They were sure after 1998 that the climate was spiraling out of control due to global warming. They were also sure that the fate of the planet depended on them getting the word out.
In order to spur action, they took the liberty of systematically manipulating the temperature data to cool the past and warm the present. This was partly done under the thinly veiled guise of “USHCN corrections” which are otherwise known as “complete crap” or “
shit confirmation bias on a shingle“
Sometimes you have to do really bad things to save the planet (Peter Glieck™ ) but something went terribly wrong – temperatures started going down. This led to further manipulations and thrashing around idiotic ideas like Chinese aerosols, missing sea ice, evil and unnatural La Nina’s, etc.
The problem is, once they turned to the dark side, there was no going back. Science be damned – this is now about saving their sorry reputations and incomes for as long as they can.