The Long and the Short of It - The Changing Arctic Environment: The Arctic Messenger - page 346

Climate
Anticipation:
Using our interpretation of Jared Diamond's analytical scheme, when could humankind
have anticipated climate warming? The basic physics of the greenhouse effect were
worked out in 1827 by Jean Baptiste Joseph Fourier, one of Napoleon's savants. In 1896,
Svante Arrhenius calculated how much our global temperature would change from a giv-
en rise in CO 2 . In other words, he had made an estimate of climate sensitivity. His cal-
culation of 5°C for the tropics and 6°C for high latitudes remains close to those estim-
atedtodaybytheIntergovernmental PanelonClimate Change(IPCC),whichputsclimate
sensitivity (for a doubling of atmospheric CO 2 ) as most likely lying between 1.5°C and
4.5°C. Thus, we have no excuse - we should have seen it coming since at least 1900.
Perception:
By 1938, Guy Stewart Callendar had shown that CO 2 levels and temperature in the atmo-
sphere had been rising over the previous 50 years. In 1960, Charles Keeling confirmed
that CO 2 levels in the atmosphere were rising and produced what is now called the Keel-
ing Curve to describe it. In 1979, the U.S. National Research Council concluded: “When
it is assumed that the CO 2 content of the atmosphere is doubled and statistical thermal
equilibrium isachieved, themorerealistic ofthemodelling effortspredictaglobalsurface
warming of between 2°C and 3.5°C with greater increases at high latitudes.” Notice the
anticipation of greater temperature increases in the Arctic and in Antarctica. In 1988,
the WMO organised a World Conference on the Changing Atmosphere: Implications for
Global Security. The conference concluded that changes in the atmosphere due to human
activity “represent a major threat to international security and are already having harm-
ful consequences over many parts of the globe”. They recommended that by 2005, world
global emissions of CO 2 should be 18% lower than in 1988.
Therefore, the date at which humankind's scientific community perceived that climate
warming was under way and attributable to anthropogenic GHG emissions could be said