One tonne of fossil carbon is not the same as one tonne of carbon in trees or soil

Or why offsets are not a solution. An excellent critique by Wesley Morgan at Griffith University

Australia’s government is currently looking at the country’s rules to regulate greenhouse gas emissions from the industrial sector. The changes to the “safeguard mechanism” are supposed to prevent Australia’s top 215 emitters from exceeding certain thresholds, or baselines.

The new regulations do not require Big Polluters to actually cut their emissions. Instead they can buy carbon offsets. And there are no limits on how many offsets companies can buy.

Wesley Morgan, a Research Fellow at Griffith University, has written an excellent critique, published on The Conservation website. Morgan explains in clear terms why we can’t use trees and soil to offset emissions from burning fossil fuels.

Offsets will not save us

Morgan writes that,

“One tonne of carbon dioxide pumped into the atmosphere by burning fossil fuels is not the same as one tonne of carbon stored in the tree trunks of a newly planted forest.”

(We’ll skip over the fact that Morgan means an area of newly planted trees, and not a forest. If left long enough, of course, the newly planted trees may form a forest, but that’s far from certain to happen.)

He continues:

“The carbon in coal, gas and oil has been safely stored underground for extraordinary lengths of time. But when trees take carbon dioxide back out of the atmosphere, they may only store it for a short period.

“There is simply no way around it. Avoiding the worst of climate change means stopping the extraction and burning of fossil fuels. Offsets will not save us. In fact, unlimited use of offsets could see even more emissions, if coal and gas companies ‘offset’ emissions and ramp up exports.”

Morgan explains that it would be easier for policymakers, and the rest of us, if we could carry on burning fossil fuels and offset the emissions by planting trees. “But it doesn’t work,” he writes.

It is simply not possible to offset billions of tonnes of emissions from burning fossil fuels by planting trees or increasing the amount of carbon in soils.

The two carbon cycles

Morgan explains that the carbon stored in trees, soils and wetlands is part of the “active” carbon cycle:

“Carbon is everywhere on Earth — in the atmosphere, the ocean, in soils, in all living things, and in rocks and sediments. It is constantly being cycled through these different parts. Carbon is also being continually exchanged between the atmosphere and the ocean’s surface. Together these processes make up the earth’s ‘active’ carbon cycle.

“When we burn fossil fuels, we release carbon locked away for millions of years (hence “fossil” fuels), pumping vast new volumes of carbon into the active carbon cycle. This is very clearly altering the balance of carbon in the Earth system and faster than ever recorded in the Earth’s geological history. Planting trees does not lock carbon away again deep underground. Instead, the introduced fossil carbon remains part of the active carbon cycle.

“To compound the problem, much of the carbon stored in land-based offsets does not stay stored. Forests can easily be destroyed by fire, disease, floods and droughts, all of which are increasing with climate change.”

Morgan uses a simple diagram to highlight the difference:

Eliminating offsets would be even better than a few offsets

Morgan writes that “offsets will still have a small role”. He gives the example of the steel industry, where low-emissions technologies are “still scaling up”. He suggests that these offsets should be strictly limited and set to decline over time.

I think this is a mistake in an otherwise excellent piece. Eliminating offsets completely would be even better than allowing a “strictly limited” number of them.

We’ve known about the climate crisis for decades. If Big Polluters were actually serious about addressing the crisis, or if governments were serious about regulating the pollution, polluting industries could have scaled up low-emissions technologies by now.

There’s a serious danger of offsets being used to give the impression that something is being done, when in fact they are greenwashing business as usual. Big Polluters have been getting away with this for far too long.

Offsets are worse than doing nothing. They are a distraction from the changes that are urgently needed. And a distraction from the need to address the violence of extractivism and the fossil fuel industry.

Offsets are not a solution

Morgan quickly gets back on track. “Offsets are not a solution,” he writes. “There is no substitute to actually ending the routine burning of fossil fuels.”

“We all want our comfortable lives to continue with a minimum of change. Offsets seem to deliver that. But all they really do is offset our guilt and responsibility. They cannot solve the central problem which is that every year, we add another 33 billion tonnes of carbon dioxide to the atmosphere by burning fossil fuels.

“The atmosphere doesn’t respond to good intentions or clever schemes. All it responds to is the volume of greenhouse gases which trap ever more heat.”

Morgan concludes that, “We have to give up on offset pipe dreams. The only thing that matters is cutting emissions.”