Dennis Meadows probably doesn't mean to be a downer at a cocktail party.

But the researcher, who has spent decades studying Earth's capacity to endure human population growth and extractive economies, says we've run out of time to turn around our global version of the Titanic.

Call him a realist. "We're not talking about problems our grandchildren will have to deal with. We're talking problems we'll deal with in the next three to five years," said Meadows, professor emeritus at the University of New Hampshire and winner of the 2009 prize for original and outstanding achievements from the Science and Technology Foundation of Japan.

Meadows thinks humans can adapt to what is around the corner, such as higher fuel costs and warmer weather.

Meadows will discuss the limits to growth and "Achieving the Best Possible Future," tonight at the James A. Little Theater. It is one of two back-to-back free lectures at the theater sponsored by the Santa Fe Institute, a place where scientists from varied disciplines work on solutions to complex problems such as climate change.

Meadows will discuss ways communities and nations can begin adjusting to climate change, peak oil, less water and other realities. "We have been progressively putting things on the market that used to be taken care of by communities, such as caring for seniors," Meadows said. "People need to deliberately recreate communities."

Rebuilding local food supplies, living within an area's existing water resources and producing energy locally from renewable sources are all ways communities can prepare for what's ahead, he said. New Mexico is making progress on some of those fronts, such as promoting renewable energy. "New Mexico is moving in the right direction. It isn't moving at the right speed," said Meadows, who was preparing to lecture a group of 30 scientists and policymakers from around the country at a two-week Sustainability School at the Santa Fe Institute.

Meanwhile, New Mexico is mining its groundwater and importing water to make up the difference. "We can't resolve our problems by importing resources from elsewhere," he said.

Meadows and colleagues from the Club of Rome, a think tank focused on global challenges, produced a report in 1972 called "The Limits of Growth." Their research concluded humans and their economies would outstrip the earth's resources if growth wasn't limited.

They updated the report in 2004 and found that on a planet-wide scale, humans hadn't made much progress on saving the Earth's resources. "We've seen so much population growth and industrial growth that we're worse off then we were 20 years ago," Meadows said.

He said people are more aware now than they once were that humans can change the Earth, irrevocably. And there are solutions. "We know how to decrease carbon dioxide emission. We know how to stop overharvesting fish and overpumping groundwater," he said. "But there will always be those who fight those solutions for short-term economic gains or because of ego."

Now, it is too late to stop climate change, he believes. "Even if you lower CO2 emission to zero, we're still going to see climate change from existing emissions for hundreds of years."

Scientists predict climate change means shorter winters, higher temperatures and less water in the Southwest. So adapting to the change means growing crops that can endure higher heat and with less water, for example, Meadows said.

For people in general, it means learning to live well on less, he said — less energy, less water, less stuff.