Carbon offsets have skyrocketed in popularity in recent years. Most people might know them only as a little feel-good box you can check when booking a plane ticket through some carriers, but now you can buy them through various providers whenever you feel particularly carbon bloated. 

With that said, you can’t just buy any carbon offset and expect that in some place around the world, carbon is being absorbed thanks to your money. The sad reality is that some carbon offset programs have questionable methods while others are just complete scams. In order to navigate the world of carbon offsets, here’s a guide from the people over at LifeHacker.

Choose wisely: The first question is how to pick programs that actually put most of the money collecting towards fighting climate change. Not all carbon offset programs are created equal. Environmentalists, for instance, have been skeptical of offsets that are focused solely on forest preservation by claiming to save forest land from logging and other destruction. Low-quality offset programs are subject to what the industry calls leakage, where the offsets pay to save one patch of forest only for the property owner to clearcut an adjacent patch.

The good news is that research is starting to tell us which programs work and don’t work—and agencies such as the Climate Action Reserve are helping to verify the programs that do their job right. Other third-party agencies such as Verified Carbon Standard and Verra can help you make the right call.

What offsets DON’T DO: Offsets are NOT a license to pollute or to go about your life as it is now with zero changes whatsoever. Rather, they’re the last step in a process of reducing your emissions. The goal is to offset carbon emissions you can’t easily reduce on your own. So while you can decide to ride a bike to the grocery store instead of sitting in car traffic, eat literally anything else except meat and can cut down on single-use plastics on your own, you can’t easily bike to your cross-country business meeting. And that’s when you buy offsets.

Want to take a deeper dive into the world of carbon offsets? Take a look at the guide right here.