You’ve probably been offered the chance to offset your emissions in the past. Perhaps you’ve even done so! Airlines and travel sites now often give you the option to add an additional charge to your bill, offsetting the amount of carbon emissions your seat on the flight will be responsible for (luxury-lovers beware: if you’re flying first class, your bill will be higher as you’re taking up more space of the plane and emissions are split on a per metre² basis). And as well as contributing at the point of purchase, there are now various third party sites that offer the same service.

Air Canada's impressively granular offsetting page

Regardless of whether you choose the retailer or a third party, what they have in common is that they will calculate how much carbon you’ve caused to be released into the atmosphere, and then come up with a price that will undo that harm.

Kind of.

Since the harm has already been done, they actually fund projects around the world that will prevent or remove the equivalent CO₂ emissions elsewhere. So your flight might have taken you to Hawaii, but thanks to your donation, somewhere in Indonesia a hydro plant has been built to power a local community so they no longer rely on coal.

These third party sites vary in how much they charge you per CO₂. That’s partly because there’s no standard price for a tonne of CO₂. Nobel laureate Bill Nordhaus suggested a global carbon tax of $25-$30, which is a modest estimate for the real price - some scientists suggest this may be as much as $150 per tonne. Ouch.

The differing cost is also because the projects themselves differ hugely. Say a hydro plant costs £10 to build (we’ve heard they’re slightly more expensive, but for the sake of simple maths...) and offsets 10 tonnes. That doesn’t mean to say that a small biogas unit that costs one tenth will automatically offset one tenth of the emissions.

And even if a project is expensive, it might still be worth doing - perhaps even more so. By picking the cheapest projects, you increase the chance of greenwashing, as companies are able to tick the ‘environmentally friendly’ box without actually properly fulfilling their obligations.

Companies donating money towards climate change projects is extremely hot right now. That means it’s more important than ever to make sure that the money is actually being used for projects that have a positive impact on climate change.

There is a lot of greenwashing out there - it’s seen in the fast fashion clothes retailer that makes a big PR announcement about their one-off ‘sustainable’ range and the company that turns the lights out for Earth Day while investing in the fossil fuel industry.

With the difficulties that come from verifying the validity of large corporations’ offsetting, it can be particularly useful to be able to put your trust in a third party organisation dedicated to this very thing. But a quick google search will show that you’ve got various options when it comes to doing this. How do you decide which to choose? How much should you be paying to offset your carbon footprint? What kinds of projects should you support? We’re here to answer all that and more.

We compared:

- Atmosfair

- Southpole

- Wren

- United Nations offset platform

And asked the following questions:

- How does it work? We wanted to see how easy it was to get to a figure of total carbon to offset.

- What’s the price per tonne of CO₂? As already discussed, a cheaper cost is something to be wary of when it comes to carbon offsetting. On the other hand, a range of prices makes this an accessible option for more people, so that's not to be discouraged.

- How much CO₂ do they calculate for a standard Toronto-London flight? Since Air Canada estimate their flight at 2.2 tonnes, we were keen to see if offsetting platforms arrived at the same figure.

- Where does the money go? It was useful to see how much information the platforms gave about the projects you can support.

- Can you verify where the money is spent? There are various standards and accreditations that projects can seek, so we looked at who was able to offer this.

Let’s begin!

Offset your carbon with them here.