Sunday 14 March 2004

Pic of the day: Winter or spring? Which one will it be?

Greenhouse revisited

Yesterday suddenly it snowed and snowed, fine powdery snow. This after I thought for sure the winter was over already. I mean, it's virtually the middle of March! And so I wrote in my LiveJournal to exhort all my friends to let their engines idle so we could get more greenhouse effect.

It was a joke, and possibly a bad joke. But most likely not as bad as some think. I like to think it's not exactly on the level of Holocaust jokes, although there are certainly people who seriously worry that humanity as a whole may be wiped out by the greenhouse effect. Or at least civilization as we know it. I very much doubt that, but it's an interesting topic.

***

The greenhouse effect is real. It follows automatically from the laws of physics. It has been observed on this and neighboring planets, and geology can trace it back billions of years. It is no more imaginary than the air we breathe. In fact, without greenhouse effect our planet would be barely habitable. Even with the tiny amounts of CO2 and methane in our atmosphere, it makes the difference between this lukewarm Earth and a perpetual grand ice age.

The climate is changing too. When I was a kid, the snow usually lay on the ground till the beginning of May. Admittedly that's on the west coast of Norway, not the south coast where I live now, but I understand that spring is coming weeks earlier now than then, on average. Of course, we don't really know how much of this is caused by man-made greenhouse effect and how much is just natural cyclic changes. Climate has never been predictable in the short term, much less both short-term and local. Even so, it is pretty clear that things are heating up. The very fact that I could think winter would be over in the middle of March is really speaking volumes. When I moved here to the south coast (nearly 30 years ago) April was the spring month.

In Scientific American lately there was a long article about how various birds had trouble because of the climate changes. The difference is greater in subarctic areas than in the tropics; the birds leave at nearly the same time as before, but when they arrive their favorite foods are past the bounty season and they starve. (Particular attention was paid to some birds called "great tits" which undeniably made the article more memorable. Or perhaps that's just me. It was the first time I heard of that species.)

***

So, will the web of life be torn asunder and the food chains broken, the ecosystem crash and burn?

The ecosystem is not such a fragile thing. Where there is supply, there will be a demand. If an ecological niche is left empty just a little while, someone will move in. It has happened often enough in the past. The ice ages, we now know, did not start and end slowly over the course of millennia. Rather the change in the climate was shockingly sudden, in fact it seems to have been faster than we are able to pinpoint it.

As the latest ice age ended, temperatures rapidly climbed to a level higher than today ... while the glaciers were still lying there, melting as soon as they could. In North America, a huge freshwater basin built up behind those walls of ice, something to dwarf the Great Lakes of today. Then the barrier burst, and a river like nothing man has ever seen flowed into the Atlantic. Such was its power that boulders larger than houses were whirled with the floodwaters and left lying randomly around, a feature known by geologists as "chaotic terrain". More to the point, though, the freshwater stopped the Atlantic heat pump dead in its tracks. In less than 20 years (that's the limit on how exact we can time it, but it could possibly be one year) the climate in northern Europe reverted back to frost. The trees died where they stood, frozen to death. The snow fell and did not melt. For a while the lands were descending into ice age again, until the layer of freshwater dissipated naturally and the Icelandic Upwelling once again started to convey heat to the atmosphere.

Please note also that temperatures for most of civilization's history were higher than today. In the early 90es we were back to around the Viking age, and we're still not back to bronze age temperatures. At that time, 6000 years ago, Sahara was green. If restoring the temperature is all it takes to make it green again, it is not a bad deal. Also there should be a lot more comfortable areas to live in Alaska, Canada, Fennoscandia and Siberia. On the down side, we may lose various tropical islands as well as much of the Denmark, the Netherlands and Bangladesh. So yeah, things will be shaken up quite a bit even if we only go back to the heat wave right after the ice melted, back when actual monkeys chattered in Spain and France and hippos bathed in the Seine near present-day Paris.

The effect of CO2 and methane also come over time, a bit after they are released into the atmosphere. So even though fossil fuels are likely to gradually lose their importance over the next few decades (with crude oil at $30-35 per barrel, windmills are going to sprout like mushrooms) we will still see a few decades of warming after that. It will be unpleasant for some people, pleasant for some others, but a lot of change all over the board.

We have far, far to go before we reach the CO2 levels prevalent in the age of dinosaurs. They were more than twice the current level. Life did not die out then and it won't now, not from that at least. There are more immediate threats. But things sure were different, and they sure will be different again.

Incidentally, I object to the claims that the greenhouse effect claimed thousands of lives during the heat wave last year in Europe. Yes, the elderly and otherwise weakened die more often during a severe heat wave. But in cold areas, they die more often during a cold wave as well, and we never hear about the deep freezes that never happened because of the greenhouse effect. People live in Africa, for crying out loud. It is not the heat that kills, it is being unaccustomed to it, unprepared for it, and physically weakened. Making the greenhouse effect into some kind of Ebola or Holocaust kind of kills off any rational discussion pretty fast.

But it's gonna be big changes. And big changes will cost. I haven't seen any nations set up Climate Change Adaptation Funds yet. They will need to have done so soon. Whether to avert disaster or grab new opportunities, there will have to be change, things will have to be done, and money will have to be spent. You know my mantra by now: "All things have a price." The convenience of modern living has depended on burning fossil fuels, and still largely does. I'm the one who doesn't drive a car and doesn't take planes if there goes a train, so I hope y'all will excuse me for not breaking down in tears of remorse when you get upset about the climate changes.

But I guess I'll stop joking about it.