Climate engineering is the intentional large-scale alteration of the planetary environment to counteract anthropogenic climate change. The term has been used as an umbrella term for both carbon dioxide removal and solar radiation modification when applied at a planetary scale. However, these two processes have very different characteristics, and are now often discussed separately. Carbon dioxide removal techniques remove carbon dioxide from the atmosphere, and are part of climate change mitigation. Solar radiation modification is the reflection of some sunlight back to space to cool the earth. Some publications include passive radiative cooling as a climate engineering technology. The media tends to also use climate engineering for other technologies such as glacier stabilization, ocean liming, and iron fertilization of oceans. The latter would modify carbon sequestration processes that take place in oceans.
Raymond Thomas Pierrehumbert is the Halley Professor of Physics at the University of Oxford. Previously, he was Louis Block Professor in Geophysical Sciences at the University of Chicago. He was a lead author on the Third Assessment Report of the IPCC and a co-author of the National Research Council report on abrupt climate change.
Kenneth Caldeira is an American atmospheric scientist. His areas of research include ocean acidification, climate effects of trees, intentional climate modification, interactions in the global carbon cycle/climate system, and sustainable energy.
Solar radiation modification (SRM), is a group of large-scale approaches to limit global warming by increasing the amount of sunlight that is reflected away from Earth and back to space. Among the potential approaches, stratospheric aerosol injection (SAI) is the most-studied, followed by marine cloud brightening (MCB); others such as ground- and space-based show less potential or feasibility and receive less attention. SRM could be a supplement to climate change mitigation and adaptation measures, but would not be a substitute for reducing greenhouse gas emissions. SRM is a form of climate engineering or geoengineering.
Stratospheric aerosol injection (SAI) is a proposed method of solar geoengineering to reduce global warming. This would introduce aerosols into the stratosphere to create a cooling effect via global dimming and increased albedo, which occurs naturally from volcanic winter. It appears that stratospheric aerosol injection, at a moderate intensity, could counter most changes to temperature and precipitation, take effect rapidly, have low direct implementation costs, and be reversible in its direct climatic effects. The Intergovernmental Panel on Climate Change concludes that it "is the most-researched [solar geoengineering] method that it could limit warming to below 1.5 °C (2.7 °F)." However, like other solar geoengineering approaches, stratospheric aerosol injection would do so imperfectly and other effects are possible, particularly if used in a suboptimal manner.
David W. Keith is a professor in the Department of the Geophysical Sciences at the University of Chicago. He joined the University of Chicago in April 2023. Keith previously served as the Gordon McKay Professor of Applied Physics for Harvard University's Paulson School of Engineering and Applied Sciences (SEAS) and professor of public policy for the Harvard Kennedy School at Harvard University. Early contributions include development of the first atom interferometer and a Fourier-transform spectrometer used by NASA to measure atmospheric temperature and radiation transfer from space.
Piers Forster is a Professor of Physical Climate Change and Director of the Priestley Centre for Climate Futures at the University of Leeds. A physicist by training, his research focuses on quantifying the different human causes of climate change and the way the Earth responds. He is best known for his work on radiative forcing, climate sensitivity, aviation-climate effects, climate engineering, climate modelling and carbon budgets. He has contributed heavily to the writing of Intergovernmental Panel on Climate Change (IPCC) reports, including acting as a Lead Author for the Fourth and Fifth Assessment Reports, and a Co-ordinating Lead Author for the Sixth Report. He also acted as a Lead Author of the IPCC 2018 Special Report on Global Warming of 1.5 °C. He leads an international effort to annually update climate indictors, the Indicators of Global Climate Change project.
Alan Robock is an American climatologist. He is currently a Distinguished Professor in the Department of Environmental Sciences at Rutgers University, New Jersey. He advocates nuclear disarmament and, in 2010 and 2011, met with Fidel Castro during lecture trips to Cuba to discuss the dangers of nuclear weapons. Alan Robock was a 2007 IPCC author, a member of the organisation when it was awarded the Nobel Peace Prize, "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change".
The contributions of women in climate change have received increasing attention in the early 21st century. Feedback from women and the issues faced by women have been described as "imperative" by the United Nations and "critical" by the Population Reference Bureau. A report by the World Health Organization concluded that incorporating gender-based analysis would "provide more effective climate change mitigation and adaptation."
Cirrus cloud thinning (CCT) is a proposed method of climate engineering. Cirrus clouds are high cold ice that, like other clouds, both reflect sunlight and absorb warming infrared radiation. However, they differ from other types of clouds in that, on average, infrared absorption outweighs sunlight reflection, resulting in a net warming effect on the climate. Therefore, thinning or removing these clouds would reduce their heat trapping capacity, resulting in a cooling effect on Earth's climate. This could be a potential tool to reduce global warming. Cirrus cloud thinning is an alternative category of climate engineering, in addition to solar radiation management.
The Industrial Ecology Programme, or IndEcol, in the Department of Energy and Process Engineering at NTNU is an interdisciplinary research programme specialising in sustainable development, circular economy research and environmental issues.
Ursula J. Gibson is an American materials scientist who specialises in novel core optical fibres.
Anne Borg is a Norwegian professor of physics and was rector (2019-2023) at the Norwegian University of Science and Technology in Trondheim. She was prorector of education at NTNU from August 1, 2017, to August 20, 2019. She was appointed acting rector of NTNU on August 21, 2019, later being officially employed as rector on December 13 the same year.
Signe Helene Kjelstrup is a Norwegian professor of physical chemistry at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway. She is a principal investigator at PoreLab, a Center of Excellence at NTNU.
Mark G. Lawrence is an American atmospheric scientist whose research focuses on a range of sustainable development topics at the science policy and science-society interface. He is scientific director at the Research Institute for Sustainability (RIFS) in Potsdam (former Institute for Advanced Sustainability Studies in Potsdam.
Inés Angela Camilloni is an Argentine climatologist, specializing in climate change in South America. She is a professor at the University of Buenos Aires and an independent researcher at the Center for Research on the Sea and Atmosphere. She is also the academic secretary of the Faculty of Exact and Natural Sciences of the UBA. Camilloni is a resident in the Solar Geoengineering Research Program of Harvard University and director of the Master's in Environmental Sciences at the Faculty of Exact and Natural Sciences of the UBA.
Ulrike Lohmann is a climate researcher and professor for atmospheric physics at the ETH Zurich. She is known for her research on aerosol particles in clouds.
Anders Hammer Strømman is a professor of industrial ecology in the Industrial Ecology Programme at the Norwegian University of Science and Technology (NTNU). He has collaborated with Francesco Cherubini in developing a method to analyse the climate impact of CO2 emissions from biomass combustion, and his fields of expertise include life cycle studies of producing electric car batteries.
Patricia Lago is an Italian computer scientist. She is a full professor at the Vrije Universiteit Amsterdam in the Netherlands, where she leads the Software and Sustainability Research Group S2, which she established and has led since 2011. Her research interests are software engineering, software architecture and software sustainability.
