Reducing emissions that would quickly require a breakneck transition to new technologies, as well as a sharp reduction in energy demand. That would require unprecedented changes in human behavior and efficiencies, all of which “would be quite challenging in the real world,” said Zeke Hausfather, a contributor to a previous working group for the latest UN climate report and the leader of climate research at Streep.
Easing the target to 2C would in fact provide an additional decade to halve climate pollution, to 29 billion tons of emissions by 2040.
The speed and magnitude of the cuts needed in either case is simply not realistic, said Julio Friedmann, chief scientist at Carbon Direct, a research and investment firm focused on carbon removal. Nations will have to do “huge” levels of carbon removal, he says.
The Essential Problems: The world has already emitted too much. We haven’t done nearly enough to switch to cleaner ways to run our economies. And we still don’t have available and affordable ways to repair certain industries and products, such as aviation, shipping, fertilizers, cement and steel.
The promise of carbon removal is that it can give countries more time to switch to sustainable practices, and balance the ongoing emissions from sources we don’t know how to replace.
2. We will have to do a lot
To prevent the planet from warming 2°C, or to pull its climate back from it, it may be necessary to cut down billions of tons of carbon dioxide every year.
Models that limited warming to 2°C were based on three main methods of removing carbon: planting trees, restoring forests and adopting similar land management practices, developing and deploying carbon aspiration machines, and relying on plants to produce energy while they capture the emissions, which is known as BECCS. Together, according to the report, they should remove as much as 17 billion tons of carbon dioxide per year by 2050 and 35 billion tons by 2100.
3. We need a portfolio of carbon removal options
The report highlights that different approaches to carbon removal have very different benefits and challenges.
Nature-based approaches, such as planting trees and restoring forests, are the most widely adopted today. But the carbon can be released back into the atmosphere right away if the plants die or burn. Thus, these solutions likely have shorter lifespans than other methods, such as geological storage, which trap carbon underground.
Direct air capture can permanently remove and store carbon, but the machines are currently limited in size and duration, and the technology consumes large amounts of energy and water, the report said.
The IPCC report’s models rely heavily on BECCS, a hybrid of nature-based and technology-based approaches, with some advantages of each. However, BECCS requires huge amounts of land that can compete with the needs of food production, among other things.
The report lists a host of other ways to capture carbon dioxide, including ocean-based approaches such as using minerals to increase the alkalinity of seawater. But these have largely not been tested.
4. Scaling up requires funding and policy decisions
The climate panel authors emphasize that achieving high levels of carbon removal will require a great deal of research and development to determine the most effective methods, minimize environmental impact and rapidly develop major real-world projects.
“We need all hands on deck to explore a diverse set of options to both achieve deep decarbonization and remove carbon dioxide,” Frances Wang, program manager at ClimateWorks Foundation, which funds research efforts for carbon removal, wrote in a response to an MIT Technology Review inquiry.
Probably the biggest hurdle to building a large carbon removal industry is cost. Who is going to pay the hundreds of billions to trillions of dollars it takes to remove so much carbon dioxide year after year?
The report says accelerating research and development on carbon removal – and getting companies to do it – will require “political commitment” from governments. That means establishing policies to mandate or incentivize carbon removal, as well as methods to ensure the practices achieve the claimed climate benefits.
If history is any guide, the grim findings of a new IPCC report won’t change anything radically. The world pumps out about 6 billion tons more emissions annually than when the last major assessment was published in 2014. But work is increasingly underway to remove carbon as the importance of its role in combating climate change becomes more apparent.