Part of this is the belief that man always messes everything up, including paradise (Garden of Eden). Yet, it seems grandiose to believe that man could totally ruin a planet. Is there conclusive scientific proof?
They could have said opinion but judgment sounded more official. Do we pay scientists to be judges, politicians, and opinion writers?
Scientific proof requires double-blind experiments with a control. These experiments must be repeatable and the cause and effect relationship must be provable and strong to be of use. CO2 levels rising 0.1% over several hundred years, from 0.28 to 0.38%, is not significant enough to be entirely responsible for a 5% increase in temperature.
We are short on experiments that show us the optimum temperature to support quality of human life. That setting is likely warmer than it is today. And we are short on how to inexpensively make white reflecting clouds and snow to actively manage where and when the Sun's energy heats the surface. Why do we spend billions on detecting a tiny amount of global warming and very little on technologies that can manage the climate?
Climate management technologies will eventually be funded by the Department of Defense. They will never come from scientists or the UN. If we could induce a directed hurricane we could do more damage to North Korea than an atomic bomb.