a) We think we would have tried to cary out more research on today's hybrid and electricity cars. If we had found a better hybrid/electricity technology, we wouldn't have used all this fossil fuels and we wouldn't have had that much CO2-emissions. We have the same thing with airplanes. Today we use kerosin to fly but if we had had another 100 years, we would have found a better way to fly.

b) The global temperature is increasing because of the COs-emissions. This has lead to the glaciermeltings and all the changes in the environment. These meltings have lead to a higher sea-level, which can flood huge cities like New York or countries (the Netherlands, for example).