This is all very pessimistic.

Couldn't a warmer planet absorb more of our pollution?

Yes indeed. Warmer temperatures and the fertilising effect of more carbon dioxide in the air will stimulate faster growth of trees and other vegetation, which in turn will help to soak up some of the CO2 in the atmosphere. This can already be seen in some places. But plants need other things besides CO2 to grow. 

They need water, which could be in short supply as greater evaporation dries out soils. They need space, which we are eating up. They also need climatic stability. Recent studies by the Intergovernmental Panel on Climate Change (IPCC) suggest that climate change could soon be so fast that many forests, particularly in northern latitudes, will be unable to adapt and could die off.

What about organisms in the oceans?

Once dissolved in surface waters, a lot of CO2 is absorbed by plankton and other marine organisms and turned into organic compounds. Most of this eventually falls to the ocean floor. The strength of this sink for carbon depends on how much life the ocean is producing. 

It is not clear to what extent global warming will affect the oceans' biological productivity--it could rise or fall. Cooler seas tend to produce more life, but iron dust from expanding deserts could make warm seas more fertile. And some scientists have investigated whether we could boost this effect artificially by seeding the oceans with iron.