Can carbon offsets actually work?

The market for carbon offsets is booming. These credits are supposed to balance out the carbon emitted by individuals and companies, helping to slow the progress of global warming. That's the theory – but does it work in practice?

Home Life Sustainability Can carbon offsets actually work?

Carbon dioxide emissions cause global warming. This is not opinion, but scientific fact. For the last million years, every time atmospheric carbon dioxide concentrations have breached the critical level of about 250 parts per million, the climate has heated up, as sure as night follows day. And since carbon is already well above that level today – and rising faster than ever before – we have a problem.

This is where carbon offsets come in. Since just about everything we do emits some carbon dioxide, the prospect of being able to counter those emissions simply by buying an offset for a few dollars seems a very attractive solution.

A growing market

Many people and companies are doing just that. The market for carbon offsets has been growing fast over the past few years, and so has the price. In the past nine months alone the price of the most common sort of offset has grown threefold, to just over $14 for a tonne of carbon. These ‘nature based' offsets represent a tonne of actually emitted carbon that gets locked up in something such as a newly planted forest (although there are also offsets that represent emissions cuts, for example, by replacing older carbon-intensive technologies with more efficient systems).

That's real money, but still not too expensive when you consider what you get for your carbon. For example, the average UK household emits just under three tonnes of carbon a year through heating. If you can offset the global warming effects of a whole year's worth of heating for around $42, that sounds like a good deal.

And it is – but only if the offsets really work. So, let's look a bit harder at these climate credits to make sure we are getting what we are paying for.

Know what to look for

There are several tests of a good carbon offset. The first and most important is that they have to be permanent. Something that locks up a tonne of carbon forever is good – but we have to be sure that forever really means forever: temporary carbon storage is useless or maybe even worse than useless because it diverts attention away from long-term carbon reduction.
While the idea of locking up atmospheric CO2 in a pristine slice of rainforest seems a good one, you have to make sure your forest isn't going to be felled in 10 years' time, or even in the foreseeable future. Securing adequate guarantees is hard.

Next, we have to be sure that our carbon-reduction offset isn't just shifting emissions from one place to another. This is what climate scientists call ‘carbon leakage'. If we pay to have carbon emissions removed from the economy in one country, we need to be sure those carbon-intensive activities will not be exported to some other part of the world.

There are other sorts of offsets that are designed to cut emissions at source rather than lock them up. A popular version of this is the ‘cook-stove' offset which invests in projects to replace wood-burning domestic stoves – especially in Africa – with lower-emissions portable gas stoves. But would such projects have happened anyway, even without the offset finance? If so then the offset doesn't pass the ‘additionality' test. A recent EU study concluded that for this reason three-quarters or more of these kinds of offsets fail to deliver the benefits promised.

Study the small print

None of this means that climate-change offsets cannot work – that EU study, for example, identified several greenhouse gas offsets that are likely to be effective, including carbon-reducing biomass fuel projects, and offsets targeting methane and industrial gases. But it does mean that they must stand up to critical examination, especially because the offset market remains largely unregulated.

The lesson is ‘buyer beware'. Offsets can be part of the climate-change battle, but we have to look closely at the small print. As the price of carbon offsets continues to rise, it is likely that people will increasingly do just that – which is no bad thing.

Better still, we should reduce emissions in the first place. Because the best thing that could happen with offsets is that they become obsolete.

Illustration by Davide Bart. Salvemini