What is Carbon Removal (& other FAQs): 

Curtailing climate change requires reducing emissions and cleaning up excess CO2 from the atmosphere.


What are the leading approaches to achieve large-scale carbon removal?

Carbon removal approaches fall into roughly two categories: land use or industrial (or a hybrid of the two). Land use approach harness the power of photosynthesis to capture carbon from the air, storing that carbon in plants and soils. Industrial approaches involve technologies that filter carbon directly from the air, storing the captured molecules deep underground or in building materials. For more information on each pathway, see our Research and Links page.

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How much do carbon removal approaches cost, and what is their scale potential?

Today, cost and supply estimates for carbon removal approaches are highly uncertain, as most carbon removal technologies have not entered large-scale commercial deployment. In addition, more systems-level analysis of carbon removal approaches is needed to assess global scale potential. A handful of academic estimates of carbon removal potential have been published, which have been compiled in the illustrative supply curve graphic, below. 

Above: Curve uses midpoint estimates from Working Group 3's contribution to the IPCC's AR5, as well as from analysis conducted by the Virgin Earth Challenge.

Above: Curve uses midpoint estimates from Working Group 3's contribution to the IPCC's AR5, as well as from analysis conducted by the Virgin Earth Challenge.


Why pursue carbon removal?

Carbon removal techniques provide a critical option for mitigating climate change -- they provide a complement to other GHG abatement techniques, not an alternative:

Image adapted from The Climate Institute report titled: Below Zero - Carbon Removal and the Climate Challenge

Image adapted from The Climate Institute report titled: Below Zero - Carbon Removal and the Climate Challenge

Without carbon removal, we can not overshoot our carbon budget and still prevent significant climate change, defined by scientists as a 2 degrees Celsius rise in mean global temperatures:

Image adapted from UNEP Emissions Gap Report 2014

Image adapted from UNEP Emissions Gap Report 2014

The scientific consensus on the need for carbon removal as an option in the fight against climate change has grown increasingly strong:

The large majority of scenarios produced in the literature that reach roughly 450 ppm CO2eq by 2100 are characterized by concentration overshoot facilitated by the deployment of carbon dioxide removal (CDR) technologies.
— IPCC - Fifth Assessment Report on Climate Change. Chapter 6 from Working Group 3

Increasingly, carbon removal approaches are not just critical for keeping global temperatures below 2°C, but are also deployed heavily in modeling scenarios that involve 3+ °C climate change. Major uncertainties exist as to the viability and scalability of the carbon removal techniques assumed in these scenarios. Because existing technologies cannot generate negative emissions, it is critical to resolve these key uncertainties surrounding carbon removal approaches that have such great impact on our ability to prevent climate change.

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Why should we invest in developing carbon removal solutions today?

Carbon removal technologies may not deliver the greatest short-term carbon impact per dollar spent on GHG abatement today, but there still remains a large imperative to invest in these technologies today for several reasons:

1. The carbon removal field today is much more nascent than other GHG abatement fields, and investments in R&D in the field today could increase the competitiveness of carbon removal approaches in the future considerably. In many ways, the carbon removal field is reminiscent of the solar energy field in the 1970s: 

Many energy and environmental technologies follow "learning curves" which require considerable investment in deploying technologies before they can be produced at economically-viable costs:

2. Only carbon removal approaches are capable of generating negative emissions. If we find that we need large scale negative emissions sooner than expected, it will be critical to have viable, scalable carbon removal developed, as more mature GHG abatement techniques cannot provide negative emissions.

3. Carbon removal offers more opportunities for companies and countries to fight climate change. The greater the opportunities we have for fighting climate change in economically and politically viable manners, the greater the likelihood that multilateral cooperative action to prevent climate change will materialize.

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What are the largest challenges facing the carbon removal field?

Many different approaches to achieve carbon removal have been proposed, but considerable research and development is needed to understand which approaches can be scalable, cost-effective, and sustainable:

Who are the leaders in the carbon removal field today?

Organizations across industries and sectors are paving the pathway to a carbon-removing economy. Some of the leaders in this field are below:

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Which carbon removal approaches are best suited for private-sector investment today?

There are good business cases to make for a number of potential carbon removal strategies today, including:

  • Conservation and restorative agriculture and forestry
  • Biochar

While the true carbon removal potential of some of the above approaches is uncertain, these investment can be profitable and have positive environmental/social impact regardless of carbon sequestration potential.

There are also profitable investments in carbon negative "pathway" technologies (i.e. projects that are not carbon negative but can de-risk and develop critical elements necessary for carbon removal solutions), including:

  • Fossil CCS / Bio-CCS for enhanced oil recovery
  • Low carbon cements/plastics
  • Fuel synthesis using direct air capture

What is critical for investments in these technologies is to ensure that learning from "pathway" approaches get translated into fully carbon-negative systems in the near future.

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By "carbon removal," do you mean "carbon capture and storage?"

No. A wide range of approaches can achieve carbon removal. Bio-CCS is one of those many carbon removal approaches, and fossil-CCS can provide a pathway to negative emissions, but the two terms are distinct.

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By "carbon removal," do you mean "geo-" or "climate-engineering?"

No. Most carbon removal approaches fit the popular conception of "mitigation" much better than the popular conception of geoengineering. Here at the Center for Carbon Removal, we focus only on carbon removal mitigation approaches. Check out this blog post for more info. 

At the Center for Carbon Removal, we only focus on carbon removal solutions that fall outside the popular conception of geoengineering.

At the Center for Carbon Removal, we only focus on carbon removal solutions that fall outside the popular conception of geoengineering.