Mainly - you can’t argue this one, not in the way you think (by proving that the claims are false).
Firstly, because it's about (anti-)morality, ingroup outgroup, us and them stuff – so there is no real arguing.
But mainly because it is a false claim to knowledge. Nobody knows anything about this stuff ! Nobody knows If the climate is warming, because there is no validated understanding of what causes climate.
Also because a large majority of the data is contaminated with dishonesty – we cannot trust ‘the science’.
(Indeed, science is all-but dead – in the sense that science existed until a generation or two ago. The ‘evidence’ nowadays comes from research bureaucrats and entrepreneurs who are motivated by careerism; not truth seeking and truth speaking.)
Even If (which is not known) there Is a long term trend of getting warmer – that is in the past, not predictive of the future: nobody knows whether such trends continue, or plateau or reverse … nobody knows.
Even If ‘They’ did know that the climate was going to get warmer in the future, and If they knew it was mostly due to CO2 (which obviously it isn’t) then this may well be a Good Thing For The World overall – indeed it probably is (given that our real problem on earth is ice ages).
Even If it was getting warmer, due to CO2 and that was proven to be A Bad Thing; ‘They’ have No Idea At All if this can be prevented, or how it might be prevented. (James 'Gaia' Lovelock said it is already way too late to prevent it.)
So if they really believed this stuff, they would Prepare For Global Warming, not waste trillions on a futile attempt to stop it.
Even if CO2 caused global warming was true and preventable by cutting down CO2 – then this is not going to happen with proposed policies because they are all about creating a multi-trillion dollar industry of fake ‘sustainable’ technologies (liek wind turbines and hybrid/ electric cars) that do Not reduce CO2 and instead increase it; not least because they require five yearly cycles of re-tooling and infrastructure replacement.
Put it together and look at who is funding and pushing the Climate Emergency/ Extinction Rebellion (the richest and most powerful people and organisations) and it is obvious that this is about funding (with compulsory and subsidised ‘sustainable’ technologies) a totalitarian takeover (totality being justified by the fact that CO2 is the gas of life, and thus every living thing needs regulating).
So, in discussion, I would just reframe the whole thing in terms of being the dishonest product of evil motivation: an excuse for the rich and powerful to fund and implement global totalitarianism.