The Paris Agreement, with its international climate commitments, is ratified and comes into force Nov. 4. It is an enormous achievement. For the first time, a majority of nations representing a majority of emissions have agreed to significant emissions reductions and to clean energy deployment. These commitments focus largely on increased energy efficiency and renewables. Some also call for nuclear power, carbon capture and storage, and electric vehicles.

All are needed — but even together, they’re not enough. What’s required for the U.S. and the world to meet that commitment has not yet been widely appreciated. To accept the science of climate change, you must accept the math as well.

Fossil energy is unavoidable now and for many decades to come. Most of our electricity comes from coal and gas, and dozens of new such plants are being built each year despite their climate implications.

It will take many more years to transition to low- or no-carbon vehicle fleets, especially in heavy-duty vehicles and air transport. And 20 percent of the world’s carbon emissions come from the world’s cement, oil, chemical and steel factories because they use huge amounts of fossil energy as part of their core chemistry.

Sinking carbon

We have many options to accomplish the shift to zero carbon energy. However, even in aggregate, these options are not sufficient. The math is harsh and the challenge enormous. If we want to avoid the climate-energy scenarios spelled out in Paris, we must embrace — and invest in — negative emissions technology to facilitate the removal of billions of tons of CO2 from the atmosphere, starting in 25 years. For perspective, 1 billion tons is roughly twice the weight of all the people on Earth. 

To accept the science of climate change, you must accept the math as well.

Engineered approaches to removing CO2 from the air have existed for years (think submarines and Apollo 13). Those approaches are expensive, but there are a dizzying set of approaches that are likely to prove much cheaper.

Two companies, one in Canada and one in Switzerland, today operate small projects (cleaning about one ton of CO2 per day), powered by renewable energy, that demonstrate how carbon removal can be done at more modest costs. Other projects convert CO2 pulled from the air into fuels or plastics.

Biomass energy, which stores CO2 in the bodies of plants, can be combined with carbon capture and storage to pull CO2 from the air and store it deep underground — one such project has operated in Illinois for years. Other companies are beginning to turn asbestos mine wastes into cement or road aggregate through carbon removal.

Biological pathways to carbon removal are more complicated, but likely will be required as well. Restoration of damaged ecosystems stores some carbon, as does the reforesting large areas of deforested terrain.

Charcoal from biomass can be buried in soils and in some cases can make them more fertile. It may prove that changing agricultural practice can accelerate carbon update in soils or reduce the rate of loss, as well as complement the critical work of ecosystem preservation.

A bold investment

To understand and develop these options requires investment. Like most innovative energy technologies, costs for carbon removal projects and technology will not come down until we gain more experience and achieve greater scale. This was true for early solar and wind projects, which initially cost more than 10 times the price today.

Government support will be necessary to create and sustain innovation in carbon removal. The National Academies are beginning a study to assess which tasks are most relevant. However, as of today, there are no government research and development (R&D) projects supporting carbon removal in any country.

1 billion tons [of CO2] is roughly twice the weight of all the people on Earth.

Many nations must begin with substance and determination in order to get on track. Thankfully, there is a good vehicle to begin: Mission Innovation, announced by 20 heads of state in Paris, declared a doubling of R&D budgets for clean tech. The Mission Innovation targets and commitments today are $30 billion per year of new investment worldwide by 2021.

Carbon removal should be part of this bold innovation agenda, with some substantial fraction of these funds committed both to discovery science and large-scale pilot projects. In the U.S., first and foremost, legislators must lay the foundation for R&D programs that can demonstrate viable negative emissions approaches and account for their reductions and costs.

Some groups, like the Center for Carbon Removal, support these efforts. However, many in the environmental community oppose these approaches. They consider carbon removal a moral hazard and claim that it may diminish interest in clean energy deployment.

That’s shortsighted. Getting serious about climate means emissions can’t be wished away. The mission to spare the planet’s ecosystems and reduce atmospheric concentrations of greenhouse gasses requires this crucial technology — and it is still the right time to act and support its deployment. The best time to plant a tree is 20 years ago. The second best time is now.