In 1824, a French scientist named Joseph Fourier postulated that an in crease in atmospheric gases might be able to warm the atmosphere. Swedish physicist Svante Arrhenius was the first scientist who tried to measure atmospheric gases, specifically whether increases in CO2 could warm the earth's atmosphere. Rather than being concerned about warming, however, Arrhenius thought that it could be beneficial, resulting in such things as a more livable planet and higher crop yields.
In the 1950's it became possible to measure the amounts of CO2 in the atmosphere, this first being done at Mauna Loa in Hawaii. The measurements showed a continued upward trend in CO2 concentrations in the atmosphere.
In 1979, with funding from various government sources, the World Meteorological Organization created the first World Climate Conference. Going beyond its original mandate, which was to assess the level of scientific knowledge of climate change, and realizing that their funding sources would more likely remain constant or increase if they did so, the WCC issued a "Call to Nations", which urged governments to take the lead in projecting and preventing man's influence on the climate. Thus, from the outset, there existed prejudice in favor of blaming man for climate change, and an incentive for governments to feed the beast.
James Hansen, a NASA physicist, rose to prominence by writing that global warming was suddenly a very important issue and that temperatures were slated to go up much faster than once thought.
A meeting of scientists in Villach, Austria in 1985 constituted the first time that the term "scientific concensus" was used with regard to global warming.
On a sweltering hot day in 1988, James Hansen testified before the United States Congress that earth was hotter in that year than it had ever been in measured history and that it was bound to get much worse if something wasn't done quickly. Hansen's scary scenario ended up being reported around the world.
British Prime Minister Margaret Thatcher was influenced by the furor and gave much more weight to the claims by herself claiming that "adding greenhouse gases to the air...is changing [our] environment in damaging and dangerous ways."
In that same year, 1988, the Intergovernmental Panel on Climate Change was formed.
The IPCC's First Assessment Report admitted that the earth had been warmer in the past, but pointed out that it appeared that atmospheric levels of greenhouse gases seemed to have been much smaller during those warming periods. The IPCC admitted that it was very unclear what relationship apparently higher concentrations of greenhouse gases had to changes in atmospheric temperature. The IPCC attached a graph to its First Assessment showing, among other things, that earth's temperature had indeed been much warmer in the Medeival Warming period from the 11th to the 15th centuries.
When David Deming, a scientist from the University of Oklahoma, published a paper that showed moderate warming in North America since 1850, the politicized scientific consensus switched into high gear, latching onto Deming's article as a means of helping them conveniently hide the warming of the Medieval Warming period. Deming said of their attempts to woo him:
With the publication of the article in Science I gained instant credibility. They thought I was one of them, someone who would pervert science in the service of social and political causes. One of them let his guard down, [saying] 'We have to get rid of the Medieval Warm Period.'A couple of years later, Deming was a reviewer for a compelling borehole study written up to be included in the journal Nature. The study, by Shaopeng Huang of the University of Michigan, showed that warming was indeed worldwide during the Medieval Warming Period. Because it did not fit into the politics of the man-causes-global-warming consensus, the article was delayed several times by Nature; it was then ultimately spiked (i.e. never published).
Spiking of research articles expressing the same sentiment as Shaopeng's became common.
This early and nearly immediate politicization of global warming established the foundation for its so-called scientific consensus. The chicanery continues to this day.