What are We Doing about Melting Ice? Nothing!

Over my more active years I often returned home from the UK with a flight to Los Angeles, and the flight inevitably flew over Greenland. For somewhat selfish reasons I tried to time my work visits in the northern summer, thus getting out of my winter, and the return flight left Heathrow in the middle of the day so with any luck there was good sunshine over Greenland. My navigation was such that I always managed to be at a window somewhere at the critical time, and I was convinced that by my last flight, Greenland was both dirtier and the ice was retreating. Dirt was from dust, not naughty Greenlanders, and it was turning the ice slightly browner, which made the ice less reflective, and thus would encourage melting. I was convinced I was seeing global warming in action during my last flight, which was about 2003.

As reported in “The Economist”, according to an analysis of 40 years of satellite data at Ohio State University, I was probably right. In the 1980s and 1990s, during Greenland summers it lost approximately 400 billion tonnes of ice each summer, by ice melting and by large glaciers shedding lumps of ice as icebergs into the sea. This was not critical at the time because it was more or less replenished by winter snowfalls, but by 2000 the ice was no longer being replenished and each year there was a loss approaching 100 billion t/a. By now the accumulated net ice loss is so great it has caused a noticeable change in the gravitational field over the island. Further, it is claimed that Greenland has hit the point of no return. Even if we stopped emitting all greenhouse gases now, it was claimed, more ice would be progressively lost than could be replaced.

So far the ice loss is raising the oceans by about a millimetre a year so, you may say, who cares? The problem is the end position is the sea will rise 7 metres. Oops. There is worse. Apparently greenhouse gases cause more effects at high latitudes, and there is a lot more ice on land at the Antarctic. If Antarctica went, Beijing would be under water. If only Greenland goes, most of New York would be under water, and just about all port cities would be in trouble. We lose cities, but more importantly we lose prime agricultural land at a time our population is expanding

So, what can be done? The obvious answer is, be prepared to move where we live. That would involve making huge amounts of concrete and steel, which would make huge amounts of carbon dioxide, which would make the overall problem worse. We could compensate for the loss of agricultural land, which is the most productive we have, by going to aquaculture but while some marine algae are the fastest growing plants on Earth, our bodies are not designed to digest them. We could farm animal life such as prawns and certain fish, and these would help, but whether productivity would be sufficient is another matter.

The next option is geoengineering, but we don’t know how to do it, and what the effects will be, and we are seemingly not trying to find out. We could slow the rate of ice melting, but how? If you answer, with some form of space shade, the problem is that orbital mechanics do not work in your favour. You could shade it some of the time, but so what? Slightly more promising might be to generate clouds in the summer, which would reflect more sunlight.

The next obvious answer (OK, obvious may not be the best word) is to cause more snow to fall in winter. Again, the question is, how? Generating clouds and seeding them in the winter might work, but again, how, and at what cost? The end result of all this is that we really don’t have many options. All the efforts at limiting emissions simply won’t work now, if the scientists at Ohio State are correct. Everyone has heard of tipping points. According to them, we passed one and did not notice until too late. Would anything work? Maybe, maybe not, but we won’t know unless we try, and wringing our hands and making trivial cuts to emissions is not the answer.

Another Wellington storm

Yet another storm hit Wellington; this time winds were a mere maximum of 165 k/h (about 100 mph). Is this climate change? Whatever, it is interesting that climate change is now a major concern, which raises the question, what can we do about it? Suppose we answer, “Stop burning fossil fuels,” what would the effect be? Currently, the atmospheric concentration of carbon dioxide is about 400 parts per million (compared with about 280 ppm at the beginning of the Industrial Revolution). If we are concerned about the effects of such atmospheric carbon dioxide, then if we stop producing it right now, the 400 ppm remain. Now, as noted in the last post, the climate shows strong signs of what physicists call hysteresis. This is when the effect is something depends on how you got there, where the system has “memory” of previous times. In this aspect, the Greenland ice sheets are actually the last remnants of the last great Ice Age. As we heat the planet, all that happens first in some places is that ice melts, the extra heat being absorbed by the melting ice without any temperature increase. In other words, for a while what you see is not what you are going to get!

In my opinion, the major problem civilization is going to face is rising sea levels. If the Greenland Ice Sheet melts, then the sea will rise about 7 meters. Take a look at Google Earth and see what goes. Amongst other places, a significant fraction of Bangla Desh, and essentially all Pacific islands based on coral reefs (as opposed to the volcanic basalt peaks, but you cannot live on the side of them). So, how do you defend against that?

 One suggestion is to build sea walls. These would have to be around all the land, including alongside riverbanks, and they may have to last tens of thousands of years. And, of course, while you are making all the required concrete and moving rock, you are probably generating massive amounts of further carbon dioxide, which will lead to more of the Antarctic ice melting, thus cancelling any value from your efforts. You could build walls of up to fifty meters high, and that would certainly be adequate for as long as the walls last.

 You could try removing the carbon dioxide from the environment. At first sight this seems futile; there is just too much there. However, at least some can be removed without much effort if we regrow forests. You would have to start planting them, but once underway, they would happily consume carbon. Even more spectacular would be to grow marine algae. The kelps such as Macrocystis pyrifera are extremely fast growing, and you can harvest them by mowing them. I rather fancy collecting such kelp and using it to make either biofuel or other chemicals. The key is to ensure that the carbon is removed from the ocean.

 Currently, we produce about 10 billion tonne per annum of carbon dioxide. That means we have to remove 10 billion tonne per annum just to break even. It is unlikely we can do that, although what we can do, we should, so what other options are there? A massive deployment of nuclear power would slow the fossil fuel burning, but it would not remove any of the current 400 ppm, and who wants nuclear power?

 The simplest answer is for every tonne of water melted by the ocean currents, we deposit a tonne of snow into the ice sheets. That involves geoengineering, and the problem is, when you interfere like that with nature, the effects are probably not that readily calculated. Such proposals in the past have been met with opposition. The problem is, some countries are going to be adversely affected by the geoengineering, and these are the ones that, in the first place caused the problem. Of course if we do nothing, it is the Pacific Islanders and the Bangla Deshis who pay. Do we know what will happen if we intervene? No, we do not, but we know what will happen if we do not. Of course there is another problem: how do we decide, and who decides?