Paul Bolstad, a professor in the University of Minnesota’s Forest Resources Department, was one of the many authors of the National Climate Assessment released last week.

The report said that climate change was already having an impact on the world, with more extreme weather and rising seas. The report was also pretty clear in stating that humans were one of the main culprits.

So when I met Bolstad for coffee near his St. Paul office recently, I had to ask if he was one of those “greedy alarmists” and “money-hungry scientists” I had heard about on certain news channels.

Bolstad laughed.

“Maybe the Trojans thought Cassandra was alarmist too, until the Greeks started sliding out of the wooden horse,” he said.

It turns out, Bolstad can look dire predictions in the face with a decent sense of humor.

The peer-reviewed Third National Climate Assessment, which included input from about 300 scientists and 13 federal agencies, argues that climate change is already causing substantial financial, health and ecological harm. The report pointed to droughts in the West and flood damage to roads in the East. Bolstad co-authored one of the chapters.

As Bolstad and I talked, severe storms were building just a few miles from us. Were they more signs of an eventual apocalypse?

No, Bolstad said. Using one anecdote to predict climate “works both ways.”

“Some people see a huge storm and say it’s due to global warming, but you don’t know,” Bolstad said. “It’s like saying Barry Bonds’ 400th home run was due to steroids. You don’t know.”

“One anecdote, or one study, doesn’t mean anything in science,” said Bolstad. “But through hundreds of studies you build a narrative of how the world works.”

“You can always find one study, or one scientist, who disagrees” with a finding on climate change, Bolstad said. “It’s the meta-analysis that matters. Every objection to human-caused climate change has been rejected.”

The argument among the vast majority of scientists is no longer whether climate change is happening, or whether humans are partly to blame, “it’s over how much we are causing it, or over whether doing something about it is too expensive.”

Those who claim scientists rig studies to come up with the result they want simply don’t understand how science works. If your data is bad, another scientist will come along to say so, and their criticism is added to the climate change narrative.

Scientists become more well known by debunking bad science than by going along with it. Bolstad points out that even the oil companies employ climate change scientists to help them assess the financial challenges coming. As for accusations that those advocating climate change are greedy, Bolstad says his students who go to work for corporations can make triple his salary.

I told Bolstad that one poll showed that only about 36 percent of Americans are worried about climate change. He wasn’t surprised.

“I don’t know why the public believes what it believes,” said Bolstad. “They think it’s related to politics, but it’s not. The earth’s climate doesn’t care what you believe. A lot of people just have more immediate concerns and don’t think about climate much.”

He even has a relative who disagrees with him on climate change. “I just say you are wrong on this, but I won’t tell you how to be a dentist, and we agree to disagree.”

Bolstad can’t say exactly when Minnesota will look radically different. But if climate change continues, he expects the state to eventually look more like central Missouri or Illinois. Aspen and spruce will give way to oaks. Trout will be replaced by more bass. Water could be a problem, but probably not for a long time.

Studies like the one released last week are essential to helping us plan for the future, Bolstad said. It will determine everything from whether we need to increase the size of culverts, or put a flood wall around Miami or calculate whether we need to increase subsidies for poor people who can’t afford rising energy prices.

Despite the sometimes grim nature of his science findings, Bolstad remains cautiously optimistic. He thinks changes by individuals (yep, he drives a Prius) and both local and national government bodies can all make a difference.

“I think people will adjust when they have to,” said Bolstad. “It’s a shame there will be a lot of damage before then. I don’t lose sleep over it, but it could be better.”