There is surely no doubt that our use of fossil fuels is leading to acccumulation of CO2 in our atmosphere and giving an associated increase in world temperatures.
There are many charts showing CO2 and temperature. This one is taken from: Basic Research Needs for the Hydrogen Economy, US DOE.
For a view on what happens to the carbon in the fossil fuels we use go to Carbon Balance.
To see in what ways we consume energy - and hence consider how to reduce CO2 by 60% by 2050 go to Domestic use.