Earlier quoted context omitted.
I'm not sure I understand. Why deny something that you claim not to know enough about?
Isn't that the default stance in philosophy? Assume something is false until evidence proven true. You cannot begin with the assumption that something is true, otherwise we're back to the mystical dark ages of magic monsters and alchemy
Or maybe you're thinking of the burden of proof concept from jurisprudence? That is a high standard because it keeps innocent people from having their lives destroyed.
The IPCC reports [0], predicated upon the anthropogenic theory of climate change, predict a lot of people will have their lives destroyed, and the theory specifies the mechanism which will determine the magnitude. You and I as agents in democracies (I'm guessing) can help determine that magnitude - maybe whether it's millions of families displaced and destroyed or hundreds of millions.
I think the philosophical stance we should apply is the precautionary principle. If we're unsure of whether or not it is harmful that our activities are changing the composition of our atmosphere, of our oceans, and of our soil, we should at least, as a precaution, reduce the rate at which we're changing our environment.