Climate-Change Debate Shifts

The world's climate system may be veering dangerously close to irreversible and highly disruptive changes, according to researchers at a conference convened in Washington, D.C., Sept. 18-21. The tone of much of the climate-change debate is changing from what is going on to what can be done about it.

In addition to descriptions of the latest evidence that climate change may be accelerating, government and business leaders at the conference outlined measures they are already taking to reduce greenhouse gas emissions—the major cause of rapid climate change. Representatives of religious and campus groups described efforts to mobilize individuals to take concrete steps to reduce their own impact on the atmosphere.

The conference, "Washington Summit on Climate Stabilization," was organized by the Climate Institute, a Washington, D.C.-based nonprofit organization established to address global warming issues.

Crispin Tickell, chancellor of the University of Kent, in England, and a former British ambassador to the United Nations, opened the conference by noting the change in how governments and businesses are responding to the climate problem. "There are very substantial signs that the U.S. business community is moving to solve the problem," he said. Many companies, such as Wal-Mart, have undertaken concrete steps to reduce emissions, he explained.

Tickell described three stages in confronting a crisis: recognizing the problem, working out methods of dealing with it, and taking necessary action. In its response to the climate crisis, the U.S. government is still somewhere between stages one and two, and the U.K. is well-advanced on stage two, he said. He noted, however, that "we are now at a point where mitigation will not solve all the problems. Some adaptation to climate change will be necessary."

A. Barrie Pittock, honorary fellow at CSIRO Marine & Atmospheric Research, Australia, said there are a number of reasons why global climate change may be more severe and abrupt than previously expected. One is accelerated melting of permafrost in the Arctic, he said. The rapid melting is increasing methane emissions in areas where permafrost is replaced by swampland and CO₂ emissions where permafrost is replaced by dry soil, he observed. Both add to the already high levels of greenhouse gases in the atmosphere.

Furthermore, "In some regions, biomass, which in the past has been a sink for CO₂, is now a source," Pittock said. Since 1978, for example, soil and vegetation in England and Wales have been acting as net CO₂ sources. In areas of Alaska that used to be sinks for CO₂, droughts are leading to vast forest fires with correspondingly large CO₂ emissions.

In addition to permafrost melting, there has been a dramatic loss of sea ice in the Arctic, reported Claire L. Parkinson, a climatologist at the National Aeronautics & Space Administration Goddard Space Flight Center. Since the late 1970s, the extent of sea ice in September, when it is at a minimum, has shrunk from about 7.5 million km² to 6 million km². "The annual average decline is about the size of Maryland and Delaware combined," she said.

"Sea ice in winter has also been decreasing, though not at as large a rate as in summer," Parkinson said. Between the late 1970s and 2004, "the average annual loss of winter sea ice was about 2% per decade, while summer sea ice loss was 7-8% per decade."

The early retreat of sea ice is reducing the time polar bears can hunt in the Hudson Bay region, Parkinson said. As a result, "polar bear populations in the Hudson Bay area have fallen from 1,200 in 1989 to 950 in 2004, and their average body weight dropped 22% from 1980 to 2004."

Andrew E. Derocher, professor of biology at the University of Alberta, explained why polar bears are vulnerable to climate warming. They evolved from grizzly bears beginning about 400,000 years ago, he said. In the process, their teeth, skulls, and claws evolved to fit their predatory lifestyle. Polar bears are adapted to making a living on ice by eating mammals, primarily ringed seals and bearded seals, rather than consuming vegetation, which forms much of the grizzly's diet. They generally fast while on land. "Polar bears are marine mammals but can't swim like seals," Derocher said. "Generally, they take in large amounts of fat from seals during the spring and rely on it for the rest of the year. The earlier the breakup of sea ice, the worse the condition of the bears."

In studies of polar bears in the Beaufort Sea and Hudson Bay regions, "we see more drowning bears and more problem bears" that approach humans in search of food, Derocher said. "The bears are losing areas where they want to live-the sea ice close to land-and being forced to live in deepwater areas where they can't survive. As Arctic warming continues, I expect to see changes in prey, more cannibalism, and lower survival rates."

As recently as 2003, climate models predicted that the Greenland ice sheet would take at least 1,000 years to melt, even if little effort was made to curb greenhouse gas emissions. But new research shows the melting process is rapidly accelerating.

Eric Rignot of NASA's Jet Propulsion Laboratory described how quickly Greenland's glaciers are moving toward the sea and melting. From his analysis of glacier flow, snow accumulation, and summer ice melt data, he determined that the total ice loss from the Greenland ice sheet increased from 96 km³ in 1996 to 220 km³ in 2005. (For comparison, Los Angeles uses less than 1 km³ of water annually.) To put this in different terms, "Near the coast, some of Greenland's glaciers are thinning at rates up to 50 meters per year and others at 30 meters per year, and the areas of accelerated flow are propagating inland," Rignot said.

There is no trend in snowfall that can make up the loss of ice from the glaciers, Rignot explained. "If Greenland is melting fast today, it can only melt faster in the future," as air temperatures keep rising. If all the ice there melts, which is unlikely, "it would raise sea level by 7 meters," he warned.

It is obvious where models have failed to predict current melting in Greenland, Rignot said. For example, he explained, ice models had not predicted the loss caused by meltwater descending to the glacier base through cracks and moulins-vertical shafts in glaciers-and lubricating the bedrock so glaciers' progress toward the sea accelerates. "An even more important unpredicted process is the thinning of glacier fronts from surface or subsurface melting, which allows the upstream part of the glacier to flow faster," he said. "We need new models with finer resolution of ice sheet dynamics."

Moving south, Robert A. Bindschadler, chief scientist at the Hydrospheric & Biospheric Sciences Laboratory at NASA Goddard Space Flight Center, Greenbelt, Md., presented strong evidence that glaciers in West Antarctica are also melting quickly. Some glaciers there are now changing in ways that models don't predict, he said. "The glaciers exhibit the fingerprint of collapse, meaning that toward the coast the ice is thinning up to 5 meters per year, the flow is accelerating up to 20% per decade, and the grounding line [that is, the outermost point where the bottom of the glacier contacts the ground] is retreating more than 1 km per year.

"The glaciers that are accelerating and retreating most rapidly are deep, with bases hundreds of meters below sea level," Bindschadler explained. "It appears that warm subsurface ocean water is responsible for this behavior. There is a large part of West Antarctica where the ice sheet is grounded well below sea level," he said. Warmer water in contact with the base of the ice sheet is weakening it, and the ice sheet could possibly melt very quickly, he said. "A similar process is taking place in Greenland."

Combined melting in Greenland and West Antarctica could cause what is called a "sea-level pulse," he said. "During human history, large sea-level pulses have not occurred. But in Earth's history, there have been meltwater pulses that caused sea level to rise a few meters in a few centuries."

Warming climate is not only affecting areas of ice and snow. Evidence is strong that hurricanes are growing more intense as global temperatures rise, said Judith A. Curry, chair of the School of Earth & Atmospheric Sciences at Georgia Institute of Technology. "The recent increase in North Atlantic hurricane intensity can't be explained solely by natural variability seen in the historical record since 1851," she said. Also, globally, the proportion of Category 4 and 5 hurricanes has nearly doubled since 1970.

Two major factors control hurricane intensity, Curry said: sea-surface temperatures and wind shear. Although wind shear strength has varied from year to year, it has shown no overall trend since 1970, she observed, so the only logical way to explain the doubling in the number of Category 4 and 5 storms is the 1 °F average rise in sea-surface temperatures since 1970. "Climate model simulations attribute this temperature increase to human-induced global warming," she said. "The combination of greenhouse warming and natural variability is expected to produce unprecedented tropical cyclone activity in the coming decades."

The air pollution tragedy in Donora, Pa., in the fall of 1948 may offer a lesson relevant to the climate problems unfolding today, said Devra Lee Davis, director of the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute. For decades before the tragedy, Donora had been a gray town with dark overcast skies polluted by emissions from a zinc mill and other factories that provided jobs for most of Donora's workers, Davis said. In many neighborhoods, air pollution made it impossible for either trees or grass to grow. People who complained about the pollution were told it was a sign of progress that couldn't be avoided without shutting down the mills that provided high wages, she observed.

But in the fall of 1948, the toxic fumes grew so thick that they hung over the town for five days. The fumes sickened half the population of 12,000 and killed 20 people, she said. The mills closed and have never been restarted. "What happened to Donora is like what is happening to climate today," she warned, because most people are unaware of the potential for tragedy.

In light of the growing evidence that warming may be occurring more rapidly than had been thought, a number of speakers described steps that businesses are taking or could take that might help avert abrupt climate change. Thomas R. Casten, chairman and chief executive officer of Primary Energy, Oak Brook, Ill., said there are profitable ways to reduce CO₂ emissions by recycling energy. When 100 units of fossil fuel are burned in a centralized power plant, 67 units are lost as waste heat and in distribution, and the end user receives only 33 units, he said.

With combined heat and power systems that recycle waste heat, however, 100 units of fuel produce on average 33 units of thermal energy and 33 units of electricity, wasting only 33 units. "To recycle waste heat, you have to have local power generation," he said. "Denmark made the change to combined heat and power in about 20 years," he said. Now, about 50% of its total power generation involves combined heat and power. In the U.S. that fraction is less than 10%.

The U.S. can profitably recycle industrial waste energy streams to provide the same amount of electricity as would be produced by 64 new nuclear power plants, he said. But current federal and state regulations affecting utility rates, taxes, and connection to the grid discourage combined heat and power.

BP is taking many steps to reduce its greenhouse gas emissions and promote clean energy, said William E. Gerwing, director of Western Hemisphere health, safety, security, and environment for BP America. "First, BP decided to put its own operations in shape. It has already met its target of reducing greenhouse emissions 10% by 2010," he said. Second, BP is investing $8 billion in alternative energy. It has purchased a wind company and is increasing the capacity of its photovoltaic plants threefold in three years.

Third, BP is investing in carbon sequestration projects, Gerwing said. Its Carson Hydrogen Power Project will be a $1 billion facility in Carson, Calif. It will use petroleum coke, a by-product of oil refining, to produce CO₂ and hydrogen. The hydrogen will fuel an electric power plant, and the CO₂ will be used for enhanced oil recovery and stored in depleted oil wells.

"We have reached a tipping point today where we have the potential to take renewable technologies into the mainstream within the next five years," said Christopher Flavin, president of Worldwatch Institute. Although renewables-defined as photovoltaics, wind energy, and biofuels-now provide only 6% of the world's energy, they are growing at annual rates of 20-30%, he said. The average annual growth rate for photovoltaics is 29%, for wind, 26%, and for biofuels, 17%. "These rates are similar to those for telecommunications and computers in the early days of commercialization," he said.

Renewables are beginning to attract substantial investment from General Electric, BP, Shell, and mainstream banks, Flavin said. "They are a hot area for venture capital, and some people are becoming billionaires from such investments.

"We face a potentially historic turning point today in renewable technologies," Flavin continued. "If the U.S. does not move aggressively into renewables, China and India will be way ahead of us."

Even if some attitudes on climate change are shifting, there is a continuing need for good climate information. To that end, the Climate Institute is facilitating a collaborative project that will aid research on climate change, according to Luis R. Acosta, director of Sistema Internacional de Monitoreo Ambiental. SIMA, a Mexico City-based nongovernment organization, and the Climate Institute, with help from U.S. government agencies, are establishing a National High Altitude Global Climate Observation Center on top of a 4,500-meter-high mountain in the Mexican state of Puebla.

The center will measure meteorological variables, CO₂, ozone, solar ultraviolet radiation, trace gases, and dust particles, especially from the Sahara Desert and the Amazon region. It will fill a crucial gap in the Global Atmospheric Watch Network, which is coordinated by the World Health Organization, Acosta told the conference.

Mexico's astrophysics agency is installing a $200 million telescope at the same high-altitude site, and the climate-observing center will be placed near the telescope. The U.S. National Oceanic & Atmospheric Administration's Climate Monitoring & Diagnostics Laboratory in Boulder, Colo., has shipped instruments worth about $450,000 to Mexico that will be used in the climate-observing center. NASA will be contributing radiation-measuring instruments, and Sun Microsystems will be supplying computers. Acosta expects the center will be functioning in the spring or summer of 2007.

Over the past year, a number of religious groups have become interested in grassroots action to try to avert irreversible climate change. Some are asking their members to take steps to reduce the CO₂ emissions associated with their personal lives. They argue that climate change will cause great suffering for the poor and disadvantaged in the world and destroy much of God's creation.

At the meeting, speakers from several faiths described measures being taken to protect climate. The Presbyterian Church has asked its members to try to become "carbon neutral" by reducing the use of energy, especially fossil fuels, said Pamela P. McVety, moderator of the Presbyterian Resolution Energy Task Force. Members are urged to reduce their personal use of fossil fuels and to pay for offsets to compensate for uses that cannot be avoided, she said. A fairly typical family of four releases 32 tons of CO₂ (measured as carbon) per year from fossil fuels used to support daily activities. The church asks them to cut that in half with energy-conserving steps and to offset the remainder by paying for emission-reducing projects, such as reforestation.

It is evident from the talks at the meeting that discussions about global climate change have shifted recently. What is happening in nature as a result of rising atmospheric concentrations of greenhouse gases is more threatening and more visible than it was a few years ago. As a result, more businesses and governments and some religious groups are taking concrete action, and the opposition to such action is less strident than it once was.