That is simply false.Who are basing their beliefs on computer modeling while ignoring empirical climate data.
Guess what these are?

The Raw Truth on Global Temperature Records - NASA Science
Ensuring the accuracy of Earth’s long-term global and regional surface temperature records is a challenging, constantly evolving undertaking.


Climate Change: Atmospheric Carbon Dioxide
In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.


Is a detailed absorption spectrum available for carbon dioxide from 300-1100nm?
I believe that carbon dioxide does not absorb light in the visible region, but is a spectrum available somewhere online that shows this as a fact? As in a straight horizontal line at 100% transmiss...

EMPIRICAL DATA SUPPORTING THE THEORY OF AGW