Energy

Hydrates and climate changes

Methane is much more opaque to infrared radiation than CO₂ and consequently it produces a greenhouse effect 20 times greater than that of carbon dioxide. It is a gas whose effect on the atmosphere is much more dangerous than that of CO2: its effects are not very important because, at the moment, it is found in very limited quantities. Geological evidence in Antarctic ice cores show, however, that periods when the climate was warmer are always associated to increases in the methane concentration in the atmosphere. The exploitation of methane hydrates potentially creates the risk of releasing great amounts of methane, either accidentally or as an undesired consequence of the extractive process. What must be avoided is that the exploitation of this enormous energy source should happen in an irresponsible way: the release of great quantities of methane could cause an increase in the greenhouse effect and, consequently, a warming of the oceans. This would bring about the melting of great amounts of hydrates beneath the ocean floor, in the land covered with permafrost and in the polar ice causing a further release of methane: this would trigger off a series of processes whose final effects are difficult to foresee. Man’s contribution to the greenhouse effect as a result of the burning of all the fossil fuels available, would be of ‘only’ 200 billion tonnes of CO₂: nothing, when compared to the possibility that hydrates could release 10,000 billion tonnes of methane ‘spontaneously’! Moreover, when hydrates are absent, the sediments of continental slopes are made up of loose and unstable elements. Therefore it is likely that the melting of hydrates could trigger off landslide phenomena, even on a large scale, in the areas where extraction is taking place.