Is carbon offsetting a con?

The government says a new coal mine will be “net zero”. But can climate-friendly actions elsewhere truly cancel out its damage?

February 14, 2023
A protest near the site of the new coal mine. Photo: PA Images / Alamy Stock Photo
A protest near the site of the new coal mine. Photo: PA Images / Alamy Stock Photo

Late last year, as he approved the first new UK coal mine for decades, Michael Gove made an announcement in the House of Commons: the project would be “net zero”. But what, you might ask, is a net-zero coal mine?  

It’s a good question—and not as easy to answer as the politicians and business leaders who have facilitated this return to Victorian Britain would have you believe. 

The coal from this mine shaft in Cumbria will be relatively low grade, containing high quantities of sulphur and potentially contributing to acid rain. Used for making steel, it will be sold mainly outside Europe, where environmental regulations are laxer. We could be sending people down this mine until 2049.

If this sounds like a throwback to less enlightened times, that’s because it is. 

During the Industrial Revolution, and the heyday of our coal-based industrial expansion, we were largely ignorant of the impacts that burning energy stored in the earth over millions of years would have. We didn’t know that after it is quickly released into the atmosphere, it can remain there for 1,000 years altering our climate. Today we do. 

Therefore, to preserve any vestige of credibility in terms of climate leadership, this coal mine had to be accompanied by some green commitments. Enter the concepts of “net zero” and “climate neutral”—meaning that actions would be taken to “offset”, or compensate for, the impact of the mine on the climate. The claims in this case were sketchy at best, with the impact of the coal itself incredibly being left out of the equation. 

But the burning question is whether such a thing could ever really be achieved. Can the impacts of coal mining and other climate-damaging activities truly be offset by buying evidence of climate-friendly actions elsewhere? 

I’ve spent (too many) years working on policies that assume we can create a market which trades in climate impacts. Throughout that time I’ve witnessed many problems in these fledgling markets, while concentrations of greenhouse gases have continued to rise inexorably. There are many explanations for this—not least that politicians have yet to overcome the fierce resistance they face from incumbent industries. But a central flaw is also the oft-cited claim that “a tonne is a tonne”, or “all tonnes are equal” when it comes to greenhouse gases.

This is wrong on many counts—for example, there are important implications related to where emissions occur, not least for those whose health is impacted by local pollution, due to proximity to industrial zones and busy roads. But it is also wrong in terms of global fairness, given that some countries have emitted vastly more than others and essentially used up any safe capacity that the atmosphere may have had, making themselves very rich in the process. 

Location matters, then, but so too does the nature of the actions being traded. Take, for example, a coal-fired power station and the planting of trees—in theory the trees can increase the uptake of carbon from the atmosphere, thereby “offsetting” the coal burn. And yet, while we can have very high certainty about the impact of the coal burn, exactly what happens due to the tree planting is incredibly uncertain. This is especially so in a world with a destabilised climate and increased risk of wildfires, floods, heatwaves and droughts, all of which have substantial—but yet to be fully understood—impacts upon the growth of trees and the health of the forests. For even if the planted trees survive, we now know that forests must be treated as a whole. It’s not enough to simply count the tree trunks; the net contribution of greenhouse gases from the entire ecosystem has to be taken into account, including what is happening below the canopy and in the soil. These environments can for example be sources of methane—especially in areas prone to flooding, including some rainforests.

If the uncertainty around planting trees is very high, offsetting by preserving existing forests is even worse. Claiming to preserve an area of forest that would otherwise be cut down is fraught with assumptions and uncertainties: whether the deforestation risk is real, whether it can be truly eliminated (and not just moved elsewhere) and whether the mature forest is indeed a net remover of greenhouse gases in the first place. Alarmingly, there is some evidence the Amazon rainforest may already be tipping into a net source of emissions.  

It is not enough to simply count the tree trunks; the whole forest ecosystem has to be taken into account

Countries like New Zealand, Brazil, Switzerland and indeed the UK have helped develop methods to measure the net greenhouse gases emitted over time from different ecosystems, and the cost of technologies for doing this is coming down. This can help give us more certainty over so-called “biospheric sinks”, thus creating trust in the offsetting market. 

But while you may think, “please, yes, let’s preserve our forests”, we must not get trapped in a self-defeating cycle where paying for forest conservation permits unchecked, climate-wrecking fossil fuel emissions that destroy forests. 

So where does that leave us? Are all efforts to offset worthless? It is instructive to return to guiding principles here. The overriding aim must be to open up existing markets where greenhouse gases dominate (such as power generation, transport, industrial manufacturing, and red meat and dairy production) to solutions that fully replace, rather than merely compensate for, the harm they cause. 

You can theoretically accomplish a version of this with offset projects. Our mine in Cumbria should be paying for coal-free ways of producing base metals (which do already exist but are not yet competitive); oil companies for the electrification of transport; beef and soy producers for alternative sources of protein. 

But this only gets you so far. Ultimately governments should be clear about the need to halt the licensing of new supplies of fossil fuels in the first place, and support instead applications for clean infrastructure. In the UK, an electric arc furnace in Cumbria (using electricity to melt waste metals), instead of the coal mine, could have helped us reuse the metal waste we currently export for recycling and created as many, if not more, future-proof jobs. 

Beware the false equivalence of nature-based offsets being used to compensate for fossil emissions. As companies’ green claims are put under increased scrutiny, I hope it won’t be long before “easy but questionable” options are taken off the table. “Net zero”, “carbon offsetting” and “carbon neutral” have entered our lexicon relatively recently and variations will undoubtedly be added over time. “True zero” is, however, what we should be aiming for.