Nobel laureate Rajendra Pachauri has been talking about the consequences of climate change for 20 years, but suddenly he's finding more receptive audiences.

In the years since Pachauri began focusing on the topic, the world's scientists have reached an ever broader consensus that the Earth's climate is changing and human activities are contributing to the buildup of greenhouse gases. Much of that growing understanding has come from the work of a prestigious group of scientists that Pachauri leads -- the Intergovernmental Panel on Climate Change.

Now Pachauri, who resides in India, makes a brief return to N.C. State University, where he studied and taught in the 1970s, as a visionary leader in the scientific community and guru of global warming with a Nobel Peace Prize to show for it.

Fresh from appearances before a congressional committee and the World Economic Forum and attending the Nobel Prize ceremonies, Pachauri will speak today on the science of global warming at the university's Emerging Issues Forum and collect a distinguished alumnus award.

Richard H. Bernhard, a professor at NCSU and member of Pachauri's dissertation committee, said Pachauri was interested in environmental issues and in protecting the environment long before it was a trendy cause.

"The idea he has been pushing since the 1980s about global climate change, people have now come to believe he is right," Bernhard said. "Scientific opinion is turning his way, and the environment is going to hell."

Gore and 'Patchy'

Bernhard said Pachauri's special talent for working with people from diverse backgrounds made him a natural leader of the IPCC, which shared the 2007 Nobel Peace Prize with former U.S. Vice President Al Gore.

"This guy has a way of galvanizing people," Bernhard said. "There is an inner grace and charm about the guy. If you are running a committee and have a bunch of people who are disagreeing, there is an inner peace about him that gets people actually listening to each other. That is a real gift."

Pachauri, 67, spent much of the 1970s as a graduate student and teacher at NCSU, earning a master's degree and a joint Ph.D. in industrial engineering and economics. He is remembered by those who knew him as serious, gracious and soft-spoken. His friends called him "Patchy" -- a nickname he still uses.

"It was a remarkable experience," Pachauri said of his years at NCSU in an interview. "I look forward to getting back to my home, North Carolina."

Pachauri came to the university as an engineer educated at La Martiniere College, an elite private school in India. But when he enrolled in a graduate-level economics course at NCSU, the professor, Tom Grennes, inspired him to broaden his interests.

"I said I'm going to move into economics, which is what I did," said Pachauri, who can still cite the course number of that class. "A combination of engineering and economics has been enormously beneficial. The problems of the world are multidisciplinary."

Grennes, who is still a professor of economics at NCSU, recalled that Pachauri demonstrated a much broader interest in economic issues than the typical engineering student.

"When we were talking about capitalism and markets, he was asking about how all these pieces fit together," Grennes said. "He was very thoughtful and articulate, asking lots of questions and also having good answers."

After teaching briefly at NCSU, Pachauri returned to his native India and soon assumed his current duties as head of The Energy and Resources Institute, a nonprofit scientific and policy research organization that focuses on global warming and energy issues. It's based in New Delhi, India, and has offices throughout the world.

Pachauri took center stage in the debate about climate change in 2002 when he was elected chairman of the IPCC, a group set up by the United Nations and the World Meteorological Organization. Through scientific investigation, the panel of several thousand researchers and scientists has forged a widening consensus about the link between human activities and global warming.

2015 deadline

Pachauri said the science is clear on climate change, which will have serious consequences as temperatures change and sea levels rise. He said world leaders need to start reducing carbon emissions by 2015 at the latest.

"That doesn't give us too much time," Pachauri said. "We need to get an agreement in place as quickly as possible."

In his Nobel lecture, Pachauri said the world must approach the challenge of climate change from the perspective that the planet is one family. He told members of Congress last month that the rest of the world looks to the United States for leadership on a new pact to reduce greenhouse gas emissions.

"The U.S. has to be part of the agreement, not only because the United States is a major source of emissions of greenhouse gases," Pachauri said in an interview. "It provides a lot of credibility to any kind of global effort. That is a reality."

While in Raleigh, Pachauri will also address a state legislative commission on climate change.

Rep. Pricey Harrison, one of the leaders of the state panel, said the policy reports that the intergovernmental panel is publishing about global warming provide justification for steps that states and countries need to take to reduce greenhouse emissions.

"We're hoping he might be able to give us the silver lining," Harrison said, referring to economic opportunities brought about by restrictions on greenhouse emissions. She said he also could offer insights into what other countries are doing and what opportunities are available.

Pachauri also will be presented an alumnus award from the Edward P. Fitts Department of Industrial and Systems Engineering. The honor is given to individuals whose contributions to their profession merit special recognition.

As one of NCSU's most accomplished alumni, Pachauri has unwittingly inspired a rush on applications to his alma mater from students in his native India.

"We're getting greatly increased numbers of applications from India from people who know Pachauri did his graduate work here," said Bernhard, the NCSU professor. "Sometimes the applicants actually note on the application, 'I know our guru Rajendra Pachauri got his graduate degrees at N.C. State.' "