What the IPCC says about geoengineering

From the IPCC Working Group II contribution to the Sixth Assessment Report:

Solar Radiation Modification (SRM) approaches have potential to offset warming and ameliorate other climate hazards, but their potential to reduce risk or introduce novel risks to people and ecosystems is not well understood … Due in part to limited research, there is low confidence in projected benefits or risks to crop yields, economies, human health, or ecosystems … There is high agreement in the literature that for addressing climate change risks SRM is, at best, a supplement to achieving sustained net zero or net negative CO2 emission levels globally.


Modeling studies show SRM could reduce surface temperatures and potentially ameliorate some climate change risks (with more confidence for SAI [Stratospheric Aerosol Interventions] than other options), but SRM could also introduce a range of new risks.

Their discussion is a good overview of the field. The meat of it starts on page 2848 of this gigantic PDF, or page 83 of the Chapter 16 PDF.

(Potential) Technological Solutions to Climate Change

What this is and why I’ve made it

Many people and organisations are attempting to use technology to solve climate change. Their work spans a broad range of areas, including energy production (nuclear fusion, next-gen geothermal energy), new materials (carbon-free cement, biopolymers), and tech that will help us adapt to a worst-case scenario (solar geoengineering, water desalination, wildfire-fighting drones).

I struggled to find a good overview of all the climate tech solutions out there, so I decided to do some research and build my own. I think more people should be aware of the potential benefits of climate tech: I’ve noticed lots of climate-related pessimism and negativity among my friends, and think that learning about potential solutions to climate change can help alleviate that pessimism.


I’ve focused on deep-tech/hardware rather than software solutions, in part because deep-tech interests me the most, and in part because including all software areas would make the list unwieldy.

I’ve not included technology that is commonplace today, such as electric cars, solar panels, or plant-based food.

I’m not an expert in any area of this, so may have made mistakes; if you spot a mistake please let me know in the comments or email me.

Strictly categorising things is hard, so some solutions may belong to categories other than the one I’ve put them in.

I am not endorsing any of these ideas or startups, or making any claims about their chances of success. When I mention startups working on the problems, I’ve just selected ones that I’ve come across; there may be others working on the problems that I have not named.

This list is far from comprehensive; please make suggestions for other areas I should include in the comments.


  1. Energy
  2. Agriculture
  3. Transport
  4. Materials
  5. Carbon Capture and Storage
  6. Solar Geoengineering
  7. Adaptation

(Potential) Technological Solutions to Climate Change: A Categorised List

1. Energy

1.1 Energy Production

Nuclear fusion, which would fuse atoms together to produce large amounts of clean energy.

Producing green hydrogen with new electrolysis technology.

Converting natural gas into hydrogen and solid carbon, which can be sequestered.

  • Startups working on this: C-Zero.

Converting coal-fired power stations with small, modular nuclear reactors.

Advanced nuclear power stations, which are easier to build and cheaper to run.

Next-generation geothermal power stations, which could provide 24/7 “baseload” power.

Producing gas from waste using gasification.

Floating wind turbines, which could allow us to deploy turbines further out to sea — where winds tend to be stronger.

  • Organisations working on this: Equinor.

Broad spectrum solar panels, which help solar panels turn more light into electricity, increasing the amount of power produced.

1.2 Energy Storage

Iron flow and iron air batteries, for long-duration grid energy storage.

Organic redox flow batteries, which are cheap and stable.

Electro-thermal energy storage, for long-duration grid energy storage.

  • Startups working on this: Malta.

Geomechanical pumped hydro storage, which stores energy underground in the form of pressurised water.

Gravity storage, which lifts composite bricks when energy is plentiful then drops them when electricity is needed.

Solid-state batteries, which have higher energy densities and can charge faster.

Coating lithium-ion batteries in graphene to increase their energy density.

Making battery anodes from silicon, increasing energy density.

  • Startups working on this: Sila.

Making carbon nanotube electrodes for “ultra-fast carbon batteries”.

Producing paper biofuel cells, which are biodegradable.

  • Startups working on this: BeFC.

1.3 Energy Transmission

Aluminium-encapsulated carbon core conductors, for long-life and efficient power transmission.

Evaporative cryogenic cooling systems for high-temperature superconductors, allowing for higher levels of power transmission.

  • Startups working on this: Veir.

Grid management software and monitoring.

2. Agriculture

Using robots and AI to increase farming efficiency.

Making pet and human food from insects.

  • Startups working on this: Ynsect.

Growing meat in a lab.

Using microbes to provide crops with nitrogen, as an alternative to synthetic fertiliser.

Creating alginate microcapsules for biofertilisers.

Using microbes to produce proteins from electricity and air.

Using microalgae to produce proteins and fatty acids.

Shocking livestock slurry with synthetic lightning to eliminate methane emissions.

Masks for cows that contain a catalytic converter to neutralise exhaled methane.

  • Startups working on this: Zelp.

Feed supplements containing garlic powder and bitter orange extracts, to reduce cattle methane emissions.

3. Transport

Replacement, decarbonised-fuel engines for diesel-powered machines.

Electric and hydrogen-powered planes.

A new ion exchange process to extract lithium (needed in electric vehicle batteries) from brine more efficiently.

Using AI to find more rare minerals to mine.

Electric freight ships.

Battery powered freight trucks.

Hydrogen fuel-cell powered freight trucks.

4. Materials

Using electro-extraction to remove and recycle minerals from e-waste.

Using a new manufacturing process to make silicon wafers for solar panels at lower cost and higher efficiency.

Using electricity to produce carbon dioxide free steel.

Producing cement with lower or no CO₂ emissions.

Using CO₂ to make concrete.

Creating cellulose and bioplastics from biomass, using aldehyde-assisted fractionation.

  • Startups working on this: Bloom.

Producing amino acids and sweeteners through fermentation.

  • Startups working on this: DMC.

Using microorganisms to turn air and greenhouse gases into a thermoplastic.

Using catalysts to replicate photosynthesis, turning CO₂ into jetfuel and other materials.

  • Startups working on this: Twelve.

Using casein to make plastic alternatives.

Growing microalgae and using them to produce ingredients for cosmetics and food products.

Using hydrothermal processing to return clothing to its raw ingredients, which can then be reused.

  • Startups working on this: Circ.

5. Carbon Capture and Storage

Pulling CO₂ from the air and turning into rock using enhanced carbon mineralisation.

Using satellite imagery to improve forest carbon markets.

Using electrochemistry to de-acidify the ocean and enhance its carbon-storing properties.

Dissolving olivine-containing rock into oceans, increasing its CO₂ uptake and decreasing its acidity.

Using electrochemistry to sequester the ocean’s CO₂ as a seashell-like material.

Growing kelp to capture carbon, then sinking it beneath the ocean to sequester it.

Mixing pulverised minerals into agricultural soil to accelerate carbon capture through rock weathering.

Using abundant minerals to create cost-efficient direct air capture.

Baking forestry waste in a low oxygen environment to produce biochar, a stable form of carbon.

Turning biomass into bio-oil using pyrolysis, then injecting the bio-oil underground.

  • Startups working on this: Charm.

6. Solar Geoengineering

N.B.: All of this research is very early stage, and a long way away from being used (if it ever is used).

Putting a giant solar sail in space (around 1.5 million kilometers away from Earth) to reduce the amount of sunlight reaching Earth, cooling the planet.

Injecting aerosols into the stratosphere to reflect or absorb sunlight, cooling the planet.

Adding aerosols to marine clouds to make them more reflective, cooling the planet.

7. Adaptation

7.1 Water shortages

Drawing water from the air, using solar-powered panels, to produce more drinking water.

  • Startups working on this: Source.

Adding silver iodide to clouds to encourage precipitation and alleviate drought.

Using 3D printed membranes to improve the efficiency of water desalination.

Solar-powered desalination systems.

7.2 Food shortages

Producing single cell proteins from CO₂ and hydrogen.

Producing single cell proteins from natural gas.

Scaling up seaweed farming.

Genetically modifying crops to increase resilience and yield.

  • Organisations working on this: CGIAR.

7.3 Natural disasters

Drones that can fight wildfires.

Satellites for disaster monitoring and early warning systems.

Further reading and sources

Breakthrough Energy, Bill Gates’ climate fund.

Stripe Climate, Stripe’s carbon removal fund.


PwC State of Climate Tech 2021


Can tech help fight climate change? Five innovations making a difference today — Secure Futures

This is climate tech — GreenBiz

Clean Energy Ventures

The Next Generation of Climate Innovation — BCG

High-tech climate solutions that could cut emissions in the long term — Reuters

10 adaptation technologies — Climate Action

10 European startups tackling natural disasters and other emergencies — EU Startups

Seven emerging technologies that will be vital for fighting climate change — Recharge

Reflections on a meeting about space-based solar geoengineering — Harvard Solar Geoengineering Research Blog