CO2 is only one danger
Climate change science is under political attack, but even if global temperature rise is much lower than projected, many other issues would force us to cut back resource use. They constitute a very long list, never complete.
Here's a short list:
- The ozone hole and ozone depleting chemicals. The hole is still there, no longer growing, but not really shrinking. And it could start growing again.
- Mercury in the air is a latent danger. It ascends into the upper atmosphere to fall out much later over much of the globe, including the ocean, where it accumulates in fish, concentrating more as it moves up the food. That's why pregnant women are advised not to eat tuna, big fish that have lived a long time to absorb a load of mercury. (Much mercury comes from burning coal, but there are other sources, like burning batteries.)
- After Freon, the dominant greenhouse gas is expected to be nitrous oxide, and it many also be an ozone depletion catalyst. It is not nearly as potent as Freon, but there's a lot more of it. a major source is emissions from ammonia-based fertilizer. Since we are dependent on this fertilizer for high crop yields, stopping its excess application will require a major learning program. (Excess fertilizer run off is also a prime cause of eutrophication zones in lakes and off the mouths of rivers. They're dubbed "dead zones" because marine life is severely curtailed within them.)