Tech companies think they can reverse climate change with fancy new tools to remove carbon dioxide from the atmosphere. But the new research throws cold water on the idea that cooling the planet after it has already warmed past a key tipping point could avoid serious damage. Much of the toll climate change takes – from rising seas to lost homes – cannot be undone, recent research published in the journal Nature warns.
This makes it all the more urgent that climate-minded governments and companies cut fossil fuel pollution now, rather than offsetting or capturing their greenhouse gas emissions after the fact.
“Climate change comes with irreversible consequences.”
“Climate change comes with irreversible consequences. Every degree of warming, or every point of a degree of warming … comes with irreversible consequences,” Carl-Friedrich Schleussner, lead author of the paper and head of the integrated climate impacts research group at the International Institute for Applied Systems Analysis ., said in a phone call with journalists before the publication of the newspaper.
Startups are developing a range of technologies to help big polluters capture their carbon dioxide emissions – from filtering CO2 from the air or ocean to capturing CO2 in rocks or concrete. These technologies have yet to prove whether they will be able to scale up to a level that would have a significant impact on climate change.
Tech giants like Microsoft and Google have been among the biggest backers of these new carbon removal tactics. They have made commitments to eventually reach net zero or net negative emissions, but their carbon footprints have grown in recent years as they expand AI data centers. And there is not yet enough renewable energy installed to run these companies’ operations without still generating greenhouse gas emissions. Increasingly, tech companies are signing carbon offset deals to try to reverse the impact their pollution has had on the climate.
Globally, emissions must reach net zero around 2050 to keep the planet from warming much more than it already is. Almost every nation on Earth has signed the Paris climate agreement to stop average global temperatures from exceeding roughly 1.5 degrees Celsius above pre-Industrial Revolution temperatures. The world is fast approaching this threshold – having already warmed by around 1.2C, which is increasing climate-related disasters such as monster storms and wildfires.
One of the hopes with carbon removal is that it potentially can the opposite climate change, reducing temperatures if we exceed the target of 1.5 degrees. But things won’t just go back to normal, new research by 30 scientists shows. Melting ice from glaciers will continue to raise sea levels “for centuries to millennia,” for example, a phenomenon that has already pushed people from their homes along vulnerable coasts. And even if the global average temperature drops, it’s hard to say exactly what outcome to expect from region to region.
The recent devastation caused by Hurricanes Helene and Milton—disasters exacerbated by climate change—shows what is at stake if we wait to take action. The number of lives and homes lost from these types of disasters will continue to rise the longer we fail to stop climate change. And repeated disasters take a compounding toll on the communities most at risk. Florida barely had time to recover from Hurricane Helene before Milton hit less than two weeks later.
Exceeding climate targets “involves deeply ethical questions about how much additional climate-related loss and damage people will have to endure, especially those in low-income countries,” the paper says.
There is also the possibility that the planet will heat up more than expected. Scientists calculate carbon “budgets” to understand how much carbon dioxide humans can emit before missing climate targets such as keeping warming to 1.5 degrees. But these estimates are not accurate. The pollution “budget” we think we have left may, in reality, lead to more severe climate change than expected.
In that case, we may also need more carbon dioxide removal than expected to stabilize the climate. But increasing carbon removal to that level may not be feasible. If greenhouse gas emissions raise temperatures higher than expected, several hundred gigatons of carbon removal may be needed to prevent the worst climate impacts, according to the paper.
“Although this concept is interesting, it assumes that there will be a reserve of [carbon dioxide removal] capacity that can be rapidly deployed around the world – an assumption that I would consider overly optimistic,” writes Nadine Mengis, a research group at the GEOMAR Helmholtz Center for Ocean Research, in a separate. Nature article commenting on the research.
Existing facilities that can filter carbon dioxide from the air only have the capacity to capture 0.01 million metric tons of CO2 worldwide today, costing companies like Microsoft up to $600 per ton of CO2. This is a very small capacity at a very high price.
“We cannot waste removing carbon dioxide to offset emissions we have the ability to avoid,” study co-author Gaurav Ganti, a research analyst at Climate Analytics, said in a press release. The priority should be to prevent contamination now rather than clean it up later.