PIEDMONT -- Climate change has the potential to kill millions of people and disrupt the lives of billions more and a rise in the sea level will have devastating effects on Earth, said a UC Berkeley professor who spoke at Piedmont Community Church.
However, Andrew Guzman, who wrote a new book, "Overheated: The Human Cost of Climate Change," said in concluding his talk that if humans manage to lower greenhouse gases, millions of lives would be saved.
About 60 people filled the church's youth chapel Sunday to hear Guzman, a professor of international law at UC Berkeley who earned his law degree and a doctorate in economics from Harvard University.
"I'm glad to see so many people here today," Guzman said. "It's good for my book, although it's probably bad for the world."
Guzman was welcomed to Piedmont by the church's associate pastor, the Rev. Don Ashburn.
"The title of Andrew's book is intriguing because 'overheated' is a word that can be used to describe the debate on climate change," Ashburn said. "However, Andrew is trying to move beyond that ... to see what's actually happening to our world."
Guzman stressed that he's not a scientist but that his book is based on scientific research and predictions.
"A conservative assumption is that we will see a rise in global temperature of 2 degrees Celsius in this century," Guzman said.
He said that type of rise in global temperature will kill hundreds of millions and "badly damage" billions of people.
"Those numbers are alarming, but that is because we should be alarmed," he said.
Guzman went on to explain that shrinking glaciers because of global warming are already affecting runoff and vital water supplies throughout the world.
"We need water every day," Guzman said. "If water isn't there, we have real problems."
He pointed to the indigenous Uru Chipaya tribe in Bolivia, which has survived for thousands of years on the watershed of the Lauca River. Now the river is drying up because of rising temperatures and the retreat of Andean glaciers, threatening the existence of the Uru Chipaya.
"It's a simple story: one group, one river fed by glaciers," Guzman said. "But it's the same dynamic for larger social groups all over the world."
Closer to home, Guzman said California faces the same dilemma with the shrinking of the Sierra snowpack.
"Californians are already stressed over water supply; that supply will be 25 percent to 40 percent less by 2050," he predicted.
The potentially shrinking water supply will affect agricultural output and the cost of food, not just in California but throughout the world.
"For poor people in the United States and worldwide that will be a real struggle," Guzman said. "If people are priced out of the market, they face famine and starvation on a large scale."
A rise in sea level would also have devastating effects.
"Bangladesh, the most densely populated country in the world, would lose 17 percent of its land if the sea rises 1 meter," Guzman said. "After storms and floods, there will be disease, famine and displacement that would affect about 20 million people."
Guzman estimates that one in every 33 people worldwide will be displaced by climate change in this century. "Do you think Congress is going to allow millions of poor, sick, hungry refugees into the country?" Guzman said. "No, they will end up in camps or die of hunger or violence ... a refugee is a very dangerous life."
He said climate change will affect everything, including civil wars and other conflicts. "Climate change is a vice that squeezes problems and makes them worse," he said.
For example, Guzman said, Nigeria is important to the United States because of oil and the growing threat of terrorism.
"Climate change will make everything more dangerous," Guzman said. "If Nigeria is squeezed for water, oil won't flow and it could become a breeding ground for terrorism."
Similarly, existing tensions between neighboring India and Pakistan would be exacerbated if they have to fight over water from the Indus River, which flows through both countries.
"Pakistan is no match for India in size or military force," Guzman said. "The only way Pakistan can respond is with a nuclear threat."
In conclusion, Guzman said that if we manage to lower greenhouse gases, we would save millions of lives.
"There's no doubt it's a heavy lift; we've dug a deep hole, but there's an opportunity to save lives and improve life for billions of people."
Guzman then took questions from the audience. Someone asked why Guzman seemed reluctant to offer solutions to the climate change problem.
"It's not in my book," replied Guzman, adding that countries need to use less carbon and make renewable energy sources more appealing through financial incentives. He said people have to lobby their politicians to work for change.
An audience member questioned whether the 2-degree predicted rise in global temperature was certain and if climate change was really man-made or just a cyclical phenomenon. "The rise in greenhouse gases is measurable," Guzman said. "Today, 97.5 percent of climate scientists believe that global warming is caused by humans. You won't find any discussion on global warming ... it's a given with climate scientists."
Another audience member said she was skeptical about governments and politicians doing anything about carbon and asked about other mitigations.
Guzman described a proposal to take carbon out of the air and store it in massive carbon caves, but that we don't yet have the technology to do this. "The oceans are growing more acidic with carbon dioxide," he said. "There are algae that soak up carbon, but that is currently inefficient ... we need too many of them.
"I'm not optimistic about these options."
The event was sponsored by Piedmont Connect, a community organization that promotes environmental sustainability. For more information, visit www.piedmontconnect.org. Guzman's 250-page, hardcover book is published by Oxford University Press.