Global cooling
As global cooling is generally referred to a reduction in the global average temperature. In particular, however, so that the observed cooling of the lower atmosphere and the oceans 1940-1975 is meant the probable cause was the anthropogenic emissions of aerosols. The forecast of a part of science further cooling in the case of increasing aerosol emissions was particularly widespread in the 1970s by the media and frequently dramatized.
The cooling
In the years 1940-1975 a global cooling trend was observed; 1958-1965, the global average temperature dropped by 0.3 ° C. However, this "global" designated as cooling loomed especially in the northern hemisphere.
Causes
McCormick and Ludwig came in 1967 to the conclusion that the anthropogenic aerosol emissions were caused by the cooling of the albedo increased and. In fact, the global sulfur emissions have risen since 1950 enormously to decline again in 1989.
Media Coverage
Worldwide, the media picked up the cooling and glaciation scenarios. Time magazine reported in 1974 under the title Another Ice Age? droughts and hunger deaths in Africa, record floods in the U.S., Pakistan and Japan and crop failures in Canada's grain belt. The unusually cold winter would herald a new ice age, according to the statements of a growing number of scientists. The New York Times headline in 1975, a "massive cooling is generally regarded as inevitable " ( "Major Cooling Widely Considered to Be Inevitable "). A Newsweek article in 1975 warned against dryness and thereby caused crop failures and epidemics, as well as from potential climate refugees from the affected areas. Similar articles there was at the same time also in the German media, including in the mirror.
Scientific observation
Rasool and Schneider predicted in 1971 for the case that the global aerosol emissions would quadruple, a decrease in the average global temperature by about 3.5 ° C and warned that this could trigger an ice age. In other scientists forecast a further cooling, however, were controversial. While keeping in the early seventies heating and cooling forecasts the scale, sat down in the late seventies, the realization that the cooling effect of aerosols would be overshadowed by the CO ₂ emissions, according to a study by Peterson et al. from the year 2008. consensus about an impending global cooling has never existed among scientists, the study says.
Today it is believed that the present interglacial, the Holocene, will continue for 50,000 years since the Earth's orbit is in a Exzentritätsminimum.