Before deciding what we did, it might be important to examine what we didn't do. As far as I can gather, the number one thing that people dwell on is the concern that by our actions, we can anticipate a few inches rise in sea levels.

Source
As you can see from this graph, the rise in sea level has been marginal for a few thousand years. Prior to this, the sea has risen by hundreds of feet. You only need to look at cities like Dwarka, and areas like Doggerland and off the coast of Egypt, to see the impact that non-human factors have played. Even in current cities like Dublin, the rise in sea level isn't due to human factors but due to rebound from glaciers during the last glaciation. While Dublin is "sinking" the other side of Ireland is actually rising from the water as the landmass is tilting.

What isn't considered is that tectonic plates are like rafts. The Pacific Ocean has not seen the same increase in water levels that the Atlantic has. We have seen an increase in volcanic activity around the ring of fire. My current hypothesis is that as more water enters the Pacific, the Pacific plate is pushed downward by the increased weight. This can be seen in water levels taken at the testing station at Fort Denison, Australia has not seen the increase that other places have seen:

Source

If this hypothesis is true, we might not see the anticipated rise in water as the planet adjusts itself.

Another thing to consider is the importance of CO2 for life. During the last glaciation, the CO2 level dropped to 180 ppm. At 170 ppm 95 percent of plant life starts to die off. By de-sequestering CO2, we have returned the levels to those comparable to a few hundred thousand years ago. If not for man, during the next glaciation (roughly 80k years from now) the majority of life could have died off once CO2 dropped below the critical point - leaving the surface similar to Mars.

Sixty million years ago, the temperature of the planet was about 18 degrees warmer than it is now. The forests ranged from pole to pole. In the short run, terrible things can happen, but the assumption is that once the water goes into the oceans it will stay there. Increased temperature (if CO2 was the main driver) should increase the amount of evaporation of the oceans causing areas that are currently dry (2/3s of the planet is considered desert) to retain more moisture and in turn grow more plants etc.

As unpopular as it may be, people need to change themselves and not the planet. We need to stop building houses on seashores. We need to stop polluting our air and water with toxins. We need to provide people with education so we aren't so unwise.