The renewable energy industry may fall off an economic cliff if Congress doesn’t come up with some renewals of its own, a panel of renewable energy figures said Thursday.

Unless Congress acts to extend the tax incentives that currently serve as renewables’ lifeline, they said, investments in wind, solar and other energy sources will face a major setback.

“We want immediate enactment of the pending extension, no ifs, ands or buts. We want these credits extended, and as rapidly as humanly possible,” Greg Wetstone, an executive at the American Wind Energy Association, said in an interview.

LEIPZIG, Germany — Participants at a major conference on transport and climate change were strongly challenged yesterday by the United Nations’ top climate change official to act more forcefully to reduce greenhouse gas emissions.

“The question is whether you, as transport stakeholders, are willing to proactively shape the Copenhagen deal or have your policies shaped by it,” said Yvo de Boer, executive secretary of the U.N. Framework Convention on Climate Change, referring to the 2009 meeting where a successor to the Kyoto Protocol will be debated. DeBoer told the transport ministers and industry officials that political action in their industry “is woefully inadequate.”

“New technologies will certainly be part of the answer. But we simply cannot afford to wait for ’silver bullet’ solutions which may be commercially available in the future,” he added.

Facing accusations of inaction in Amazon conservation, Brazil’s state-run National Economic and Social Development Bank will set up a fund for international donations, the bank president Luciano Coutinho said yesterday.

“The fund is being structured because Brazil wants to receive hefty donations,” Coutinho said, adding the bank was already negotiating a $200 million contribution with the Norwegian government.

Brazilian President Luiz Inacio Lula da Silva has derided foreign statements on the Amazon, saying countries that have already depleted their forests are in no position to offer environmental criticism and should not treat the Amazon as international territory. Lula said he is against unfettered development but the forest should not be turned into an untouchable reserve.

NEWARK, N.J. — As the clean energy revolution builds up steam, a group of five engineers and dreamers here is hoping to put this long-suffering, hardscrabble town back on the nation’s technology map.

While the odds are long, the group’s chances for success have recently improved as Americans face record gasoline prices and higher utility bills and vote for presidential candidates and legislators who seem eager to get a handle on the nation’s greenhouse gas emissions.

Housed at the New Jersey Institute of Technology, the small team is busy enhancing and improving upon two patented technologies that could revolutionize how energy is produced and vehicles are powered in the United States. Although their facilities are sparse and the technology is still a work in progress, the group’s members feel that with the right corporate partnership their ideas and designs could have a big impact in a relatively short period of time.

The Lexington-Fayette region in Kentucky has the worst per capita carbon footprint of the nation’s 100 largest metropolitan centers, while Honolulu and car-dependent Los Angeles, surprisingly, fare the best, according to a new survey of urban emissions.

An area’s mass transit use, level of sprawl, freight traffic, electricity pricing and air conditioning and heating use all played major roles in determining how it ranks in the study from the Brookings Institution, a Washington, D.C., think tank.

The Mississippi River essentially divides the high and low carbon emitters, with nine of the 10 worst metro areas appearing in the East. The West was the only region to decrease its per capita carbon footprint from 2000 to 2005.

NEW YORK — Have spiking crude prices created a “commodities bubble”? Some market watchers say so. They see rapid increases for a wide range of commodities as a repeat of other booms in which money latched on to popular investment vehicles and drove prices through the roof.

But traders and speculators insist such talk is wishful thinking.

“I’m convinced that there is no commodities bubble,” said Steve Benard, an independent trader who runs Global Capital Reserves in Utah. “Industrial metals have been flat for about 90 days. … The one exception is that anything related to energy is going up, up, up.”

Rising sea levels threaten to overtake large portions of the Everglades, damaging sensitive ecosystems and potentially frustrating expensive efforts to restore the massive marsh, according to scientists observing the project.

Projections indicate that sea level rises associated with melting ice sheets and expanding, warming water could cause saltwater to move “well into the Everglades,” degrading animal and plant species as it makes its way toward the center of southern Florida, said Hal Wanless, a scientist with the Department of Geological Sciences at the University of Miami.

“What we simply see is when saltwater moves into the freshwater marshes, the marshes die,” Wanless told reporters Tuesday, indicating that scores of species, from fish to birds, could be displaced.

BERLIN, Germany — In a plain office above the busy streets of Berlin, seven people are trying to make the path run smooth for renewables, easing the way as grid operators and regular citizens learn to work together in new ways.

Set up in the fall of last year, the Clearingstelle EEG, or Renewable Energy Sources Act Clearinghouse, is a quasi-legal group set up by the German environment ministry to mediate disputes that arise as people take advantage of generous supports for clean power from a wide range of sources.

The organization aims to help individual citizens and other small power producers clear the hurdles to selling power into their local electricity grid. In the United States, such challenges, thrown up by well-meaning bureaucrats and wary utilities, have slowed and stopped many early adopters seeking to bring clean power online.

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With gasoline consumption down, hybrid car sales up and Wal-Mart selling millions of energy-efficient lightbulbs, are we seeing a new wave of environmental consciousness?

Not entirely. For all the talk about global warming, dwindling cash in Americans’ pocketbooks is doing more to reign in fossil-fuel use than the dwindling polar ice caps.

The United States is at a “tipping point,” with people beginning to factor energy use into everyday decisions, said Lee Schipper, who has studied energy consumption for decades, earlier for Royal Dutch Shell PLC and now as a visiting scholar at the University of California at Berkeley. But the driver isn’t ecology, he said. “Sadly, it’s economics. No pain, no gain.”