The UN's Inter-governmental Panel on Climate Change (IPCC) was formed to increase the political power of the UN by embellishing an existing environmental boogeyman.
The claim of a coming catastrophe of some sort is a centuries-old strategy used by religious or political leaders to gain power and tell others how to live.
The UN (M. Strong) came up with a reason to seize more power over individual governments of member nations.
The reason they chose was an existing belief / conclusion among some scientists that humans were ruining the planet.
If that conclusion was true, it could be claimed only a world government like the UN could stop the destruction.
The IPCC was charged with adding any complex science and math they could find, or make up, to support an existing unproven conclusion about CO2.
Get enough PhD's involved, using complex computer models, and you can have an impressive "dog and pony show".
Much better for "selling" a coming climate catastrophe than a bunch of pointy-headed scientists stating their opinions by presenting papers at scientific conferences.
In plain English, the unproven conclusion was that humans are destroying the planet by burning fossil fuels, and the unspoken conclusion was that the UN must have the power to stop it.
This was originally all about political power for the UN.
Unfortunately for the UN, member nation leaders latched on to the climate catastrophe fantasy to increase their own power (for their governments to exert more control the private sector).
Predicting the future (climate) has nothing to do with science.
It is climate astrology.
Especially when the causes of climate change are just unproven theories.