U.S. Rep. Darrell Issa is calling for a significant increase in the number of nuclear power plants in the United States as a way of reducing carbon dioxide levels in the atmosphere.

Those levels have risen to what the National Oceanic and Atmospheric Administration says are the highest in the past 420,000 years, an increase that many scientists say threatens the planet.

They say that because the soil and oceans are not able to process all of the carbon dioxide produced by the burning of fossil fuels such as petroleum and coal, concentrations of carbon dioxide in the atmosphere are rising, potentially increasing the risk of climate change.

"Nuclear power must be a major part of the solution to the carbon cycle imbalance," Issa wrote in a recent news release. "It is a zero-emission technology that is available now."

But not everyone is enthusiastic about the idea of increasing the use of nuclear power in the United States. The Sierra Club, a national environmental advocacy group, opposes increased use of nuclear energy as an alternative to fossil fuels, saying that it produces dangerous radioactive wastes, is too expensive and could cause catastrophic accidents. The group also says that nuclear waste could be stolen by terrorists and used to make bombs.

Issa has received thousands in campaign contributions from companies involved in nuclear power. He made his remarks on the subject following a late September hearing over which he presided as chairman of the Committee on Government Reform's Subcommittee on Energy and Resources. The hearing came in the wake of a May subcommittee staff report entitled "Securing America's Energy Future."

Among the report's conclusions:

- "The energy crisis is potentially an economic and national security threat of such magnitude that governmental action is necessary to 'provide for the common defense' and the 'general welfare' of the United States."

- The U.S. is especially vulnerable to a "catastrophic" supply shortage of petroleum.

- Fuel economy standards must be increased.

- The U.S. must pursue a dual strategy of increasing petroleum production and promoting conservation.

- The country must also "aggressively" pursue alternative transportation fuels, renewable energy and advanced technologies such as clean coal and next generation nuclear power.

- Nuclear energy must become the primary source of energy for most of the nation's electrical power.

According to the World Nuclear Association, there are just more than 100 nuclear reactors in the United States.

In 2005, President Bush proposed increasing the number of them as a way of avoiding the environmental risks posed by coal-burning power plants.

In a Thursday phone interview from his Washington office, Issa said that technology is being perfected for the next generation of nuclear reactors that would reduce by as much as 90 percent the amount of radioactive waste currently produced in the nuclear fission process.

Regardless of the possible reduction in the amount of nuclear waste that is produced, those uranium supplies still represent a threat, one that will exist for a long time, Dave Hamilton, director of global warming and energy programs for the Sierra Club, said Friday in a phone interview.

"There are things that have happened in this nation in the past decade like 9/11 and Hurricane Katrina that led us to believe that things can change -- storage requires a stable world farther than the eye can see," he said.

Issa said that while the U.S. dawdles, the rest of the world is increasing the use of nuclear energy, including some European countries that are very environmentally conscious. According to the World Nuclear Association, France, for example, generates about 80 percent of its electricity through nuclear energy, whereas U.S. government statistics show that about 20 percent of electricity comes from nuclear power plants.

Another reason the Sierra Club says it opposes nuclear energy is because of the threat of serious accidents the groups says it poses.

However, Issa said that although there have been several nuclear accidents in the U.S. over the years, "we have had zero release of radioactive material (into the environment) and zero deaths in the U.S."

Hamilton said Issa needs to put things into perspective.

"Remember, you have no room for error with nuclear power," he said.

Nuclear energy has only been around for a relatively short time, he said.

"(He's) talking about 50 years on a 200,000-year time scale and saying, 'Hey,' we're doing great so far,' " Hamilton said.

Sierra Club officials also say they are worried that nuclear waste could fall into the hands of terrorists who could then use it to make bombs.

Issa said that once again, the Sierra Club is blowing things out of proportion. He said a much bigger threat already exists in the form of the 11,000 nuclear weapons that exist in the United States.

"All it takes is a truck to take away a nuclear bomb," he said.

On the other hand, "there has never been a theft of nuclear material from nuclear power plants," Issa said.

The Web site opensecrets.org -- a group that tracks campaign finances -- shows that Issa's top campaign contributors over the years include three companies involved to varying degrees in the nuclear power industry: Science Applications International Corp., which produces several products for the atomic energy industry, $33,450; Edison International, which among other things owns a majority interest in the San Onofre nuclear power plant, $27,500; and General Atomics, which offers research, development and consulting services to the nuclear industry, $27,182.

Contact staff writer William Finn Bennett at (760) 740-5426, or wbennett@nctimes.com.