Even though he doesn’t practice what he preaches and a British court found that his film contained 9 clear errors. Evidently, being a hypocrite doesn’t impact the vote (awarding Arafat proved that):

Climate change campaigner Al Gore and the UN’s Intergovernmental Panel on Climate Change have been jointly awarded the Nobel Peace Prize.
The committee cited “their efforts to build up and disseminate knowledge about man-made climate change”.
[…]
The Norwegian Nobel Committee said it wanted to bring into sharper focus the “increased danger of violent conflicts and wars, within and between states” posed by climate change.

This seems somehow ironic to me. Here they’re giving him a Peace Prize for potential wars when we are in the middle of actual wars. Shouldn’t we be focused on those who are attempting to broker peace today instead of hypothetical wars in the future?