Two writer's who do some pretty smart writing on science and the environment, Jonathan Golob of dearscience.org and Jacon Liebenluft, author of Slate.com's The Green Lantern column, have both at various times come out talking some shit about carbon offsets.  It is not an uncommon point of view.  It is also, one I just do not understand.

I will be starting from the assumption that you, the reader, understand and accept the importance of reducing carbon emissions.  It is not my goal to convince you of the truth in global warming science, or the urgency in the matter.  If you aren't convinced by now, then I would also probably have a hard time selling you an umbrella in a rainstorm.  Instead, it is my goal to convince you that carbon offsets are an important, useful, and valid tool in reducing your personal carbon emissions.


But wait! Haven't I previously said that global warming is not the problem, it is just a symptom of a more serious underlying problem? Haven't I said that the real issue is that our current lifestyle is unsustainable, and that by addressing that issue, we would also address global warming? Still true, of course.  But just because you need to take antibiotics to get rid of your cold, that doesn't mean you also should wipe your nose while you are still sick.

And even that comparison is not quite fair.  Carbon offsets can be a means to cure the underlying issue.  Yes, I will now, finally, explain what a carbon offset is.

A thought experiment: it is your wish to keep your carbon emissions completely flat..  You need to take a cross-country flight on a commercial airline, which will result in additional carbon emissions over your baseline.  That means you need to reduce your baseline carbon output in some way to make up the difference. What changes can you make in your life that will offset the carbon emissions from that flight?

You could take the bus (or ride an electric bike) instead of driving to work.  You could reduce the amount of meat in your diet.  Or, you could do something really drastic, like erecting a wind turbine in your yard to produce electricity cleanly, instead of getting it from the coal power plant in your region.  Yes, I said erect.

Now let's take it a step further.  You and I both need to offset some carbon emissions.  So, why don't we pool our money together and split the cost of the wind turbine.  We could erect it together (hehe).  Or why don't we get a group of 100 people together, split the cost of a wind farm, and offset our emissions that way.

Eventually, economies of scale kick in, and it actually becomes relatively cheap to offset the emissions from your airplane rides, or your car use, or whatever.  As an added bonus, you now have a wind farm producing electricity, which helps to solve the underlying problem of sustainability.

This is what carbon offset companies like Terrapass do.  They have calculated the carbon that is emitted by activities like driving, flying, and home use of electricity, and then you can purchase offsets for that carbon use.  This money is then used to fund alternative energy projects that result in the reduction of carbon emissions elsewhere in the world. 

Sounds great, right? So, what is the problem? (Other than the "indulgence" argument, which is dumb.)

The real problem is this: I get my power from 100 MW coal plant.  My carbon offset goes towards building a 10 MW wind farm.  Will the coal plant now start putting out 90 MW? Or will the excess supply of electricity just drop the price, thus increasing consumption such that we all now use 110 MW instead of 100 MW?

In a static world, maybe.  But demand for electricity is growing all the time.  You aren't offsetting 10 MW from the coal plant down the street.  Instead, you are offsetting 10 MW from the coal power plant that was going to be needed tomorrow.  Now, instead of building another 100 MW plant, we'll only need a 90 MW plant. 

Because there is no immediate reduction in carbon emissions, I'll admit that the carbon offset is the last tool in the green toolbox.  The $20 offset for that flight from Houston to Newark is better spent on reducing consumption first - CFL light bulbs, energy efficient clothes dryer, electric bikes (come on people! they are awesome!), yadda yadda yadda. 

But there is only so much you can do to be more efficient.  At some point you have to look outside your own home, and the best way to do it is with carbon offsets.