2025-19-7-Global-Hemispheric Influence Chart-MCM_3_RBed.xlsx

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1	2025-19-7-Global-Hemispheric Influence Chart-MCM_3_RBed
2	Descriptions of Column Values
3	Ordering Priority			1	2	3	4	5
4	Method and specific objective for moderating global-scale warming and climate change	Type of Approach (adding to or pulling out materials from the atmosphere)	Sustaining cooling requires a: continuing, or once and done, effort	Potential for plausible 2050 deployment in combination with other methods to contribute to reduction of risk of crossing tipping point(s)	Realistic time to significant at-scale deployment assuming near-term explicit or implicit policy support or openness	Risk of adverse consequences compared to non-use	Potential magnitude of plausible deployment by 2050 to contribute to near-term global/hemispheric scale climate cooling (relative to global warming by 2050 without near-term cooling)	Benefits of reduced global/hemispheric warming relative to projected cost	Technological readiness level	Current level of scientific confidence and efficacy compared to non-use	Projected level of additional beneficial health and ecological effects (not directly related to cooling, or more related to local rather than global cooling impacts)	Current level of policy consideration
5	Reduce methane emissions (fossil fuel, etc.) to reduce their global warming influence	Intervention to reduce warming due to trapping of long wave, or solar shortwave, radiation in the Atmosphere	Once and done	Substantial	Years <= 10	Negligible	Up to 0.5 C	Moderate	High	High, cause of warming	High	High
6	High-latitude injection of aerosols into lower stratosphere to directly cool polar regions and indirectly cool lower latitudes	Intervention to exert cooling influence by increasing reflection of solar shortwave radiation out of the Atmosphere	Continuing	Substantial	Years <= 15	Small	Up to 0.5 C	High	Medium	Modest, natural analog	Moderate	Low
7	Global-scale injection of stratospheric aerosols	Intervention to exert cooling influence by increasing reflection of solar shortwave radiation out of the Atmosphere	Continuing	Substantial	Years <= 20	Small	Up to 1.5 C	High	Low	Modest, natural analog	Moderate	Low
8	Catalytic reduction of atmospheric methane to reduce global warming influence	Intervention to reduce warming due to trapping of long wave, or solar shortwave, radiation in the Atmosphere	Continuing	Substantial	Years <= 20	Small	Up to 0.5 C	Moderate	Low	Low, proven in laboratory	Moderate	Negligible
9	Ease marine sulfur regulations for ships on high seas to restore tropospheric aerosol cooling influence	Intervention to exert cooling influence by increasing reflection of solar shortwave radiation out of the Atmosphere	Continuing	Possible	Years <= 5	Small	Up to 0.2 C	High	High	High, recent history	Moderate	Low
10	Reduce black carbon emissions (vehicles and industry) to reduce their global warming influence	Intervention to reduce warming due to trapping of long wave, or solar shortwave, radiation in the Atmosphere	Once and done	Possible	Years <= 10	Negligible	Up to 0.2 C	Moderate	High	High, cause of warming	High	Modest
11	Non-fossil fuel generated benign tropospheric aerosol injection to exert global cooling influence	Intervention to reduce warming due to trapping of long wave, or solar shortwave, radiation in the Atmosphere	Continuing	Possible	Years <= 20	Moderate	Up to 0.2 C	Moderate	Medium	Low, past history	Moderate	Negligible
12	Marine cloud brightening to exert global/hemispheric cooling influence	Intervention to exert cooling influence by increasing reflection of solar shortwave radiation out of the Atmosphere	Continuing	Possible	Years <= 20	Moderate	Up to 0.2 C	Moderate	Low, at global scale	Low, natural analog	Moderate	Low
13	Reduced deforestation and increased carbon dioxide uptake by reforestaion/afforestation and other means of increasing ecosystem uptake	Intervention to reduce warming due to trapping of long wave, or solar shortwave, radiation in the Atmosphere	Once and done	Unlikely	Years <= 20	Negligible	Up to 0.2 C	Low	Medium	Modest, ecological examples	High	Modest
14	Place mirrors (or sunshades) in high-Earth orbit to reduce absorption of incoming solar radiation	Intervention to exert cooling influence by increasing reflection of solar shortwave radiation out of the Atmosphere	Continuing	Very Unlikely	Years > 20	Small	Unknown	Unknown	Very Low	Modest, theoretical	Moderate	Negligible
15				NOTE: Approaches deemed unlikely to make a noticeable global to hemispheric scale contribution to near-term cooling (not just reduce the rate of warming) by 2050 include: Reroute aircraft to reduce formation of IR trapping contrails; Increase albedo of global ocean; Thin wintertime cirrus and/or mixed clouds; Reduce global emissions of CO2 and other long-lived greenhouse gases; Restore ocean ecosystems to increase carbon uptake; Deploy carbon capture and storage to reduce power plant emissions; and increase the albedo of the global land surface. Some of these approaches may, however, be able to contribute to local and regional reduction of, especially severe, climate impacts.
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