Global Warming: Where we are and what we can do
Things are heating upThe consensus among climatologists worldwide is that the globe is warming and WE are almost entirely to blame. The Intergovernmental Panel on Climate Change (IPCC website), 2,500 scientific experts from 130 countries, spent six years looking at all the research and data available. According to their findings, released in 2007, there's a 90% likelyhood that human activity has caused most of the warming observed over the last 50 years. The IPCC received the 2007 Nobel Peace Prize for their report, sharing the prize with Al Gore. There's no denying that we are having a significant impact, mostly by increases in CO2 levels. NOAA's excellent Global Warming FAQ sums it up well...
"There is no scientific debate on this point. Pre-industrial levels of carbon dioxide (prior to the start of the Industrial Revolution) were about 280 parts per million by volume (ppmv), and current levels are greater than 380 ppmv and increasing at a rate of 1.9 ppm yr-1 since 2000. The global concentration of CO2 in our atmosphere today far exceeds the natural range over the last 650,000 years of 180 to 300 ppmv."Suffice it to say, the IPCC report, along with hundreds of peer reviewed scientific articles and studies, cannot be dismissed. Any hypothesis that does would require believing in a vast global conspiracy involving not only thousands of scientists, but most of the governments of the world. Even Exxon, long affiliated with anti-warming views, has bent to the overwhelming evidence for human-caused global warming, shutting off their "misinformation spiget". Nevertheless, certain points of contention and confusion persist, fueled in large part by sceptics who receive money from the fossil-fuel industry (eg this ABC report, Ross Gelbspan's work, and this guide to the information and disinformation from the Society of Environmental Journalists).
But Antarctica is getting cooler!
Global temperatures are on the rise, as illustrated in the chart at right, including in the southern hemisphere, though at a slower pace (Trenberth et al. 2007), however Kirk Bryan and Syukuro Manabe showed that the Southern Ocean around Antarctica actually cooled slightly over their 50 year study. Confusion abounds around this subject, but interestingly, this was predicted by even the earliest climate change models. Despite incredible advances in computer models and data collection, the prediction hasn't changed. According to the models, by the time Antarctica shows signs of change, warming in the rest of the world will have progressed significantly, possibly beyond the point of no return.
Paleoclimatology data, from ice cores, coral-rings, tree-rings and sedimentary layers, have shown that during previous warming periods the globe warmed more slowly in the south. Several factors can be pointed to as possible explanaintions for this discrepency, including the astronomical or Milankovitch theory of climate change which posits that glacial/interglacial cycles are driven by changes in the amount of summer solar radiation (insolation) at high northern latitudes. Also, the southern hemisphere is dominated by water to a larger degree than in the north, and since the oceans act as large heat sinks, this means more heat overall can be absorbed in the south. Perhaps more significantly, in our current era, the hole in the ozone layer over Antarctica has had a strong cooling affect by helping to shift the southern Westerlies poleward (Gillett and Thompson 2003, Shindell and Schmidt 2004). As stratospheric ozone recovers, we can expect uncharacteristic, widespread warming in Antarctica. For more on this see this article by the Pew Center on Global Climate Change.
poised to collapse, as it's anchorage to Charcot Island disintegrates. By the time you read this it will likely be gone a chunk of Antarctica once the size of Connecticut. As a consequence, the flow of glaciers on neighboring islands may increase dramatically, sending a cascade of ancient ice into the ocean.
Meanwhile, in the Arctic, conditions are rapidly deteriorating... more rapidly than previously thought, according to the latest report from NASA. Less and less of the ice that forms in winter survives through the summer, so that now 70 percent of Arctic ice melts, compared to 40-50 percent in the '80s and '90s. "Thicker ice, which survives two or more years, now comprises just 10 percent of wintertime ice cover, down from 30 to 40 percent." Such a strong trend seems sure to bring us a completely thawed Arctic ocean some summer day in the not too distant future. While the loss of the Wilkins Ice Shelf and melting of ice in the Arctic ocean doesn't contribute to increasing sea levels, the wider implications for the globe can't be overstated.Excerpt from the Wikipedia entry on global warming:
Increasing global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, likely including expansion of subtropical deserts. The continuing retreat of glaciers, permafrost and sea ice is expected, with the Arctic region being particularly affected. Other likely effects include shrinkage of the Amazon rainforest and Boreal forests, increases in the intensity of extreme weather events, species extinctions and changes in agricultural yields.
Global Warming: Where we are