Scientist studying the fossil record on Ellesmere Island near the North Pole have published their results in the peer journal,
Geology. What they found adds more scientific evidence to support the hypothesis that the Earth will undergo fundamental changes as a result of anthropogenic global warming. Fossils from the Pliocene Epoch (2.6 to 5.3 million years ago) show that the island was very different from the barren, tundra covered rock it is now. Ellesmere had forests of larch, dwarf birch, and northern white cedar, as well as mosses and herbs. The island was inhabited by extinct mammals such as small deer, ancestral bears and horses, small beavers, rabbits, badgers and shrews. Using three different methods, the scientist were able to arrive at a consistent estimate of mean annual air temperature on Ellesmere during the Pliocene. It was about 34℉, and levels of atmospheric CO₂ were only slightly lower than they are today. Their findings indicate that a CO₂ level of 400ppm is sufficient to elevate mean annual air temperatures in the Arctic to above freezing. The current level of CO₂ is about 390ppm, very near the tipping point. Arctic air temperatures have risen by about 1.8 degrees in the past two decades. Arctic sea ice is melting at a rate of 11.2% per decade. Some experts believe that Arctic summers will be ice free within a decade or two.
