Global Warming and the Ozone Hole

Many people have asked me whether global warming and the ozone hole are related. The short answer is "no". The long answer starts with "tangentially". Here's the scoop.

The ozone layer, found in the lower part of the stratosphere 9 to 20 miles up, prevents harmful ultraviolet radiation from reaching the Earth's surface. The depletion of the ozone (which is now recovering) was due to man-made chemicals like chlorofluorocarbons.

Global warming, in contrast, is what happens when high concentrations of greenhouse gases such as carbon dioxide (CO2) trap heat in the Earth's atmosphere. The increase in CO2 concentration is mainly due to the burning of fossil fuels and deforestation.

So they are separate problems, but there is one way they do interact. Greenhouse gases raise the temperature in the lower atmosphere, but decrease it in the upper atmosphere or stratosphere, where the ozone layer is.

I know that sounds counterintuitive – here's why it happens. Heat leaves the Earth by radiating into space, and CO2 is one of the radiators. With higher CO2 concentrations, the altitude at which the CO2 radiates to space increases. This causes more cooling in the stratosphere, and thus lower temperatures.

The cooling in the stratosphere leads to the creation of more ice crystals. Since reactions that destroy ozone occur on the surface of ice crystals, higher CO2 concentrations exacerbate ozone depletion. The role of ice crystals in ozone depletion is also why the problem is worse in cold places like Antarctica, where the ozone hole appears.

Year-to-year fluctuations make it hard to tell for sure, but the ozone layer appears to be mending, and the hole over Antarctica could be gone in a few decades. The recovery is thanks to an international treaty banning the use of chlorofluorocarbons – a hopeful reminder that nations can come together to solve global environmental problems.

This entry was posted in News. Bookmark the permalink. Both comments and trackbacks are currently closed.

3 Comments

  1. Hangman
    Posted July 10, 2007 at 2:40 am | Permalink

    Again, I ad…

    Man is just the salt on an open wound that already exists. Adding to the effect of a cause that started eons ago. The Sun is blasting out thousands more times of energy than it ever has, causing a polar shift of the Earth. The magnetic field that surrounds the Earth is changing, this is whats happening to the Honeybees, whales getting lost or beeching themselves, bird migration, etc. etc., Animals use the earths magentic field to guide themselves.
    This has happened 6 previous times in Mother earths life, every 25,837 years, 1 Solar year. This is also the reason why the other Planets in our Solor system are turbulent & changing colors. The Planets move around the sun in a sort-of Cosmic Symphony, & the end of an Epoc is near, where the Cosmic Clock or Symphony will be resetting or restarting, a new Solar Year.

    Have you felt the pressure in your head?
    There is much more going on than whats being reported. Why do you think that their not doing much about it.
    Pay attention to whats going on around you, contemplate. The answers are within as well as without.

    Blessings & Light.

  2. science teacher
    Posted July 11, 2007 at 11:10 pm | Permalink

    I am trying to wrap this issue around our state chemistry content standards to design a project. Thanks for the concise answers to difficult questions. I have access to ozone data from a NASA site and need to develop some driving questions that will grab the attention of teenage chemistry students. Any ideas?

  3. Hank Roberts
    Posted July 17, 2007 at 4:44 pm | Permalink

    >teenage chemistry students

    Q: Why did Crutzen, in his Nobel speech, say we were lucky?

    http://www.google.com/search?q=Crutzen+Nobel+bromine+lucky

    A: We wouldn't be here now if …

    The Weather Makers: How Man Is Changing the Climate and What It … – Google Books Result
    2006 – Science – 357 pages

    … if industrial chemists had used bromine instead of chlorine. Bromine and chlorine can be used interchangeably for many purposes, …
    books.google.com/books?isbn=0871139359…

    - Prometheus: Pop Quiz Archives
    If industry had chosen bromine instead of chlorine as its base for halogen fluorocarbon development, the ozone layer would have been gone before the science …
    sciencepolicy.colorado.edu/prometheus/archives/science_policy_general/000910pop_quiz.html

One Trackback

  • [...] The same chemical reactions that produce smog also increase ozone in the upper troposphere, where it acts as a greenhouse gas. The authors estimate that the indirect warming effects of ozone through its effects on plants could be as large as the direct warming impact of ozone in the upper troposphere. (Ozone is also found in the stratosphere. See Bill's post on "Global Warming and the Ozone Hole".) [...]

  • About this blog

    Expert to expert commentary on the science, law and economics of climate change.

  • Categories

  • Get blog posts by email

    Subscribe via RSS

  • Meet The Bloggers

    Megan CeronskyMegan Ceronsky
    Attorney

    Nat KeohaneNat Keohane
    Vice President for International Climate

    Ilissa Ocko
    High Meadows Fellow, Office of Chief Scientist

    Peter Zalzal
    Staff Attorney

    Gernot Wagner
    Senior Economist

    Graham McCahan
    Attorney

    Mandy Warner
    Climate & Air Policy Specialist

    Pamela Campos
    Attorney

    Kritee
    High Meadows Scientist