For the last six months, Jeffery Czerwiec has walked 15 to 20 miles a day, six days a week.
His ankles have a distinctive tan line near the top of his socks and his dark black beard has grown thick and bushy.
When he stops for a few minutes to chat in the Blackwell Forest Preserve near Warrenville Thursday afternoon, his brow is glistening with sweat and mosquitoes bite at his face.
Clearly, the walking -- which is being done as part of the cross-country Great March for Climate Action -- has taken a toll on the 33-year-old's lean body. But that's the least of Czerwiec's worries.
"You get good shoes and socks and rain gear when it rains and you're good to go," he says. "We talk a lot about that, but in the end, the possible consequences of climate change are going to be a lot worse than what's happening to my body right now."
Czerwiec is one of about three dozen activists who are traveling through the suburbs this week en route to Washington, D.C., where they expect to complete a nearly 3,000-mile journey on Nov. 1.
The march, which was launched by a former Iowa lawmaker, began March 1 in Los Angeles with the goal of "inspiring action on the climate crisis," Czerwiec says.
"Walking eight months across the country speaks to people in a different way," he says, adding that he is one of only a few walkers who have taken every step. "Without words, it expresses the urgency of the issue and the passion that we all have for making sure something is done."
From talking with drivers and coffee shop customers to making presentations for church and community groups, the marchers have found many opportunities to educate, Czerwiec says.
"What we've found is people get it," he says. "They see climate change happening, especially the farmers and the ranchers that we've gone past in the Southwest, and to the plains now. They're concerned about how climate change is affecting their livelihood because they depend on the weather and they depend on regular weather, but with climate change it's become more extreme."
Some local activists have decided to join the marchers for just a few days or weeks, too. That includes Monica Jenkins of Geneva, who met with the group early Thursday morning at an organic farm in Elburn, where they had spent the night.
"It's very unusual," she says of the walk. "It's not really typical behavior, but we aren't in typical times. We're facing a crisis. I think a lot of people don't realize the level of crisis we're in. This is one way of drawing attention to that."
"It's going to affect us, not in some future, mysterious date. It's happening right now," she adds. "We can see it just in the change of our seasons that we've experienced. Even though we might be having cold weather here, globally, there's record heat waves everywhere."
Jenkins was one of about two dozen activists who took a detour on the rainy morning to visit Fermilab. For the next two days, she will help the marchers by driving a truck filled with food.
Some other equipment the group has brought along includes a trailer with a solar panel that provides energy for their electronics and a moving van stuffed with supplies.
"They're all trying to take turns driving the support vehicles, and to have someone volunteer to drive so they can walk or ride a bike is really important to them," Jenkins says.
On Friday, the marchers will travel from their campsite in Warrenville -- where they enjoyed a dinner with local Sierra Club members -- to Unity Temple in Oak Park.
They will begin their day Saturday with a rally in Oak Park, followed by gatherings at the Garfield Park Conservatory and Buckingham Fountain. The group is expected to arrive at Daley Plaza in Chicago for the last rally around 2 p.m., where there will be speakers from a variety of environmental groups.
Anyone is welcome to join the group for any stretch of the march. Route maps are available at climatemarch.org and more detailed information about the marchers' exact location Friday and Saturday can be found by calling (515) 505-2974.
Whether or not more walkers join, the marchers hope at the very least, they will inspire people they meet to take a look at how they can help in small ways, from eating less meat and buying local foods to taking public transportation and living more simply.
"We just really want people to know that whatever they're doing on the climate issue, they need to take that one step further," Czerwiec says.