Understanding the Urgent Need for Direct Climate Cooling

Abstract

The intensifying impacts of climate change are exceeding projections and amplifying the risk of catastrophic harm to the environment and society throughout the 21st century. Planned and proposed rates of emissions reduction and removal are not proceeding at a pace or magnitude to meet either the 1.5°C or 2.0°C targets of the Paris Agreement. Moreover, the impacts, damage and loss occurring at today’s 1.2°C of global warming are already significantly disrupting the environment and society. Relying exclusively on greenhouse gas (GHG) emissions reduction and removal without including climate cooling options is thus proving incompatible with responsible planetary stewardship. Multiple approaches to exerting a cooling influence have the potential to contribute to offset at least some of the projected climate disruption if deployed in the near term. Employed thoughtfully, such approaches could be used to limit global warming to well below 1° C, a level that has led to large reductions in sea ice, destabilization of ice sheets, loss of biodiversity, and transformation of ecosystems. An effective plan for avoiding “dangerous anthropogenic interference with the climate system,” would include: a) early deployment of one or more direct cooling influence(s), initially focused on offsetting amplified polar warming; b) accelerated reductions in emissions of CO2, methane and other short-lived warming agents; and c) building capacity to remove legacy GHG loadings from the atmosphere. Only the application of emergency cooling “tourniquets,” researched and applied reasonably soon to a “bleeding” Earth, have the potential to slow or reverse ongoing and increasingly severe climate disruption.

Bad science and good intentions prevent effective climate action

“…Moreover, there are many more potentially safe and useful direct climate cooling methods. The following may merit early consideration and investigation for possible, carefully monitored implementation (Baiman et al, 2023):…”

An Open Letter to the IMO Supporting Maritime Transport that Cools the Atmosphere While Preserving Air Quality Benefits

“…Following Partenan et al (2013), it may be possible to offset the global warming harm of these regulations by temporarily relaxing them for "high seas" sulfur emissions (i.e., far from ports and population centers) while largely preserving air quality benefits in ports and coastal areas like current IMO "Emission Control Areas". 1 It may also be possible to replace the cooling effect of fossil fuel based shipping emissions while preserving or enhancing air quality by releasing benign tropospheric aerosol precursors from ships (Baiman et al, 2023).…”

“…We therefore ask that the International Maritime Organization and other international and national health and environmental organizations urgently support and sponsor research, pilot testing and emergency regulations, that would: 1) Partially relax the IMO's maritime bunker fuel sulfur emissions regulation for "high seas" non-ECA maritime transport in ways that -as much as possible--would increase the global cooling benefits of sulfur or similar aerosols without causing harm to humans or natural systems, and 2) Support the possibility that benign tropospheric aerosol precursors such as sea water referred to as the "marine cloud brightening method") or other possible tropospheric aerosols (referred to as the "climate catalysts method") that can be released from ships and that would replace the global cooling benefits of sulfur aerosols without -as much as possible -causing harm to humans or natural systems, could be deployed in maritime transport (Baiman et al, 2023;Feingold 2024).…”