“Chasing Ice” is the best and most important documentary you’ve probably never seen or even heard of. Period.

For years I’ve been debating climate change with deniers who simply will not listen to science or reason. My best strategy has been to ask them to google aerial photographs of mountaintops, glaciers, and polar ice caps over the last 50 years. The evidence is clear. The only thing that can melt massive amounts of ice and snow so quickly is rapidly warming temperatures.

Finding that evidence takes effort that deniers simply won’t make, and I have not had the wherewithal to do it for them.

But just a few weeks ago my daughter Emma recommended to me a documentary entitled “Chasing Ice.” I’m embarrassed to admit that I hadn’t seen it or even heard of it.

Launched in a limited release in 2012, “Chasing Ice” grossed less than $1.4 million in theaters. But after airing on the National Geographic Channel in 2013, it won an Emmy Award for Outstanding Nature Programming. And since then it has been seen in more than 172 countries on all seven continents and won many other awards.

Directed by Jeff Orlowski, written by Mark Malone, and backed by National Geographic, Chasing Ice (74 minutes long, $19.95 on DVD) shows irrefutable evidence that global climate change, resulting from increasing air temperatures exacerbated by human activity, is melting ice at the coldest places on earth.

Increasing levels of carbon dioxide in the atmosphere make this warming possible. Since the beginning of time, the atmosphere has kept the planet at life-sustaining temperatures. Air consists mostly of nitrogen (78 percent) and oxygen (21 percent), which are essential for life, but it is carbon dioxide (0.03 percent) that traps heat and keeps the earth warm. This is the “greenhouse effect.”

By burning carbon-based fuels (wood, coal, oil, natural gas) at ever increasing rates since the beginning of the Industrial Revolution circa 1760, the concentration of CO2 in the atmosphere has steadily increased. This magnifies the greenhouse effect, thereby warming the planet.

In “Chasing Ice,” National Geographic photographer James Balog uses time-lapse photography under the harshest conditions to prove that glaciers are shrinking rapidly in Iceland, Greenland, Alaska and Montana. At the present pace of warming, Montana’s Glacier National Park will need to be renamed Glacier-less National Park in just a few decades, the documentary suggests.

Watch a glacier the size of Manhattan calve, disintegrate, and flow into the ocean. Watch through the magic of time-lapse photography as glaciers recede miles in just a few years. These are the images everyone needs to see. Evidence of warming temperatures is undeniable and irrefutable.

Climate change is the biggest threat facing humanity today. Extreme weather events occur more frequently every year. Recall Hurricanes Katrina and Sandy, and just last week Hurricane Harvey dumped more than 50 inches of rain on parts of the Texas coast. In other parts of the world, extreme drought plagues humanity.

There is no quick fix to climate change. The first step, however, is to acknowledge the problem. That’s what Chasing Ice can do. WATCH it. Show it in classrooms, libraries, retirement communities, and nature centers all across the country.

Children as young as 12 years old will ask, “How can anyone watch this and not understand what’s happening?”

Children 50 years from now will ask their parents and grandparents, “How could you have known about this since 2012 and not done anything about it?”

Mere words cannot do Chasing Ice justice. It must be seen. And then it must be discussed. I simply cannot conceive how anyone could deny climate change after watching this film. Understanding it requires no special knowledge or education.

Every politician at every level, every journalist, every talk show host, every human in every country who cares about the future of the planet should see “Chasing Ice.”

Over the years, I’ve watched many documentaries about nature and the environment. Many have been very good, and some have been excellent. “Chasing Ice,” however, is the best and the most important. The planet itself will survive, but human civilization, as we know it may not.

Dr. Shalaway can be heard on Birds & Nature from 3-4 p.m. Sunday afternoons on 620 KHB Radio, Pittsburgh or live online anywhere at www.khbradio.com.Visit Scott’s web site www.drshalaway.com or contact him directly at sshalaway@aol.com or 2222 Fish Ridge Road, Cameron, WV 26033.