The language was apocalyptic. Last month, a leading climate scientist warned that Earth's rising temperatures were poised to set off irreversible disasters if steps were not taken quickly to stop global warming.
''The climate is nearing tipping points,'' the NASA climate scientist James E. Hansen wrote in The Observer newspaper of London. ''If we do not change course, we'll hand our children a situation that is out of their control.''
The resulting calamities, Dr. Hansen and other like-minded scientists have warned, could be widespread and overwhelming: the loss of untold species as ocean reefs and forests are disrupted; the transformation of the Amazon into parched savanna; a dangerous rise in sea levels resulting from the melting of the mile-high ice sheets in West Antarctica and Greenland; and the thawing of the Arctic tundra, which would release torrents of the greenhouse gas methane into the atmosphere.
But the idea that the planet is nearing tipping points -- thresholds at which change suddenly becomes unstoppable -- has driven a wedge between scientists who otherwise share deep concerns about the implications of a human-warmed climate.
Environmentalists and some climate experts are increasingly warning of impending tipping points in their efforts to stir public concern. The term confers a sense of immediacy and menace to potential threats from a warming climate -- dangers that otherwise might seem too distant for people to worry about.
But other scientists say there is little hard evidence to back up specific predictions of catastrophe. They worry that the use of the term ''tipping point'' can be misleading and could backfire, fueling criticism of alarmism and threatening public support for reducing greenhouse gas emissions.
''I think a lot of this threshold and tipping point talk is dangerous,'' said Kenneth Caldeira, an earth scientist at Stanford University and the Carnegie Institution and an advocate of swift action to reduce carbon dioxide emissions. ''If we say we passed thresholds and tipping points today, this will be an excuse for inaction tomorrow,'' he said.
While studies of climate patterns in the distant past clearly show the potential for drastic shifts, these scientists say, there is enormous uncertainty in making specific predictions about the future.
In some cases, there are big questions about whether climate-driven disasters -- like the loss of the Amazon or a rise in sea levels of several yards in a century -- are even plausible. And even in cases where most scientists agree that rising temperatures could lead to unstoppable change, no one knows where the thresholds lie that would set off such shifts.
Nevertheless, the use of the tipping point concept has intensified recently, as the Obama administration and Congress work on legislation to curb greenhouse gas emissions and the world's nations negotiate a new climate treaty.
In reports released this month, both the World Bank and the United Nations Environment Program focused on tipping points as a prime concern. And last year, a team of European scientists published an influential paper in the Proceedings of the National Academy of Sciences compiling what is known and not known about various climatic tipping points -- including the loss of summer sea ice around the North Pole and worrisome changes in the West African monsoon.
The authors said they wanted to reduce the chance that ''society may be lulled into a false sense of security by smooth projections of global change.''
On the other hand, the United Nations Intergovernmental Panel on Climate Change, in its influential 2007 report, expressly avoided specifying tipping points and instead concluded simply that the gradient of risk for a host of ''large-scale discontinuities'' increased with each degree of warming.
Dr. Hansen defends the use of the term tipping point and said that it accurately depicts some probable consequences of unchecked global warming. There is abundant evidence, he says, that rising temperatures can have an abrupt, calamitous and ''nonlinear'' effect on glaciers and ecosystems.
''I assure you that nonlinear systems exist,'' Dr. Hansen said. ''Ice sheets really do disintegrate. Documented sea-level rises of 4 to 5 meters per century exists -- that was nonlinear collapse. Ecosystems also can collapse.''
He said that in discussing global warming, he refers not only to tipping points but to more general threats and that he was ''not sure where the confusion about tipping points comes from.''
But other scientists, who study the response to climate change of polar ice and tropical forests, said that they saw scant evidence of runaway disruption.
For example, the idea that recent sharp retreat of summer sea ice around the North Pole has now taken on its own momentum has been challenged recently in papers by the earth scientists John S. Wettlaufer of Yale and Ian Eisenman of the California Institute of Technology. They contend that thin ice floes have the capacity to regrow quickly as summer ends, balancing out the melting that occurs as sunlight hits and heats dark open water.
More generally, Dr. Wettlaufer has stressed the importance of being ''caustically honest about what we know and don't know.''
As policymakers try to address the risks facing the planet from a warming climate, some experts worry that focusing on tipping points and thresholds will perpetuate paralyzing debates over specifics -- and obscure the reality that decisions need to be made, even in the face of uncertainty.
''It would be far better to spend less time musing over tipping points,'' said Christopher Green, an economist who studies energy and climate at McGill University.
''Whether the probability is high, medium, or low, I think the response is the same: climate cannot be stabilized without an energy technology revolution,'' he said. ''One way or the other, we just need to get busy.''
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The New York Times March 29, 2009 Sunday
Late Edition - Final
Mother Nature's Dow
BYLINE: By THOMAS L. FRIEDMAN.
While I'm convinced that our current financial crisis is the product of both The Market and Mother Nature hitting the wall at once -- telling us we need to grow in more sustainable ways -- some might ask this: We know when the market hits a wall. It shows up in red numbers on the Dow. But Mother Nature doesn't have a Dow. What makes you think she's hitting a wall, too? And even if she is: Who cares? When my 401(k) is collapsing, it's hard to worry about my sea level rising.
It's true, Mother Nature doesn't tell us with one simple number how she's feeling. But if you follow climate science, what has been striking is how insistently some of the world's best scientists have been warning -- in just the past few months -- that climate change is happening faster and will bring bigger changes quicker than we anticipated just a few years ago. Indeed, if Mother Nature had a Dow, you could say that it, too, has been breaking into new (scientific) lows.
Consider just two recent articles:
The Washington Post reported on Feb. 1, that ''the pace of global warming is likely to be much faster than recent predictions, because industrial greenhouse gas emissions have increased more quickly than expected and higher temperatures are triggering self-reinforcing feedback mechanisms in global ecosystems, scientists said. 'We are basically looking now at a future climate that's beyond anything we've considered seriously in climate model simulations,' Christopher Field, director of the Carnegie Institution's Department of Global Ecology at Stanford University, said.''
The physicist and climate expert Joe Romm recently noted on his blog, climateprogress.org, that in January, M.I.T.'s Joint Program on the Science and Policy of Global Change quietly updated its Integrated Global System Model that tracks and predicts climate change from 1861 to 2100. Its revised projection indicates that if we stick with business as usual, in terms of carbon-dioxide emissions, average surface temperatures on Earth by 2100 will hit levels far beyond anything humans have ever experienced.
''In our more recent global model simulations,'' explained M.I.T., ''the ocean heat-uptake is slower than previously estimated, the ocean uptake of carbon is weaker, feedbacks from the land system as temperature rises are stronger, cumulative emissions of greenhouse gases over the century are higher, and offsetting cooling from aerosol emissions is lower. Not one of these effects is very strong on its own, and even adding each separately together would not fully explain the higher temperatures. [But,] rather than interacting additively, these different effects appear to interact multiplicatively, with feedbacks among the contributing factors, leading to the surprisingly large increase in the chance of much higher temperatures.''
What to do? It would be nice to say, ''Hey, Mother Nature, we're having a credit crisis, could you take a couple years off?'' But as the environmental consultant Rob Watson likes to say, ''Mother Nature is just chemistry, biology and physics,'' and she is going to do whatever they dictate. You can't sweet talk Mother Nature or the market. You have to change the economics to affect the Dow and the chemistry, biology and physics to affect Mother Nature.
That's why we need a climate bailout along with our economic bailout. Hal Harvey is the C.E.O. of a new $1 billion foundation, ClimateWorks, set up to accelerate the policy changes that can avoid climate catastrophe by taking climate policies from where they are working the best to the places where they are needed the most.
''There are five policies that can help us win the energy-climate battle, and each has been proven somewhere,'' Harvey explained. First, building codes: California's energy-efficient building and appliance codes now save Californians $6 billion per year,'' he said. Second, better vehicle fuel-efficiency standards: ''The European Union's fuel-efficiency fleet average for new cars now stands at 41 miles per gallon, and is rising steadily,'' he added.
Third, we need a national renewable portfolio standard, mandating that power utilities produce 15 or 20 percent of their energy from renewables by 2020. Right now, only about half our states have these. ''Whenever utilities are required to purchase electricity from renewable sources,'' said Harvey, ''clean energy booms.'' (See Germany's solar business or Texas's wind power.)
The fourth is decoupling -- the program begun in California that turns the utility business on its head. Under decoupling, power utilities make money by helping homeowners save energy rather than by encouraging them to consume it. ''Finally,'' said Harvey, ''we need a price on carbon.'' Polluting the atmosphere can't be free.
These are the pillars of a climate bailout. Yes, some have upfront costs. But all of them would pay long-term dividends, because they would foster massive U.S. innovation in new clean technologies that would stimulate the real Dow and much lower emissions that would stimulate the Climate Dow.
SECTION:Section A; Column 0; National Desk; Pg. 16
LENGTH: 417 words
The Obama administration announced Saturday that it had organized a series of meetings among representatives of 16 countries and the European Union to discuss energy and climate issues.
The meetings, to be held in Washington in April and in La Maddalena, Italy, in July, will seek to resolve longstanding issues that have blocked the development of an international climate treaty.
The participants, who include Chinese and Indian representatives, will also try to create ''concrete initiatives and joint ventures that increase the supply of clean energy while cutting greenhouse gas emissions,'' according to a White House news release. The talks, called the Major Economies Meetings on Energy Security and Climate Change, echo in name and goals an initiative begun in the last two years of the Bush administration.
Those meetings gathered developing and developed countries that were the largest emitters of the heat-trapping gases linked to global warming. The meetings were cast by the Bush administration as intended to set long-term goals for reducing emissions and to seek actions that could be taken in sectors of economies like power generation and manufacturing.
The talks organized by the Bush administration were criticized by some small developing countries, European officials and environmental groups as an effort to circumvent global climate negotiations led by the United Nations, although President George W. Bush said at the time that the meetings were intended to support the global talks.
The United States refused to ratify an earlier international agreement, the Kyoto Protocol, objecting that developing countries like China and India were not bound by its restrictions on emissions of heat-trapping gases.
Negotiations for a new global treaty are under way and will culminate in talks in Copenhagen in December.
The president of the National Wildlife Federation, Larry Schweiger, said Saturday that any such meetings were useful as ways to seek common ground among the world's biggest emitters of heat-trapping gases.
At the time, some environmentalists credited the Bush administration's effort for initiating direct exchanges about climate with China and India.
But Mr. Schweiger said he expected the Obama administration's initiative to be more productive.
''It's a matter of intent,'' he said. ''I think the Bush administration never intended to come up with a big solution. I think this administration is truly committed to finding a solution for everybody.''
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The New York Times March 28, 2009 Saturday
Late Edition - Final
An Arctic Circle of Friends
BYLINE: By SCOTT BORGERSON and CAITLYN ANTRIM.
Scott Borgerson is the visiting fellow for ocean governance at the Council on Foreign Relations. Caitlyn Antrim is the executive director of the Rule of Law Committee for the Oceans.
LENGTH: 752 words
THE North Pole is under siege by global warming. The sea ice there has lost half its thickness in the past six years, and all signs point to further rapid melting. By 2013, the entire Arctic could be devoid of ice in summer, and the region is likely to experience an influx of shipping, fishing and tourism. Russia planted its flag in the North Pole's ocean floor two years ago, and other northern nations find themselves under mounting pressure to lay claim to huge swaths of the seabed. Before the land grab goes too far, the nations most involved should turn the northernmost part of the Arctic into a great park -- a marine preserve that protects the polar environment and serves as a center for peaceful, international scientific research.
The Arctic's pristine waters are a leading indicator, and an important regulator, of global climate health. They are the beginning and the end of the so-called great ocean conveyor, the mighty current that connects all the world's oceans. And they are home to a vibrant ecosystem that supports whales, polar bears and terns.
Driving much of the new interest in the Arctic, however, are the stores of oil and gas that lie beneath the water -- amounting to an estimated 22 percent of the earth's remaining supplies. The largest deposits, however, are likely to be found in the shallower parts of the continental shelf, within the surrounding countries' existing economic zones. Any fields found at greater depths, within the boundaries of the proposed park, would be prohibitively expensive to exploit for at least decades to come. For sovereignty claims, North Pole oil is a red herring.
The Convention on the Law of the Sea, the international treaty that sets the rules for ownership of ocean resources, recognizes that Canada, Denmark, Norway and Russia, the four countries neighboring the Arctic Ocean, may be entitled to extend their seabed boundaries -- and even sets a deadline for doing so. (Because the United States has not joined the Convention, it cannot make a claim to the extended continental shelf.) But it leaves it to those countries to resolve overlapping claims among themselves. Disputes over jurisdiction stand to slow the process of setting up a system for protecting the Arctic and could also poison international relations elsewhere. The creation of an international park would head off both problems.
One approach would be for the states and international organizations most involved in the Arctic to designate everything above 88 degrees latitude north -- a circle with a 120-nautical-mile radius -- as a marine park. This would be consistent with an idea presented in 1987 by Mikhail Gorbachev of the Soviet Union to create an Arctic ''zone of peace.'' And it has precedent in the 1959 treaty that created an international zone for scientific research in Antarctica, and that has governed that continent so well ever since.
Like Antarctica, the park could be managed by an international cooperative, including not only Canada, Denmark and Russia but also the United States, China, Finland, Germany, Japan, Norway, Sweden and any other countries that engage in Arctic research.
Canada, Denmark and Russia would benefit from such an initiative because each would avoid the kind of legal conflict and jurisdictional uncertainty that could discourage private investment in the surrounding areas. And the sovereignty extensions that have already been approved by the Continental Shelf Commission, a body established by parties to the Convention on the Law of the Sea, could be put into effect without delay. All three countries could also use the new scientific research to help them better manage their Arctic resources. And the park would not interfere with any nation's freedom of navigation.
It might seem presumptuous for Americans to suggest that our northern neighbors forgo ownership of even a small part of the Arctic seabed. Admiral Robert Peary may have planted the American flag at the North Pole 100 years ago, but we have no territorial stake in the Lomonosov Ridge, the submarine link between Eurasia and North America that is the source of the competing claims. We do, however, have a vested interest in the peaceful development of the Arctic as a region. As citizens of a shared earth, we also have a stake in the greater good that can come from exploring the depths of the fastest warming part of the planet. American leadership on a polar park would send a clear message that we are attuned to the climate crisis.
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The New York Times
March 27, 2009 Friday Late Edition - Final
In a City in Italy, the Schoolchildren Walk Where Once They Rode
BYLINE: By ELISABETH ROSENTHAL
SECTION: Section A; Column 0; Foreign Desk; Pg. 6
LENGTH: 1160 words
DATELINE: LECCO, Italy
Each morning, about 450 students travel along 17 school bus routes to 10 elementary schools in this lakeside city at the southern tip of Lake Como. There are zero school buses.
In 2003, to confront the triple threats of childhood obesity, local traffic jams and -- most important -- a rise in global greenhouse gases abetted by car emissions, an environmental group here proposed a retro-radical concept: children should walk to school.
They set up a piedibus (literally foot-bus in Italian) -- a bus route with a driver but no vehicle. Each morning a mix of paid staff members and parental volunteers in fluorescent yellow vests lead lines of walking students along Lecco's twisting streets to the schools' gates, Pied Piper-style, stopping here and there as their flock expands.
At the Carducci School, 100 children, or more than half of the students, now take walking buses. Many of them were previously driven in cars. Giulio Greppi, a 9-year-old with shaggy blond hair, said he had been driven about a third of a mile each way until he started taking the piedibus. ''I get to see my friends and we feel special because we know it's good for the environment,'' he said.
Although the routes are each generally less than a mile, the town's piedibuses have so far eliminated more than 100,000 miles of car travel and, in principle, prevented thousands of tons of greenhouse gases from entering the air, Dario Pesenti, the town's environment auditor, estimates.
The number of children who are driven to school over all is rising in the United States and Europe, experts on both continents say, making up a sizable chunk of transportation's contribution to greenhouse-gas emissions. The ''school run'' made up 18 percent of car trips by urban residents of Britain last year, a national survey showed.
In 1969, 40 percent of students in the United States walked to school; in 2001, the most recent year data was collected, 13 percent did, according to the federal government's National Household Travel Survey.
Lecco's walking bus was the first in Italy, but hundreds have cropped up elsewhere in Europe and, more recently, in North America to combat the trend.
Towns in France, Britain and elsewhere in Italy have created such routes, although few are as extensive and long-lasting as Lecco's. In the United States, Columbia, Mo.; Marin County, Calif.; and Boulder, Colo., introduced modest walking-bus programs last year as part of a national effort, Safe Routes To School, which gives states money to encourage students to walk or ride their bicycles.
Although carbon dioxide emissions from industry are declining on both continents, those from transportation account for almost one-third of all greenhouse-gas emissions in the United States and 22 percent in European Union countries. Across the globe, but especially in Europe, where European Union countries have pledged to reduce greenhouse gas production by 2012 under the United Nations' Kyoto protocol, there is great pressure to reduce car emissions.
Last year the European Environmental Agencywarned that car trips to school -- along with food importing and low-cost air travel -- were growing phenomena with serious implications for greenhouse gases.
In the United States and in Europe, ''multiple threads are warping traditional school travel and making it harder for kids to walk,'' said Elizabeth Wilson, a transportation researcher at the Humphrey Institute of Public Affairs at the University of Minnesota. Among those factors are a rise in car ownership; one-child families, often leery of sending students off to school on their own; cuts in school-bus service or charges for it as a result of school-budget cutbacks and fuel-price gyrations; and the decline of neighborhood schools and the rise of school choice, meaning that students often live farther from where they learn.
Worse still, said Roger L. Mackett, professor at the Center for Transport Studies at University College in London, there is growing evidence that children whose parents drive a lot will become car-dependent adults. ''You're getting children into a lifelong habit,'' he said.
In Lecco, car use has proved a tenacious habit even though the piedibus has caught on. ''Cars rule,'' said Augosto Piazza, the founder of the city's program, an elfin man with shining blue eyes, a bouncing gait and a yellow vest. As he ''drove'' along a bus route on a recent morning, store owners waved fondly to the familiar packs of jabbering children.
Yet as they pulled up to Carducci School, dozens of private cars were parked helter-skelter for dropoffs in the small plaza outside as gaggles of mothers chatted on the sidewalk nearby. ''I have two kids who go to different schools, plus their backpacks are so heavy,'' said Manuela Corbetta, a mother in a black jacket and sunglasses, twirling her car keys as she explained why her children do not make the 15-minute trek. ''Sometimes they have 10 notebooks, so walking really isn't practical.''
Some children are dropped off by parents on their way to work, and some others live outside the perimeter of the piedibus's reach, although there are collection points at the edge of town for such children. But many live right along a piedibus route, Mr. Piazza noted.
Yet other parents praised the bus, saying it had helped their children master street safety and had a ripple effect within the family. ''When we go for shopping you think about walking -- you don't automatically use the car,'' said Luciano Prandoni, a computer programmer who was volunteering on his daughter's route.
The city of Lecco contributes roughly $20,000 annually toward organizing and providing staff members for the piedibus. The students perform a public service of sorts: they are encouraged to hand out warnings to cars that park illegally and chastise dog owners who do not clean up.
Naturally some children whine on rainy mornings. Participation drops 20 percent on such days, although it increases during snowfalls. On rainy days, ''She says, 'Mom, please take me,' and sometimes I give in,'' said Giovanna Luciano, who lives in the countryside and normally drops her daughter Giulia, 9, at a piedibus pickup point in a parking lot by a cemetery.
To encourage use, children receive fare cards that are punched each day. The bus routes have distinctive names (the one through the graveyard is the mortobus), and compete for prizes like pizza parties for the students. Teachers have students write poems about the piedibus.
In Britain, about half the local school systems now have some sort of incentives to encourage walking, although generally less formal ones than the piedibus, said Roger L. Mackett, a professor at the Center for Transport Studies at University College in London.
''It's quite a lot of effort to keep it going,'' he said. ''It's always easier to put children in the back of the car. Once you've got your two or three cars, it takes effort not to use them.''