Explore interventions

The built environment takes up an ever greater portion of the earth’s surface. This mostly unused surface area could be coated in albedo enhancing paints or material which would allow them to reflect incoming sunlight.

Apart from proposals to destroy atmospheric methane or capturing it, some have suggested it could be possible to prevent methane from reaching the atmosphere or flaring it.

Ocean fertilization schemes seek to increase the amount of available nutrients in the top layer of the ocean to stimulate the growth of phytoplankton.

Carbon uptake in the ocean mainly occurs directly through ocean-atmosphere interaction or through weathering processes. Due to this uptake of carbon, the oceans turn more acidic overtime, and since the start of the industrial revolution oceans have become 30% more acidic. This has all sorts of effects as it, for example, impacts marine biochemistry, and prevents certain organisms from successfully growing.

Natural climate solutions like conservation or restoration can significantly contribute to climate change mitigation efforts (Griscom et al. 2017). One such category of natural climate solutions is re-wilding.

Zeolites are porous minerals that can capture methane (Jackson 2019).

One of the main issues with methane removal is that atmospheric methane concentrations are very low. This means that very large volumes of air, and related energy demands, are required, making the use of ventilators like those used for DACCS (see direct air capture) more complicated (Nisbet-Jones et al. 2021).

Some have suggested that it might be possible to capture methane or methane hydrates and transform it into useful materials.

Biotic processes play an important role in oceanic carbon uptake, with most attention going  to carbon-consuming photosynthesising organisms. Moore et al. (2023) argue that the potential role of shellfish and other calcifiers in carbon sequestration is significantly overlooked in the CDR literature.

Thermosyphon technologies that passively cool soils if the air temperature is colder than surface temperatures have been used on a smaller scale to stabilize permafrost that supports infrastructure (Xu and Goering, 2008).

There have been several isolated suggestions to mitigate permafrost thaw or influence the thaw processes in the active layer by physically covering the surface with materials (see for example https://groups.google.com/g/geoengineering/c/u2b9Xb5B0C8/m/aXQia-nNDbcJ) in a similar way to how glaciers might be preserved (see Glacier Insulation, and Passive Radiative Cooling). Although different materials have been suggested, these have not been worked out further, and are likely to be a very costly, and impractical solution.

Artificial upwelling (AU) is an idea to increase carbon uptake of upper ocean layers by fertilizing it with pumped-up colder nutrient-rich waters from the deep, which would encourage the biological sequestration of carbon through photosynthesis (NASEM 2022).