I'm glad don't live beside the seaside ...

I like the ocean, honestly, but living down next to it may not prove a safe place nor a good investment in the longer term, or so it appears after reading a fascinating and disturbing book, 'A Farewell to Ice; A report from the Arctic' by Peter Wadhams.

This is a chilling (no pun intended) review of the state of the Arctic ice and the consequences of continued warming for sea level rise. Peter Wadhams is the world’s foremost expert on sea ice and is professor of Ocean Physics, at the University of Cambridge.

Of the impacts of warming our planet, sea level rise has been one of my biggest concerns (I once owned a house that will almost certainly get flooded by sea level rise). The earth has had large fluctuations in sea levels in the past, including in recent human history. So it is not new (hopefully we can put that furphy out of the way!)

What is new is the speed of this artificial (human forced) melting of the polar regions, the heating of the oceans, and the fact that so many people live within a meter or two of the high tide mark. The rising water will be almost unstoppable if we reach certain tipping points that Wadhams discusses. The costs of this to society are enormous, if not overwhelming. How do we protect or shift large parts of our major coastal cities, our coastal communities, our heritage? This is not academic. Ask the good folk of Tuvalu and the Marshal Islands.

It is hard to predict how fast sea levels will rise. Since about 1880, sea levels have risen about 20 cm. Not much you may say. Well, this rate is now speeding up and is about 30 cm per century. So far: unfortunately the past rate is never a reliable prediction of the future! As Wadhams patiently explains, the amount of frozen water locked up in the Arctic, Greenland and the Antarctic is simply enormous, and if it all melted we are talking about dozens of meters of rapid sea level rise (we have seen this is the past record, so it s not just a theory).

While is highly unlikely all of this will melt in the next century or two, we will see non-linear (meaning quick bursts) of melting that will inundate vulnerable parts of our low lying cities. And it does not just come like a slow rising tide over decades, it comes with extreme storm events on top of increasingly higher tides that begin to overrun our sea walls, flooding our communities, on an increasingly more frequent basis. It is death by a thousand cuts.

The immediate risk for rapid sea level rise has to do with the melting of the summer Arctic ice. The lessons Wadhams gives from the science here are deeply worrying. As more of the Arctic summer ice melts (a trend that is now undeniable), more of the frozen seabed warms up. Permanent ice cover protects the sea underneath from wave action, but as this ice cover melts, waves circulate the warmer surface water down to the previously frozen (and quite shallow) seabed. As the sea bed melts it releases methane into the atmosphere, which increases the greenhouse effect, thus further warming the atmosphere and causing more melting.

Second, because there is less ice cover, this reduces the ability of the Arctic to reflect heat back to space (the albedo effect in scientific terms; white ice reflects an amazing amount of the sun's energy back to space). Adding these two things together, along with the actual melting trends Wadhams shows in his book, means that it is very likely more rapid melting with occur. And this greatly increases the risk of much higher than predicted sea levels. He adds that on the basis of the amount of melting of the summer sea ice, it is almost certain by 2020 we will see our first ice free Arctic summer.

This is not something to celebrate.

Wadhams stays focused on the ice of the most part. Few people know the history of these changes better than him, after some decades out there, on boats and submarines, collecting and analysing data. So he has the right to issue a chilling warning. It is not one that we are yet taking up. Denial will not longer cut it; humans are having a dangerous impact on our own future.

To give Wadhams the final word:

'Our planet has actually changed colour … Today, from space, the top of the world in the northern summer looks blue instead of white. We have created an ocean where there was once an ice sheet. It is Man’s first major achievement in reshaping the face of his planet' (Peter Wadhams).