Permafrost - the ticking bomb

If you have been closely following the climate change debate, especially the predictions, you are aware that there has been frequent adjustment in the numbers thrown up for warming and its consequences. As also the reductions in emissions required to keep life cruising along.

Every new study indicates that the climate change danger has been underestimated by earlier studies. This is largely due to the complexity of the climate model that has so many dynamic parameters. But there is the other aspect which is that of incomplete understanding of positive and negative feedback systems that add or remove from the warming effect.

The impact of the biosphere’s response to global warming has not been fully considered. Like the way warming seawater releases carbon dioxide. Or soil bacteria that heat up will respire more, generating more CO2. As temperatures rise, tropical forests will die, releasing the carbon they contain. Feedbacks account for about 18% of global warming.

The 4th impact assessment report of Intergovernmental Panel on Climate Change (IPCC) has a table which links different cuts to likely temperatures. To prevent global warming from eventually exceeding 2°, it suggests, by 2050 the world needs to cut its emissions to roughly 15% of the volume in 2000. The IPCC admits that “emission reductions … might be underestimated due to missing carbon cycle feedbacks”.

The findings of a recent peer-reviewed study published in the July 13 issue of the journal Nature Geoscience provides evidence that current climate models are still underestimating the amount of warming that an increase in atmospheric carbon dioxide can cause.

In other words, the potential consequences of global warming are likely worse than what scientists are predicting.

The study examined the extent to which increased carbon dioxide levels could explain a 5 to 9 degree Celsius increase the Earth experienced 55.5 million years ago. The authors concluded that current estimates of how much carbon dioxide increases the average Earth temperature only explains 3.5 degrees of warming.

This in turn means forecasts of future warming could be severely underestimating the problem in store as ghgs accumulate.

Some of the changes due to warming could aggravate the problem. For example, increasing CO2 concentrations:
melt tundra, which then releases methane and other heat-trapping gases into the atmosphere; warm the air, which then can hold more water vapor, another heat-trapping gas; and
melt white ice, which exposes the ocean and land, which, because they are darker in color, absorb more heat from the sun and reflect less of it back into space.

Large amounts of methane, which has roughly 20 times the warming potential of CO2, could make an enormous difference. And, compared to the carbon in the atmosphere, there is about twice as much carbon in the permafrost as we thought, roughly 1.5 trillion tons.

Any thawing of permafrost due to global warming may lead to significant emissions of the greenhouse gases carbon dioxide and methane. Carbon deposits frozen thousands of years ago can easily break down when permafrost thaws releasing greenhouse gases to the atmosphere, according to another recent study by University of Florida.

Carbon in permafrost is found largely in northern regions including Canada, Greenland, Kazakhstan, Mongolia, Russia, Scandinavia and USA.

Is that a good enough reason for all nations to take this climate change seriously and do something, and do it fast? Can we afford to keep feeling around, eyes blinded, till we decide that there is an elephant in the room?