Time is running out to prevent catastrophic consequences from global warming, a leading climate scientist warned a packed audience Thursday at Stanford University.
Physicist James E. Hansen, director of NASA's Goddard Institute for Space Studies, said hundreds of millions of people will lose fresh water sources and hundreds of millions of others will be displaced by rising sea levels if fossil fuel emissions remain on their current course.
"We've reached a point where we have a crisis, an emergency, but people don't know that," Hansen told a packed Stanford audience Thursday night.
"There's a big gap between what's understood about global warming by the scientific community and what is known by the public and policymakers."
Hansen, who first warned about climate change in testimony to Congress in the late 198s, said a path out of the crisis is, "barely, still possible."
Introduced as an "iconic leader" in the science of climate change by biology professor Stephen Schneider, he spoke in a free public lecture sponsored by Stanford's Center for Ethics in Society in a series called "The Ethics of Food and the Environment."
China has surpassed the United States as the biggest emitter of carbon dioxide into the atmosphere, Hansen said. However because of the long lifetime of the compound, the U.S. is over three times more responsible than any other country for the carbon dioxide now in the atmosphere, and will remain so for decades to come.
Atmospheric carbon dioxide is already at 385 parts per million, well over the 350 parts per million, or less, that is considered "safe," Hansen said. And more warming is already in the pipeline because of inertia in the climate system.
"To preserve creation, the planet on which civilization developed, we must draw down carbon dioxide to less than 350 parts per million," he said.
Hansen advocates a "carbon tax with a 100 percent dividend," with funds returned to households based on how much they reduce their carbon footprints.
Fossil fuels should be taxed at their source—the wellhead or port of entry—to create incentives for the most efficient behavior. For example, he said, "we import food from New Zealand because there's no tax on aviation fuel, even though it makes no sense from a planetary standpoint.
"If you had a 100 percent dividend, there would be a big incentive to reduce carbon emissions and a motivation to develop technologies that reduce carbon emissions. The person who does better than average in reducing their carbon footprint will actually make money."
Aside from the carbon tax and strict efficiency standards for vehicles, construction and appliances, he called for development of renewable energy and an improved electric grid to get the energy to where it's needed.
He also advocated possible use of the next generation of nuclear power, which creates smaller and shorter-lived volumes of waste. "Most environmentalists are beginning to realize that they probably need to soften their attitude toward nuclear power if they're going to solve the greenhouse problem."
The single most important thing to do immediately, he said, is to impose a moratorium on new coal-fired power plants. "Because coal is available and relatively cheap, China and India have relied mainly on that," he said. "They're getting a big public reaction to local air pollution. There have been a lot of riots there, which the government tries to keep quiet."
Flashing photos of his grandchildren, Hansen said there's a basic conflict between fossil fuel special interests and the interests of young people, nature and animals.
"Fossil fuel interests have influence in capitals worldwide; young people and nature don't have much voice. Animals don't vote and don't talk. It's a challenge."
He said he is hopeful that young people involved in the recent election will be aggressive in pushing for government policies to address global warming. He said he is also encouraged that seven of the 12 members of Congress identified as the "Dirty Dozen" by the League of Conservation Voters were voted out of office this month.
The next lecture in Stanford's Ethics of Food and the Environment series is by Frank Rijsberman, director of water and climate adaptation issues for Google.org, the philanthropic arm of Google. Free and open to the public, it will be Dec. 4 at 7 p.m. in Stanford's Annenberg Auditorium.
(Writer Chris Kenrick, a former editor at the Weekly, can be e-mailed at email@example.com.