Climate geoengineering is the intentional, large-scale manipulation of the Earth’s climate system to reduce the effects of climate change. Our climate is a result of the amount of solar radiation hitting the Earth and the amount of heat reflected and radiated back into space. This balance depends on several variables including reflectivity, cloud coverage, the amount of heat absorbed by the Earth, and the amount of heat trapped in our atmosphere by greenhouse gasses. For geoengineering to succeed, at least one of these variables must be changed. Geoengineering strategies consist of either increasing Earth’s reflectance or blocking incoming solar radiation so we receive less heat, or reducing greenhouse gasses in the atmosphere to allow more heat to radiate back into space. Scientists also worry about the albedo effect. As Earth warms and ice melts, this white reflective surface is replaced by dark heat-absorbing oceans and lands, creating a feedback loop that melts more ice and forces our planet to retain more and more heat.

Proposals to increase the reflectance of incoming solar radiation include the injection of sulfur particles into the stratosphere, the seeding of clouds and the placement of millions of tiny orbital mirrors or sunshades into space. Other geoengineering proposals are designed to remove CO2 from the atmosphere. One calls for building machines to capture CO2 in sorbent material and remove it for burial. However, scientists warn geoengineering by itself will not fix our climate crisis. These techniques are meant to augment carbon reduction efforts, not replace them. Unfortunately, all large-scale climate geoengineering research has consisted of computer modeling and laboratory testing.

Proposed Legislation: H.R.4586 - Geoengineering Research Evaluation Act of 2017 (115th Congress (2017-2018)
Prospective Sponsor: Rep. Jerry McNerney (CA)

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