Wikipedia page for geoengineering entry list a lot of proposals to decrease global temperature:

Solar radiation management methods[5] may include:

  • Surface-based: for example, surface-based mirror infrastructures,[29] protecting or expanding polar sea ice and glaciers, including the use of insulating blankets or artificial snow,[30][31] using pale-colors for roofing materials and other man-made surfaces (i.e. roadways and exterior paints), attempting to change the oceans' brightness, growing high-albedo crops, or by distributing hollow glass beads in selected areas to increase ice coverage and lower temperatures.[32]
  • Troposphere-based: for example, marine cloud brightening, which would spray fine sea water to whiten clouds and thus increase cloud reflectivity.
  • Upper atmosphere-based: creating reflective aerosols, such as stratospheric sulfate aerosols, specifically designed
    self-levitating aerosols,[33] or other substances.
  • Space-based: space sunshade – obstructing solar radiation with space-based mirrors, dust,[34] etc.

Carbon dioxide removal

  • Creating biochar (i.e. in biomass-fired thermal power plants), for mixing into the soil to create terra preta
  • Bio-energy with carbon capture and storage to sequester carbon and simultaneously provide energy Carbon air capture to remove carbon
    dioxide from ambient air
  • Afforestation, reforestation and forest restoration to absorb carbon dioxide
  • Ocean afforestation and ocean fertilization (which includes iron fertilization of the oceans)

Why have none of these methods been implemented?

What are the risks of developing geoengineering?

  • 2
    $\begingroup$ The lack of political will & the lack of money. All of the solar management "proposals" are just ideas. I can think of numerous reasons for each, why nothing has been done about them. As for CO2 removal, some of those have been tried on a small scale: biochar, CO2 sequestration & afforestation & reforestation. Two examples of CO2 sequestration that I'm aware of have been failures: one test done by the CSIRO in western Victoria, Australia & an ongoing example of the Barrow Island. $\endgroup$ – Fred Apr 12 at 6:21
  • 2
    $\begingroup$ For the solar management ideas, there is a large issue of risk and governance. The risks are around unintended consequences and unanticipated feedbacks. To achieve worthwhile effects these would be very large scale interventions. Changes that might moderate warming for one country or region's benefit might cause negative consequences elsewhere. An added issue is that solar management options don't address acidification of oceans at all. $\endgroup$ – Andy M Apr 12 at 15:32
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    $\begingroup$ Because we know shit about possible undesired side-effects and some ideas are not really reversable. $\endgroup$ – Erik Apr 13 at 7:31

We don't know, and that's why we have to develop it.

that's the thing about undeveloped sciences we don't know what many of the risks are, Its a case of knowing what we don't know. Which is one big reason to develop it, so we don't cause harm accidentally.

Lets be clear we already are geoengineering right now, by driving cars, changing the landscape, polluting the air, we are just doing it blind. We have to research things to understand the risks, and geoengineering has barely be scratched.


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