Thursday, August 2, 2007

Blobal Garming

You know, for all the uproar over global climate change you hear these days, you hear very little about what it actually is or what its real ramifications might be. Ask anyone on the street what the story is, and you'll be lucky if whoever you ask has seen "An Inconvenient Truth," much less studied any actual climate science on even a casual basis. Many people know - or think they know - that it's caused by pollution, and it involves gases keeping heat in the atmosphere. That's about all most people know.

Well, I'm not here to give lectures. I recommend you read up on the topic elsewhere, preferably in papers by reputable climatologists, geologists, ecologists, and atmospheric chemists. Suffice to say here that I was thinking a bit about global warming today.

Now, I'm an evolutionary biologist, and an ecologist. I think about biospheres and ecosystems. I was thinking today, partly because I'm in the middle of an excellent popular science book by Bill Bryson called A Short History of Nearly Everything. I don't necessarily agree with the way he states everything in the book, and I don't like the emphasis he gives some coincidences while barely mentioning other relevant factors, but all in all it is a highly readable and even entertaining book that teaches a broad overview of natural history from which more or less every single person on earth could benefit. I recommend it.

But back to the point: I was thinking.

This isn't a novel idea, I'm sure, though as yet I haven't had time to look around and see which greater minds have already propounded it, but here it is: we're headed for an ice age that will be orders of magnitude worse than any scenarios we have previously envisioned as consequences of global warming. The only question is whether it's sooner or later... but not that much later. Sounds counterintuitive, right? Well, it's complicated.

The short version is this: we don't understand the global climate very well, but we can observe certain patterns. One is that phenomena that disrupt oceanic currents, especially the big, deep ones, disrupt the global climate in destabilizing ways. Another, with more certain outcomes, is that plants create atmosphere and plants like carbon dioxide, so when there's lots of carbon dioxide (and lots of water), plants grow and change atmospheric composition.

Put the two together, and, excepting the unpredictable and certainly not probable intervention of other factors like geothermal heat or extraterrestrial impact, you have a climate destabilized by melting ice caps and glaciers, diluting and raising the oceans and changing ocean currents and unpredictably altering weather patterns. Simultaneously, you have extremely rapidly increasing levels of carbon dioxide in the atmosphere from our own combustion output. Plants love extra water and extra carbon dioxide, so we can expect enormous plant growth, even if we cut down all the rain forests and it comes in the form of algal blooms or grasses.

Plants eat carbon dioxide. Lots of plants eat lots of carbon dioxide. Now, sooner or later, our excessive output of that gas is going to end. Either we'll run out of fuel, or we'll decide it's time we stop wrecking everything. Either way, what we'll be left with is more plants than the resulting lower output can sustain. They'll suck up a whole lot of carbon dioxide from the destabilized atmosphere, for a while, at least, and levels will not only go back down, but will go down even lower than they were at preindustrial levels.

As you probably know, carbon dioxide is a greenhouse gas - it allows the atmosphere to retain heat. Now, what do you think will happen when it's all sucked out of the atmosphere? Cooler temperatures. Crashingly cooler. Disastrously cooler. Cool summers don't melt all the snowfall of the winter. Unmelted snow reflects incident sunlight, which causes less heat to be absorbed, resulting in further cooling. A positive feedback loop leads to an ice age. This is established climatological theory, established by geological record.

No, I'm not claiming I know exactly what's going to happen. Obviously no one does. I certainly don't know as well as the people who study this stuff for a living. But it's an entirely logical, predictable sequence of events, and it's more or less a certainty in the long run. It's not so much a certainty, however, exactly how long a run, or whether people will be around to see it.

Still, based on what research I've had time to do so far, including remaining fuel reserves and histories of previous climate changes, I wouldn't be too surprised if my generation's great-grandchildren ended up being well-served by stocking up on winter clothing.

1 comment:

John Marshall said...

To mkfreeberg:

Please post your insane screeds elsewhere in the future. Your comments are welcome if they're rational and on-topic. Your last one was neither.