So what is a carbon offset, anyway?

Let’s start with our energy usage: As you probably know, more than 80% of the energy we use comes from dirty fossil fuels like oil and coal, which emit greenhouse gases such as carbon dioxide — this is the leading cause of global climate change. The more dirty energy you use, the bigger your personal carbon footprint and the more responsible you are for causing climate change.

So what can you do about it? Well, the first step to fighting climate change is to reduce the amount of dirty energy you use in your everyday life. Check out our conservation tips for some ideas. But short of becoming a completely self-sufficient hermit, it’s impossible to eliminate your use of dirty energy. You can trade your car for a bike, but the road you ride on takes dirty energy to build and maintain. The food you eat takes dirty energy to grow and harvest. The clothes you wear take dirty energy to make and transport. Dirty energy is so intertwined with our economy that it’s impossible to escape completely: That’s where carbon offsets come in.

A carbon offset represents a quantity of greenhouse gases that someone either removed from or avoided emitting into the atmosphere. The idea is that even if you can’t reduce your personal emissions to zero, you can invest in a project that reduces emissions elsewhere and take credit for those reductions. Let’s say you reduce your personal emissions from 20 tons of carbon each year to 10 tons. No matter how hard you try, you can’t avoid emitting those last 10 tons. So you invest in a wind farm, which replaces a coal power plant that emitted 1,000 tons of carbon each year. Building the wind farm creates 1,000 tons of offsets each year — the 1,000 tons of carbon the coal plant would have emitted. If you paid for a hundredth of the wind farm, then you can take credit for 10 tons of offsets. You’re carbon neutral!

The actual details get a bit more complicated — for example you’d want to know that the wind farm wouldn’t have been built without your investment because otherwise you’re claiming credit for emissions reductions that would have occurred anyway, but those are details that will come in another post. But the basic idea is that renewable energy projects create carbon offsets by supplanting dirty energy sources. By helping to build renewable energy projects you can earn offsets to counteract emissions you can’t reduce.

– Ian