Nuclear winter is a severe and prolonged global climatic cooling effect that is hypothesized to occur after widespread firestorms following a large-scale nuclear war. The hypothesis is based on the fact that such fires can inject soot into the stratosphere, where it can block some direct sunlight from reaching the surface of the Earth. It is speculated that the resulting cooling would lead to widespread crop failure and famine. When developing computer models of nuclear-winter scenarios, researchers use the conventional bombing of Hamburg, and the Hiroshima firestorm in World War II as example cases where soot might have been injected into the stratosphere, alongside modern observations of natural, large-area wildfire-firestorms.
Climate engineering is a term used for both carbon dioxide removal (CDR) and solar radiation management (SRM), also called solar geoengineering, when applied at a planetary scale. However, they have very different geophysical characteristics which is why the IPCC no longer uses this overarching term. Carbon dioxide removal approaches are part of climate change mitigation. Solar geoengineering involves reflecting some sunlight back to space. All forms of geoengineering are not a standalone solution to climate change, but need to be coupled with other forms of climate change mitigation. Another approach to geoengineering is to increase the Earth's thermal emittance through passive radiative cooling.
Paul Jozef Crutzen was a Dutch meteorologist and atmospheric chemist. He was awarded the Nobel Prize in Chemistry in 1995 for his work on atmospheric chemistry and specifically for his efforts in studying the formation and decomposition of atmospheric ozone. In addition to studying the ozone layer and climate change, he popularized the term Anthropocene to describe a proposed new epoch in the Quaternary period when human actions have a drastic effect on the Earth. He was also amongst the first few scientists to introduce the idea of a nuclear winter to describe the potential climatic effects stemming from large-scale atmospheric pollution including smoke from forest fires, industrial exhausts, and other sources like oil fires.
Georgy Sergeyevich Golitsyn is a prominent Russian scientist in the field of Atmospheric Physics, full member of the Academy of Sciences of the USSR since 1987, Editor-in-Chief of Izvestiya, Atmospheric and Oceanic Physics, ISSN 0001-4338, member of the Academia Europaea since 2000. 1990-2009 - Director of the A.M. Obukhov Institute of Atmospheric Physics, RAS, Moscow, Russia. He is a member of the princely house of Golitsyn. His father is the Russian writer Sergei Mikhailovich Golitsyn.
The cumulonimbus flammagenitus cloud (CbFg), also known as the pyrocumulonimbus cloud, is a type of cumulonimbus cloud that forms above a source of heat, such as a wildfire or volcanic eruption, and may sometimes even extinguish the fire that formed it. It is the most extreme manifestation of a flammagenitus cloud. According to the American Meteorological Society’s Glossary of Meteorology, a flammagenitus is "a cumulus cloud formed by a rising thermal from a fire, or enhanced by buoyant plume emissions from an industrial combustion process."
Vladimir Valentinovich Alexandrov was a Soviet/Russian physicist who created a mathematical model for the nuclear winter theory. He disappeared while at the Second International Conference of Nuclear Free Zones Local Authorities in Cordoba, Spain on 31 March and his ultimate fate remains unknown, though speculation continues. One of his last papers was Man and Biosphere published in 1985; it is said to have charted the moving trend in the science of nuclear winter. It was co-authored with Nikita Moiseyev and A. M. Tarko.
A nuclear holocaust, also known as a nuclear apocalypse,nuclear Armageddon, or atomic holocaust, is a theoretical scenario where the mass detonation of nuclear weapons causes globally widespread destruction and radioactive fallout. Such a scenario envisages large parts of the Earth becoming uninhabitable due to the effects of nuclear warfare, potentially causing the collapse of civilization and, in the worst case, extinction of humanity and/or termination of all biological life on Earth.
Solar geoengineering, or solar radiation modification (SRM), is a type of climate engineering in which sunlight would be reflected back to outer space to limit human-caused climate change. It is not a substitute for reducing greenhouse gas emissions, but would act as a temporary measure to limit warming while emissions of greenhouse gases are reduced and carbon dioxide is removed. The most studied methods of SRM are stratospheric aerosol injection and marine cloud brightening.
Stratospheric sulfur aerosols are sulfur-rich particles which exist in the stratosphere region of the Earth's atmosphere. The layer of the atmosphere in which they exist is known as the Junge layer, or simply the stratospheric aerosol layer. These particles consist of a mixture of sulfuric acid and water. They are created naturally, such as by photochemical decomposition of sulfur-containing gases, e.g. carbonyl sulfide. When present in high levels, e.g. after a strong volcanic eruption such as Mount Pinatubo, they produce a cooling effect, by reflecting sunlight, and by modifying clouds as they fall out of the stratosphere. This cooling may persist for a few years before the particles fall out.
Marine cloud brightening also known as marine cloud seeding and marine cloud engineering is a proposed solar radiation management climate engineering technique that would make clouds brighter, reflecting a small fraction of incoming sunlight back into space in order to offset anthropogenic global warming. Along with stratospheric aerosol injection, it is one of the two solar radiation management methods that may most feasibly have a substantial climate impact. The intention is that increasing the Earth's albedo, in combination with greenhouse gas emissions reduction, carbon dioxide removal, and adaptation, would reduce climate change and its risks to people and the environment. If implemented, the cooling effect is expected to be felt rapidly and to be reversible on fairly short time scales. However, technical barriers remain to large-scale marine cloud brightening. There are also risks with such modification of complex climate systems.
Mark Zachary Jacobson is a professor of civil and environmental engineering at Stanford University and director of its Atmosphere/Energy Program. He is also a co-founder of the non-profit, Solutions Project.
Stratospheric aerosol injection 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 eruptions. 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, with high agreement that it could limit warming to below 1.5°C." 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.
Owen Brian Toon is a professor of atmospheric and oceanic sciences. He is a fellow at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. He received an A.B. in physics at the University of California, Berkeley in 1969 and a Ph.D. in physics at Cornell University in 1975 under Carl Sagan. His research interests are in cloud physics, atmospheric chemistry, and radiative transfer. He also works on comparing Earth and other planets such as Venus.
Richard Peter "Rich" Turco is an American atmospheric scientist, and Professor at the Institute of the Environment, Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles. He won an award in 1986, from MacArthur Fellows Program.
Martin Bunzl is professor of philosophy emeritus at Rutgers University in New Brunswick, NJ, where he directed the Rutgers Initiative in Climate and Social Policy from 2007 to 2011.
Cynthia E. Rosenzweig is an American agronomist and climatologist at NASA Goddard Institute for Space Studies, located at Columbia University, "who helped pioneer the study of climate change and agriculture." She is an adjunct senior research scientist at the Columbia Climate School and has over 300 publications, over 80 peer-reviewed articles, has authored or edited eight books. She has also served in many different organizations working to develop plans to manage climate change, at the global level with the IPCC as well as in New York City after Hurricane Sandy.
Julie Michelle Arblaster is an Australian scientist. She is a Professor in the School of Earth, Atmosphere and Environment at Monash University. She was a contributing author on reports for which the Intergovernmental Panel on Climate Change (IPCC) was a co-recipient of the 2007 Nobel Peace Prize. Arblaster was a lead author on Chapter 12 of the IPCC Working Group I contribution to the IPCC Fifth Assessment Report in 2013. She has received the 2014 Anton Hales Medal for research in earth sciences from the Australian Academy of Science, and the 2017 Priestley Medal from the Australian Meteorological and Oceanographic Society. She has been ranked as one of the Top Influential Earth Scientists of 2010-2020, based on citations and discussion of her work.
Nuclear famine is a hypothesized famine considered a potential threat following global or regional nuclear exchange. It is thought that even subtle cooling effects resulting from a regional nuclear exchange could have a substantial impact on agriculture production, triggering a food crisis amongst the world's survivors.
Joyce Penner is an atmospheric scientist known for her research on climate change, especially on the impact of aerosols and clouds.
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.
