• In the past few years, I’ve taken a deep dive into the issue of climate change, reading scores of news accounts, scholarly articles and books on the topic. What I learned frankly terrified me. What was true and what was hyperbole? I recently asked one of the world’s leading climate scientists, Camille Parmesan, to help me separate one from the other.

She is an ecologist and conservation biologist who has been investigating the effects of climate change since the 1990s and is now a prominent member of a scientific working group formed by the United Nations to study global warming.

“My understanding is that the Earth has been warming much faster than scientists expected it to,” I said to Parmesan in a recent telephone interview. “And if that is true, our window for taking necessary action to forestall the worst has gotten much narrower than it seemed 15 or 20 years ago. Is that fair?”

“Yes,” she said.

“The warming is more than what the climate scientists expected,” she told me. “We weren’t expecting this level of impact at this time, the 2020s. It’s something I really thought of as happening in the 2050s. We thought we had more time.”

I did, too. Scientists have been warning about climate change for decades, but I more or less assumed that any noticeable effects would not be felt until I had passed on. I was wrong.

The heat of the summers in Texas, where I have lived for many years, typically began to abate in September, but now the heat seems to stretch to Halloween and beyond. Most years, campfires have been prohibited on my annual camping trips in the Colorado Rockies. And so on. My day-to-day experience of climate change so far has been one of modest discomfort and inconvenience.

But so many others have already been less fortunate. The wildfires and water shortages in the West. The increasing frequency and intensity of hurricanes. Temperatures of 110 degrees in Portland, Ore. Melting polar ice caps. Tornadoes that seem more vicious and deadly by the year. The crushing heat wave afflicting India and Pakistan since March, one that has been particularly devastating and sometimes fatal among the hundreds of millions of people who cannot afford air conditioning.

Then there is what I saw in Minnesota last summer.

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I moved to Texas in 1982, but every year since, I have made the trip back north to visit family and friends in the Twin Cities and taken the five-hour drive north to my hometown of Crookston.

It is a beautiful place of 8,000 people tucked into scenic bends of the Red Lake River, a farming hub in the heart of the Red River Valley, with its notoriously black dirt and fertile topsoil. I grew up there in the 1960s and 1970s, playing hockey on outdoor ice rinks in the winter and on the sweet-smelling, newly mown green grass of our baseball fields in summer. The people there possessed a modesty and a decency that have helped make me the person that I am now. It’s always been a joyful experience, going back.

But this past summer, the experience of Crookston was altogether different. It was late July, a time when normally my hometown was green and lush. But then it was brown and gray — rendered in sepia tones by months of horrible drought. At my favorite Crookston watering hole, IC Muggs, the talk focused on the cruel lack of rain and the devastation of the farmers. Old-timers said they hadn’t seen anything like it.

As I listened to them and drove around town, my heartbreak was compounded by foreboding. Over the decades, there had been many other years of not enough rain or too much. That was just the weather, part of normal cycle of things. But there’s something different happening, not just the short-term vagaries of weather but a fundamental shift in the climate. I knew that there was a very good chance that this drought was only the beginning. In the years to come, this kind of weather calamity could be more the rule than the exception.

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In our recent conversation, Parmesan went on to describe what could be the most significant threat that a warming planet poses to civilization. I had not heard of it before we talked. She said it is not generally understood by the world’s policymakers, either, which was an obvious source of concern and frustration to her.

It has to do with what is known as carbon sink, a natural process in the biosphere by which more carbon is drawn from the atmosphere than is released. For example, carbon dioxide is a necessary component of photosynthesis in plants, which absorb carbon during growing seasons and store it in the ground, where it is gradually released through decomposition.

But in recent years, particularly as forests burn or are denuded, less and less carbon is being taken from the atmosphere. At the same time, rising temperatures have increasingly turned vegetation into carbon sources, emitters, as it were. A prominent example is the release of carbon from melting permafrost layers in the arctic tundra. Eventually, if the world continues to warm, that natural process could release more carbon into the atmosphere than fossil fuels, Parmesan said.

“If we allow these ecological processes to continue as they are, at some point, we’re going to lower our (human) emissions and it won’t matter,” she said. “It won’t reduce global warming because we’ve put into place in the natural biosphere processes that we cannot stop. That is what scares me a citizen, as well as a scientist and as a human being on the planet. I don’t want to see that happen.”

To prevent it, she said, we must dramatically reduce our carbon emissions. The next decade is critical. I asked her to imagine what the world might be like in the year 2070 if we fail to do so.

Parmesan described mass starvation and food shortages because of the droughts that would cripple agriculture as we know it (in Crookston and so many other places around the globe.)  Decimated coastlines from melting icecaps in Greenland and in the Antarctic. Mass migrations to northern countries because so much of the Southern Hemisphere had become too hot to be habitable. The very existence of cities like Phoenix threatened because water sources had dried up.

The word hellscape came to mind.

“It’s not the kind of world I would want to live in,” she said.

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It is hard for human beings to get their minds around — the urgency necessary to prevent what now only exists in our imaginations — what might be the terrible state of things well in the future, when so many of us will be gone.

“So you are asking people now to make quote-unquote sacrifices while the first benefits will accrue to their children and the real benefits will accrue to their grandchildren,” another eminent climate scientist, Vaclav Smil, said recently. “You have to redo the basic human wiring in the brain to change this risk analysis and say, I value 2055 or 2060 as much as I value tomorrow. None of us is wired to think that way.”

In this, my first essay on climate change, I submit that we have to rewire. I’ve held my tongue until now because I did not feel I could speak out as long as I drove a vehicle powered by fossil fuels. A few weeks ago, finally, I purchased an electric vehicle, a Chevy Bolt, which I absolutely love. Buying that beautiful bright blue car (the color itself represents hope to me) was a profound thing. For the first time I felt like I was making a difference.

I hope you soon have that feeling, too. The bottom line is this. What I have learned the past few years is not hyperbole. Civilization faces a bleak future … or it doesn’t. We still have the power to decide.

My dream is that in 50 years, whoever comes after me can still experience the peace and beauty of my hometown, where the Red Lake River flows placidly through the green spaces, where farmers harvest sugar beets the size of watermelons, and at I.C. Muggs, the complaints are about the Twins and Vikings and not about a civilization laid low because we were too late to act.

Crookston, Minn., native Tim Madigan is the New York Times best-selling author of “The Burning: The Tulsa Race Massacre of 1921.” He lives in Fort Worth, Texas. This originally appeared in the St. Paul Pioneer Press.