Fossil fuels have already contributed to rising sea levels, and they will continue to. One way to stop this is to stop pulling fossil fuels out of the ground - this is possible, but many nations have to make an agreement in order for this to work. Given President Trump's resistance to the Paris Climate Agreement, we need to demand more cooperation to stop pulling fossil fuels out of the ground.
The UN delegation conversed more about stopping fossil fuel extraction. However, without help from the United States, this is a very difficult feat.
The island of Fiji, which was present at the UN conference, made a large push to end fossil fuel usage because of imminent dangers to their population - some protesters think that they had a direct impact on how hard Fiji pushed for this.