The San Diego Union-Tribune reported last month on a briefing given to the press in the course of the Feb. meeting of the American Association for the Advancement of Science. -- At the briefing, Tim Barnett, a marine physicist, said: "It's really undeniable that global warming is going on, whether you see it in the ocean or in the ecosystems," he said. "There's really a gazillion places to look for it." -- One concern scientists are expressing is this: "Melting snow and ice in the Arctic are adding fresh water to the North Atlantic, a situation that could disrupt the flow of warm water from the tropics to the north," journalist Bruce Lieberman wrote in the Union-Tribune. "This 'conveyer belt' brings cold and salty water from the Arctic to the south and moves warm water from the tropics to the north. A slowdown or shutdown of this circulation could drastically change the world's climate. For the U.S. Northeast and northern Europe, continued global warming could lead to a deep freeze." -- You may have heard that some are drawing even more alarming conclusions, citing evidence that global climate change can occur quite abruptly, in ways that would have an enormous and sudden impact upon human societies. -- How worrisome are such claims? -- You'll be better able to judge after you participate in Digging Deeper IV, a study circle on climate change and global warming facilitated by United for Peace of Pierce County. -- Among the books that will be discussed (available for borrowing or for purchase from UFPPC) are High Tide: The Truth about Our Climate Crisis, by Mark Lynas (Picador, 2004); The Long Summer: How Climate Changed Civilization, by Brian M. Fagan (Basic Books, 2004); Meltdown: The Predictable Distortion of Global Warming by Scientists, Politicians, and the Media, by Patrick J. Michaels (Cato Institute, 2004); and The Two-Mile Time Machine: Ice Cores, Abrupt Climate Change, and Our Future, by Richard B. Alley (Princeton University Press, 2002). -- Digging Deeper IV will meet Monday evenings at 7:00 p.m. at the Mandolin Cafe, 3923 S. 12th St., Tacoma. -- For more information, see here....
OCEAN WARMING, FOSSIL FUEL GASES LINKED
By Bruce Lieberman
** Cycle is detailed at science meeting **
San Diego Union-Tribune
February 18, 2005
WASHINGTON -- For the first time, scientists have linked the world's warming oceans to a rise in greenhouse gases produced by the burning of fossil fuels and other industry.
The research was conducted by scientists at the Scripps Institution of Oceanography in La Jolla and the Lawrence Livermore National Laboratory in Northern California. It showed that temperature readings in the oceans during the past 40 years matched computer models simulating how higher levels of human-generated greenhouse gases were expected to heat the oceans.
"We were stunned by the degree of similarity between the observations and the models," said Tim Barnett, a marine physicist who wrote the study with fellow Scripps scientist David Pierce.
Barnett spoke yesterday at a briefing coordinated by the American Association for the Advancement of Science, which is holding its annual meeting this week in Washington, D.C.
"It's really undeniable that global warming is going on, whether you see it in the ocean or in the ecosystems," he said. "There's really a gazillion places to look for it."
The rise in ocean temperatures has varied around the world, but none of the increases can be explained by fluctuations in energy output from the sun, Barnett said. Some scientists have said the sun can drive climate changes at least as much as greenhouse gases.
However, the close match between actual temperature readings and what the computer models predicted rules out any other cause for warming oceans, Barnett said. It also suggests that the models are powerful tools for predicting how increases in carbon dioxide might change the global environment, he added.
Oceans, which cover more than 70 percent of Earth's surface, are the major regulators of climate. Average global temperatures have risen about 1 degree Fahrenheit during the past century, and scientists estimate that the oceans have absorbed about 90 percent of that heat.
Put another way, the oceans have sucked up enough heat energy during the past 40 years to power California for the next 200,000 years, Barnett said.
Warmer oceans are expected to have a profound impact on the global environment, said Barnett, who plans to publish his findings soon.
Drought would be the most immediate and lasting change for San Diegans and the rest of the western United States. Severe water shortages are looming large in some nations that rely exclusively on snow packs and glaciers for water, such as Peru and certain regions of China, Barnett said.
While many of the world's temperate zones receive less rain and snow, precipitation is shifting to the higher latitudes -- toward the North and South poles, said Ruth Curry, a researcher at the Woods Hole Oceanographic Institution in Massachusetts.
Melting snow and ice in the Arctic are adding fresh water to the North Atlantic, a situation that could disrupt the flow of warm water from the tropics to the north.
This "conveyer belt" brings cold and salty water from the Arctic to the south and moves warm water from the tropics to the north. A slowdown or shutdown of this circulation could drastically change the world's climate.
For the U.S. Northeast and northern Europe, continued global warming could lead to a deep freeze, scientists have said.
Scientists aren't sure whether the current ocean warming might slow or halt the conveyer belt. But they're worried by such changes as an accumulation of fresh water in the northern seas and a drop in salinity in currents that feed the conveyor belt.
"These are the first steps that would constitute a movement toward a slowdown or shutdown of the ocean conveyer," Curry said. "The system is moving in that direction."
Other changes are afoot.
Rising temperatures are damaging ecosystems for birds that travel to the Arctic. In 1997, warming waters spawned a bloom of phytoplankton called coccolithofore, obscuring fish that a bird called the short-tailed shearwater feeds on, said Sharon Smith, a researcher at the University of Miami. Smith is studying how a warming Arctic is changing life for plants and animals there.
The result: Hundreds of thousands of the birds starved to death in 1997 and for several years afterward.
Ricardo Letelier, a researcher at Oregon State University, has seen evidence for an even more ominous change.
By warming the ocean's waters, rising levels of greenhouse gases might be disrupting the ability of oceans to continue absorbing carbon dioxide from the atmosphere.
Marine organisms that form calcium carbonate shells help the oceans absorb carbon in atmospheric carbon dioxide. When those animals die, they sink to the bottom of the ocean and carry the carbon with them. Scientists have observed that changes in ocean temperature can upset the productivity of these creatures.
Faced with such negative consequences, governments should think seriously about reducing the emission of greenhouse gases, said Barnett, the Scripps scientist.
"I think it's a good time for the nations that are not now a part of Kyoto to re-evaluate their positions," said Barnett in reference to the international agreement that sets limits on greenhouse gases. The protocol, which the United States did not sign, went into effect Wednesday.
--Bruce Lieberman: (619) 293-2836;