Payton Strobel stood on the steps of the Iowa State Capitol late Friday morning looking out at a tie-dyed sea of climate activism.

Strobel, a 14-year-old-freshman at Waukee Prairieview School, wore a black T-shirt as she held a microphone and summarized the feelings of student climate activists in the crowd.

"Our generation is the last, best hope," Strobel said.

Hundreds of students and activists from throughout central Iowa gathered on the steps of the Capitol in a gathering intended to demand action in response to climate change. Students in 150 countries were expected to skip school Friday to send a message to world leaders to act more aggressively, according to organizers. Before the rally, local organizers said they anticipated 300 people would turn out.

Most of the protesters were high school or college students. Some wore yellow and black pins or T-shirts bearing the logo of the Sunrise Movement, a youth-led political action committee that focuses on climate change.

Isabell Hanson, a 16-year-old junior at Norwalk High School, told the crowd about growing up in Clinton and struggling with asthma.

At age 6, Hanson moved to Norwalk and said the air felt much cleaner. Hanson's mom teaches science at Norwalk High, which helped her get interested in climate change at a young age, Hanson said.

"It struck a chord with me that I had a voice to fight for those without a voice," Hanson said.

A handful of adults from out of town came to see the students in action.

Charlie Mitchell, a food and agriculture writer from New England, said he came out to Iowa to be part of where agricultural and environmental policy meets electoral politics.

"There are massive environmental consequences of factory farming, industrial agriculture, and new confined operations are sprouting up across the country," Mitchell said.

More than 200 scientists from 38 Iowa colleges and universities signed a report released Thursday that said Iowa will have more than 67 calendar days per year above 90 degrees by 2050, compared with 23 days in recent decades.

A November report by 13 federal agencies warned that climate change will touch every corner of the United States by 2050. The number of warm-season temperature days are expected to increase in the Midwest more than in any other region, the report warned.

Increasing humidity increases daily minimum temperatures and increases rain, the report said. By 2050, warmer temperatures, increased rain and eroding soils could cause agricultural output to decline to 1980 levels, the report warned.

A March United Nations report warned that millions of people could die from increased air pollution and other environmental consequences of climate change. The U.N. report warned that only 11 years remain before the effects of climate change will be irreversible.

Winter and spring precipitation is expected to increase 30% across the Midwest by the end of the century, the federal report said.

This spring, heavy rains clogged the Missouri and Mississippi River basins and caused severe flooding across, portions of western Iowa, eastern Iowa, Nebraska, Missouri and Illinois. On Friday the Iowa Department of Transportation closed a stretch of Interstate Highway 29 between Loveland and Crescent for the third time this year.

Strobel said the flooding and other natural disasters were tied to climate change. Scientists say it's difficult to establish a causal between climate change and individual weather events.

Isabella Cook of West Des Moines told the crowd that strong thunder and lightning from a recent thunderstorm roused her into climate activism. Like others, Cook wants businesses and politicians to find alternatives to plastic waste that harms the environment.

Strobel, Hanson, Cook and other students said politicians have failed to act and routinely sacrificed the environment to help big businesses.

"We will declare a future for ourselves," Cook told the crowd.

Several students called for Congress to pass the "Green New Deal," a resolution authored by Rep. Alexandria Ocasio-Cortez, D-N.Y., that sets a series of goals to address climate change.

Amy Varcoe, a Waukee Community School District spokeswoman, said two students from Waukee High School attended the protest. Waukee High did not see an increased number of absences because of the event, Varcoe said. A spokesman and spokeswoman for Des Moines Public Schools did not return calls seeking comment.

A handful of politicians said they had the students' backs.

Eddie Mauro, a Democrat, is challenging Sen. Joni Ernst, a Republican, for her seat. Mauro called for the Iowa to adhere to a net-zero emissions standard and said Ernst still does not acknowledge that climate change exists.

Last year after the federal climate report was issued, Ernst said "our climate always changes and ebbs and flows through time," according to CNN.

"Anytime that we are putting regulation out, we need to consider the impact to American industry and jobs," Ernst told CNN at the time.

U.S. Sen. Elizabeth Warren, D-Mass., began a speech to more than 2,000 people in Iowa City Thursday evening by commending people who planned to participate in the climate change strike.

"This is a moment when young people have stepped up when their elected officials have failed to do their business for decade after decade after decade," the Democratic presidential candidate said. "I commend everyone who participates in that strike tomorrow, everyone who supports it.”

Throughout the morning people chanted things like "I believe that we will win." A march to the office of Rep. Cindy Axne, D-West Des Moines, where police were called to respond to protesters, followed the rally on the steps of the capitol.

Philip Joens covers breaking news for The Des Moines Register. He can be reached at 515-284-8184 at pjoens@registermedia.com or on Twitter @Philip_Joens.

Your subscription makes our journalism possible. Subscribe today at DesMoinesRegister.com/Deal.