The Dictionary of the Climate Debate (DCD)

Manabe, Syukuro

(1931) A Japanese meteorologist who pioneered using computers to simulate climate change, and who — while at NOAA's Geophysical Fluid Dynamics Laboratory — worked with Joseph Smagorinsky to develop three dimensional models of the atmosphere.

In 1967 he created the first model to calculate climate sensitivity for CO2. It came out to 2°C. If you'd like to read the paper, click here. Here's a key quote:

"According to our estimate, a doubling of the CO2 content in the atmosphere has the effect of raising the temperature of the atmosphere (whose relative humidity is fixed) by about 2C."

Note: In 2015 Carbon Brief asked lead authors and review editors of the IPCC AR5: What was the most influential climate change paper of all time? The above paper came in first.

The origin of the standard modern climate sensitivity estimate

The standard modern estimate of climate sensitivity, which is 3°C ± 1.5°C, originated with a committee on AGW chaired by Jule Charney that was convened in 1979 by the US National Academy of Sciences.

Two sets of models were available:
(1) Manabe's which showed a climate sensitivity of 2°C and
(2) James Hansen's which showed 4°C.

According to Manabe, "Charney chose 0.5°C as a not-unreasonable margin of error, subtracted it from Manabe's number, and added it to Hansen's. Thus was born the 1.5°C-to-4.5°C range of likely climate sensitivity that has appeared in every greenhouse assessment since, including the three by the Intergovernmental Panel on Climate Change (IPCC)."

1. The source for the above anecdote is an article by Kerr CLIMATE CHANGE: Three Degrees of Consensus. If you'd like to read it in full, click here.

2. In 1969 Manabe and Kirk Bryan published the first planetary climate simulations that used coupled ocean and atmosphere models.

3. Throughout the 1970s and 1980s Manabe's research group published seminal papers using these models to explore the sensitivity of Earth's climate to changing greenhouse gas concentrations. These papers formed a major part of the first global assessments of climate change published by the IPCC.

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