Humans do affect climate/weather, and that is beyond doubt since it can be observed without needing to fudge data (e.g. compare the temperatures in Lakewood and Monsey to Manhattan and Philadelphia – cites are warmer, which is people of all types prefer to “go away to the country”).
The issue is how much of climate variability is natural and how much is due to humans (and in particular, due to industrialization). The climate alarmists like to assume that the 1600-1700s were normal, but there is strong evidence that was one of the coldest periods in human history (sort of like looking at February and freaking out since it is warmed in August). While thermometers were invented only a few centuries ago, there are records of what rivers frozen and when, and what crops grew where – and these suggest the medieval period (time of the Rishonim) was even warmer than today. Similarly the “classical age” (period of Bayis Sheini) was warmer than the period that followed.
If the goyim’s scientists are to be believed, Long Island Sound used to be dry land, and it used to be possible to walk from England to France, or from Siberia to Alaska, without getting your feet wet – and all those changes did not involve humans messing with the climate.
So the question isn’t so much “do you believe in global warming” but rather do you believe that the primary cause is human activities, since if not, there is nothing the government can or could do about it. This doesn’t address the question as to whether global warming is good or bad, though given the large number of climate refugees fleeing to Florida every winter, I tend to think that warmer would a good thing.