A common belief among progressive activists outside of climate/energy policy nerds is the idea that promoting clean energy, and clean energy jobs, will address climate change. A typical blogpost calls for clean energy as part of a progressive manifesto, and a typical list of progressive demands includes green energy instead of oil and coal.

These are good things. Clean energy jobs will reduce unemployment, grow America's manufacturing, construction, and service sectors, and make our air and water safer.

But we can't fool ourselves into thinking that clean energy jobs will save the planet. Below the fold, an analogy.

Your doctor tells you that you need to lose 200 pounds in the next five years. Losing any weight will make you feel better, she says, but to prevent a heart attack you really need to lose the whole 200 pounds. To slim down that much, you'd need a crash diet-and-exercise program: 1500 calories per day, every day for the next five years, and an hour on the treadmill per day, every day for the next five years. It's a tough program. Do you have the willpower to do it?

Leaving the doctor's office, you take decisive action: you sign up for a once-a-week yoga class.

Yoga reduces your stress level. Your back pain is gone. You're less depressed. You're busier. You sign up for a second night of yoga, doubling all the health benefits.

And on the way to the yoga class, once a week, you grab a bag of Cheetos to munch on.

You make no other changes to your lifestyle.

And you continue merrily along, until your next doctor's visit. Surprise! You haven't lost weight on your yoga-and-Cheetos routine. Now you need to lose 250 pounds in three years. Now you'd have to cut down to 1200 calories per day, and two hours on the treadmill.

So you start bargaining with the doctor. Do you really have to lose 250 pounds - can't you just lose 100 pounds to avoid the heart attack? (She shakes her head, sadly.) What if the heart attack won't kill you? (It might not, she admits.) What if, you ask sincerely, you can just adapt to a heart attack? (She turns pale.)

Because if the choice came down to either that strict diet-and-exercise routine, or learning to live with a heart attack, you prefer the f*cking heart attack.

Shortly before the 2009 Copenhagen conference, climate scientists warned (pdf) that the world needed to reduce carbon emissions beginning in 2015, and reach zero by 2050, to keep warming to 2 degrees Celsius. It would be technically possible, if only humanity had the political willpower.

Since 2009, President Obama has nearly quadrupled renewable energy on public lands, put out the first-ever mercury regulations, and mandated tough new auto fuel economy standards, among other yoga-class activities. All of these, and more, have generated jobs while reducing pollution. And they'll slowly reduce the demand for carbon. A Breakthrough Institute report estimates that the mercury rule (along with another rule) will reduce carbon dioxide emissions 1.1 to 4.2%.

At the same time, Obama has us snacking on offshore oil leases, fracked wells, and - especially - doubling the size of coal leases in Wyoming's Powder River Basin, the equivalent of adding 300 new coal plants. Across the Pacific Ocean, China's surge in renewables is outweighed by its coal consumption. Neither the United Nations, nor the United States Congress, have the political will to reduce the supply of, or cap, carbon. Just as you need both diet and exercise, carbon reduction requires reduction of both supply of and demand for carbon.

Carbon emissions showed their biggest jump ever in 2010, which the International Energy Agency terms a serious setback to holding emissions to 2 degrees Celsius and 450 ppm. Robert Socolow, author of the "wedges" strategy, now believes 2 degrees is too hard. Reputable economists wonder, without any apparent irony, if 800 ppm really means human extinction - after all, they reason, the mass extinction of life at the Paleocene-Eocene Thermal Maximum didn't occur until the atmosphere hit 1700 ppm. The brutal logic of climate change is growing bleaker.

Because we'd rather adapt to a world going haywire, with a risk of human extinction, than make radical changes to our lifestyles and political systems.

I like clean energy jobs, and I like my once-a-week yoga class. But I don't kid myself that they're going to save humanity.

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