[ 16/9/20 ]
The answers by Paul Eshelman and Robert Knight are both wrong, and climate change is the norm over geological time, mostly in response to long term orbital dynamics but also impacted by volcanism, plate tectonics, comet/meteor strike, and maybe other factors.
Humans are definitely changing the climate, and there is potential for runaway positive feedbacks that could result in very large rises in sea level. Nothing that hasn’t happened before in geological time in a sense, but much more than has happened in any written history of humanity.
Technological management of climate to maintain sea level is possible, but in order to deploy such powerful technology we would need to have global cooperation. And to be very clear, global cooperation is nothing like global control. Cooperation between multiple levels of independent agents is not only possible, but is actually the only way forward that has any significant probability of long term survival. The current focus on competitive systems must end badly – eventually.
The how is complex, and to do it effectively would require developing fully automated production systems, deploying them on the moon, replicating them to produce solar cells across the entire moon’s surface, then using that energy to launch moon mass into orbit, and refine it into materials that could be used to orbitally manage the amount of sunlight reaching the earth. We only need to be able to vary it by 3% to more than offset any possible CO2 warming.
And the technology to do that does not as yet exist, but isn’t that hard to develop.
Developing technology like that while nation states were still in a non-cooperative war like footing would be very unwise, we would be much more likely to survive the climate change and sea level rise.