Pay no attention to the sobbing caused by the documentary on National Geographic last summer.

The one about the polar bears and their cubs, fighting to stay alive on the ever-vanishing ice. The one that instilled a sense of urgency in these sisters from Andover, alerting them that the science community believes we’re running out of time. Not only in this country.

But on the planet, as well.

That’s why the girls – Ember Morgan, 9, and her sister, 7-year-old Azalea – accompanied their mother, Molly Morgan, on a 250-plus mile bike trip, hoping to raise awareness about climate change.

They pedaled to New York City last month to attend the United Nations Climate Action Summit, pushing themselves to navigate on shoulderless roadways, battling hunger and the unknown that come with sleeping bags and tents rather than hotels and warm beds, trying to explain to public transportation officials why they should bend the rules and allow mom and her two daughters on the train or bus.

With their bicycles, of course. Judge their toughness on all of that.

Not on those tears, and certainly not on the fact that the family arrived in the Big Apple a tad late, missing the guest speaker on the first day on the 20th and – because of hassles boarding a train – the closing ceremonies a week later.

But once they saw desperate polar bears and the tears flowed, responding to climate change in a big way became more than a goal.

It became an obsession, something that needed to be done.

“I saw the sea ice was melting and there was hardly any left,” Azalea, referring to the documentary, told me in her living room. “I got sad.”

Sometimes, toughness comes in small packages, petite, wiry, strongwilled, boundless energy. Sometimes, stories surface that don’t seem real, or even possible. Riding from the rural flavor of Andover to perhaps the busiest, most intimidating city in the world, with cabs that switch lanes and accelerate like Mario Andretti, is a challenge, indeed.

Bringing along your daughters, though, a second- and fourth-grader, adds a whole new ingredient - more stress, more worry – into the formula.

Tom Morgan, an English teacher at Proctor Academy, suggested what he thought was a better idea for his wife and kids, safer, more reasonable, more doable.

“When Molly brought up the idea, she had that look in her eye that told me she was serious,” Tom said outside his house, on a raw day. “I said, ‘How about riding to Concord?’ but Molly said a bike ride to Concord wouldn’t get them the same attention.”

That’s what they wanted. A spotlight, not on them, but on the issue that, these days, seems to grow louder and louder. The summit was a week-long event, Sept. 20-27. Other protests were held around the world, as this movement to open eyes hit the ground like acid rain.

“The truth is, the kids were very sad about the polar bears,” Molly told me. “Azalea was grief-stricken, and sobbing herself to sleep one night. This was not a Band-aid on a boo-boo. This was a complex problem that I didn’t have an answer for, but I promised them we would do something about it.”

Thankfully, Molly, along with Tom, had a rugged background. As teachers at Proctor Academy, they’d take groups of students on a 10-week trip to the west coast and down to Mexico as part of their curriculum. They’d pack tents and food and a cookstove into a trailer, attach the trailer to a bus, and off they went.

Plus, Molly had an educational background full of environmental science. This was a perfect storm of factors, polar bears and tears and a mentor with a social conscience, creating an adventure that the girls felt had to be completed.

“Clearly, these kids have a lot of passion,” Molly said.

These people, Buddhists, love animals. They have a dog and a cat and a snake. The girls’ brother, 11-year-old Linden, lets mosquitoes hang on his skin, figuring all God’s creatures deserve a meal.

Once, during the 16-day trip, Ember started crying, “Not because she was challenged that they had to push their bikes uphill,” Molly said, “but because she was sad about all the roadkill they encountered. She started saying, ‘I hate you, Henry Ford.’ ”

Obstacles and hardships were expected. Drivers honked at them when the shoulder turned to a narrow strip, forcing them too close to the road. Once, forced to stop and camp near a dead-end of trees and dirt piles, they were awoken to the rumble of a backhoe heading their way, a morning monster-turned-friend, with workers who used the equipment to clear a path so the girls could continue.

“We woke up and heard this ‘beep, beep, beep,’ Ember said. “You could hear the driver talking, but we couldn’t hear what he was saying.”

They searched for homes with children’s toys out front, figuring the people who lived there would be sympathetic, leading them to the backyard and a place to pitch their tent. A pancake breakfast once followed.

They rode over the Brooklyn Bridge and made it to Grand Central Terminal in 11 days. They had set a goal to get there earlier, hoping to hear a 16-year-old Swedish girl named Greta Thunberg – a YouTube and Ted talk sensation – speak at the UN. She had arrived in a special boat, avoiding a charge of hypocrisy.

“She really inspired us to do something drastic,” Ember said. “She used a solar-panel boat and sailed across the Atlantic, so if she could do that, we could ride to New York City.”

At various times, they were denied access to buses and trains. Where in the world would they store their bikes, attendants wanted to know? Here is where I learned that Ember and Azalea’s mother was one tough cookie as well.

In protest, she sat on an Amtrack train in Hartford, Conn., and planted her legs on the platform. She wouldn’t budge, for at least a half-hour. She demanded to speak to the conductor. The cops came and, in time, convinced her to move.

“I was desperate to get the girls to their goal,” Molly said. “It was me being a mama polar bear. I wanted (the conductor) to have some humanity. These little girls had shown grit and power, and they would not be flexible.”

Once in Manhattan, Molly rode behind her daughters on busy city streets, acting as a buffer between the traffic behind them. They stayed one night in a hotel, another at the home of Zayne Cowie, a 9-year-old boy who, like Greta Thunberg, had made national headlines through his climate-change activism.

They raised about $300 for the cause, stashing it in a jar, which sat on the living room table. They took a Concord Coach bus home, with complimentary seats and storage for their bikes.

I wondered why and how. Why push so hard? How do you maintain the intestinal fortitude needed to complete the journey?

“We made it because we had passion,” Azalea explained.

At which time Ember added, “We made it because we were passionate enough to not let the whole world burn on fire and melt and have a total climate crisis and just sit back and relax.”

Near the end of our meeting, mom and her two girls went outside to ride on a narrow path behind their house, combining powerful pedaling with big smiles.

Ember’s front wheel collided with Molly’s bicycle, forcing the 9-year-old to the ground in a nasty crash. It could have been an awkward scenario. Ember could have cried.

Instead, she popped back up, a scrape here or there, and blamed her mother for the wreck.

There were no tears.

“She’s tough,” Mama polar bear said.