UN climate report: Carbon removal is now “essential”

UN climate report: Carbon removal is now “essential”

As carbon emissions continue to rise, the limit of greenhouse gases that the world can release before pushing the planet beyond very dangerously high warming thresholds has become alarmingly close, warns the Monday report. It concludes that reducing emissions by itself will not be enough. The world will need to develop the infrastructure, systems and policies necessary to remove billions of tons annually of carbon dioxide from the atmosphere.

“Carbon dioxide removal is essential to achieve net zero [greenhouse-gas emissions],” Diana Urge-Vorsatz, vice-chair of the working group that produced the nearly 3,000-page report, said during a conference call on Monday.

The UN’s Intergovernmental Panel on Climate Change (IPCC) has produced a series of sweeping reports for policymakers, assessing the state of the science and the mounting risks of global warming. The third part of the sixth major IPCC assessment evaluates the options available for reducing emissions and limiting the effects of climate change.

To support MIT Technology Review’s journalism, please consider becoming a subscriber.

The report concludes that all sectors of the economy, including transportation, energy and heavy industry, will have to reduce their emissions. This will require rapid and drastic shifts from fossil fuels to renewable energy sources as well as major changes to the way we produce food, and other goods.

The jury has reached a verdict and it is damning,” Antonio Guterres (secretary-general of United Nations) said on the call. “We are on the fast track to climate catastrophe .”

The report devotes a chapter on carbon removal. It highlights just how important a role it may need to play and how difficult it could be for it to reach the goals set out in the next decades.

Here are four of the crucial findings on carbon removal:

1. Carbon removal is basically non-optional

The UN report suggests that it’s now nearly impossible to prevent 1.5 @C of global warming without substantial efforts to remove carbon–and very, very difficult to steer clear of 2 @C without it as well.

Preventing the former with only minimal levels of carbon dioxide removal would require cutting global greenhouse-gas emissions to about 31 billion tons per year by 2030, as the median estimate, the report finds. This would mean that emissions could be cut by nearly half in just eight years.

Cutting emissions that rapidly would require breakneck transitions to new technologies as well as steep reductions in energy demand. This would require unprecedented human behavior changes and efficiency improvement, which would all be “quite difficult to achieve in the real world”, says Zeke Hausfather, who was a contributor to an earlier UN climate report working group and is the climate research lead at Stripe.

Loosening the goal to 2 @C would basically provide an additional decade to halve climate pollution, to 29 billion tons of emissions by 2040.

The speed and scale of reductions required in both cases is simply not realistic, according to Julio Friedmann (chief scientist at Carbon Direct), a research and investment firm that focuses on carbon removal. He says that nations will need to remove carbon at “enormous” levels. The fundamental problem is that the world has already emitted far too much carbon dioxide. We have not done enough to shift towards cleaner ways of operating our economies. We still lack affordable and available solutions to certain industries and products like steel, maritime shipping, fertilizers cement, cement, and maritime shipping. The promise of carbon removal is that the country can have more time to adopt sustainable practices and offset ongoing emissions from sources we don’t know how to replace.

But …

2. We’re going to need to do a whole lot of it

Preventing the planet from warming 2 @C, or pulling the climate back from that, could require pulling down billions of tons of carbon dioxide every year.

Models that limited warming to 2 @C relied on three main methods of carbon removal: planting trees, restoring forests and adopting similar land management practices, developing and deploying carbon-sucking machines, and relying on plants to produce energy while capturing the emissions, which is known as BECCS. Together, they’d need to remove as much as 17 billion tons of carbon dioxide per year by 2050 and 35 billion by 2100, according to the report.

3. We need a portfolio of carbon removal options

The report stresses that different approaches to carbon removal have very different benefits and challenges.

Nature-based methods like planting trees or restoring forests are the most popular. However, the carbon can be released back into the atmosphere if the plants die or are burned up in fires. These solutions are likely to be less effective than other methods such as geological storage which stores carbon underground.

Direct air capture can permanently remove carbon and store it away, but machines are limited in scale and costly, and the technology requires large amounts of energy as well as water. The IPCC report heavily relies on BECCS, which is a combination of technology-based and nature-based approaches with some of the advantages of each. BECCS, however, requires vast amounts of land that could compete with the needs of food production, among other challenges.

The report notes a wide variety of other ways to capture carbon dioxide, including ocean-based approaches like using minerals to increase the alkalinity of seawater. These methods are not well-tested.

4. Scaling up will require funding and policy decisions

The climate panel’s authors stress that achieving high levels of carbon removal is going to take significant research and development to determine the most effective methods, minimize environmental impacts, and rapidly develop major projects in the real world.

We need everyone on deck to explore a variety of options to enact deep decarbonization and remove CO2. This was Frances Wang, ClimateWorks Foundation program manager, who responded to an inquiry from MIT Technology Review. The biggest obstacle to building a major carbon removal sector is likely to be the cost. Who will pay the hundreds of billions or trillions of dollars it will cost to remove this amount of carbon dioxide year after year. The report states that governments must make a political commitment to accelerate research and development in carbon removal. This means that governments must adopt policies to mandate or encourage carbon removal and methods to ensure that these practices achieve the climate benefits claimed. If history is any indication, the grim findings from the new IPCC report will not radically alter anything. The world is pumping out about 6 billion more tons of annual emissions than it was when the last major assessment was published, in 2014. As the importance of carbon removal in combating climate change increases, more work is being done.

Read More