It is a well-established scientific fact that carbon dioxide is a greenhouse gas, and it is well-known that human activity can and does produce carbon dioxide; same goes with some other greenhouse gases, such as methane.
I don't think there's any significant objection to the position that climate change is real, it does impact the environment, it is partially caused by human activity, and it has been happening ever since the planet formed an atmosphere.
However, the doom and gloom being projected by the climate change alarmists is not in fact a well-established scientific fact. It entails predictions that are not well-rooted in the scientific method; for instance, science involves observation and repeatability, and with predictions of human-caused global warming reaching achieving, and exceeding disastrous & catastrophic levels, such observations have not yet occurred (thus have not yet been repeated). The main fundamental trait of science is that a theory can be falsified; how does one falsify something that hasn't been observed, yet?
BTW yes, I get that it's desirable to avoid a disaster or catastrophe if possible, and I'm not saying that individuals shouldn't be able to make whatever personal decisions they want to make regarding human-caused global warming or climate change.
If there really is some sort of worldwide desire by all (or most) nations and the UN to (as they put it) "combat" climate change, then they'd be accommodating to at least allowing people living in places that are being affected by adverse changes in the environment to take mitigating action such as relocating.
The point is that there's more than one way to deal with a problem other than government-imposed bans, fines, taxes, etc.
When the government imposes, "carbon" taxes, bans ICE vehicles, gas-powered items (stoves, water heaters, home heating systems, etc.), coal-fired power stations, etc., and imposes fines for violating such laws, and they're doing it on the basis of climate change alarmism, then it's unconstitutional.
It infringes on the 1st clause of the 1st Amendment, which prohibits merger of church and state.
With climate change alarmism, it involves the claim that we must make sacrifices and pay "carbon" taxes, or else we'll all burn up from global warming; that's essentially no different from any conventional religion saying "pay for your sins or you'll burn in hell."