23 novembro 2006

Rebooting the?Ecosystem

Repeat after me: We humans have screwed up our planet. Feels better, doesn't it? Now that we've accepted this reality, at least we don't have to argue about it anymore. Atmospheric carbon dioxide levels are at the highest they've been in at least 800,000 years. Greenland's ice sheet is melting fast. Some – probably a lot – of the current warming trend is because of us, and so are the consequent threats to ecosystems, food supplies, coastal cities, and all that other stuff from An Inconvenient Truth.

Of course, that means we're responsible for repairing the damage, but stopgaps like carbon sequestration just aren't going to cut it. Luckily, a growing number of scientists are thinking more aggressively, developing incredibly ambitious technical fixes to cool the planet. These efforts to remedy the accidental experiment of climate change with intentional, megascale experimentation are called geoengineering. Thus far, ideas include reflecting sunlight with gazillions of orbiting featherweight mirrors or by saturating the stratosphere with sulfur, or increasing the volume of microbes that eat CO2 by fertilizing the oceans with iron.

Harebrained? Well, maybe. But somebody has to save the world. Typically, sober environmentalists have looked askance at geoengineering. In fact, they mostly think it's nuts. All the ideas on the table reek of foolhardiness. We have only one Earth, and it is a system of unparalleled complexity (in other words, no one knows exactly how it works). What if we muck it up? "If you go down the path of geoengineering, it leads to taking ever-increasing environmental risk, and, eventually, you'll be unlucky," says Ken Caldeira, a climatologist at Stanford University.

What's more, many greens worry that just talking about geoengineering could deflect funding and focus from the task of cutting greenhouse gas emissions. They'd rather we legislate higher fuel-efficiency standards and design better photovoltaics. Enviros are right about the urgency of kicking the fossil fuel habit – that's a no-brainer. The problem is inertia; the changes we have wrought in the atmosphere will play out over decades (or longer) whether we junk all the SUVs tomorrow or not.

That's why it makes sense to start thinking seriously about radical countermeasures. One of the biggest boosts to the idea of climate manipulation came last summer from Paul Crutzen, an emeritus at the Max Planck Institute for Chemistry. Writing in the journal Climate Change, Crutzen, who shared the 1995 Nobel Prize in chemistry for work examining ozone depletion, described a plan to shoot massive quantities of sulfur into the stratosphere. In theory, the sulfur would reflect sunlight – just as particles blown into the air by the eruption of Mount Pinatubo did in 1991 – cooling Earth and buying enough time for civilization to shift into green gear. Crutzen's not crazy, and he's no renegade terraformer. "Until a few years ago, I would also have been against the idea," he recently told an Australian newspaper.

His journal article – and his clout – gave geoengineering an almost instant credibility boost. Soon other heavies, like Ralph Cicerone, president of the National Academy of Sciences, were also writing in favor of the concept. Their message: Geoengineering isn't, and shouldn't be, fringe science. "Given that the climate-change problem might be more serious than we previously thought," says Tom Wigley, a mathematical physicist at the National Center for Atmospheric Research, "we should consider these radical solutions more seriously." Stanford's Caldeira is keeping an open mind – he's even helping to organize an international geoengineering meeting at NASA Ames Research Center.

The shortsighted mistake here would be getting mired in the details of these wild plans. (Crutzen's scheme would mean we'd have to start loving smog – but imagine the psychedelic sunsets!) Yes, these ideas sound crazy. But we're in the earliest stages of what is potentially the single most crucial new science in history. Let's give the researchers a minute or two to get their PowerPoint slides in order and, more important, grab a slice of the admittedly modest budget for climate-change research. Just remember: Advocating the study of geoengineering does not mean campaigning for the deployment of every ludicrous notion that comes along.

Smart people finally convinced us that we need to stop burning fossil fuels. Let's do that. But because what has already been set in motion tends to stay in motion, we need a well-researched, measured plan to get us (or, more realistically, our grandchildren) out of this mess. The real worst-case scenario is some kind of Bruce Willis-movie scheme deployed at the eleventh hour, after the climate shift has already hit the fan.
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My 2 cents: As much as I believe in all this, I tend to react against the idea that we are destroying the planet. We are not. We are just making it less and less bearable to live in. It's a stupid, egocentric idea that we can destroy this planet (for instance, a full new ecosystem is blossoming around Chernobyl, with cougars and new flora finding their way, startling those biologists that believed the area to be wasteland the next million years). The earth will go on without us. Life always finds a way to prevail. Deal with it.

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