Month: April 2012

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Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?

Originally posted at Skeptical Science

  • The climate effects of bitumen development are significant once viewed in the perspective of probable emissions over the rest of this century.
  • The climate impact of coal consumption is greater than that of bitumen, particularly when non-mineable coal is considered.
  • Accelerated expansion of bitumen extraction will make climate mitigation efforts much more difficult.
  • Because of its high carbon emissions and high extraction costs, further bitumen development would not be viable if stringent global emissions policies were adopted.

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DeConto et al: Thawing permafrost drove the PETM extreme heat event

Originally posted at Skeptical Science

Sudden spikes in global temperatures that occurred 50-55 million years ago were caused by thawing of permafrost in Antarctica and northern high latitudes, according to recent research. The trigger for this sudden destabilization was a variation in orbital configurations that resulted in warmer polar summers. This model also provides an analogue for the releases of carbon from modern permafrost caused by current man-made global warming. Modern permafrost volumes are smaller than the estimates for those of 55 million years ago, but will nevertheless amplify the climatic effect of fossil fuel consumption and will provide continuing warming feedbacks for centuries after human emissions cease. Continue reading →

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Eocene Park: our experiment to recreate the atmosphere of an ancient hothouse climate

Originally posted at Skeptical Science

Fifty million years ago, during the Eocene Epoch , the world had a very different climate, with temperatures much higher than today’s, especially at the poles. This hothouse climate was caused mainly by CO2 levels that were twice as high, or more, than now. On our current emissions trajectory, we could recreate the chemistry of the hothouse atmosphere before the end of this century, with potentially drastic consequences for our climate.

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