Arctic's greenhouse effect

Melting polar ice could cause hefty damage faster than we think

A new study on global warming suggests that time frames for policy action are much shorter than previously believed. The costs could also be much higher. According to the study, Climate science: Vast costs of Arctic change, published on July 25 in the scientific journal, Nature, one key variable alters prior scenarios. The melting of polar ice and the consequent release of methane could, in itself, cause damage amounting to $60 trillion. This is an enormous estimate, since 2012 global gross domestic product amounted to about $70 trillion.

The debates about global warming have always been more about the politics and economics, rather than the science. Scientists present a solid consensus that the Earth is warming. Although there are differences of opinion about probable degree and time frames of warming, there are few naysayers in the scientific community.

However, there is an utter lack of policy consensus about mitigation measures. There are several reasons for this. Climate science models have large error ranges across long time frames. The models present multiple scenarios with varying degrees of probability and different assumptions. Further, assessing the costs requires applying economic models to these multiple scientific scenarios. Since large error ranges are also intrinsic to economic models, the cost estimates all have extremely wide ranges.

Multiple economic scenarios based on multiple scientific scenarios lead to confusion on the part of the laypersons who determine policy. Adding to the problem, politicians aren't geared to think in time frames exceeding electoral cycles. All the mitigation measures show positive outcomes only across decades. The practising politician will note that the rewards of mitigating, or the costs of not mitigating, are likely to arrive many election cycles down the line, while the costs of mitigation mean instant pain. Hence, a lack of political will to combat climate change.

The science underlying the new study is experimentally verified. Everybody agrees huge quantities of methane and crude oil are trapped under Arctic permafrost and ice. By some estimates, up to 30 per cent of new global gas reserves and maybe 10-15 per cent of crude oil could be in these regions.

Vast deposits of methane hydrates - that is, frozen crystalline mixtures of methane and ice - exist under the permafrost. As the ice melts, the gas is released. Prior studies have confirmed this. In 2010, Science journal published Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf, a study by a team of six scientists led by Natalia Shakhova.

That team found 1 km long plumes of methane were released as the East Siberian Sea ice melted. The abstract says, "More than 5,000 at-sea observations of dissolved methane demonstrates that greater than 80 per cent of East Siberian Arctic Shelf bottom waters and greater than 50 per cent of surface waters are supersaturated with methane."

Methane is an extremely powerful greenhouse gas and greenhouse effects are a primary cause of warming. The heating component of solar radiation, infrared, is long wavelength, while visible light is shorter wavelength (and ultraviolet is even shorter). Greenhouse gases allow shorter visible wavelengths to pass through, while trapping infrared. This causes a rise in temperature. The commonest greenhouse gas is carbon dioxide (CO2).

Methane (CH4), also called marsh-gas and firedamp, has a stronger greenhouse effect than CO2. Methane is about 70 times as efficient in trapping infrared inside a time frame of 20 years. Methane also constitutes about 80-90 per cent of natural gas. During World War II, the Germans pioneered processes wherein coal bed methane could be transformed into fuel. Along with shale gas, methane is seen as a new, almost-untapped source of fossil fuel.

As Arctic ice has melted, the interest in Arctic mining operations has risen. The marine and industrial insurance major, Lloyds of London, reckons that over $100 billion will be invested in such efforts over the next decade, judging by covers it has issued. Alarm bells about damage caused by drilling in this fragile environment, and of course, the plight of polar bears, seals and other wildlife have drawn worldwide attention.

The new Nature study is the first one modelling the potential economic damage. The trio of Gail Whiteman, Chris Hope and Peter Wadhams used updated versions of the Stern model used in the 2006 review of the Economics of Climate Change. The Stern model is also used by the US Environmental Protection Agency.

The study assumes that around 50 gigatonnes (One gigatonne is equal to 1,000 million metric tonnes) of methane will be released into the atmosphere from the East Siberian Sea over the next decade. This one variable could seriously accelerate global warming. The global mean temperature may rise much faster than previously assumed. Most models assume a rise of about 2 degree Celsius by the end of the 21st century whereas this study says this could happen by somewhere between 2070-2085.

The ill-effects will become apparent immediately, not 60 years later. There would be catastrophic flooding of low-lying regions and extreme weather action over the next decade. If mitigating measures are not implemented now, the costs across multiple scenarios will average out to about $60 trillion. About 80 per cent of those costs would hit developing nations, with their low-lying coastlines and vulnerable agricultural economies. If ocean acidity and other effects come into play, the costs could be a lot higher in more extreme scenarios.

The time frames are therefore, much compressed. The science seems solid and even in the most benign scenarios, the damages will be steep. Existing methane emission control technology doesn't deal with the scale of CH4 emission that is envisaged in this study. Vast investments would be required on a war footing to develop technology that can cope in the time frame. However, given the toxic nature of the global warming debate, it is sadly, quite likely that not much will be done.