I’m a skeptic by nature. So when I first started hearing about carbon offsets, my initial reaction was that they must just be a sugar pill, an empty way to make people feel less guilty about their carbon-intensive lifestyles. But I’m becoming more of a believer, and here’s why. Carbon offsets are a way to counterbalance your carbon emissions by investing in solutions such as wind energy. You purchase the “offset,” and your money goes toward developing new wind farms or preserving rainforest acreage or capturing methane. There are several companies and nonprofits that do this, in varying ways.

The downside of carbon offsets is the obvious: It allows people with disposable income – those also more likely to have higher carbon emissions from activities like air travel – to engage in a form of armchair activism. Simply write a check, and you don’t have to make any changes to your lifestyle. Not that there’s anything wrong with writing checks to good causes; without philanthropy, we’d be nowhere. But most climate policy experts agree that multiple solutions, on all different scales and of all different varieties, wil be necessary to combat global warming – so just writing a check isn’t enough.

But it is, it turns out, a pretty good start. I asked an expert in wind energy if she thought carbon offsets – at least those that fund wind energy - would be useful even if no one purchasing them made any change to their personal carbon emissions, and she said yes. The reason is that for every megawatt generated by wind power, that’s a megawatt not produced by burning fossil fuels. And the more wind plants that are up and running, the lower the cost of wind power will be, and the more people will choose to purchase it instead of fossil fuel power.

Beyond this concrete impact, though, the act of purchasing carbon offsets represents a way of engaging with the issue. “While carbon offsets represent an opportunity to discretely reduce your carbon impact,” the head of TerraPass, a carbon offset company, wrote on the blog RealClimate, “they also represent a great way to talk about climate change, your perspective and potential solutions.”

Some carbon offsets also trade on carbon emissions markets, which allows them to purchase carbon credits and then retire them. This is a complicated system, but the overall effect is to reduce the amount of carbon being traded on the market – in other words, a company emitting more than its share of CO2 that might otherwise seek to purchase someone else’s credits now has fewer credits to purchase (which ideally means the available credits are also more expensive). Currently, such markets are voluntary, but many people believe a federally regulated carbon market might not be too far off.