Climate change is real

The question is how do we respond

Ron Cohen still remembers the moment when the reality of global warming confronted him. He had graduated in 1991 from UC Berkeley's College of Chemistry after completing his chemistry Ph.D. with Richard J. Saykally. As he made his way east to start a postdoctoral position at Harvard, he stopped to visit the Columbia icefield north of Lake Louise in the Canadian Rockies. A popular tourist attraction, the icefield is the largest in North America south of Alaska.

Cohen stayed on at Harvard as a research associate and met Kristie Boering, a fellow atmospheric chemist and research associate, who had earned her Ph.D. at Stanford University in 1992. Cohen returned to UC Berkeley's College of Chemistry as an assistant professor in 1996, and Boering arrived two years later to start her assistant professorship at the college.

The couple married in early 1998 but waited for the end of the semester to take their honeymoon. That summer, Cohen returned with Boering to the Columbia icefield, and he was stunned by what he saw. "There was yards and yards of retreat in the icefield," says Cohen, "and it had only been seven years since I had last been there. I began to see global warming in a much more serious and personal way."

In January 2006, the NASA Goddard Institute for Space Studies reported that 2005 was the warmest year since the late 1800s, when reliable record keeping began. The year 2005 was slightly warmer than 1998, the previous record holder, when a strong El Niño, a warm water event in the eastern Pacific Ocean, added warmth to global temperatures. In 2005, global warmth slightly surpassed the levels of 1998 without the help of El Niño. Rounding out the top five warmest years since the late 1800s are 2002, 2003 and 2004.

During the 20th century, precipitation increased for most of the Earth except for equatorial Africa (which has experienced drought) and the Pacific coast of South America. Global climate models generally predict increasing precipitation and bigger storms as global temperatures rise.

According to the U.S. Environmental Protection Agency, "Rising global temperatures are expected to raise sea level, and change precipitation and other local climate conditions. Changing regional climate could alter forests, crop yields, and water supplies. It could also affect human health, animals and many types of ecosystems. Deserts may expand into existing rangelands, and features of some of our National Parks may be permanently altered."

In the aftermath of Hurricane Katrina, the EPA stated, "Preliminary evidence suggests that, once hurricanes do form, they will be stronger if the oceans are warmer due to global warming. However, the jury is still out whether or not hurricanes and other storms will become more frequent."

The scientific press is echoing the growing consensus about global warming. Science magazine reported on May 12, 2006, that a puzzling variation between climate models and satellite data had finally been resolved. "Global warming contrarians can cross out one of their last talking points," the magazine states, "...the world is warming throughout the lower atmosphere, not just at the surface, about the way greenhouse climate models predict."

The Science article referred to the first report of the White House's Climate Change Science Program (CCSP), which successfully reconciled errors in the satellite temperature data. Critics had low expectations of the CCSP, but the report's chief editor, Thomas Karl, Director of the National Climatic Data Center, came out swinging. "The evidence continues to support a substantial human impact on global temperature increases," Karl says.

The growing body of evidence has trickled down into the popular media. The April 3, 2006, edition of TIME magazine featured a cover on global warming that read "Be worried. Be very worried." The article states that "Environmentalists and lawmakers spent years shouting at one another about whether the grim forecasts were true, but in the past five years or so, the serious debate has quietly ended. Global warming, even most skeptics have concluded, is the real deal, and human activity has been causing it."

The Earth’s surface temperature has risen steadily since the late 1970s. In this graph, data from 1860 to 2000 are based on actual temperature measurements. Before 1860, proxy data are measured from tree rings, ice cores and other historical records. After 2000 the estimates are based on climate models.

The next two issues of the NewsJournal will explore global warming, its implications, and how the college's researchers are helping to understand and fight the consequences of climate change. In this issue you'll meet not only two atmospheric chemists, Associate Professors Kristie Boering and Ron Cohen, but also two chemical engineering professors, Alex Bell and Harvey Blanch.

Boering and Cohen both hold joint appointments in the Department of Earth and Planetary Sciences. Between them, their research spans from the molecular to the global, from below the ground to the heights of the stratosphere, from wilderness to the world's biggest cities. They are in a race against time, trying to benchmark and quantify atmospheric processes before the influence of global warming removes the evidence.

Chemical engineers Blanch and Bell are applying their years of expertise to ramping up the production of biofuels. Unlike fossil fuels, biofuels are carbon-neutral — the carbon that is added to the atmosphere when biofuels are burned is recycled by the vegetation that is grown to provide the raw materials for the fuel.

Bell, the current chair of the chemical engineering department, is an expert in catalysis, nitrogen oxide emissions, and environmentally safe chemical processes. He is working to develop the catalytic processes necessary to remove oxygen from plant sugars, converting them to hydrocarbons known as alkanes. These alkanes can be used as raw materials for gasoline and diesel fuels.

Blanch, a veteran of the biofuels efforts during the energy crunch of the 1970s, is revisiting the alternatives armed with the tools of the biotechnology revolution — tools that were not available 30 years ago. His goal is to develop enzymes that will convert plant cellulose to sugars, allowing the utilization of a much higher portion of plant biomass.

Atmospheric concentrations of greenhouse gases carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄) have all risen since the industrial revolution. The amount of sulfate aerosols (particulates) trapped in ice samples also has risen, but has declined in recent years with better pollution controls. Unlike greenhouse gases, sulfate aerosols are short-lived and can have a cooling effect.

Together Bell and Blanch will marshal the extensive intellectual resources of the chemical engineering department and other UC Berkeley science and engineering departments to focus on developing biofuels. They will have a formidable ally in Steven Chu, Nobel Laureate and Director of the Lawrence Berkeley National Laboratory. According to Chu, "There are stronger and stronger indications that global warming is happening, that it's caused by humans, and its consequences are looking more and more ominous." Chu is eager to direct the resources of his Department of Energy-funded laboratory to the development of carbon-neutral transportation fuels.

The next issue of the NewsJournal will explore how college researchers are turning to nanotechnology, photovoltaics and biological systems to allow solar power to reduce the need to burn fossil fuels. For discussion of hydrogen storage, see our fall 2005 issue.

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