We have known about the possibilities of climate change for a long time. The NSW based The Braidwood Dispatch and Mining Journal of Wed 17 Jul 1912 Page 4, states
COAL CONSUMPTION AFFECTING CLIMATE.
The furnaces of the world are now burning about 2,000,000,000 tons of coal a year. When this is burned, uniting with oxygen, it adds about 7,000,000,000 tons of carbon dioxide to the atmosphere yearly. This tends to make the air a more effective blanket for the earth and to raise its temperature. The effect may be considerable in a few centurieshttps://trove.nla.gov.au/newspaper/article/100645214
Various scientists confirmed the likely speculation, but it hit the mainstream with the 1965 Report Restoring the quality of our environment which was presented to US President Johnson and gives some ideas of the social knowledge and approach to climate change. They took it as likely and serious. Here are some paragraphs with a few comments in [ ]s:
President Johnson wrote:
the technology that has permitted our affluence spews out vast quantities of wastes and spent products that pollute our air, poison our waters, and even impair our ability to feed ourselves…. Pollution now is one of the most pervasive problems of our society.
Johnson points out that pollution is a general and serious problem resulting from the way societies have gained affluence. The Report, itself, opens with some history of the knowledge of CO2 Pollution, climate change, and its consequences:
The possibility of climatic change resulting from changes in the quantity of atmospheric carbon dioxide was proposed independently by the American geologist, T. C. Chamberlain (1899) and the Swedish chemist, S. Arrhenius (1903), at the beginning of this century.
They point to some existing evidence of climate change.
One might suppose that the increase in atmospheric CO2 over the past 100 years should have already brought about significant climatic changes, and indeed some scientists have suggested this is so. The English meteorologist, G. S. Callendar (1938, 1940, 1949), writing in the late 1930’s and the 1940’s on the basis of the crude data then available, believed that the increase in atmospheric CO2 from 1850 to 1940 was at least 10%. He thought this increase could account quantitatively for the observed warming of northern Europe and northern North America that began in the 1880’s….
As Mitchel (1961, 1963) has shown, atmospheric warming between 1885 and 1940 was a world-wide phenomenon.
The authors point to the difficulties of prediction of climate….
Even today, we cannot make a useful prediction concerning the magnitude or nature of the possible climatic effects.
Although clearly they recognise that climate change is a problem. They also recognise that sea level rise is a likely result.
It has sometimes been suggested that atmospheric warming due to an increase in the CO2 content of the atmosphere may result in a catastrophically rapid melting of the Antarctic ice cap, with an accompanying rise in sea level…. But such melting must occur relatively slowly on a human scale…. The melting of the Antarctic ice cap would raise sea level by 400 feet. If 1,000 years were required to melt the ice cap, the sea level would rise about 4 feet every 10 years [They add that this is not yet happening]
They think CO2 increase is induced by the actions of a particular social formation, and is therefore humanly induced.
Through his worldwide industrial civilization, Man is unwittingly conducting a vast geophysical experiment. Within a few generations he is burning the fossil fuels that slowly accumulated in the earth over the past 500 million years. The CO2 produced by this combustion is being injected into the atmosphere; about half of it remains there.
We can conclude with fair assurance that at the present time, fossil fuels are the only source of CO2 being added to the ocean-atmosphere-biosphere system.
By the year 2000 the increase in atmospheric CO2 will be close to 25%. [They were wrong, the increase was much bigger than they thought] This may be sufficient to produce measurable and perhaps marked changes in climate, and will almost certainly cause significant changes in the temperature and other properties of the stratosphere. At present it is impossible to predict these effects quantitatively…
Again, they suggest that humanly induced climate change could be bad for humanity
The climatic changes that may be produced by the increased CO2 content could be deleterious from the point of view of human beings. The possibilities of deliberately bringing about countervailing climatic changes therefore need to be thoroughly explored.
The solution they propose, appears to involve an early suggestion of geoengineering, rather than a cutback in fossil fuel consumption.
A change in the radiation balance in the opposite direction to that which might result from the increase of atmospheric CO2 could be produced by raising the albedo, or reflectivity, of the earth.
So, the Report could warn that global heating and climate change was likely to occur because of human burning of fossil fuels, but made no suggestion of cutting back consumption of those fossil fuels.
Sounds pretty contemporary.