Tuesday, August 17, 2010

Loading the Dice: What Games of Chance Can Teach Us About Asian Floods and Russian Wildfires


My son has been interested in probability lately, so we've been tossing a lot of coins and dice.  You can learn a lot about how the world works from watching the way dice fall.  If you throw a pair of dice repeatedly, you will notice patterns: fewer 2's and 12's, for example; more 6's and 7's.  And it's not that difficult to see why this happens.  There are many ways you can come up with a 7 (1+6; 2+5; 3+4; 4+3; 5+2; 6+1); but there is only one way you can come up with 2 (1+1). 

But sometimes you do roll a pair of 1's.  A doctor once told a friend of mine that he shouldn't worry too, much, but according to a screening test, there was a 1 in 6 chance he'd be getting some very bad news shortly.   A week later, the doctor said there had been a mistake: the chances of bad news were only 1 in 36.  In the end, a more thorough battery of tests showed no problem whatsoever, but for a couple of weeks, my friend said he couldn't stop thinking about dice.

There has been a lot of extreme weather in the news lately. Flooding in India, Pakistan, and China has affected millions of people. Now we see a record heat wave and a severe drought in Russia leading to fires that bring to mind words like apocalyptic.  Of course, droughts and floods have always been a fact of life and the causes of any individual weather event are too complex to pin down completely. But we do know this: according to the best science we have, climate change will lead--is already leading--to an increase in extreme weather events. 

If you think I'm jumping to conclusions too hastily, consider that the UN estimates that over 150,000 people already die each year due to climate change--mostly because extreme weather events are rising.  Or go see what the good people at the Indian Institute of Tropical Meteorology in Pune have to say about the flooding in Leh.  

We will have more floods, more droughts, more severe cyclones, etc.  Not every day.  Not everywhere, but most every year, and in more and more places.  Climate is not the same as weather.  But climate change will change the weather, just as surely as loading your dice will change the way they fall.


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Update: After drafting this yesterday afternoon, I returned to find these two articles in The Hindu, both of which are worth reading:
Is Weather Chaos Linked to Warming? Probably.  (Here you will find more detailed analysis than I've gone into in this post. )
Russian nuclear centre still under threat  (Why climate change should keep you up at night worrying.)

We'll look at the power of rivers--and nature generally-- through a different lens entirely on Thursday: poetry.  Do check your feed!

2 comments:

  1. I don't think it's wise to draw climate conclusions from the short term weather. I mean, I'd like nothing more than to have solid proof, but things like this can bite one in the ass later on.

    For example, recent speculations that the himalayas were melting and later rebuttals harmed the perception of climate science greatly. If we start looking at short term trends, we can't blame others for saying "Look it's so cold! And you say global warming is real?"

    For this reason I prefer not to draw any conclusions about climate change from what I can observe...

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  2. @Bhagwad, I think you make an important point. The problem is, extreme weather events ARE what we expect from climate change. But you are right, if we continue to blame every cyclone on global warming, we may not be credible.

    There are people who will do anything to discredit the idea that climate change is real. What we can't do is let that stop us from telling the truth as nearly as we can. You are right about the Himalayan ice controversy. But in the end, the evidence suggests that the ice is melting!

    In the end, we have to be honest, and we have to avoid claims we can't substantiate. I think if more people had a basic understanding of the way probability worked, we'd be in better shape. It goes back to that pair of dice. You WILL roll 2's and 12's from time to time; just not as often as 6's and 7's. And the dice often don't give you what you expect in the short run--but if you roll a thousand times, you start to see patterns. Every 7 cannot be explained by the way dice are made only; but the fact that you get so many 7's and so few 2's can be. It's a tricky line, no?

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What do you think?