Explore interventions

Sixty-one proposed climate interventions in six categories and assessed according to twelve criteria.

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Sea ice melting, North of Dickson, Taymyr, Russia

Sea ice & icebergs

Pykrete usage

Arctic sea ice extent has rapidly decreased over the last few decades, with most multi-year ice disappearing altogether. This has already had major effects on local communities and ecosystems. The disappearance of the relatively reflective sea ice also leads to a dramatic decrease of albedo in the Arctic and subsequent high energy uptakes by the darker water during the Arctic summers.

Sea ice, North-West Spitsbergen National Park, Svalbard

Sea ice & icebergs

Sea Ice growth management

Sea ice & icebergs

Ice shields and “volcanoes”

Mountain pine and spruce forest in winter, Hillestadheia, Norway

Atmosphere / solar radiation

Snowfall enhancement

With the exception of some regions like Antarctica, global snowfall amount and frequency have decreased, and the timespan during which snow cover remains has shortened (Zender 2012). This has multiple effects on human and natural systems as it influences widely diverging processes such as reducing surface albedo and changes in the hydrological cycle.

Clouds over peaks in Uummannaq, Greenland

Atmosphere / solar radiation

Arctic winter high-latitude seasonal stratospheric aerosol injection

GHG emissions reductions and future negative emissions are the only sustainable solutions to stabilize or even reverse global warming as they counter the cause of the problem. However, the required actions will likely take time to materialize, and inertia in the climate system and locked-in warming already ensures major changes in global temperatures and the nearing of several tipping points. Solar radiation management (SRM) techniques seek to reduce global temperatures by reflecting incoming solar radiation. They would thereby not fix the underlying issue of the warming effects of GHGs but are, according to the United Nations Environment Programme (UNEP) Review on Solar Radiation Modification Research (2023), 'the only known approach that could be used to cool the Earth within a few years'.

Clouds over Setesdalsheia, Norway, October 2013

Atmosphere / solar radiation

Cirrus cloud thinning

Cirrus clouds are high altitude ice clouds. They influence the Earth’s radiation budget as they reflect both incoming and outgoing radiation. However, they ultimately have a warming effect as they are more efficient at trapping outgoing longwave radiation (Kärcher 2017).

Atmosphere / solar radiation

Arctic Marine Cloud Brightening

Roughly one-third of the incoming solar radiation is directly reflected back into space by the Earth’s atmosphere and surface albedo. Clouds play an important role in this, although their role is double as water droplets can also interfere with outgoing longwave radiation, thereby contributing to the greenhouse effect. Over open water clouds can make a particularly big difference as the albedo of the water is below 0.1, thereby absorbing most of the sun’s energy.

Atmosphere / solar radiation

Space-based solar radiation management

GHG emissions reductions and future negative emissions are the only sustainable solutions to stabilize or even reverse global warming as they counter the cause of the problem. However, such actions will likely take a while to materialize, and inertia in the climate system and “baked-in” warming already ensures major changes in global temperatures and the nearing of several tipping points. Solar radiation management (SRM) techniques seek to reduce global temperatures by reflecting incoming solar radiation. They would thereby not fix the underlying issue of the warming effects of GHGs, but are according to the United Nations Environment Programme (UNEP) Review on Solar Radiation Modification Research (2023) ‘the only known approach that could be used to cool the Earth within a few years’.

Fishing boat in between icebergs, Disco Bay, Greenland

Oceans & marine

Improved fishing practices and management

Fisheries contribute to global CO2 emissions by the extraction of fish, disturbance of coastal and oceanic blue carbon ecosystems, and the use of fossil fuels as their main energy source. Fishing vessels are moreover a major source of short-lived climate forcers like black carbon (McKuin and Campbell 2016), which can have a major effect in Arctic and Northern regions (see Black carbon reduction).

Oceans & marine

Ocean fertilization

The oceans are the largest carbon sink for atmospheric carbon, and have taken up over 30% of anthropogenic emissions. Carbon uptake occurs abiotically through processes like ocean-atmosphere interaction and weathering processes, and biotically, mainly through carbon consuming photosynthesising organisms.

Cultivating algae for export to Japan, Zanzibar

Oceans & marine

Seaweed and macro algae cultivation

The potential of carbon sequestration by marine based plants such as mangroves, seagrass and algae, often referred to as blue carbon, and the importance of better understanding it, has clearly been recognised (Mcleod et al. 2011). The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate (2019) concluded blue carbon can play an important role in both climate regulation and adaptation. The term algae groups together several kinds of marine photosynthetic organisms. These are often subdivided into very small microalgae like phytoplankton, and larger macroalgae like kelp and seaweed. Although there is still large uncertainty about the total amount of carbon sequestered by these marine organisms, a recent estimate by Duarte et al. (2022) indicated that all macroalgae took in as much CO2 as the Amazon rainforest.

Cape Petrel (Daption capense), Antarctic Peninsula

Oceans & marine

Reflective foams and bubbles on oceans

Sea water has a low albedo of around 0.1 and therefore absorbs most of the incoming solar energy. Since water covers over two thirds of the Earth’s surface, changes to this albedo can potentially cause significant changes in global temperatures.