Do we need to?
Switch to coal, we have plenty. (I know, it doesn't solve the CO2 issue.) Switch to wind and hydro and solar. Use the electricity to split H2O and burn it as mobile fuel.
Save the oil for petrochemicals.
Grow more plants and trees and recapture the CO2, replenish the O2.
Capture and burn methane for fuel (it does more harm per given quantity than the CO2)
Lots of solutions that will help mitigate greenhouse gases, that would be good for the economy and the environment. I'm not against moving these technologies forward. I'm in favor. I just don't think it will have an impact on the overall climate.
The sun warms this planet's surface and atmosphere. Nothing else has even a percentile of the sun's effect. And the sun's is HUGE. A small change in the sun is all it takes. We're fortunate on this planet to have so much water. The oceans are a huge heat sink. Otherwise these "minor" solar flucuations would have wiped the earth of life a long long time ago.
But given that, we haven't been around long enough (and certainly not keeping records, and even more certainly, not understanding the mechanisms,) to understand, let alone predict, what's coming next.