Originally published in the September/October 2007 issue of The Environmental Forum

I wish there were an easy solution to climate change — one that didn’t require fundamental and difficult changes in our energy system, law, or behavior. I also wish I could lose weight without diet or exercise. But depending on “geoengineering” to solve global warming is a dangerous delusion. Like a fad diet or liposuction, it may not provide sustainable benefits and will undoubtedly be accompanied by unforeseen adverse consequences (think fen-phen).

Granted, tackling climate change requires a Herculean effort: emissions are on the rise, while the newest science reveals impacts occurring faster than we envisioned. We are running out of time. To avoid the most serious consequences of warming — loss of species, irreversible breakdown of ice sheets, and the human toll from more intense heat waves and hurricanes — scientists say we need to stabilize atmospheric greenhouse gases such as carbon dioxide at less than a doubling of preindustrial levels (in the range of 450–550 ppm of CO2). If we’re very lucky, that might hold us to a 3.6ºF (2ºC) global average temperature rise.

It’s tempting to dismiss projected impacts as hyperbole or to believe that we can engineer a “fix,” the way the Apollo 13 crew saved themselves by using duct tape to fashion a make-shift filter in their struggle against rising CO2 levels on board their malfunctioning space capsule. I applaud those working on grand fixes and wish them every success. But I place more stock in solutions that exist now. A Princeton University study shows that choosing just seven current technologies from a number of options, including renewables, energy efficiency, and nuclear power, can curb emissions growth sufficiently now, while buying time for technological breakthroughs. Each of these so-called “wedges” can cut emissions by 1 gigaton per year within 50 years.

But these technologies won’t be deployed on the necessary scale without the right policies. One key policy is emissions trading, which has worked for traditional air pollutants such as sulfur dioxide and is even better suited to curbing greenhouse gases. The European Union has already developed the world’s largest carbon market. Some U.S. states are following suit, and a number of cap-and-trade proposals are pending in Congress. By combining cap-and-trade with efficiency standards for cars and appliances, advanced technology research, and development of geological storage, we can reach our emissions reductions goals.

So the essential first step is simple: stimulate existing technologies through demonstrated, cost-effective policies. This takes political will, and there is no time to lose. Greenhouse gases differ from traditional air pollutants, which can be eliminated with more than 99 percent efficiency at the stack. Greenhouse gases remain in the atmosphere — and our oceans — for hundreds of years. Even if geoengineering manages to cool a warming planet, it won’t solve other problems, such as ocean acidification from conversion of CO2 to carbonic acid. And the risks of such “fixes” as seeding the oceans with iron and adding cooling particles to the atmosphere are too big to ignore.

Yes, we should research all options. But right now our focus should be on putting policies in place to reduce our emissions and on preparing to cope with a changing world.

(Ms. Arroyo offers a view on the direction for climate policy that differs from one advocated by Alan Carlin, a senior economist at the EPA. Carlin advocates a “geoengineering” approach called solar radiation management as an effective and economical climate policy. While such long-shot approaches may be necessary to consider in the future, Arroyo argues that the current focus should be on greenhouse gas mitigation.)