcing the system rapidly into a totally new equilibrium. Dramatic changes within the carbon cycle, the eco- and hydrosphere and most obviously within the kryosphere would exceed our society’s ability to adapt to these changes. Unmanageable and most likely irreversible consequences could put our mankind on the edge of extinction. (1)