What We Really Mean by “The Massive Scale” Required for CDR in Climate Goals

How much CO₂ we’ll need to remove from the atmosphere — in addition to direct decarbonization goals — in five charts.

In previous articles, RMI experts have explained the need for carbon dioxide removal (CDR), alongside aggressive and urgent decarbonization efforts, to meet climate goals. Recent estimates based on IPCC projections of emissions reductions indicate that the world may need to remove up to 10 gigatons of CO₂ each year by 2050 to stay below 1.5°C of warming. Those working in the CDR field often describe this scale as “massive” or “enormous” and the necessary speed of growth as “unprecedented” or “ambitious.” But these terms alone do not allow people to truly envision the magnitude of a gigaton.

The prefix “giga-” translates to billion; each gigaton of CDR deployment means removing 1,000,000,000 metric tons of CO₂ from the atmosphere. In the same way that it is difficult to conceptualize the vastness of the solar system, the microscopic size of a cell, or the age of the Earth, it is hard to grasp what “gigatons of CDR” means without helpful comparisons and visuals. This article will break down the massive scale of CDR needed by 2050, using five key graphics.

While reaching the scale of CDR required to complement direct decarbonization for a safer climate future is not insurmountable, it is certainly an enormous effort that will require scientific rigor, dedicated innovation, and a strong policy and funding commitment this decade.

1. The amount of CDR required to stabilize the climate would make it one of the world’s largest commodities

The burning of fossil fuels and other industrial processes released 41 gigatons of CO₂ into the atmosphere in 2023. For comparison, the total municipal solid waste produced in 2023 — collected in landfills, compost heaps, recycling facilities, and incinerators — weighed 2.3 gigatons. If global CO₂ emissions were compressed into a visible solid waste pile, it would be 15 times larger than a pile of all the trash collected from towns and cities around the world.

The scale of CO₂ waste can also be compared to the scale of the world’s largest industries. The total mass of the top eight commodities traded in the world today is 27 gigatons. This is a huge amount of material, but it is still only three-quarters of the mass of CO₂ produced each year. Deploying ten gigatons of CDR per year by 2050 would mean that, within a few decades, this nascent industry would need to grow to a size larger than today’s global coal industry. This goal is achievable but will require significant and deliberate investment and growth in relevant supply chains.

2. Achieving a gigaton of CDR in any given approach category would require large-scale deployment

There are several approaches for pulling CO₂ out of the atmosphere and the ocean. RMI’s CDR taxonomy classifies CDR approaches in three categories —  biogenic (bCDR), geochemical (gCDR), and synthetic (sCDR) — which are defined by their respective requirements for biomass, alkaline minerals, and low-carbon energy. Exhibit 2 below shows the scale of these inputs needed to remove 1 GtCO₂ within each of these categories. Because of the scale of these requirements, global coordinated efforts across a portfolio of CDR approaches will be required to remove several gigatons of CO₂ from the atmosphere each year.

3. Achieving a gigaton per year of CDR would require a workforce of millions of people

In unpacking the scale of CDR deployment needed by 2050, it’s also important to consider the many people whose efforts will be needed to remove gigatons of CO₂. Interviews with CDR companies across approaches suggest that removing 1 gigaton of CO₂ per year may require between 400,000 and 1,800,000 workers in areas including construction, operations, and ancillary corporate positions such as finance and legal support. Reaching 10 gigatons of removals per year could therefore require a total workforce of ~10 million workers. To put this in perspective, the global renewable energy industry employed 13.7 million people in 2022.

4. Achieving a gigaton per year of CDR would require CAPEX spending of $32B-$1.1T

In addition to workforce and physical inputs, scaling the CDR industry will require significant capital expenditures (CAPEX). Depending on the approach, one gigaton per year of CDR represents CAPEX costs of between $32 billion and $1.1 trillion. The reason for this massive range is that some approaches, such as gCDR, have very little CAPEX because they do not require large infrastructure buildouts. By contrast, CAPEX needs for sCDR are highest, estimated at around $800 billion-1,150 billion for one gigaton per year of capacity because they require the construction of large air contactor facilities and processing systems. While these levels of CAPEX can at first seem overwhelming, they are not impossible to achieve. In fact, many industries — including manufacturing, utilities, finance and insurance, real estate, transportation, and mining — spend hundreds of billions in CAPEX every year.

5. Achieving a gigaton of CDR in any category requires significant time to scale supply chains

Reaching a gigaton-scale CDR industry will require substantial changes to global supply chains and practices as permitting and practice changes may take years to decades to accomplish. This is especially true for open-system projects on our lands or oceans and for the development of sufficient supply chains. Exhibit 5 shows three examples across CDR categories that outline the shifts needed in supply chains and industry practices.

sCDR approaches rely on low-carbon energy as a key input. To filter enough air to extract one gigaton of CO₂, a DAC plant would require 700 TWh of energy or more. At current generation levels, this would consume 17 percent of US electricity production.

Removing 1 GtCO₂/y via enhanced weathering, a gCDR approach, would require spreading alkaline minerals on more than 90 percent of US cropland. Successful scale-up would require further research on the safety of mineral additions, development of protocols to quantify and monitor removals, and farmer awareness of and interest in these practices, all of which will take time.

All bCDR approaches require biomass inputs such as wood or other plant matter. The biomass needed to store 1 GtCO₂ would weigh around 0.6 gigatons. If this quantity of biomass were transported between sites with trucks, this scale would increase total US truck freight by 5 percent.

Improving CDR technologies today will help us reach gigaton scales

A gigaton of CO₂ is a lot of material. Removing several gigatons from the atmosphere each year by 2050 will require establishing an industry to rival some of the largest in the world today. Now is the time to develop improved technologies to improve efficiency, build the workforce, optimize CAPEX costs, and establish sufficient supply chains. By making these investments now, the efforts required for each additional ton of CO₂ will decrease, bringing the gigaton scale within reach.