In the battle to reduce greenhouse gas emissions, carbon offsets have been touted as a key tool for emissions reduction. But what are carbon offsets? And how can you purchase the right ones?

What are Carbon Offsets?

So it’s likely you’re reading this post because you’re wondering what are carbon offsets. It’s actually a pretty simple concept: To minimize the carbon footprint for your emission-producing activity, you purchase an offset from a company that engages in carbon reducing projects.

The best way to understand this is with an example. Let’s look at air travel. Suppose you’re planning a trip from New York to London for a special event. There’s no way to avoid it and you’re flying economy class. You know, intuitively, that this flight will generate carbon emissions, but you don’t know by how much. You also don’t know how to avoid your part in releasing carbon dioxide into the atmosphere. What do you do? Purchase carbon offsets to cancel out the emissions from your trip.

How Much Should You Purchase?

Use a carbon footprint calculator to determine your emissions for a trip. For example, a round-trip flight from New York to London, flying economy class, would set you back 1.66 metric tons. To “offload” that 1.66 metric tons, you’d need to invest in a project that eliminates the emissions you’ve effectively released into the atmosphere.

Are Offsets Expensive?

Most offsets are inexpensive and, since most projects are implemented by non-profit 501c3 organizations, they’re tax-deductible.

In our NY to London scenario, it would cost you less than $15 to purchase an offset from, for instance, the Cool Effect organization to offset your 1.66 tonnes emitted. Other reputable organizations are equally as reasonable in their offset prices.

Which Carbon Offsets Should You Buy?

So now you know what are carbon offsets. Which ones should you buy? There are numerous projects you can fund, ranging from renewable energy and energy efficiency programs, to reforestation initiatives.

How do you know which company or organization is legitimate? It can be difficult to determine whether your dollars are being spent on reputable projects, so do your homework before you open your wallet. Project criteria to look for:

Additionality. This means the project wouldn’t have happened unless it had received the offset financing. Think about it: What if that solar project you’ve funded would’ve happened anyway, without your dollars? It therefore wouldn’t be cancelling out the emissions from your flight. So look for a project that provides additional carbon-reducing benefits.

This means the project wouldn’t have happened unless it had received the offset financing. Think about it: What if that solar project you’ve funded would’ve happened anyway, without your dollars? It therefore wouldn’t be cancelling out the emissions from your flight. So look for a project that provides additional carbon-reducing benefits. Permanence. The project that you’re funding needs to last and have a lasting impact.

The project that you’re funding needs to last and have a lasting impact. Verification. Make sure your offset purchase is from a reputable organization. To help you, below are some accreditation entities that verify carbon offset projects. In addition, I include some recommended carbon offset standards to look for.

Carbon Offset Certification and Verification Sources

World Wildlife Fund’s comparison of carbon offset standards is a good place to start.

The Gold Standard is truly the gold standard of verification programs. It also includes a registry of certified projects on its site.

The Verified Carbon Standard is administered by the non-profit Verra organization. It includes a searchable database.

The Climate Action Reserve is one of the premier carbon offset certification entities in North America.

Green-e is the trusted global leader in clean energy and carbon offset certification. As a third-party certifier, it doesn’t sell offsets, but provides a list of vendors that do.

Carbon Offset Programs

I offer a few certified programs here, with the disclaimer that it’s always important to do your own background check for verification and authenticity.

Carbon Fund is a Gold Standard certified organization that conveniently categorizes tax-deductible offset donations by activity.

Cool Effect carbon projects are verified by the The Gold Standard and other leading verification bodies. 90% of each dollar donated goes toward their projects. You can calculate your emissions and purchase offsets for travel emissions directly on their site.

Terrapass, another certified organization, includes a carbon footprint calculator by vehicle type and offers an array of projects to fund. They also include gift cards for purchase.