Just as we live in a world that has changed the word "monopoly" to mean something that allows Amazon and Microsoft to exist (and others), the word conspiracy has also changed.
Information is so quick these days, and info so easy to update as well, that sources don't even need to collaborate to weave apparent webs of deceit. They simply comply with the unspoken.
I don't advocate conspiracy in the case of global warming, but imagine the dilemma of a researcher who could prove it wrong (hypothetical of course). That researcher would not get backing from the accredited funders, since it would be so discounted against the science-politic.
And further research, no way.