Industry

Permafrost patterns of tundra soil, Northeast Greenland National Park

Industry

Direct air carbon capture and storage DACCS

Direct air carbon capture and storage (DACCS) aims to reduce the amount of carbon dioxide in the atmosphere by taking it directly out of the air, and removing it from the carbon cycle.

Industry

Atmospheric Methane destruction: Tropospheric iron salt aerosol injection

Tropospheric Iron Salt Aerosol injection (ISAI) has recently received significant attention as a potential methane mitigation technique.

Nickel Smelters, Norilsk, Siberia, Russia

Industry

Carbon capture and storage

Both emission reductions and CDR measures that actively reduce carbon dioxide are essential to reduce the amount of GHGs in the atmosphere and mitigate the effects of climate change. However, some carbon emissions, especially in the industrial and energy sectors, will be difficult to fully decarbonise.

Industry

Built-environment albedo enhancement (white roofs etc.)

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.

Gentoo Penguins (Pygoscelis Papua), Antarctic Peninsula

Industry

CO2 “snow” deposition in Antarctica, cryogenic CO2 capture

Inspired by the discovery of CO2 ice caps on Mars, Agee et al. (2013) suggested it might be possible to artificially create similarly cold conditions in the already frigid temperatures of Antarctica that would allow CO2 to 'snow' out of the air.

Industry

Polar chimneys

Some have suggested modifying incoming and outgoing radiation budgets in the Arctic to mitigate the warming in the region.

Polar bear looking for whale cadaver under water, Svalbard

Industry

Direct ocean capture

The majority of the inorganic carbon on Earth is stored in the oceans. There is a natural carbon exchange between the ocean and the land.

Industry

Enhanced weathering (on land)

Enhanced weathering (EW) is a measure that seeks to enhance and speed up the process of rock weathering in which CO2 reacts with minerals (Schuiling and Krijgsman 2006) that naturally occurs and already consumes 1.1 Gt CO2 per year (Ciais et al. 2014).

Agriculture landscape with small villages and forests in Baden Würtemberg, Germany

Industry

Bio-geoengineering to increase crop albedo

Surface albedo has a significant impact on global climate (Zhang et al. 2022). Plants play an important role in this. Matthews et al. (2003), for example, estimate that the spread of agriculture has led to a global cooling of around 0.17°C, as agricultural crops tend to have a higher albedo than wild vegetation (Monteith and Unsworth 1990).

Industry

Bio-energy with carbon storage BECCS

Bio-Energy with Carbon Storage (BECCS) offers a nature-based way to remove CO2 from the atmosphere by consuming biomaterial and removing the remaining carbon residues from the carbon cycle.

Old whale bone providing fertile conditions for vascular plants, Antarctic Peninsula

Industry

Biochar

The most widely studied carbon storage technique is the large-scale application of biochar. Biochar is produced when biomass is pyrolysed - a thermal process in which oxygen for combustion is lacking.

Industry

Radiative covering and building technologies/ Passive daytime radiative cooling

Passive daytime radiative cooling (PDRC) promises to provide energy free cooling through thermally-emissive surfaces that reflect incoming solar radiation whilst simultaneously enhancing longwave heat transfer to space through the infrared window of the atmosphere (8–13 µm) (Yin et al. 2020).

Industry

Arctic methane capture and usage

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

High Arctic Tundra, Northern Taymyr, Russia July 1990

Industry

Methane flaring (not industrial)

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.

Industry

Black carbon reduction

Black Carbon (BC), also known as soot, is produced through the incomplete combustion of fossil fuels and biomaterials. Apart from its negative health impacts, BC also has significant climate effects because it generally has a lower albedo than its surroundings, which increases the amount of radiation absorbed both when BC is present in the atmosphere and when it is deposited on land (Stjern et al. 2017). Due to the large albedo differences, the effects of BC are especially significant in areas that are normally covered in snow or ice (Hadley and Kirchstetter 2012; Sand et al. 2016; Kang et al. 2020).

Alternating layers of limestone and dolomite, Eleonore Bay, Northeast Greenland National Park

Industry

Atmospheric methane capture by zeolites

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

Industry

Atmospheric methane removal: Solar chimney and photocatalytic semiconductor technology

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).