Buying more time

Founded: 2017

HQ: Cambridge, MA

Researching strategies to reduce solar radiation on Earth

Big Picture

Solar radiation management (SRM) or “solar geoengineering” is a theoretical approach to mitigating some of the adverse impacts of climate change by reflecting inbound sunlight back into space and cooling the atmosphere. Such large-scale, deliberate climate interventions have potentially significant and wide-ranging implications, yet the associated efficacy and risks remain insufficiently understood.

How it Works

Harvard’s SGRP program is one of the leading global efforts to model the impacts and study the governance of SRM. Unless policy and science conspire to radically reduce emissions in the coming years, hundreds of millions of people around the world will be at greater risk of disease, draught, flooding, and death in the near future. In that scenario, knowing if and how to shade sunlight will prove critical.

Unfair Advantage

Harvard’s SGRP employs Harvard’s convening power to bring together scientists, environmental leaders, and government officials to discuss the technology and its governance. The program produces research that advances the science and technology frontier while disseminating ideas taken up by other researchers and government research programs.


David is a Professor of Applied Physics at Harvard’s School of Engineering, a Professor of Public Policy at the Harvard Kennedy School, and the leading scholar in geoengineering.

Follow: @DKeithClimate


Prior to Harvard, Lizzie worked for the non-profit advocacy organization Opportunity Nation. She holds a BA from Williams College and MPP from the Harvard Kennedy School.

Solar geoengineering as part of an overall strategy for meeting the 1.5°C Paris target

Philosophical Transactions of the Royal Society

The potential for climate engineering with stratospheric sulfate aerosol injections to reduce climate injustice

Journal of Global Ethics