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The Science Behind Enhanced Weathering
The principle behind enhanced weathering is based on the Earth's natural rock weathering process – a slow, ongoing geological cycle that has regulated the planet's climate for millions of years. By accelerating this process, enhanced weathering aims to increase the rate at which CO2 is removed from the atmosphere. When silicate rocks are exposed to CO2 and water, they undergo a series of chemical reactions that ultimately convert CO2 into bicarbonate ions, which are then washed into the oceans and precipitate as carbonate minerals, locking away the carbon for millennia.
Types of Enhanced Weathering Projects
Enhanced weathering projects can differ based on the mineral used, application area, and targeted outcomes. Key types include:
- Basalt Powder Application: Spreading finely ground basalt rock on agricultural lands to enhance weathering rates, sequester CO2, and improve soil quality. The most notable example of this is UNDO.
- Olivine Beach Projects: Adding olivine grains to beaches where wave action speeds up weathering processes, increasing CO2 sequestration and potentially combating ocean acidification at the same time.
- Agricultural Enhanced Weathering: Integrating silicate rocks into farmland soils not only for carbon sequestration but also to release nutrients beneficial for crops.
- Urban Enhanced Weathering: Using silicate materials in urban construction, such as roads and buildings, to passively capture CO2 over time through weathering.
The Role in Achieving Net Zero Emissions
The Intergovernmental Panel on Climate Change (IPCC) has recognised enhanced weathering as an effective carbon removal method. Major companies like Stripe, Shopify, and Microsoft have invested in enhanced weathering projects, demonstrating strong support for its potential in combating climate change.