Can we predict climate, if we can’t predict weather?

Recently, the New Scientist
http://environment.newscientist.com/article/dn12453-prepare-for-another
quoted some predictions of climate change. Interesting article! – so I quoted it on a chat system.

Response: “And the weather forecast for tomorrow will in all areas be 100% accurate, as it is always!”

Why do so many people try to make a connection between weather forecasts and climate forecasts? I asked the question, and got a prompt answer:

“Because at the end of the day climate is made up of weather? A case of micro and macro.”

So I started looking for examples of situation where the micro is a good guide to the predictability of the macro. Not to make too much fuss about it, I can’t find them. I can find plenty that go the other way!

A good example: a gramme of radioactive material. It has a half life of one hour. You cannot predict the moment of decay of any particular atom of that material. And yet, you can be absolutely sure that after an hour, half the atoms will have decayed.

Or the monsoons of India. You can never say which day the monsoon will start, and there are even years when it fails. And yet, you can be absolutely sure that in a decade, there will be at least nine monsoons in India.

Take climates of opinion. I can’t tell you when the next paedophile scare will occur; but I can be sure that over the next twelve months, there will be several.

Right now, it’s summer. I can’t tell you which day will be the hottest of the year; but I can be sure that the hottest day this summer will be about ten degrees above the hottest day from December through February.

Knock over an anti-hill. Ants run everywhere; bring your foot down in their midst. I can guarantee that you’ll kill many on the macro level; I have no way of looking at the swarm in advance and saying which, at the micro level, will live or die.

Start a business. Will you succeed? or will the fledgling enterprise go titsup in its first year? Millions are thrown away each year by investors who  people would love to be able to say “Yes!” or “No…” in advance; and yet, year on year, eleven out of twelve startups die before they reach their first birthday.

If the economic climate changes, of course, and recession sets in, you can see that in the number of business failures. Does it help you predict  which businesses will survive?

Twenty horses line up at the starting gate. I can predict with astonishing accuracy that at least nineteen of them will be past the finish line half a mile away within roughly a minute of the “off” – but anybody who pretends he knows which of the horses will be first across the line, is a conman (or “tipster”) who is out to get your cash.

A storm hits London. Winds shake the windows and doors; any actuary will tell you that next day, he’ll get claims for roof damage. Can he tell you which house will be hit by the gust?

I can think of any number of examples where, with little skill, the macro situation is predictable by the feeblest intellect, but where the micro events which make it up are going to elude the cleverest forecaster. We all know this!

Even the people who deny that climate is changing, work on the same basis: they look at average highs and lows over an extended period, and try to see what the macro trend is. Individual years will vary; on the micro level, it’s impossible to say “next year will be an El Nino!” or “in two years, a volcano will fill the Northern hemisphere with dust, causing unusually low temperatures” – but average your observations out over a sufficiently macro level, and you’ll have a good picture of what is going on.

 So, what instinct compels quite smart minds to reach for this comfort – “weather forecasters get it wrong!” – when it comes to climatic predictions?

And while you’re thinking about that, check out NewsWeek:

Global-Warming Deniers: A Well-Funded Machine – Newsweek Technology – MSNBC.com

After ExxonMobil was chastised by senators for giving $19 million over the years to the Competitive Enterprise Institute and others who are “producing very questionable data” on climate change, as Sen. Jay Rockefeller said, the company has cut back its support for such groups. In June, a spokesman said ExxonMobil did not doubt the risks posed by climate change, telling reporters, “We’re very much not a denier.”

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One Response to “Can we predict climate, if we can’t predict weather?”

  1. Steve Says:

    The whole comment is cack from start to finish.

    We can’t measure the drivers contributing to spontaneous atomic fission
    We can’t measure the factors driving paedophiles to strike at a certain time
    We can’t measure what drives ants to be at a certain place at a certain time
    We can’t measure what drives one horse to race faster than another
    We can’t measure the future state of variables and uncertainties driving a business
    We CAN measure the factors driving weather, we’ve been doing that for decades.

    The Monsoon example is a nested argument, as are the hottest day and the storm examples (we are talking about predicting weather, you can’t use examples of predicting weather as support).

    The flaw in the examples given is that, unlike the local weather, the precursors are not available for monitoring. We can, and have been, measuring and analysing the variables contributing towards the short-term local weather system for decades.

    Hence short-term weather can’t be considered as ‘micro’; perhaps it could if compared against the long-term trends, but certainly not in its own.

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