Wednesday, February 10, 2010

Question for Dr. Boulter

Dr. Boulter (or anyone else who may have an answer to share),

Last week, I came up with a question concerning the reading in the Climate Change: Picturing the Science book. In chapter 1 on page 26, the book mentions the shrinking of the stratosphere due to it's decrease in temperature. My first question is what is causing the stratosphere to get cooler? My only guess is that it's on the outside of the "blanket" of emissions that is trapping the heat. Second, is there any risk that comes with having a smaller, denser stratosphere? The book jokingly says, "Chicken Little might not have approved," but that's not reassuring to me.

Thank you.


  1. Jason,

    You've touched on a well-understood but totally unintuitive aspect of climate change. The lower atmosphere (and surface: land, ice and ocean) are expected to warm - on average; however, this doesn't apply to the upper atmosphere. In fact, the layers above the troposphere (where we live) including the stratosphere and mesosphere (going up) are expected to cool - and indeed this is being observed now.

    The reason why is not easy to explain via blog; if you'd like, check out the following link for a somewhat technical explanation:
    Or I'd be happy to talk you through it next Friday at our discussion about the mechanism of warming...

    While I'll wait to explain it for now, one thing that should be said is that this is a clearly predicted outcome from climate models on computers as we've discussed. The facts are that models predict cooling in the upper atmos. ANSD warming in the lower atmos,- both due to the same root cause - AND both have been observed to occur over the past few decades. This lends credence to the idea that our models work and our mechanism is valid. More later - or feel free to stop by,

    Dr. B

  2. Dr. Boulter,

    Thank you for the link. I checked out the website, and I feel like I better understand what's happening in the stratosphere. It concerns me that this could enable a hole in the ozone layer in the arctic especially after the introduction to our book explained how we successfully stopped producing CFCs. Well, we can't expect to get away without any affects after already producing so many.

    Thank you,
    Jason J. Hansen


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