The Fuzzy Math of Net-Zero Is Under Attack

We cannot plant enough trees or suck enough CO2 to make a difference.

Forest fires in California are depleting carbon credits
Forest fires in California are depleting carbon credits.

David McNew / Getty Images

The concept of net-zero has troubled us at Treehugger for some time. We first discussed it in terms of architecture and building, where, according to the International Living Future Institute's definition, "One hundred percent of the project's energy needs being supplied by onsite renewable energy on a net annual basis." But in our post, "The Grid is Not a Bank," I quoted Passivhaus architect Bronwyn Barry, who wrote, "The reality is that the grid does not have the capacity to store all excess energy generated in summer, so buildings employing this 'fuzzy math' still require that the grid supply their winter deficit." 

Treehugger contributor Sami Grover has also asked: Is net-zero a fantasy? He discussed pledges from countries, cities, and companies, noting that "the very idea of net-zero has become a problematic excuse for inaction." The problem comes in the second half of our definition:

What Is Net-Zero?

Net-zero is a scenario in which human-caused greenhouse gas emissions are reduced as much as possible, with those that remain being balanced out by the removal of greenhouse gas emissions from the atmosphere.

How are these greenhouse gas emissions being removed? Is anyone actually doing it at scale? Or is it all just a dangerous distraction? Some big hitters are now questioning the concept. 

The most interesting is a new and important website, Climate Uncensored, set up recently by Dan Calverley and Kevin Anderson, both formerly with the Tyndall Centre for Climate Change Research. In a recent post, they note that the concept of net-zero started with buildings and apparently got co-opted.

"The language of 'net zero' is now virtually ubiquitous throughout the mitigation modelling and policy discourse, but it is worth reflecting on how just how recently it has penetrated the literature and been adopted as a kind of 'groupthink'. Compare the incidence of the term in the IPCC's fifth and sixth assessment reports. 'Net zero' appears 23 times in the WGIII contribution to AR5, published in 2014 – almost all in the context of net-zero energy buildings, such as Passivhaus design; i.e. proven, tried-and-tested tech. Jump to this year's WGIII contribution to AR6, and the incidence of 'net zero' skyrockets to 963 mentions – overwhelmingly now in the context of negative emissions and carbon capture; technologies that remain speculative at scale." 

Got some carbon dioxide (CO2) emissions you have to get rid of? Plant some trees or build a big machine to suck them out of the air. Both seem a stretch given the amount of CO2 we are emitting, but they note: "What were once considered fringe policies for their riskiness and highly-speculative nature are now a mainstay of the mitigation scenario and policy landscape, despite the continuing lack of evidence that they can be scaled up in time."

I thought the mention of Passivhaus was interesting because Passivhaus Consultant Monte Paulsen told Treehugger earlier that it was all a numbers game and a setup from day one, and he knows numbers. "Check out the various commentary on the intergovernmental 'net-zero' emissions targets," said Paulsen. "They assume GHG remediation tech that does not exist. the target is BS and the COP knows it, but it was reportedly the only way to make the numbers work and get an agreement. Can't blow a bigger hole in net-zero emissions (on a national scale) than that."

scale of collectors
Climeworks is removing CO2 from the air in Iceland.


In an MIT Technology Review article—titled "We must fundamentally rethink "net-zero" plans" and a subhead reading, "Corporate climate plans are too often a mix of fuzzy math, flawed assumptions, and wishful thinking"—journalist James Temple complains that many companies are planning to get to net-zero through shopping for offsets. "In other words, they can continue to emit planet-warming gases, so long as they pay someone else, somewhere else to make up for it," wrote Temple. "And that's where many of the problems arise."

He suggests that instead, they must slash direct emissions (our radical efficiency plan), avoid offsets, and while he does support research and investment in carbon removal technologies, he noted:

"There's a slippery-slope risk for carbon removal as well. It's best to think of it as an essential tool to help us fix the really difficult, really expensive last parts of the problem. But it can't cover up for an economy still running at the most fundamental level on fossil fuels. And thus, we can't afford to allow the pursuit of carbon removal tools to distract from the essential task of overhauling our industries."

Almost everybody is piling on offsets, even American late-night host John Oliver. There are a few exceptions; Nick Aster was Treehugger's first chief technology officer and built the first Treehugger website; he is now the marketing director for global sustainability solutions provider South Pole. He published a defense of offsets and a critique of Oliver:

"The vast majority of carbon projects in the world are sound. They span many types, from tree planting and forest conservation, to large scale ecosystem restoration, renewable energy, cookstoves, solar and even high-tech projects that literally suck CO2 out of the air....Many of these projects have myriad benefits beyond just removing CO2, including economic and social justice issues around the world. But the overall point is that carbon offsets, properly vetted, are the single most powerful tool we have right now to avoid the worst case scenario which we are very much headed for if we do nothing."

Loath as I am to disagree with our former CTO, as I noted in "Net-Zero Is a Dangerous Distraction," it's too late for this. "It is silly to say we will plant trees when parts of North America are under a pall of smoke from burning forests that were counted as offsets. It's silly to say we have the technology to suck carbon dioxide out of the air when we have seen how well carbon capture, utilization, and storage (CCUS) works." 

The only real solution is to radically reduce demand for fossil fuels and aim for absolute zero carbon dioxide emissions, or as we have also suggested, zero carbon without a net. We know how to do this; it's just so inconvenient.

But, as Emily Partridge wrote in Architype: "We are in a climate emergency. We need to be completely clear, honest and truthful, use the knowledge and the technology we already have, and drop the greenwash." 

The net is full of holes and it is time to get real about this.