NEW HAVEN >> The world's energy future will be marked by massive urbanization, transformed utilities and a race to adapt to a changing climate.

Those are just a few of the revelations from an international climate change summit convened Thursday at Yale University. Dubbed "EnergyFuture 2030," the day-long conference cast a critical eye at everything from government regulation to the impact of dwindling water resources on the power grid.

"We have no choice but to adapt," said Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change and first director of the Yale Climate & Energy Institute. YCEI held the conference.

Mitigation of global warming also is necessary, Pachauri said, adding, "That's not impossible. That's not something that's unreasonable."

Pachauri and another speaker at the conference, Karen Seto of the Yale School of Forestry & Environmental Studies, helped write sections of a new IPCC report on climate change that has made headlines worldwide.

Those reports point to major urbanization in the next two decades, led by Africa and Asia. Globally, it's the equivalent of adding 20,000 football fields of urban space every day through 2030.

"I'm increasingly of the opinion that the developing countries have to take the lead," Pachauri said. "Why should we follow a resources-intensive path to development? It would be utterly foolish to replicate what's happened in the rest of the world."

Certainly, the possible consequences of climate change are daunting, Pachauri said. He noted that the length, frequency and intensity of heat waves will increase, the frequency of heavy precipitation will increase and the risk of extinction to marine species will rise. Concentrations of CO2 are higher than at any time in at least the past 800,000 years, he said.

Other participants in the conference included one of China's leading economists, Zhang Xiliang; Shell Oil Co. executive Niel Golightly; Canadian Parliament member Stephane Dion; and Daniel Esty, a Yale law professor and former commissioner of the state Department of Energy and Environmental Protection.

Esty said individual states must develop their own policies to thwart climate change. Those policies, he explained, should take a "portfolio approach" that allows the marketplace to determine which companies and technologies emerge as most effective.

"We need innovation in every arena to see who's going to break through," Esty said.

Karen Hussey, of Australian National University, spoke of the role water will play in the future of energy.

She said worldwide stress on water resources will determine where power generation plants will be located and what type of power they'll produce. The warming of the oceans also will have an impact on the power supply.

"It's difficult to use water as a coolant when it's already warm," Hussey said.

Panelists lauded the emergence of new suppliers from the ranks of renewable energy companies. That will inevitably lead to changes in energy storage and distribution, government regulation and a transformation in the role of public utilities.