Limiting climate change now requires carbon capture, study finds

Even if we stopped emitting greenhouse gases today, the Earth would continue to heat up for centuries. Arctic ice and permafrost are already on an irreversible path of melting.

This is the finding of new research published Thursday in the journal Scientific Reports. The model suggests that even if emissions were to drop to zero this year, global temperatures would ultimately rise 5.4 degrees Fahrenheit in 2500 from 1850 (or 3 degrees Celsius).

“The tundra will continue to melt over the next 500 years – however fast humanity reduces its greenhouse gas emissions,” Jørgen Randers, lead author of the new study, told Business Insider.

That’s because climate change is a vicious, self-sustaining cycle: As permafrost thaws, it releases more greenhouse gases, like methane and carbon dioxide, which keep warming over time. time. To stop this cycle, Randers said, we will need to suck carbon dioxide out of the atmosphere.

8 feet of sea level rise

Randers’ study modeled the effect of various emission reduction scenarios on Earth’s climate between 1850 and 2500.

Data showed that if emissions stopped for good in 2020, sea level in 2500 would still be over 8 feet (2.5 meters) higher than in 1850.

Felipe Dana / AP

To avoid the predicted rise in temperature of 3 degrees Celsius, greenhouse gas emissions would have had to cease entirely between 1960 and 1970, according to the model. In this sense, Earth blew to a climax of no return 50 years ago – before much of the public understood the realities of climate change.

“Yeah, that’s an irony,” Randers said. “But of course, the scientific community was already aware of global warming in the 1960s.”

We need to suck carbon from the atmosphere

The Paris climate agreement was created with the intention of reducing greenhouse gas emissions enough to prevent the global temperature from rising more than 2 degrees Celsius by 2100. But even if all emissions would stop by 2100, according to Randers’ model, sea level in 2500 would be nearly 3 meters higher than they were in 1850.

Earth temperatures are already on track to exceed the targets of the Paris Agreement. Last year was the second warmest on record for surface temperatures and the hottest on record for oceans. Polar melt is set to lift seas 3 feet by 2100 and threatens to displace hundreds of millions of people.

What is needed, Randers said, is for businesses and governments to “start developing technologies for the large-scale removal of greenhouse gases from the atmosphere.”

In technical terms, this strategy is known as carbon capture and storage (CCS). To prevent further warming after emissions stop, the new study found that at least 33 gigatonnes (36.5 billion tonnes) of carbon dioxide would need to be sucked out of the atmosphere each year. That’s roughly the total amount of carbon dioxide that the global fossil fuel industry emitted in 2018 (36 gigatons).

Power plants in the United States, Canada and Switzerland have already started using CCS to reduce their emissions. In 2014, the Boundary Dam power plant in Saskatchewan became one of the first in the world to successfully use this technology.

A total of 21 commercial-scale carbon capture projects are underway around the world and 22 more are under development, according to the Center for Climate and Energy Solutions. These projects typically store carbon deep underground in depleted oil and gas fields or in bioreactor containers filled with algae that eat carbon dioxide.

Santiago Urquijo / Getty Images

Two US carbon captures completed in 2017 – one in Illinois, the other in Texas – can capture 1.1 million and 1.6 million tonnes of carbon dioxide, respectively, per year. But the amount of CO2 that needs to be removed from the atmosphere requires many more plants than current plans foresee.

“In other words, build 33,000 large CCS factories and keep them running forever,” the study authors wrote.

The advantages and disadvantages of geoengineering

Carbon capture is increasingly accepted as a safe and potentially effective form of geoengineering. This climate intervention and others are increasingly being initiated by scientists and politicians; Andrew Yang, the 2020 Democratic presidential candidate, has suggested budgeting $ 800 million for new geoengineering research in the United States.

But most climate hacking proposals would be much riskier than CCS. Take solar geoengineering, for example, which involves injecting aerosols into the sky to send sunlight back into space. Critics of this idea point out that most models predict that the effects of solar geoengineering would not stay localized. If a country decided to independently deploy such measures, varying and unpredictable effects would likely be observed elsewhere in the world.

Aerosol injections deployed in the southern hemisphere, for example, could impact ocean temperatures and wind speeds, resulting in more hurricanes in the northern hemisphere.

Aleksandar Georgiev / Getty Images

“Solar geoengineering has geopolitical ramifications, unlike carbon capture,” Juan Moreno-Cruz, an associate professor at the University of Waterloo who studies geoengineering, previously told Business Insider.

Randers said his study advocates carbon capture only, not other more experimental forms of geoengineering.

“I’m generally against geoengineering because of its unintended side effects. But if the world continues to delay meaningful and achievable actions to phase out fossil fuels, we may have to resort to geoengineering,” he said. Randers said.

As an immediate priority, he added, countries should also invest in efforts to reduce emissions and build more CCS factories.

“It would be a formidable task for a government funded Green New Deal,” he said.