Antarctic Warming Shows "Human Fingerprints"
The rapid ice melt and temperature rise in the Arctic region has been widely reported, with a record summer ice melt occurring last year in the Arctic ocean, and a near-record this year (the volume of sea ice, if not the extent, did reach a record low this year, with autumn temperatures in the Arctic 9 degrees Fahrenheit above normal).
The February 2007 report from the Intergovernmental Panel on Climate Change (IPCC) stated that humanity’s impact on climate is felt on every continent on the globe except Antarctica.
A recent study by researchers from the U.K. Meteorological Office’s Hadley Center and Environment Canada have compared over fifty years of data records from Antarctic weather station and a century’s worth of weather data from the Arctic. By comparing the data between the Arctic and Antarctic, as well as against several computer climate simulations, the researchers have determined that natural influences, such as amount of sunlight or volcanic eruptions, could not account for the warming trends. The data didn’t match the measured temperature change until increasing levels of greenhouse gases were added to the equation.
Peter Stott, climate modeler for the Hadley Centre and co-author of the study published in the journal Nature Geoscience says “We have detected the human fingerprint in both the Arctic and Antarctic regions."
In the past few decades average temperatures in the Arctic have risen by about 3.6 degrees Fahrenheit, in Antarctica a bit less than 1.8 degrees Fahrenheit.
The collapse of the Larson B and Wilkins ice shelves on the Antarctic Peninsula, which scientists say has warmed more than any other part of the world, has already been linked to human-caused global warming.
Some researchers fear they may have actually underestimated the temperature change by giving equal weight to readings from the cold continental interior (made even cooler in the spring and summer by the ozone hole over the region) and coastal regions where warming is more pronounced.
These areas are most susceptible to climate warming in the coming century in Antarctica, because they are the closest to the melt threshold”, says Andrew Monaghan of the National Center for Atmospheric Research in Boulder, Colorado (and who was not part of the research study published in Nature Geoscience), “One quarter to one half of the Antarctic coastline has some substantial warming going on as of now."
If the ice shelves along the eastern and western Antarctic where to melt completely (nobody is anticipating that – yet), sea levels would rise by about 230 feet. With the collapse of smaller ice shelves like Larsen B comes the relentless slide of glacial ice behind it into the sea, adding to the persistent creep of high tides around the world.
There will be continued residual warming no matter what greenhouse gas reductions we make. We really need to pay closer attention to what is going on with this ice sheet."