Manabe, Syukuro (Global Warming)

(1931- )

As a Japanese meteorologist generally regarded as the world’s leading scientist in the field of numerical modeling of climate and climate change, Syukuro Manabe pioneered the use of computers to simulate global climate change and natural climate variations. Manabe was one of the first scientists to study the phenomenon of global warming in the 1970s, when he investigated the possibility that the emissions of great quantities of carbon dioxide and other greenhouse gases from the combustion of fossil fuels such as coal, oil, and natural gas could affect climate.

Born in 1931, Manabe graduated from the University of Tokyo in 1958. The post-war period was a difficult time for scientists in Japan. Manabe was among those who, like Akio Arakawa, found better career opportunities in the United States, where the Cold War kept steady government funding for fields such as geophysics and computer science. Manabe was hired as a researcher by Joseph Smagorinsky, then the director of the U. S. Weather Bureau near Washington, D.C. Sma-gorinsky wanted to develop the insights of John von Neumann and Julie Charney into a general circulation model of the entire three-dimensional global atmosphere, built directly from the primitive equations.


Smagorinsky and Manabe put into their model details that would be influential for the discovery of global warming. Their model accounted for the way rain fell on the surface and evaporated, how radiation passing through the atmosphere was impeded, not only by water vapor but also by ozone and carbon dioxide gas (CO2), how the air exchanged water and heat with simplified ocean, land, and ice surfaces, and much more. Manabe had always been interested in the effects of CO2, and the impact of CO2 on the future climate. Manabe’s interest stemmed from the consideration that the gas at its current level was a significant factor in balancing the planet’s heat. When Fritz Moller theorized that even mild perturbations and human actions could cause a global catastrophe, Manabe decided to work on a model that might account for how the climate system might change. He came to the conclusion that the entire atmosphere had to be studied as a tightly interacting system. In his model, Manabe took full account of water in all its forms. It included the feedback between the air’s temperature and the amount of moisture the air would hold. In particular, Manabe calculated the way rising columns of moisture-laden air conveyed heat from the surface into the upper atmosphere.

In 1967, Manabe used a one-dimensional model to test what would happen if the level of CO2 changed. He targeted the climate’s "sensitivity," a feature that would eventually become a central preoccupation of modelers. Together with his group, he set out to calculate how much the variation of incoming and outgoing radiation would alter temperature. The answer they reached was that if the levels of CO2 doubled by the end of the century, as seemed possible, global temperature would rise roughly 3-4 degrees F (around 2 degrees C). This was the first time a greenhouse warming calculation included enough of the essential factors, including the correct estimate for water vapor feedback, to seem reasonable to many scientists. Many of them who were to play an influential role in global warming debates, such as Wallace Broecker, recalled that it was these data that made them embrace research into the phenomenon.

In 1968, Smagorinsky and Manabe’s group, which had been renamed the Geophysical Fluid Dynamics Laboratory in 1963, moved from the Washington, D.C., area to Princeton, and it eventually came under the wing of the U.S. National Oceanic and Atmospheric Administration. Manabe continued to work, together with fellow meteorologists, on general circulation models of the atmosphere, trying to make them more complex and comprehensive. In 1967, he and Richard Wetherald demonstrated that increasing atmospheric CO2 absorptions would increase the height at which the Earth radiated heat to space. In 1969, Manabe and Kirk Bryan published the first simulations of the climate which combined ocean and atmosphere models. This was the first time that the role of oceanic heat transport was taken into account in determining global climate. Throughout the 1970s and 1980s, Manabe’s research group published influential papers using these models to explore the sensitivity of the Earth’s climate to the variations of greenhouse gas concentrations. These papers formed a major part of the first global assessments of climate change, published by the Intergovernmental Panel on Climate Change (IPCC), established in 1988.

From 1997 to 2001, Manbe went back to Japan at the Frontier Research System for Global Change serving as Director of the Global Warming Research Division. In 2002, he returned to Princeton University as a visiting research collaborator at the Program in Atmospheric and Oceanic Science. During his distinguished career, Manabe has received many honors and awards. He is a member of the United States National Academy of Sciences, and a foreign member of Academia Europaea and the Royal Society of Canada. In 1992, he was the first recipient of the Blue Planet Prize of the Asahi Foundation. In 1997, Manabe was awarded the Volvo Environmental Prize from the Volvo Foundation. Manabe has also been awarded the American Meteorological Society’s Carl-Gustaf Rossby Research Medal, the American Geophysical Union’s Revelle Medal, and the Milutin Milankovitch Medal from the European Geophysical Society.

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