Only a few people in the world know ice better than Peter Wadhams. A professor of Ocean Physics at Cambridge, Peter Wadhams is a world authority on sea ice. His  book ‘A Farewell to Ice’ is a report from the Arctic, and the consequences of the loss of the summer sea ice. It is also a personal history of a scientist and his extraordinary work in the polar regions in the past 35+ years.

Peter Wadhams believes the Arctic has reached a tipping point, that is a  point at which a certain system that has been stressed beyond a certain level does not return to its original state when that stress is removed. He predicts that  Arctic will be be ice free in the next few years and that would have a series of disastrous consequences for the whole planet.

The retreat of the summer sea ice in the Arctic is important because the loss of sea ice is changing the global albedo (the reflected sunlight). A vast area will change from white (ice) to blue (sea), therefore less energy will be reflected back into space. It means that the global warming will increase.

The darker ocean will absorb more energy which warms the water which melts more ice, which further warms the ocean, which melts more ice, in a spiraling feedback loop.

Perhaps the most severe threat is the fact that the shallow waters of the Arctic Siberian coast, a huge area that is already ice free, will warm up, and that means that the hundreds of millions of tons of methane gas that are locked away beneath the Arctic permafrost,  sitting there before the last ice age,  can thaw releasing the methane into the atmosphere. It is already happening and this is a very serious alarm. Methane is a very powerful greenhouse gas, the  release of the permafrost methane in the Arctic  could cause up to 0.5°C  extra warming in just few years.

Wadhams call for immediate action  The existing level of carbon dioxide in the atmosphere today  is sufficient to cause unacceptable amounts of warming in the future. Therefore, it is not enough to reduce carbon emissions. “The  carbon dioxide levels in the atmosphere are already so high, that when their warming potential is realised in a few decades, the resulting temperature will be catastrophic”, says Wadhmas.

To avoid such a fate, we must not only go to zero emissions, “we must actually remove carbon dioxide from the atmosphere.” The possible “carbon removal” techniques are very diverse, less or more efficient or realistic, but still very expensive. It is a massive scientific challenge. “A vast and urgent research project is needed”, says Wadhams, “to develop cheaper methods; improved catalytic methods have been proposed which might bring us to $40 per tonne of carbon dioxide” (from $100 today).