Gizmo wrote:
The British Antartic survey team didn’t overlook the losses they probably looked at all the facts rather than the ones that suited, they are expected to submit a report shortly (if it is not already out) that shows that Antarctic ice has been stable if not growing for the last 30 years.
The British Antarctic Survey wrote (1 December 09):1. Hole in ozone layer has shielded most of Antarctica from global warmingThe ozone hole has delayed the impact of greenhouse gas increases on the climate of the continent. Consequently south polar winds (the polar vortex), have intensified and affected Antarctic weather patterns. Westerly winds over the Southern Ocean that surrounds Antarctica have increased by around 15%. The stronger winds have effectively isolated Antarctica from the warming elsewhere on the planet. As a result during the past 30 years there has been little change in surface temperature over much of the vast Antarctic continent, although West Antarctica has warmed slightly. An important exception is the eastern coast of the Antarctic Peninsula, which has seen rapid summer warming. This warming is caused by stronger westerly winds bringing warm, wet air into the region from the ocean.
2. Warming of the Southern Ocean will cause changes in Antarctic ecosystemThe largest ocean current on Earth (the Antarctic Circumpolar Current) has warmed faster than the global ocean as a whole. The Southern Ocean is one of the major sinks of atmospheric CO2, but increasing westerly winds have affected the ocean’s ability to absorb CO2 by causing the upwelling of CO2 rich water. If temperatures continue to rise ‘alien’ species may migrate into the region, competing with and replacing original Antarctic inhabitants. Key species in the food chain like planktonic snails could suffer from ocean acidification. Changes in the food regime are likely to decrease the rich Antarctic seabed biodiversity.
3. Rapid increase in plant communities across Antarctic PeninsulaRapid warming has been seen along the western Antarctic Peninsula, along with a switch from snowfall to rain during summer, resulting in expansion of plant, animal and microbial communities in newly available land. Humans have also inadvertently introduced ‘alien’ organisms such as grasses, flies and bacteria.
4. Rapid ice loss in parts of the AntarcticThe West Antarctic Ice Sheet has significantly thinned particularly around the Amundsen Sea Embayment as a result of warmer ocean temperatures. Regional warming caused by intensification of the westerly winds (due to the ozone hole) is melting ice shelves along the eastern Antarctic Peninsula (e.g. Larsen B Ice Shelf). Overall, 90% of the Peninsula’s glaciers have retreated in recent decades. However, the bulk of the Antarctic ice sheet has shown little change.
5. 10% increase in sea ice around the AntarcticSince 1980 there has been a 10% increase in Antarctic sea ice extent, particularly in the Ross Sea region, as a result of the stronger winds around the continent (due to the ozone hole). In contrast, regional sea ice has decreased west of the Antarctic Peninsula due to changes in local atmospheric circulation and this has also been linked with the very rapid warming seen over land on the west coast of the Peninsula.
6. Carbon dioxide levels increasing at fastest pace in 800,000 yearsAtmospheric concentrations of CO2 and CH4 are at higher levels than experienced in the last 800,000 years and are increasing at rates unlikely to have been seen in the (geologically) recent past. Antarctica was warmer in the last interglacial (130,000 years ago) and sea levels were higher, but the contribution of West Antarctica to that rise is currently unknown. Small-scale climate variability over the last 11,000 years has caused rapid ice loss, shifts in ocean and atmospheric circulation and enhanced biological production, showing that Antarctica is highly sensitive to even minor climate changes. Studies of sediments under recently lost ice shelves suggest ice shelf loss in some regions is unprecedented during this time scale.
7. Sea ice loss directly affecting krill levels and penguin colonisationLoss of sea ice west of the Antarctic Peninsula has caused changes in algal growth. This loss of sea ice has also caused a shift from large to smaller species. Stocks of krill have declined significantly. In some areas Adélie penguin populations have declined due to reduced sea ice and prey species (on the northern Antarctic Peninsula), but they have remained stable or increased elsewhere (Ross Sea and East Antarctica). Historical exploitation of seals and whales has changed the ecosystem, reducing scientists’ ability to fully understand the impacts of climate change on krill and other species.
8. Antarctica predicted to warm by around 3°C over this centuryOver this century the ozone hole is expected to heal, allowing the full effects of greenhouse gas increases to be felt across the Antarctic. Models suggest that the net effect will be continued slow strengthening of winds across the Southern Ocean, while sea ice will decrease by a third, resulting in increased phytoplankton productivity. The predicted warming of about 3°C across the continent is not enough to melt the main ice sheet and an increase in snowfall there should offset sea level rise by a few centimetres.
9. West Antarctic ice loss could contribute to 1.4 m sea level riseLoss of ice from the West Antarctic ice sheet is likely to contribute some tens of centimetres to global sea level by 2100. This will contribute to a projected total sea level rise of up to 1.4 metres (and possibly higher) by 2100.
10. Improved modelling of polar processes required for accurate predictionsClimate variability in the Polar Regions is larger than in other parts of the world, yet these remote regions are sparsely sampled. These areas need to be monitored in much greater detail in order to detect change, to improve understanding of the processes at work, and to distinguish between natural climate variability and variability caused by human influences. A detailed understanding of past climate is also crucial for understanding this distinction, as is a significant refinement of currently crude climate models.
WC1 says:I have to admit to becoming a tad exasperated with this thread. Truly there are none so blind as those that will not see. The bottom line, for those who are prepared to see it, is that the climate is changing, the changes are not following the historical climatic cycles (the ice age due to arrive at Platform 1 has been delayed) and the causes of the change are now mostly down to the effects of human activities, both agricultural and industrial, over roughly the past 8,000 years. In the immortal words of Tony Blair, 'That's it. I'm outa here.'