I should have done this long ago.

Still, now, discussions about climate is disturbed by some ignorance: Not knowing about or accepting the existence and the role of the greenhouse effect on the Earth, independently of today’s situation.

Some won’t believe that the small amount of carbon dioxide in the atmosphere (below 0,01 %) plays a role in regulating climate, together with the two other major greenhouse gases – water vapour and methane. Some other gases also contribute.

This is an entry in Encyclopedia Britannica, the 1987 edition.

Methane is not mentioned as a greenhouse gas, which has to imply that this is newer knowledge than from 1987. In the online version of Britannica it is mentioned along with the others.

greenhouse effect, heating of the Earth due to the presence of the atmosphere, named in analogy to a similar effect produced by the glass panes of a greenhouse. Most of the shortwave and visible radiation from the Sun that is not scattered back to space by the atmosphere is transmitted through the atmosphere to the surface of the Earth, very little being absorbed by the atmosphere. This transmitted energy is absorbed at the surface, thus heating the surface.

Part of this absorbed energy is reradiated to the atmosphere as longwave infrared radiation. The atmosphere is not completely transparent to this longwave radiation, however, because it contains carbon dioxide and water vapour, which absorb a considerable portion of it before partially reradiating it back to the surface. Thus, although a large portion of shortwave solar radiation is transmitted through the atmosphere to the ground, a large portion of the reradiated longwave radiation is trapped by the atmosphere and does not escape directly back into space. This causes the Earth and atmosphere to warm up to a higher temperature than would otherwise be the case. In the greenhouse analogy, the glass windows admit the solar radiation but partly trap the infrared radiation reradiated from within and return part of it back into the greenhouse; this and the blockage of convection cause the temperature in a greenhouse to rise to a higher level than that of free air outside.

It has been suggested that long-term climatic changes will result as the greenhouse effect is intensified because of the rise in carbon dioxide consentration brought about by combustion of fossile fuels (e.g., coal, oil, and natural gas). Some U.S. investigators predict that significant alterations in climate patterns will become apparent by the turn of the century. They estimate that global average temperatures could rise as much as 5° C (9° F) before the year 2100. Temperature increases in the polar regions could be as much as three times larger, which would cause the polar ice caps to melt at a rapid rate and result in appreciably higher coastal waters. The rise in global temperature would also produce extremes of drought and rainfall, which would disrupt food production.”

Published in 1987.