That's a good question. I don't think we do. What we know is that we contribute to climate change by burning fossil fuels, at a rate that is orders of magnitude higher than natural effects. We know a lot less about long term effects of burning fossil fuels than not. Given that the global effect (on something so uniquitous as temperature) is so large, it's clear to me that we're currently running an experiment that can drastically change the environment much faster than biological evolution adapts.