There is a great deal of geological evidence that shows that climates change. Likewise there is a great deal of evidence that human activity has affected climate.
The hoax is the claim that socialism will give us perfect climate.
While it is true that the left routinely fudges data to frame climate change as a disaster, the long term solution is for people who like freedom to show that socialism does not lead to perfect climate.
By making people dependent on government, socialism actually puts people in a worse position to deal with changes.
RE: THIRTY YEARS OF FAILED CLIMATE PREDICTIONS; GLOBAL WARMING HOAX