To hear some politicians speak these days, you'd think climate change could be solved as a happy side effect to creating jobs and reducing oil imports. Of course, the problem is much bigger than that. Just ask Robert Socolow, a professor at Princeton University and creator of the oft-cited "wedge" approach to reducing greenhouse gas emissions.

In 2004, Socolow published an article in the journal Science that said greenhouse gases could be reduced substantially by combining several existing technologies with conservation measures, each technology or strategy forming a wedge. No single approach would be enough, but taken together, these wedges could make a big difference. The Science paper began with the provocative statement that "humanity already possesses the fundamental scientific, technical, and industrial know-how to solve the carbon and climate problem for the next half-century." The profound optimism of that remark has been used far and wide by those arguing for action on climate change.

But now, according to a report in National Geographic, Socolow says people should have read his paper more carefully.

He originally wrote that a combination of seven wedges, including reducing automobile travel and installing huge numbers of wind turbines, would make it possible to stabilize carbon dioxide concentrations at 500 parts per million. But he notes than none of these wedges would be particularly easy. The fuel economy of vehicles would have to double, 2 million wind turbines would have to be installed, and the amount of energy supplied by solar power would have to increase 700 times. Even then, he says, all the wedges would have done is keep annual emissions at about what they are now, which would likely still allow the world to warm by 3 degrees—hardly eliminating climate change. In comparison, global climate talks have focused on trying to limit temperature increases to just 2 degrees.

Socolow also says climate activists took his theory and extrapolated from it, suggesting, for example, that adding more wedges would make it possible to to decrease emissions more than he predicted. As a result, climate change began to seem like an easy problem to solve, which he thinks contributed to the lack of action since 2004. From National Geographic:

"With some help from wedges, the world decided that dealing with global warming wasn't impossible, so it must be easy," Socolow says. "There was a whole lot of simplification, that this is no big deal."

He said his theory was intended to show the progress that could be made if people took steps such as halving our automobile travel, burying carbon emissions, or installing a million windmills. But instead of providing motivation, the wedges theory let people relax in the face of enormous challenges, he now says.

"The job went from impossible to easy" in part because of the wedges theory. "I was part of that."

And from there, he says, a disturbing portion of the population moved to doubt that the problem is even real.

"I know no one who predicted that the climate change message would be rejected on a scale that it is now," Socolow said at a recent seminar at Harvard's Kennedy School of Government. "Scientists and environmentalists interested in getting climate taken seriously have failed beyond their wildest imaginations.

"This is a time for self-assessment," he said.

The article goes on to quote Henry Lee, who directs the environment program at the Harvard Kennedy School's Belfer Center for Science and International Affairs.

"I think we were victimized more by the advocacy community than by science," Lee said. Using Socolow's wedges theory and similar arguments, advocates suggested "you could get all of this and pay nothing. I think people feel angry now, that it's going to cost them."

Here's an alternative explanation. A concerted effort to dispute the reality of climate change paired with economic hardship made Americans care less about the issue. It seems unlikely that telling people that climate change is difficult to solve will make people more likely to support climate change policy.

On the other hand, if such a policy is ever to become law--and stay law for the decades it will take to address the problem--people will certainly need to be convinced that climate change is a problem worth doing something about, and they'll need to have a realistic idea of what sacrifices will be necessary to solve the problem. Trying to convince them that forcing utilities to use more expensive sources of electricity will help the economy, as some politicians and policy experts are doing, doesn't seem to be working.

Advocates of "geoengineering"--proposed approaches to cool the planet to offset the effects of greenhouse gases--point to major volcanic eruptions as evidence that the techniques could work. Very large eruptions, like the one at Mount Pinatube in 1991, actually did cool the planet by injecting sulfates into the upper reaches of the atmosphere, where they circulated for over a year, shading the earth. Such advocates have been hoping that another major eruption would come along that could be studied for clues on how best go about artificially cooling the planet.

The eruptions of Iceland's Eyjafjallajökull volcano, while impressive and large enough to shut down air traffic in Europe, don't fit the bill. Here's what Alan Robock, a professor of environmental studies at Rutgers University, who has studied the impact of volcanoes on climate, told me:

So far the volcano has only put out less than 0.004 Mt of SO2, compared to the 20 Mt that the 1991 Mt. Pinatubo eruption injected into the stratosphere. Furthermore, the Icelandic emission was only into the lower atmosphere, where the lifetime is on the order of one week, as opposed to a couple years in the stratosphere. So too little, and staying in the atmosphere for too short a time. So far.

To make an impact globally, the volcano would have to erupt much more violently (or perhaps trigger nearby volcanoes to erupt violently) so that the larger amounts of sulfates would reach the stratosphere and stay in place, he says. To follow the size of eruptions at the volcano, click here.

This week the U.S. Congress heard testimony supporting a bill that would push to replace diesel with natural gas in heavy vehicles. It's an attempt to cut oil imports, and at the same time reduce greenhouse gas emissions. Part of the argument is that natural gas is substantially cleaner than diesel, and results in the emission of about 25 percent less greenhouse gas.

But experts are warning that natural gas might not be as clean as it seems.

In fact, using natural gas rather than diesel in vehicles could actually increase climate change, says Robert Howarth, professor of ecology and environmental biology at Cornell University. "You're aggravating global warming more if you switch," he says.

Howarth is basing his conclusion on a preliminary analysis that includes not only the amount of carbon dioxide that comes out of a tailpipe when you burn diesel and natural gas, but also the impact of natural gas leaks. Methane, the main component of natural gas, is much more effective at trapping heat than carbon dioxide, so even small amounts of it contribute significantly to global warming. When you factor this in, natural gas could be significantly worse than diesel, he says. Using natural gas would emit the equivalent of 33 grams of carbon dioxide per megajoule. Using petroleum fuels would emit the equivalent of just 20 grams of carbon dioxide per megajoule.

Howarth goes further, suggesting that natural gas could even rival greenhouse gas emissions from mining and burning coal--the dirtiest of fossil fuels. He says it's "not significantly better than coal in terms of the consequences of global warming" and is calling for a moratorium on extracting natural gas from shale, which requires more energy (and so emits more greenhouse gases) than extracting it from conventional natural gas sources.

Howarth's analysis, however, is just a preliminary one. He's already found one major error in his original calculations. "I blew it," he says, by not including the impact of methane leaks from coal mining. (Here's a link to his original, which contains the error; and here's the updated version). But he still says the gap between coal and natural gas is far smaller than generally thought. And his numbers are significantly different than those researchers at MIT came up with a year ago. (On a CO2 equivalent grams per megajoule basis, they scored diesel at 10.7 and gasoline at 14.4, with natural gas splitting the difference at 12.5). The two studies make different assumptions about the strength of methane as a greenhouse gas, and the amount of methane leakage, for example. A complete analysis should also look at the different efficiencies of natural gas and gasoline or diesel vehicles. The MIT study concludes that there is a benefit from switching to natural gas, all told, but it might not be worth the cost or the hassle. Making more efficient gasoline and diesel vehicles might work better, and be a faster way to reduce greenhouse emissions, it suggests.

But for all the shortcomings of Howarth's analysis, it points to a real need. Before Congress passes any bill promoting natural gas, a thorough study of the potential impact needs to be taken into account, including the energy it takes to obtain it, and the impact of methane leaks.

Otherwise the U.S. might end up subsidizing something that does little to reduce carbon dioxide emissions--as happened with corn ethanol.