To use an obvious example, the oil sands, it takes a lot of energy just to extract the oil, usually by using natural gas and other fossil fuels, which have their own emissions. That's not even counting the fact that much of that fossil fuel is then exported and combusted somewhere else, which also adds to climate change. You get, essentially, a double whammy from the emissions related to the extraction and production, and then you have the emissions related to the combustion in a vehicle, a boiler or a power plant overseas.
We can't continue to have this net flux of fossil carbon in the form of coal, oil and natural gas go from underground or under the seas into the atmosphere while thinking that we can somehow limit warming to 1.5°C. If we keep having that transfer of fossil carbon from underground into the atmosphere, the planet heats up. There's no getting around that.