“There is no question that climate change is happening; the only arguable point is what part humans are playing in it.” -David Attenborough

If you had never heard of global warming before, how would you figure out whether it was happening, whether humans played a role, and what the magnitude of it was?

Image credit: NASA, Johnson Space Center, Apollo 17 crew.

Image credit: NASA, Johnson Space Center, Apollo 17 crew.

Thankfully, we already have all of the scientific pieces in place, we just need for them to be put together in a way that we can understand it. What follows below is my attempt to do exactly that, with plenty of help from the planetary, atmospheric and climate science communities.

Image credit: Levitus et al., Geophysical Research Letters, 2012. S. Levitus.

Image credit: Levitus et al., Geophysical Research Letters, 2012. S. Levitus.

Go and read the whole thing.

Comments

  1. #1 John Duffield
    April 4, 2014

    “It’s been a long time since I’ve written anything about global warming…”

    Nearly a whole month. See this. But it’s been 5+ months since I cut my lawn. And Chicago has had its coldest winter on record.

    IMHO you should stick to cosmology Ethan. And IMHO you should also stop peddling the multiverse.

  2. #2 dean
    April 4, 2014

    John, it is amazing that there is a topic you are less knowledgeable about than relativity, but climate change seems to be it.

    How is you ridiculous statement about Chicago’s weather relevant in any way to climate?

    Never mind, we don’t need any more foolishness from you.

  3. #3 Doug
    April 4, 2014

    The winter of 2012 was Chicago’s warmest on record. So what? Weather is not climate and Chicago is not the whole world.

  4. #4 Michael Kelsey
    SLAC National Accelerator Laboratory
    April 4, 2014

    @dean #2: Mr. Duffield is (especially when you read his posts on several other science Websites) a decent example of crank magnetism.

  5. #5 veyd
    bucuresti
    April 4, 2014

    while i’ve long accepted that rising climate temperature is an ongoing and scientific fact, it’s also been a long time since i had any interest of reading any more about it.
    i’m not an activist and there is not very much we can do as individuals about this

    so i was going to skip this one too, but the explanation involving the planets was such an interesting twist, i just had to read on..

    amazing talent!

  6. #6 Mark
    K-town
    April 4, 2014

    Re-explained in yet, a new way… now to get the governments of our only world to understand.

  7. #7 Dale
    April 4, 2014

    “i’m not an activist and there is not very much we can do as individuals about this”

    We don’t have to do this as individuals. Become an activist.

  8. #8 Stephen Spencer
    Melbourne, Australia
    April 4, 2014

    I love your blog, Ethan, I check almost daily to see if there are any new posts.

    Thanks for this interesting astrophysical approach to Global Warming.

    I had expected lots of anti-science ideologues in the comments denouncing you. As I write this only one has appeared.

    As far as I can see the only way of getting the message out is to keep talking about the science. Keep up the good work.

  9. #9 Michael Kelsey
    SLAC National Accelerator Laboratory
    April 4, 2014

    @Stephen Spencer #8: No anti-science ideologues yet :-) Cranks, yes, but solidly pro-science cranks.

  10. #10 Lotharloo
    April 5, 2014

    My hope is that one day I’ll read an article about AGW without a silly science-denying crank comment in the first top ten.

    I really like Ethan’s explanations. It is a stake in the heart of brainless zombies who reject science in the name of politics. In fact, every time I meed a crank, I’ll tell them the story of Venus vs Mercury.

  11. #11 John Duffield
    April 5, 2014

    Dean #2: my statement about Chicago’s coldest winter on record was utterly relevant. If it had its hottest summer on record you wouldn’t dismiss that as mere weather.

    Stephen #8: I’m not anti-science. I’m pro-science. And I’m against governments taking money away from science and giving it to renewable energy that isn’t going to work when the wind doesn’t blow. You can’t do science by candlelight.

    @Michael #4: I’m no crank, and you know it. You had to admit I was correct about the point particles here. Don’t come crying to me when you lose your funding because it gets redirected to renewables.

  12. #12 dean
    April 5, 2014

    If it had its hottest summer on record you wouldn’t dismiss that as mere weather.

    That is a load of crap John – although I’m sure you believe it. If I thought mentioning a year in which the weather was warmest in recent history would be a reasonable rebuttal I would have made it. Apparently that is too complicated for you to think about. Doug’s reference illustrates that idea.

    The point you made has no relevance to climate at all, as everyone except you can see. Stamp your foot as hard as you want in faux outrage: your comment was far from relevant, to the point of being silly.

  13. #13 dean
    April 5, 2014

    Lest it somehow be taken that I was belittling Doug’s comment: My intent was to reinforce the idea that identifying a recent year in Chicago as unusually warm would say no more about long-term climate than identifying one that was cold – that is exactly what he did.

    John, maybe you should study topics instead of just looking at the words used.

  14. #14 dean
    April 5, 2014

    And if bounds of civility were bent in my recent posts – apologies. I do not appreciate the implication about me made in 11, and typed in haste.

  15. #15 Doug
    April 5, 2014

    Dean — not problem. You took it the way I intended it. I am a climate scientist — a bioclimatologist to be precise. I used to be a bit of an AGW skeptic, myself. However, I can’t maintain that position anymore. The key flaw in the denialist argument is that it cannot identify another viable mechanism to explain the current temperature increases. Once you’ve eliminated all the other potential causes, you’ve got to go with the one that’s left. Increased greenhouse gases is the only explanation that’s still standing. Incidently, I love this blog. Was an astronomy major as an undergrad, but switched to atmospheric science for grad school. this blog makes me occasionally regret that choice!