What evidence confirms climate change?

Evidence for natural climate change - plenty. For man-made - NONE; read on.

The “evidence” for man-made climate change comes from Global Climate Models (GCM).

In 2007 Al Gore famously said “The science is settled.” Now - if the science is settled, why would there be any modelling going on now? But there are more than 50 GCMs running around the world. And you would expect them to produce identical results. They all differ.

If you take the output from models from 10 years ago and compare projections with reality – they are wrong and they run hot.

Nobody knows how the climate works. The modellers think they know how CO2 will affect the climate – thus that “knowledge” is built in to the models..

Here are a few of many excellent articles that describe how GCMs work, and their shortcomings

http://www.drroyspencer.com/2009/07/how-do-climate-models-work/

https://wattsupwiththat.com/2014/10/16/a-simple-truth-computer-climate-models-cannot-work/

https://scied.ucar.edu/longcontent/climate-modeling

Briefly: GCMs are based on distorted “Cubes” derived from horizontal and vertical grids, typically 100km wide and 1km deep. Each cube has properties such as the amounts of each atmospheric gas, wind speed, air pressure etc. The model runs forward in time in steps of 30 minutes or more (any reduction in size and time makes run times impractcal).

The model needs to be checked against reality. A date in the past – say 50 years ago – is chosen and ALL CUBES ARE INITIALISED with starting properties. Now – how much of this is known – for the whole planet and up to the top of the atmosphere – from 50 years ago? How do you initialise the 5th cube up1000 kms east of New York in the Atlantic?

Well, using clever techniques (guesses) the initialisation is done. The model then runs and produces results that don’t match with what happened in the 50 years. That’s EXPECTED because there are factors that are not understood – an important one being clouds. For these factors the modellers provide parameters that are adjusted until the model produces something near to reality.

The conclusion is that the model and the parameter settings must be correct. The model is then run into the future to project what will happen. This is where, years later, it is clear that all run hot. See many places, but here for example https://judithcurry.com/2015/12/17/climate-models-versus-climate-reality/

You see, the problem is that nobody knows how the climate works.