Most people now agree it's real, but we're still asking questions. He's got answers.
His logic is impeccable.
So, good news if you care about climate change:
Yeah, baby. This is what we get to call progress. (In 2012, only about 32% of all Republicanswere concerned about climate change).
But, wait. It's a bit soon to celebrate. We can all feel it. There are questions in the air:
1. "How do we know global warming is because of humans? What if it's ... solar activity?"
You're in luck, 'cuz this guy's got an answer:
While it's true that sun flares and other solar shenanigans change over time, since 1970, when temps really started to climb, solar activity has declined.
Also, if the sun were doing all the warming, we'd see an increase in the upper atmosphere temps. But we don't.
Boom. So satisfying.
But what about this one:
2. "So, OK, there's more CO2 in the atmosphere. Plants emit CO2 also. Maybe it's just all those trees...
...how do we know humans are responsible?"
Here's your answer:
Look at types of CO2. Fossil fuels come from plants, and plants have a lot more Carbon 12 than the atmosphere, which has more Carbon 13. Guess what we find in the atmosphere?
Yep, you got it. The atmosphere shows an increasing amount of Carbon 12, from the burning of fossil fuels (aka: very old plants).
End of discussion, right?
Well, maybe you get the "so what" questions.
3. "So there's more CO2 and temps go up a bit. What's wrong with that?"
More CO2 in the atmosphere means that the oceans absorb more CO2. They become more acidic, and a lot of marine life is really sensitive to changing pH levels. By "sensitive," I mean they die.
And, do you ever hear this one:
4. "So, temps will increase only by a couple degrees. I'd love to not deal with winter!"
Well, we're already seeing dramatic changes because of the warming we've experienced in the last 30 years.
And the last time earth saw a shift in temperature just a few degrees, most of North America was covered by a...
Like he says: "This is by far the greatest issue facing our species."
There's more satisfaction to be found in the video. He'll prepare you for all the questions.