The truth is, when I was born, atmospheric CO2 levels were around 300 ppm. Today — maybe even this week — will be the last time anyone alive experiences a level below 400 ppm, and no one born in the coming century or even longer will ever see less than 400 ppm again. That is a deep, deep observation, with ramifications for our children and for every future generation. — Peter Gleick during November of 2015

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(NASA model visualization of CO2 in the Earth’s atmosphere. Image source: NASA.)

I just want to take a moment to tell you something that’s pretty important. You are now an alien. You’ve been made an alien by fossil fuel burning. And you’re now living in, breathing, a heat-trapping atmosphere that’s entirely alien to your species. Sometimes races of creatures suffering such habitat changes are capable of surviving the environmental shifts that inevitably…