Science Matters – Carbon offsets: a tool in the fight against global warming

By David Suzuki with Faisal Moola

The science is clear: human-caused global warming is a reality. Now it’s time to focus on solutions. We need strong leadership from our governments in setting firm greenhouse gas reduction targets, and we need to look at a range of policies and practices. There’s no legitimate argument about whether the problem exists, but there is still some debate about the best ways to tackle it.

Take carbon offsets. Some people compare them to "indulgences" granted by the church allowing sinners to avoid punishment for some transgressions. Others argue that offsets can be one of many legitimate tools used to tackle climate change, and that high-quality carbon offsets can result in real reductions in greenhouse gas emissions.

Carbon offsets are becoming an increasingly popular way for individuals, businesses, and even governments to reduce their impact on the environment. The "voluntary" carbon market, made up of all these purchases of carbon offsets, increased in value globally from $305 million in 2007 to $460 million in 2008. If you add in the offsets that are used in national and international regulatory programs, such as the Kyoto Protocol and European Emissions Trading System, the total carbon market now approaches $139 billion a year.

So carbon offsets are here to stay. But what are they? Well, a carbon offset is a credit for a reduction in greenhouse gas emissions generated by one project, such as a solar-power installation, that can be used to cancel out the emissions from another source. Carbon offsets are typically measured in tonnes of CO2 or their equivalent. Those who buy offsets are essentially investing in other projects that reduce emissions on their behalf, either because they are unable to do so themselves or because it is too expensive to make their own reductions.

One thing to note is that not all carbon offsets are created equal. Because the market is new and largely unregulated, some offsets are unlikely to have any benefit for the climate. This is one reason why carbon offsets have gotten a bad rap.

So, what makes a good offset? Opinions vary on some of the finer points, but most experts agree that several conditions are necessary. Good offsets are "additional"; that is, they result in greenhouse gas reductions that wouldn’t have otherwise occurred without the incentive of carbon offsets. For example, if a company is required by regulation to install technology to reduce emissions from its factory, the resulting emission reductions should not be sold as offsets.

A good carbon offset should also result in "permanent" reductions in greenhouse gas emissions. This is one reason why some organizations, including the David Suzuki Foundation, recommend against using tree-planting to generate offsets. Although trees have many benefits for the environment, they make risky carbon offsets because they are susceptible to fire, logging, and insect infestation – any one of which can release the stored carbon back into the atmosphere and render the offset worthless.

Good carbon offsets should also be verified by qualified auditors to ensure that the reductions have actually taken place.

Carbon offsets that are real, additional, and permanent can have a direct, positive impact on the climate. And they can create some other important benefits. They provide money for much-needed renewable-energy and energy-efficiency projects, which can help move society away from fossil fuels and toward a clean-energy economy. Buying carbon offsets can also help to deal with emissions that aren’t currently covered by government regulations, such as international air travel. Carbon offsets can also put a value on carbon, and help to educate businesses and consumers about the climate impact of their daily decisions, and where they should target their own reduction efforts.

Of course, people should do everything they can to reduce their greenhouse gas emissions, but when that isn’t possible or feasible, buying high-quality offsets at least ensures that an equivalent amount of reductions is made elsewhere.

Carbon offsets alone won’t solve climate change. We still need to find ways to make deep reductions in our own emissions. But the problem of climate change is so massive that it requires a whole range of solutions, and offsets can be part of that.

For additional help in guiding your decisions about carbon offsets, my foundation and the Pembina Institute have just released a guide, Purchasing Carbon Offsets, available at http://www.davidsuzuki.org/Publications/offset_vendors.asp