Geoengineering proposals fall into at least three broad categories: 1) managing atmospheric greenhouse gases (e.g.,
ocean fertilization and atmospheric carbon capture and sequestration), 2) cooling the Earth by reflecting sunlight (e.g., putting reflective particles into the atmosphere, putting
mirrors in space to reflect the sun's energy, increasing
surface reflectivity and altering the amount or characteristics of clouds), and 3) moderating specific impacts of global warming (e.g., efforts to limit sea level rise by increasing land storage of
water, protecting ice sheets or artificially enhancing mountain glaciers).
The best way to envision the relation between ENSO and precipitation over East Africa is to regard the Indian
Ocean as a
mirror of the Pacific
Ocean sea
surface temperature anomalies [much like the Western Hemisphere Warm Pool creates such a SST
mirror with the Atlantic
Ocean too]: during a La Niña episode,
waters in the eastern Pacific are relatively cool as strong trade winds blow the tropically Sun - warmed
waters far towards the west.