The Aldo Leopold Nature Center hardly could have started more humbly — just a group of volunteers working out of a converted garage.

Over the past 18 years, it grew into a premier destination for tens of thousands of school children and their teachers to learn about the environment. Now the center is poised to take its public profile to a whole new level.

On Saturday, it will open a $5 million addition, the core of which is a series of exhibits dealing frankly with climate change. The interactive displays, many designed by the National Academy of Sciences, attempt to educate people about the effects of global warming.

It's still a fought-over topic, at least politically. Public opinion surveys show about one-fourth of the U.S. population doesn't believe in global warming and another 12 percent aren't sure.

"Climate change is not scientifically controversial, but it's a little different in the public sphere," said Brenna Holzhauer, a center employee. "We hope to be a major vehicle to communicate between the two spheres."

Word is starting to spread that the center has something big on its hands. "I've seen a lot of science museums, and I think this could be a model for the country, maybe the world," said Jonathan Martin, chairman of the UW-Madison Department of Atmospheric and Oceanic Sciences. "I was just struck by how inspiring this is going to be to someone who is thinking about the science of the environment instead of the politics of the environment."

The center is a private, nonprofit organization, so it is somewhat buffered from controversy. The exhibits grew out of discussions on what the next generation of children will need to know to become good environmental stewards, said Kathe Crowley Conn, center president and executive director.

The center received no negative feedback from anyone as the plans were being developed, Conn said. She doesn't anticipate controversy.

"There's no politics in the exhibits," she said. "It's all factual. We're not trying to tell anyone what to do."

She stressed the new indoor exhibits are just one component of what the center offers, with outdoor activities and programs still a central thrust.

One of the main exhibits, "Global Warming: Facts & Our Future," was donated to the center by the Koshland Science Museum in Washington, D.C., the museum of the National Academy of Sciences. The academy provides independent, peer-reviewed scientific advice to the federal government.

The museum spent more than $1 million developing the global warming exhibit and displayed it from 2004 through 2010. The museum initially thought the exhibit would be controversial but discovered people just wanted facts, said Patrice Legro, museum director.

"What we found was that in 2004, people were asking, 'Is it true?' By 2009, we saw a shift to, 'We understand it, now what can we do about it?'"

Legro said the museum chose the Aldo Leopold Nature Center in part because it was excited to have the exhibit housed at a place where people can walk right outside and put the information into practice.

The academy will continue to be involved in the nature center's exhibits, updating them as facts warrant, said Terry Kelly, chairman of the nature center board.

"If we're successful, we hope these exhibits can be dropped into other parts of the country and form the basis of a seed program for environmental education," he said.

On a recent day at the center, a group of children attending a day camp got to try out the exhibits.

They swarmed around a sealed, glass sphere containing thousands of brine shrimp that mimics the Earth's carbon cycle, which is almost sealed itself.

Nearby, Tobias King, 7, pushed a button labeled "One meter rise in sea level." On a giant map, part of the East Coast lit up. "Oh look, it's flooding Eastern Maryland," he said.

Some of the biggest thrills for the children came in a silo-shaped room with a suspended sphere onto which real-time satellite images are projected using astonishingly high-definition technology. Viewers can witness live earthquake reports, track ocean currents, see the weather on Jupiter and view historic videos, such as Hurricane Katrina slamming into New Orleans.

"Cool and creepy," concluded Smila Reyes, 7.