I'm a dyed in the wool optimist. And it's infuriating when people coopt the label of optimism to support their particular brand of magical thinking. Here's what real optimism looks like: Global warming is a huge threat. But we don't have to change everyone. If we get about 30% of people, we can make a significant difference and slow the speed of global warming to allow the technological solutions a chance to be developed while they can still make a difference. 30% is doable. And if you shift to a plant-based diet because it's more sustainable, hey, you're also likely to lose weight and improve your health. Win-win!