In some ways, choosing not to pursue unconventional fossil fuels like the oil sands, coal from moutaintop removal mining, and shale gas is imposing a risk on those in the future. It will be up to them to find energy sources capable of powering the kind of lifestyle they want. There is no guarantee that it will be possible to do everything we do now using sustainable forms of energy. In addition to becoming more efficient, they may simply have to make do with less.
That being said, choosing to exploit unconventional fossil fuels is still akin to throwing your child into the deep end of the pool in order to teach them to swim. Instead of being pressed to learn how to use energy more efficiently, develop sustainable energy sources, and perhaps adopt a less energy intensive lifestyle, future generations in a world where we choose to exploit unconventional fossil fuels will be pressed to learn how to deal with dangerous and severe climate change, and all the unpredictable consequences that will accompany it. In addition to that, they will still need to learn how to live without fossil fuels once those last especially dangerous reserves are exhausted.
We cannot guarantee that future generations will be able to enjoy the luxuries that we do, in the form of things like cheap intercontinental travel. What we can do is choose which set of risks an challenges they will confront. It seems far more ethical to leave unconventional fossil fuels buried and challenge them to find alternatives than to burn those fuels and challenge future generations to live with a radically changing climate.