Response: Enhanced mineral weathering
Weathered basalt, Reynisfjara, Iceland – image: Sonny Whitelaw
Response
- What is being done?
- Adaptation
- IPCC: Intergovernmental Panel on Climate Change
- Managed retreat from coasts and rivers
- Plant trees…but mostly pines!
- The emissions trading scheme: ETS
- The ‘carbon free’ economy
- Carbon capture & storage
- Enhanced mineral weathering
- Forecasting the future: NZ climate models
- The Paris Agreement
- NDCs: Nationally Determined Contributions
- Governments are bankrupting the carbon budget
- New Zealand policies & strategies
- Climate Change Commission
- Brief history of climate change: who knew what, when
Other sections
Home > Climate wiki > Response > Enhanced mineral weathering
Enhanced mineral weathering
Summary
- The world’s plan by 2050: remove 8 billion tons of CO2 every single year and put it back underground (negative emissions).
- This calculation is based only on what humans are releasing. It doesn’t include the staggering volume of greenhouse gases now being released by collapsing ecosystems.
- The IPCC pathways assumed that negative emissions technology will be invented ‘spontaneously’ and rolled out across the planet. Currently, most tech that draws carbon from the atmosphere sells it as fuel, returning the CO2 back into the atmosphere.
- An alternative approach is to turbo-charge natural rock weathering, in a process known as enhanced mineral weathering:
“Biogeochemical improvement of soils by adding crushed, fast-reacting silicate rocks to croplands is one such CO2-removal strategy. This approach has the potential to improve crop production, increase protection from pests and diseases, and restore soil fertility and structure.” – Beerling et al, 2022.
How does it work?
The following is an extract from Carbon Brief: How ‘enhanced weathering’ could slow climate change and boost crop yields’ (Fig. 1)
Chemical weathering is a natural process that continuously erodes away rocks and stores atmospheric CO2 over millions of years. As natural rock weathering absorbs around 0.3% of global fossil fuel emissions, enhanced weathering can provide a boost to remove even more CO2 from our atmosphere.
The process begins with rain, which is usually slightly acidic having absorbed CO2 from the atmosphere on its journey to the ground. The acidic rain reacts with rocks and soils, gradually breaking them down into rock grains, forming bicarbonate in the process. Eventually, this bicarbonate washes into the oceans, where the carbon is stored in dissolve form for hundreds of thousands of years or locked up on the sea floor.
Enhanced weathering scales up this process. Pulverising silicate rocks such as basalt – left over from ancient volcanic eruptions – bypasses the slow weathering action because power has a greater surface area that large rocks, so it absorbs carbon much faster.
As enhanced weathering makes water more alkaline, it can help counteract ocean acidification.
When spread on large areas of agricultural land, plant roots and microbes in the soil speed up the chemical reactions, boosting nutrient levels, improving crop yields and helping restore degraded agricultural soils (Video 1).
Response
- What is being done?
- Adaptation
- IPCC: Intergovernmental Panel on Climate Change
- Managed retreat from coasts and rivers
- Plant trees…but mostly pines!
- The emissions trading scheme: ETS
- The ‘carbon free’ economy
- Carbon capture & storage
- Enhanced mineral weathering
- Forecasting the future: NZ climate models
- The Paris Agreement
- NDCs: Nationally Determined Contributions
- Governments are bankrupting the carbon budget
- New Zealand policies & strategies
- Climate Change Commission
- Brief history of climate change: who knew what, when
Other sections
Home > Climate wiki > Response > Enhanced mineral weathering
Summary
- The world’s plan by 2050: remove 8 billion tons of CO2 every single year and put it back underground (negative emissions).
- This calculation is based only on what humans are releasing. It doesn’t include the staggering volume of greenhouse gases now being released by collapsing ecosystems.
- The IPCC pathways assumed that negative emissions technology will be invented ‘spontaneously’ and rolled out across the planet. Currently, most tech that draws carbon from the atmosphere sells it as fuel, returning the CO2 back into the atmosphere.
- An alternative approach is to turbo-charge natural rock weathering, in a process known as enhanced mineral weathering:
“Biogeochemical improvement of soils by adding crushed, fast-reacting silicate rocks to croplands is one such CO2-removal strategy. This approach has the potential to improve crop production, increase protection from pests and diseases, and restore soil fertility and structure.” – Beerling et al, 2022.
How does it work?
The following is an extract from Carbon Brief: How ‘enhanced weathering’ could slow climate change and boost crop yields’. (Fig. 1)
Chemical weathering is a natural process that continuously erodes away rocks and stores atmospheric CO2 over millions of years. As natural rock weathering absorbs around 0.3% of global fossil fuel emissions, enhanced weathering can provide a boost to remove even more CO2 from our atmosphere.
The process begins with rain, which is usually slightly acidic having absorbed CO2 from the atmosphere on its journey to the ground. The acidic rain reacts with rocks and soils, gradually breaking them down into rock grains, forming bicarbonate in the process. Eventually, this bicarbonate washes into the oceans, where the carbon is stored in dissolve form for hundreds of thousands of years or locked up on the sea floor.
Enhanced weathering scales up this process. Pulverising silicate rocks such as basalt – left over from ancient volcanic eruptions – bypasses the slow weathering action because power has a greater surface area that large rocks, so it absorbs carbon much faster.
As enhanced weathering makes water more alkaline, it can help counteract ocean acidification.
When spread on large areas of agricultural land, plant roots and microbes in the soil speed up the chemical reactions, boosting nutrient levels, improving crop yields and helping restore degraded agricultural soils (Video 1).
More information
-
- University of Canterbury Civil Engineering Associate Professor Allan Scott
- The Future Forest Company (Scotland)
- Smart stones (Netherlands)
-
- 2021: Scott et al; Transformation of abundant magnesium silicate minerals for enhanced CO2 sequestration, Nature Communications Earth & Environment 2 | 25
- 2021: Introducing “Project Carbdown”: Our first “enhanced weathering” field trial aims to remove CO₂ from the atmosphere
- 2018; Beerling et al: Farming with crops and rocks to address global climate, food and soil security, Nature Plants 4, pp 138–147
- Open access/plain English; Beerling et al, Guest post: How ‘enhanced weathering’ could slow climate change and boost crop yields, Carbon Brief
- 2013/2015 Hartmann et al; Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification, AGU; Reviews of Geophysics 51 | 2