Pliocene Arctic was 10°C warmer than today, with similar atmospheric CO2
By Jeff Hecht
09 July 2010 12:20
With carbon dioxide levels close to our own, the Arctic of the Pliocene epoch may have warmed much more than previously thought – and the modern Arctic could go the same way. Ashley Ballantyne at the University of Colorado, Boulder, and colleagues analysed 4-million-year-old Pliocene peat samples from Ellesmere Island in the Arctic archipelago to find out what the climate was like when the peat formed. At that time, CO2 levels are thought to have been close to current levels – around 390 parts per million – but global temperatures were around 2 to 3°C warmer than today. It was the last warm period before the onset of the Pleistocene glaciation, and is used by climate researchers as a model for our future climate. Previous studies using computer models have suggested that the Pliocene Arctic was also warmer than it is today – up to 10°C warmer. A little warming can trigger a lot more in the Arctic because the loss of light-reflecting sea ice and the spread of plants across the land increase the amount of solar energy that is absorbed. Ballantyne’s team estimated the temperature of the period at which the peat formed by measuring three things that are affected by temperature: the concentration of various chemical compounds, levels of a certain isotope in tree rings and the amount and types of fossilised vegetation. The group’s analysis suggests the samples formed when average local temperatures were about -0.5°C. That is 19°C warmer than temperatures today – more than the previous computer models had estimated. “These results should be alarming,” says Ballantyne. Although it could take centuries for current global temperatures to respond to rising CO2 levels, we can expect the Arctic to warm much more than the rest of the planet, he says. …
We will probably see 450 ppm (C02) before we see a reduction, which means these predictions will probably all come true, but will be much worse.
The climate feedback will be horrific. 10C higher temps in the Arctic means zero ice, which means most of the inhabited regions on Earth non-hospitable.
Wet-bulb conditions would make life almost impossible for most of the planet.
And still we "debate" the meaning of all this, unbelievable.
It's as if we have a morbid death-wish and insist we extinguish all life on Earth to our own self-induced grave. ~Survival Acres~