Window Shopping for Carbon Offsets

The following is a guest post by Jen Boynton:

Finding the right carbon offset to help reduce your footprintSo, you’ve decided to take some responsibility for your carbon footprint and buy some carbon offsets to account for all your unavoidable driving and flying emissions. Congratulations on taking some responsibility for the massive situation we call “the climate crisis” Now you are wondering, which retailers are the most reliable? And how do you tell? It’s a complicated world out there, but I hope to make things a bit easier for you by recommending a few sellers and projects that are better than most and telling you why.

Before we get into the nitty gritty, let’s make sure we’re all clear on what a carbon offset actually is. In its most simplified form, a carbon offset is a commitment that 1 metric ton of C02 equivalent has been prevented from entering the atmosphere and contributing to global warming. Whew. Feel free to read that again if you need to. The offset can come about through dozens of different means like tradable credits from the Chicago Climate Exchange, or they can take the form of different carbon reduction projects which can be categorized into three main types: renewable (emissions free) energy generation, energy efficiency, and sequestration. We’ll discuss the benefits and drawbacks of each type of project a bit later. 

In addition to the type of offset, we also need to be concerned about quality. We want to buy offsets that are verifiable (the project actually happened), additional (it wouldn’t have happened without your money), leakage-free (the carbon you’ve sequestered isn’t going anywhere), permanent (those trees you paid for won’t be cut down and turned into paper napkins), and not double-counted-(the offset was sold only to you). By purchasing offsets that meet these criteria, you have the best chance of making sure that your purchase has the intended effect of ensuring that that green house gas does not make it into the atmosphere. I tell you all of this because I believe that in a Wild West marketplace, it’s very important to be an informed consumer.

But that’s just the background. You’ll be dealing with the retailers, folks who will sell a variety of offsets from different types of projects, so let’s focus on what you need to look for from your offset seller. The first thing you need to watch out for is that the offsets are verified through a third party verifier like Green-e, the Gold Standard or the  Voluntary Carbon Standard. These verification schemes will make sure that the quality of the offset is up to par. If you are curious about why those are my picks, take a look at a post I recently wrote on voluntary carbon offset regulation for

As for where you can go to purchase your offsets, there are a variety of other retailers who sell a portfolio of projects verified by some or all of the verifiers I mentioned. My favorite catch all site for offset sellers is They regularly update with new sellers, the types of projects they are offering, who verifies them, and the price at which they are selling. This site is an easy way to pick out retailers who have projects from the most trustworthy third party verifiers.

I also wanted to specifically call out the offset retailers that are verified through the Green-e certification, because Green-e is my personal favorite, due to the fact that my beloved UCS weighed in on the verification criteria.

Green-e verifies offsets that are sold by: 3 Degrees, Bonneville Energy Foundation, and Community Energy, which are all companies I would recommend buying from. 3 Degrees has some renewables and methane capture offsets that are verified through Green-e, while Bonneville and Community Energy offsets are renewable energy based. What is the difference between these types of offsets, pray tell? I am so glad you asked! These are two of the most common offset projects out there, and they are the two types of offset projects I would recommend buying if you are going to make an offsets purchase. Here’s how they work: (story continues, click on the link below…)

Methane Capture
Methane is a greenhouse gas with 20 times the global warming potency of C02 (each unit will make global warming 21 times worse than a comparable unit of C02). So, it’s really important that we prevent methane from entering the atmosphere, just like C02. You might hear methane referred to in its C02 equivalent, or C02E, which is just a means of equalizing the global warming potential of different types of gasses.

The methane capture you will hear about most frequently occurs at landfills and dairies. You might be thinking that enterprising farmers attach some kind of expandable plastic bag to the cows’ behinds to capture their emissions as a second source of income-and while that sure is an amusing image, (I personally hear an airline stewardess reminding me that while the bag may not inflate air will flow through the plastic tubing), the methane capture on dairy farms actually occurs on manure lagoons. All the poop the cows create is shoved into one heap and the heap is covered with a tarp-like enclosure. The tarp captures the gas that is released from the poop, and the gas is either burned off or used as energy to fuel the farms operations. The same type of enclosure occurs on landfill methane capture projects. I recommend these projects because they are actually the easiest to quantify-the gas is right there for the measuring–which means you can be assured that you are getting the amount of C02E that you paid for. 

The main drawback with methane capture is that if you are a systems thinker, perhaps you don’t really like the idea of huge confined animal feeding lots, and poop lagoons, and big landfills. If these realities of today’s society are really problematic for you, and you want to work toward a world with local food, composting, and closed loop systems, where methane in large quantities wouldn’t be released in the first place, giving the owners and operators of huge dairies and landfills an extra income source might give you a bit of an ethical dilemma. Methane capture is an important component of solving the climate crisis, but it’s also not a permanent fix because we really should be changing our food and waste systems so that they don’t give off methane in the first place.

With renewable energy projects, your carbon offset money goes toward the purchase of the infrastructure for clean energy, also known as an “environmental co-benefit,” a side benefit of preventing carbon emissions from entering the atmosphere. However, the carbon savings is less of a precise calculation than it is for methane.

Here’s how it works:
A company creates a renewable energy project (like a big solar farm or a windmill) and sells energy to the big utility, and the big utility has to buy less dirty energy (like that from coal or natural gas) to keep up with demand for power from its customers. The cleaner the electricity that is being sold, the less carbon is being emitted per kilowatt hour of electricity. The owners of renewables carbon offset projects measure the carbon savings by calculating the local average emission per kilowatt hour and sell the tons of carbon saved as offsets.

To look at this another way, the purchase of a renewable based carbon offset allows a company to build the infrastructure to create one ton of carbon savings. The purchase is not just about a short-term carbon savings, it’s about creating a cleaner future where we don’t get ourselves into this mess again. The downside is that the carbon savings is pretty far removed from the infrastructure investment, and also a bit tougher to quantify precisely.

Those are the two types of offsets I would recommend buying, as long as you buy verified ones. There are a couple other types of projects you might see in the marketplace, in general, and I wanted to alert you to them so that you can avoid buying them, because they are more problematic than methane capture and renewables.

Offsets to Avoid
Buying Credits from a Trading Scheme:
This type of offset is the purchase of a credit from a trading market like the Chicago Climate Exchange. Companies join the exchange, pledge to reduce their emissions, and then are able to sell these credits to other members. Offset retailers join the registry to buy up these credits, mark them up (sometimes 3x or more!) and sell them to consumers.

This offset choice is perhaps the most contested of all. Some people are very much in favor of them because a purchase on these markets is a stand in support of the market for carbon, a stand for carbon emissions as a financial liability for firms who choose not to make reductions and a financial gain for firms who become cleaner.

A purchase of these credits is a vote for the ability of markets to solve the problem of global warming with the right incentives. I have personal reservations about the Chicago Climate Exchange because its verification schemes – the way they verify that their members have made the reductions they claim to – are not available for public viewing. They are lacking on the transparency side, to put it lightly. The lack of transparency means that we can’t be sure that the companies making the reductions aren’t fudging the numbers to make their carbon savings look more impressive than they really are.

With a product as abstract as a gas emission you can’t see, if the reductions are not strictly verified, the whole system will collapse, because their will be many more sellers than buyers. Plus, I want to make sure that you get all the C02E you paid for, and it is tough to be sure when the verification is not rigorous.

When you buy a forestry offset, you are buying a commitment that a certain parcel of forested land will remain that way, and that the carbon tied up in those trees will stay there instead of burning up or being cut down and turned into plywood furniture. The carbon savings seems more direct than in some of the other project types: trees are made of carbon, it’s pretty obvious that ensuring that there are a lot of trees means that there will be less carbon in the atmosphere.

However, these projects are somewhat problematic for a few different reasons.
First, the type of tree and where it was planted make a big difference in how much carbon actually gets sequestered. It is very difficult to quantify the exact carbon savings per tree or per acre, and when you buy a carbon offset, that one ton of carbon removed from the atmosphere, you are paying for precision.
Second, it is impossible to guarantee that a forest will not burn down (at which point the carbon will be released into the atmosphere). Permanency is also problematic with forestry. How long into the future can we guarantee that that forest will stand? 100 years, max? The sequestration needs to be permanent to be effective in fighting climate change. Finally, it is very difficult to demonstrate that the forest would not have stood anyway with or without the purchase-if it would have, your offset money did not go toward that one ton of carbon.

In summary, my final recommendation is to buy offsets that are from methane capture or renewables projects. The choice between the two of them is mostly a matter of personal preference, and comes down to your values and reasoning for buying the offsets. Buy offsets that are verified through the Gold Standard, the Voluntary Carbon Standard, or Green-e. Going with any of the three companies that Green-e supports is a safe bet because all of their offsets are more than likely to be rigorously vetted in some manner, though there are many offset retailers out there who are selling verified offsets.

Happy Shopping!

Jen slings 100% post consumer recycled paper for the Union of Concerned Scientists as the Berkeley office manager, but she’s not representing said scientists on this blog. Of course, she fully intends to swipe facts and figures from their materials in addition to her own research as an MBA student in Sustainable Management. You can reach her at sustainablejen at

Thomas Schueneman
Thomas Schueneman
Tom is the founder and managing editor of and the PlanetWatch Group. His work appears in Triple Pundit, Slate, Cleantechnia, Planetsave, Earth911, and several other sustainability-focused publications. Tom is a member of the Society of Environmental Journalists.

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