The biggest and most immediate problem is we've put too much carbon in the air to expect the natural carbon sinks of trees, land, oceans, the biosphere, to absorb it before runaway effects start unlocking vast prehistoric amounts of carbon accelerating climate change https://www.npr.org/sections/goatsandsoda/2018/01/24/5752202.... The sooner we lock up carbon, the sooner we get out of the danger of having much high sea levels, and runaway global climate warming.