Ugh.
Just to be clear though, it should be "hottest year during the instrumental record period," not "hottest ever."
At any rate, you need to be delusional at this point not to accept that anthropogenic climate change is real, and we're clearly seeing its effects.
No one is saying that anthropogenic climate change is not real, it is! Human activity can and does effect the climate.
The open questions, are how large of a role does Human emitted CO2 play in the observed changes?
Are the CO2 emissions attributed to Humans large enough, that if reversed, would have a sufficient impact to be justified?
To address these questions, we have to start with how large a role does all the CO2 in the atmosphere have.
Physics, The IPCC and most researchers agree, that Earth is 33C warmer than it would be if the atmosphere were completely transparent.
https://www.giss.nasa.gov/research/briefs/schmidt_05/
Of that 33C, CO2's attribution is thought to be 20% (+6% -9%), or about 6.6C.
Now that is the attribution for old CO2, that has been there for eons, so it's energy imbalance warming is fully equalized.
If we look at doubling s of CO2, there have been 8.09 doubling s since CO2 was 1 ppm. (There could be many more doubling s,
but it is a good place to start.)
6.6C /8.09 doubling s, means that each doubling, has a fully resolved response of .815C.
How valid is the 8.09 doubling s value I used? We can check based on the energy imbalance.
The energy imbalance that causes the 33C, is stated as 150 W m-2, 20% of 150 W m-2 is 30 W m-2,
30 W m-2 /8.09=3.708 W m-2 per doubling.
If we assume that 100% of the CO2 increases since pre-industrial era, is from Human emissions,
Human emissions are ~412ppm-280 ppm=132 ppm, or about 55% of the doubling effect.
55% of the above doubling sensitivity of .815C, is .45C.
How can this be? The number is much lower that almost all the experts claim.
It starts with the ratio of long term CO2 energy imbalance, and the resulting equalized temperature.
In the greenhouse effect "thought experiment" from NASA, total forcing of 150 W m-2
results in a fully equalized temperature increase of 33C. The ratio is 33C/150 W m-2, or
.22C per W m-2.
IF we look at a 2XCO2 ECS of 3C, and go with the 2XCO2 forcing imbalance of 3.71 W m-2,
the ratio would be 3C/3.71 W m-2, or .80C per W m-2.
How can the models be so far off?
The models start with the assumption that the vast majority of the warming from the last century is from added CO2,
when in reality, it looks like is from aerosol emissions first slowing the warming, and then speeding up the warming,
as we cleared the aerosols.
https://www.mdpi.com/2072-4292/11/6/663/htm
If as much as half of the recent warming is attributable to aerosol changes, it is still anthropogenic, but subtracted away
from CO2's attribution.