Our cooler-than-usual weather prompted a reader to write and ask me: “How about a follow-up onion on this story! CR Gazette, July 29th, page 9A, ‘10 Cities set record low temperatures.’ Simply another anomaly?”
I guess my recent climate change columns made enough of an impression that he’d think of me, out of the blue, even if it was only to try to make a point. Specifically, that I should: “Study the science. Study the actual data. You too will realize manmade global warming is a myth.”
It’s not, of course, but tell that to the folks whose radiators kicked in during one of last week’s especially chilly nights. So I called Iowa State University Meteorology Professor William J. Gutowski, Jr., who studies regional climate modeling, water cycles, weather and climate extremes, to explain.
“You have to remember the term ‘global’ in global warming,” Gutowski told me. “Individual places may be relatively cool at one time, but you have to look at the whole.”
Climate change is about the big picture. And when climate scientists talk about the big picture, they mean really, really big. I think that’s part of what can make the idea so confusing. Still, the basic facts are simple.
“The fact of the matter is our gas levels are far beyond anything we know the earth has experienced in a million years, maybe even longer,” Gutowski explained.
“I don’t know how much you want to get into carbon isotopes ..."
“Um,” I hedged. Maybe we should stick with the basics.
He chuckled, then gave me the upshot: “There are signatures that tell us it’s from the burning of fossil fuels.”
Scientists also know this increase has had an impact on the climate, making temperatures warmer closer to the earth and cooler way, way up. “If it was just simply the sun growing stronger or weaker, it would not happen that way,” he said.
"It’s not rocket science,” he told me. But it is science, and thousands of professional scientists all over the globe have put in years of research to arrive at these basic conclusions.
In addition to increase in surface temperature, the oceans have been steadily warming, especially in the upper few hundred feet. The sea level is rising; Arctic ice has been gradually shrinking. Glaciers around the world have been mostly retreating. Greenland and much of Antarctica are losing ice.
Amateur skeptics will take a piece of data (like a cold snap in July) as evidence against climate change, but that’s like trying to pass an ice cube off as a glacier. Even a decades’ worth of surface temperature data is just a snapshot when we're talking about climate. You’ve got to think much bigger.
And some bits of evidence that might seem to contradict scientific consensus actually further prove the point. Take the fact that central Antarctica has been gaining ice in recent years. “That’s because of warming,” Gutowski told me.
Cold air can’t hold very much water, he explained. So if it’s very, very cold there’s little that can fall out as snow. As temperatures rise, the air is better able to hold, and release, moisture. Hence, the increase in ice. Remember? Bigger picture.
Of course that doesn’t mean there aren’t still things scientists don’t understand about climate change, what it’s going to mean for us and – especially -- what we should do about it. “There’s always going to be a certain amount of uncertainty,” he said.
To a layman, “uncertainty” means you don’t know. To a scientist, it’s simply a way of being much more specific about the limits of what you do know. It’s a range of possibilities.
“Take heavy rainfall,” Gutowski said. “There’s an expectation that heavy rainfall events are going to occur more frequently. That doesn’t mean it’s going to rain more each year than the year before. Sometimes you’re going to have a drought.”
“It’s not as if there’s a clear-cut prediction you can make. You can only talk about things being more likely or less likely. That can make it difficult to say ‘Well, what does this mean for me?’”
That’s one thing climate scientists are trying to figure out, is how to share their models with farmers, city water supervisors, politicians and others in order to help them assess risk and plan for the future. Gutowski is part of Iowa State’s Climate Science Program, which focuses not only on climate science but also on collaborations with other disciplines, such as agriculture, economics, urban and regional planning, to try to do just that.“We’re trying to learn about how do we take this information and try to do something constructive with it, rather than tell them to head for the hills,” he told me. How to think about how climate change is likely to affect them – how they might act without overreacting.