One of the never-ending tactics of climate deniers is to tell the big lie. Another is to say something that is technically true in the most limited sense, but is so misleading, so irrelevant, that it’s tantamount to a lie. And a big one.
One of the biggest and most common, a favorite of politicians who want to avoid the issue, is: Climate is always changing.
I’ve said it before and I’ll say it again because it’s such a good analogy: Climate is the rules of the game. Weather is the roll of the dice.
Dice rolls constantly change in unpredictable fashion; that’s why we roll the dice. But the mean value, what on an average we expect, doesn’t change. If we roll two dice, it’s 7 (if the dice are fair, that is). Just because you rolled 12 three times in a row, that’s not because the mean value changed — it’s still 7 (if the dice are fair). Those three 12s in a row were a random accident, a fluctuation — an unlikely fluctuation (about 1 chance out of 47,000), but a random fluctuation nonetheless. It doesn’t mean the dice have changed.
Weather is changing all the time; that’s its nature. But the mean can be constant for long periods of time, and so too can the variation, the essential nature of the fluctuations. Since they define what climate is, when they are constant we have a stable climate. Climate change is not about changing weather, we expect that to happen. It’s all about a change in what we expect — either what we expect on an average (change in the mean) or what we expect the fluctuations to be like (change in the variation).
Unfortunately, a lot of people confuse the two: weather change and climate change. This is especially true of politicians, who far too often resort to the “big lie” that “climate is always changing.” If you operated a casino in Las Vegas, and you suspected someone at the craps table had removed the fair dice and substituted loaded dice, would you accept the answer “dice are always changing”?
Or would you politely inform him, “No, dice rolls are always changing but the dice themselves aren’t” and have him arrested?
The ironic truth is that dice are always changing. Every time you roll them, a few molecules of the dice break off, a speck of dust might stick to them, even the body heat from your fingertips can make them expand and change size ever so slightly. But the casino owner knows that the physical changes of dice from these natural causes are so small that they don’t amount to a hill of beans. For all practical purposes, the dice don’t change and the game is still fair.
Likewise, climate is always changing but the changes from natural causes are so slow, that in a single human lifetime they’re generally not even noticeable, let alone worrisome. It’s true that the changes can be large — the warming of 5°C since the last great glacial time was enough to melt that three-mile thick ice sheet covering Chicago. But it took about 8,000 years for Earth to transition of those cold glacial temperatures to the moderate climate in which civilization was born.
Natural climate change can happen a lot faster within a limited area. Parts of Greenland have, in the distant past, experienced actual climate change in a matter of a few decades. But such sudden shifts generally happen, not because the total heat at Earth’s surface changes, but because it moves from one place to another; when one place on Earth gets hotter another gets colder. Change of global average climate from natural causes take a long time — in human terms.
If you’re in Las Vegas and you have a losing streak because the rolls of your dice were unlucky, that’s random accident. Don’t complain, if you couldn’t afford to lose you shouldn’t have been gambling. But if the casino dice were loaded, you’d have a valid complaint. One of the rules of the game is that the dice have to be fair, so at least you have a chance to win. When the rules of the game change, you’re going to lose — unless you’re the cheater who changed them.
For the last 10,000 years or so, a period called the holocene, Earth’s climate has been remarkably stable. It’s one of the reasons we’ve been able to develop our civilization, build cities, domesticate horses and cows and pigs (while cats domesticated us), invent the wheel and the steam engine and mathematics and electronics, all the technology that makes our world so different than it used to be. Yet even regional climate changes have been trouble for human societies; when a society goes through extended drought, the impact on agriculture can topple a civilization. For human beings, climate stability is a very good thing. Climate instability can be lethal.
It’s time to stop letting the cheaters change the rules of the game. And it’s time to get rid of all the politicians who keep telling us that the rules are always changing.
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