An item from the Union of Concerned Scientists:

Certainty vs. Uncertainty

Understanding Scientific Terms About Climate Change

Uncertainty is ubiquitous in our daily lives. We are uncertain about where to go to college, when and if to get married, who will play in the World Series, and so on.

To most of us, uncertainty means not knowing. To scientists, however, uncertainty is how well something is known. And, therein lies an important difference, especially when trying to understand what is known about climate change.

In science, there’s no such thing as absolute certainty. But, research reduces uncertainty. In many cases, theories have been tested and analyzed and examined so thoroughly that their chance of being wrong is infinitesimal. Other times, uncertainties linger despite lengthy research. In those cases, scientists make it their job to explain how well something is known. When gaps in knowledge exist, scientists qualify the evidence to ensure others don’t form conclusions that go beyond what is known.

Read it all here.


  1. #1 Ron Krumpos
    March 22, 2010

    “The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa.” –Heisenberg, uncertainty paper, 1927

    A simple statement made by one of the pioneers of quantum physics caused an uproar in its day which carries on to today. Simply stated: Nothing in certain.

    There are many naysayers about climate change. By the time they are “certain” it will be too late to do anything about it. Much of science is theoretical, premises based on the best knowledge available today. Ignore their predictions about climate change to the peril of all on Earth.

  2. #2 csrster
    March 23, 2010

    The uncertainties in climate science are not quantum in nature.

  3. #3 Greg Laden
    March 23, 2010

    csrster: what do you mean?

  4. #4 itzac
    March 23, 2010

    What are you doing Greg? Don’t you know that nuance has no place in any kind of policy discussion?

    I think csrster is trying to imply that the existence of uncertainty means the conclusions are wholly unreliable. In other words he’s completely missing the point.

  5. #5 travc
    March 24, 2010

    Could someone please contact them to fix this obvious error:

    …”very high confidence” (9 out of 10 chances of being correct) about a certain fact and “very likely” (90 chances out of 100)…

    I don’t know the climatology parlance, but the former should certainly not equal the latter. Maybe they meant 99/100?

    Anyway, I can’t find an email link and sadly I’m not a member (I will fix that before too long).

  6. #6 Greg Laden
    March 24, 2010

    Than’s funny. Adding arbitrary non-meaningful zeros changes the level of confidence. That would be something to be concerned about!

  7. #7 fling
    March 24, 2010