Overview of Solutions
This is a very brief overview of technologies that exist now and that can be scaled up enough to significantly contribute to the restoration of our climate. For more information, read our full paper on climate restoration methods. This paper is an evolving document which is updated as technology and information evolves and changes.
Removing CO2 from the atmosphere
Emissions reduction will not be enough to save the planet. We have to remove CO2 from the atmosphere. Carbon Dioxide Removal (CDR) is the foundational technology of climate restoration.
Direct Air Capture (DAC)
DAC is the process of capturing CO2 from the air so it can be converted to stable forms.
Captured CO2 can be converted into aggregate (limestone) for concrete for roads and buildings. This the only commercially viable use now.
Nature can absorb CO2 if it is buried in basalt rock fields, which are common worldwide. Other natural techniques include biochar, BECCS, and afforestation, but their max scale is insufficient for climate restoration.
Ocean iron fertilization (OIF) distributes high-iron dust onto the ocean. This increases primary productivity and sequestration. Marine permaculture grows kelp in deep water using lattice structures. Fish eat some kelp, and others die and fall into the sea, sequestering carbon. Other techniques like geochemical weathering don’t offer profit potential and would require public financing.
Cooling our planet
Temporary cooling of our planet may be needed. The range of cooling technologies is known as Solar Radiation Management (SRM). Cooling for a few decades while we reduce CO2 levels to 300 ppm could prevent social or economic collapse. Stratospheric Aerosol Injection involves pumping sulfates into the stratosphere to cool the planet. Marine cloud brightening seeds clouds with nano-particles of salt or other materials to brighten and prolong them over the ocean. In cirrus cloud thinning, high cirrus clouds are thinned by seeding them with aerosol particles, allowing more radiant heat from the earth to escape through them.
The cost of removing a trillion tons of CO2 with the current technologies and current costs would be about 1% of global GDP each year for 30 years, or about half of global defense spending. Even if the cost were astronomical, it would be less than the cost of dealing with the catastrophic warming that would result without it. While initial estimates of climate restoration costs were high, newer technologies have lower costs. Many of these technologies produce commercial byproducts, allowing commercially viable businesses to do the work.