For a long time the global warming skeptics argued that the only alternative was to shut down modern civilization and let billions starve. France, Ontario, and California getting almost 50% of its power from solar show that this is bollocks.
Some did for sure, and I agree that they were wrong. But that instinct to imagine the worst was just working in the opposite direction to those that believe there is no chance to stop global warming and humanity is doomed.
But that's really a separate discussion. What we're really discussing is how we come to know truth, and how much we can trust our conclusions. And more importantly how we treat each other in the face of the unavoidable ambiguity and uncertainty.
If people argued with less conviction in the absolute truth of their positions, i believe they would actually be more convincing and get more people willing to start pulling together in one direction.
As for global warming, your acceptance of it makes sense. We do have to proceed in life without 100% clarity in anything at all. We can only make our best assessment and then proceed in good faith.
But i'm reminded of a story about ancient astronomers who held closely guarded knowledge not known by the masses -- such as being able to accurately predict eclipses. Unscrupulous actors of the time could perform miracles by telling everyone that they were going to shut the sun off in the middle of the day. Witnesses to such an event might start off as a skeptic, but be brought around as they saw evidence of this miracle man's ability to control the sun. The moral of the story being that even when we see evidence for ourselves, the explanation we're given about why it is happening should not necessarily be accepted without skepticism.