Q. What are you chuckling at?
A. This news story. Apparently satellite photos now confirm that the polar ice caps are shrinking and the planet's temperature is increasing. As more carbon dioxide is released into the atmosphere, more of the sun's heat is getting trapped. If this keeps up, the global climate change is likely to be dramatic.
Q. And you find that funny? What human beings are doing to the planet is tragic!
As the planet warms, the polar ice caps are shrinking. The polar ice caps on Mars, that is.
A. What are human beings doing to Mars?
Q. Mars?! Who's talking about Mars?
A. I am. This article is about the erosion of the polar caps on Mars, where the ice is made of carbon dioxide and the average temperature is 81 degrees below zero. A little warming doesn't sound so tragic to me. Though you might think it's a tragedy not to have anyone to blame it on.
Q. Fine, go ahead, joke about it. I may not know know about Mars, but I know that climate change will be a disaster here on earth.
A. I doubt it. Climate change is normal. We can handle it.
Q. Normal? What do you mean, normal?
A. I mean that change is not an aberration, it's the way the world works. Look: A thousand years ago, the Northern Hemisphere was in the middle of what's called the Medieval Warm Period. Temperatures then were high enough that the Vikings could cultivate Greenland, which today is covered with ice. By 1500, the climate pendulum had swung the other way. The next few centuries were so cold that historians call them the Little Ice Age. Oranges stopped growing in China. Glaciers engulfed French villages. Then in the 20th century, the world started warming up again. Climate changes. It always has.
Q. But what's happening now is so alarming. Weather is going haywire all over the world. Remember the Newsweek cover story on global warming? It said, "The weather is always capricious, but last year gave new meaning to the term. Floods, hurricanes, droughts -- the only plague missing was frogs. The pattern of extremes fit scientists' forecasts of what a warmer world would be like." You don't think that's serious?
A. Of course hurricanes, floods, and droughts are serious. But they're not occurring more frequently; it only seems that way because the media have grown obsessed with bad-weather stories. Pro-Kyoto activists attribute every extreme weather event to global warming. Back in '96, when record lows were being set in the Midwest, Bill Clinton even blamed the cold air on global warming! It's hype, not science.
Q. But Newsweek --
A. Hey, Newsweek is fine for some things. But if you want information on climate change, you go to climate scientists. And they say there's no evidence that weather is getting more intense.
Q. They do?
A. They do. "Overall, there is no evidence that extreme weather events, or climate variability, has increased in a global sense through the 20th century, although data and analyses are poor and not comprehensive." That's a quote.
Q. From where?
A. Straight from Mount Sinai: the Intergovernmental Panel on Climate Change. That's the United Nations panel whose reports are driving most public policy on this issue. And what the IPCC says about global warming and wild weather is pretty much the case for every other sweeping claim uttered about global warming: The evidence just isn't there.
Q. Okay, so maybe the activists go too far. But the earth is warming up. That's not a sweeping claim. And the main reason is all the carbon dioxide released by the fossil fuels we burn. That's not a sweeping claim either.
A. Don't be so sure. Over the past century, surface temperatures have climbed by about 1 degree. But in the lower atmosphere, where we can measure temperatures very precisely by satellite, there hasn't been any warming trend at all. Instruments on weather balloons show the same thing. And yet the computer models that the gloom-and-doom scenarios are based on say that the lower atmosphere must be warming up.
Q. Huh? The computers can't predict what's actually happening right now?
Q. I find that hard to believe.
A. Why? Look how often TV forecasters get tomorrow's weather wrong. Global climate is far more complex than local weather. Trying to predict where that climate will be in 100 years is more complex still. And the idea that disaster looms if we don't scale back our energy use is just crazy. There are huge gaps in what scientists know about the natural causes of climate change. By comparison with those, human impacts are minor.
Q. What huge gaps?
A. Well, take clouds. Do they intensify warming by trapping heat or diminish it by reflecting solar rays back into space? It's a huge issue: Clouds cover 65 percent of the planet. But scientists just don't know what their effect is. The IPCC says this is "probably the greatest uncertainty" and a "significant source of potential error" in any climate prediction. And that's only one of the big unsolved mysteries. There is so much about climate change we just don't know. No wonder the computer models keep getting it wrong.
Q. So we should do nothing?
A. We should tune out the alarmists. We should keep the human effect in perspective. We should remember that climate change is natural. Mostly, we shouldn't panic.
(Jeff Jacoby is a columnist for The Boston Globe).
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