Paint it White: One Way to Chill the Electric Bill

SolveClimate
Renee Cho
Sunday, June 28, 2009

Could something as simple as white roofs actually make a dent in our carbon emissions and help curb global warming?

Physicist Steven Chu, our Nobel Prize-winning Secretary of Energy, thinks so. At the St. James’s Palace Nobel Laureate Symposium in London last month, he pushed for a global initiative to lighten the color of roofs, roads and pavements to cut carbon emissions by the equivalent of taking all cars off the road for 11 years.

As residents of hot countries have known for centuries, buildings painted white stay cooler because they reflect the sun’s heat. Light colored materials reflect more solar radiation, including visible, ultraviolet and infrared light (which accounts for most of the heat), than dark materials which absorb heat. Albedo, the gauge of solar reflectivity, is calculated from 0.0 to 1.0, with 1.0 being the highest measure of reflectivity.

Maximizing the number of high albedo surfaces around the world could significantly help cool the planet, said Chu, former director of the Lawrence Berkeley National Laboratory (LBNL).

Chu’s ideas have been shaped by the work of Dr. Arthur Rosenfeld (formerly at LBNL, now on the California Energy Commission), and fellow LBNL scientists Hashem Akbari and Surabi Menon. In 1985, they began studying how light colored roofs and pavement could mitigate the urban heat island effect – when urban areas are 2˚F to 8˚F warmer than surrounding areas due to the heat absorbed by pavement and buildings.

In 2004, they realized that their research might also help curb climate change.

“When we did the calculations, initially we couldn’t believe the results,” Akbari said.

They figured that changing 100 square feet of dark roof area to white would have an effect equivalent to offsetting the emission of one ton of CO2. On a global scale, increasing the albedos of urban roofs and paved surfaces would be equivalent to offsetting about 44 billion tons of CO2 emissions.

White roofs and cool roofs, those made from other high albedo materials, result in less carbon emissions because they reflect the sun, and reduce the need for air conditioning and thus the energy from CO2 emitting power plants.

Cool roofs also curtail the heat island effect and its accompanying smog, make buildings more comfortable, ease stress on the energy grid, help buildings comply with energy efficiency codes, and extend the life of roofs because lower temperatures make for less wear and tear.

White roofs, however, are difficult to keep clean and may lose up to 1/3 of their reflectivity within a few years, so resistance to dirt accumulation is important for roof coatings. And some critics have questioned whether white roofs increase winter heating costs in cooler climates. But Michelle van Tijen from the Cool Roof Rating Council, explained,

“In areas with hot summer and cold winters, the energy savings during hot weather are still greater than the incremental loss of heat in the winter.” This is because roofs do not absorb much heat from the sun in winter when days are shorter and cloudier, and the sun is less intense.

Proof Is in the Payoff

Several examples of shifting to dark to white roofs have shown the value.

In 1995, The Florida Solar Energy Center applied a white acrylic coating onto the 12,000-foot roof of Our Savior’s Elementary School in Cocoa Beach, Fla. After a year, the school’s energy consumption was down 13,000 kWh and its power usage had dropped 10 percent for an overall savings of $850.

The Heat Island Group, led by Akbari, tested light colored roofs on three commercial buildings in Davis, Gilroy and San Jose, Calif. The roofs’ albedos increased from 0.20 to 0.60, roof surface temperatures on summer afternoons fell from 175 degrees Fahrenheit to 120, and average electricity use for air-conditioning dropped by 18 percent in the Davis building, 13 percent in the Gilroy building, and 2 percent in the San Jose store.

The Philadephia Cool Homes Project, which installed white roofs on approximately 340 low-income seniors’ homes from 2001-2003, eliminated solar heat gain through the roofs, reduced ceiling temperatures by 4 to 5 degrees, and saved 560 kWh of air-conditioning electricity use per year.

White roofs also make good economic sense for cities. The 2006 report Mitigating New York City’s Heat Island with Urban Forestry Living Roofs and Light Surfaces compared the effectiveness and cost-benefits of urban forestry, green roofs, light surfaces, and some combined strategies, in mitigating the heat island effect. For every 1 degree of temperature reduction, light roofs and surfaces cost less than green roofs or tree plantings.

What Makes a Roof Cool?

A roof’s “coolness” is determined by its solar reflectance (albedo) and thermal emittance, the ability of the material to release absorbed heat.

The EPA and Department of Energy have established minimum solar reflectivity criteria for their Energy Star roofing materials. Low slope roofs, usually commercial buildings, must have an initial solar reflectance of greater than or equal to 0.65 to qualify. Steep slope roofs, usually homes, must have an initial solar reflectance of greater than or equal to 0.25.

Currently, emittance criteria are not required for Energy Star qualification. Some materials, like metal, are highly reflective, but if their emittance is low they won’t release absorbed heat effectively, so the best cool roofing materials have both high albedo and high emittance.

“Some roofing product types are more likely to be designed as cool (spray-on foam, single-ply, some metal products), while others are typically black (modified bitumen or built-up roofing),” said Molly Trobley-McCann of the Cool Roof Rating Council. “But anything can be coated white.”

Though plain white paint can increase a roof’s albedo, white roof coatings help prevent leaks and protect the roof better than simple paint. According to the Consumer Energy Center, the cost of cool roof and traditional roof products are generally comparable, but the advantage of cool roof coatings is that they can be applied every 10 to 15 years, reducing the need for expensive roof overhauls.

Because residential owners have been reluctant to put white roofs on their homes, mainly for aesthetic reasons, LBNL’s Environmental Energies Technology Division is collaborating with Oak Ridge National Laboratory and pigment and roofing manufacturers to develop high albedo roofing products in a variety of colors and materials.

Cool Roof Rules and Standards

Since 2005, California has led the movement to adopt white roofs by requiring all flat roofs to be white. On August 1, its new Title 24 building standards will require both residential and nonresidential buildings to have cool roofs.

A number of other states and cities have also adopted cool roof standards and rebate programs, including Arizona, Arkansas, Florida, Georgia, Hawaii, Illinois, Louisiana, New Mexico, North Carolina, South Carolina and Texas. Still others promote voluntary programs and initiatives. Voluntary programs such as the Green Building Initiative’s Green Globes and the U.S. Green Building Council’s LEED rating systems give credit for cool roofs.

In January, the DOE ruled that all states must certify that their building codes meet the requirements in ANSI / ASHRAE / IESNA’s 90.1-2004 Energy Standard for Buildings Except Low Rise Residential Buildings.

These standards, crafted by the American National Standards Institute, American Society of Heating, Refrigeration and Air Conditioning Engineers, and Illuminating Engineering Society of North America, provide minimum energy efficiency standards (including cool roof requirements) for new buildings, new parts of buildings, and new systems and equipment in existing buildings.

ASHRAE is currently developing standards for 2010 that will save 30 percent more energy, with a goal to have net-zero buildings by 2015.

Brazil grants land rights to squatters living in Amazon rainforest

UK Guardian
Tom Phillips
Friday, June 26, 2009

Brazil’s president Lula has approved a controversial law which grants land rights to squatters occupying land in the Amazon — campaigners fear it will result in a further increase in deforestation of the Amazon region.

The law – known as “provisional measure 458″ – is one of the most controversial environmental decisions of Lula’s two terms in office, with the president coming under intense pressure from both environmental groups and the country’s powerful agricultural lobby.

Marcelo Furtado, Greenpeace’s campaigns manager in Brazil, said the approval of the law showed that Brazil’s policy on global warming was contradictory: “On one hand Brazil is setting targets for the reduction of carbon emissions and on the other it is opening up more areas for deforestation.”

Brazil’s government says more than 1m people will benefit from the law, which covers 67.4m hectares of land, an area roughly the size of France. It believes the law will reduce violent conflicts by giving people private ownership of the land they live on, and will make it easier to track down those illegally felling trees.

But environmentalists – who have dubbed it the “land-grabbers bill” – fear the new rules will offer a carte blanche for those wanting to make money by destroying the Amazon. They say the law effectively provides an amnesty for those who have devastated the Amazon over the last four decades. Around 20% of the Amazon has already been lost, according to environmental campaigners, and deforestation globally causes nearly a fifth of all greenhouse gas emissions.

“This measure perpetuates a 19th century practice [of Amazon destruction] instead of taking us towards a new 21st century strategy of sustainable development,” said Furtado.

Furtado said the law – originally intended to benefit impoverished farmers in the Amazon – had been “hacked apart by the agricultural lobby” and now benefited wealthy farmers rather than smaller landholders. The result, he said, was “a law which will not help increase governance [or] social justice but which simply raises the risk of more deforestation.”

Under the new law, small landowners who can prove they occupied lands before December 2004 will be handed small pieces of land for free, while large areas will be sold off at knockdown rates. The government hopes this will help bring order to a region where land disputes often result in violent clashes and murder. Brazilian human rights group Justica Global, claims 772 activists and rural workers have been killed in the Amazon state of Para between 1971 and 2004.

Human rights groups also criticised the law, saying unscrupulous Amazon ranchers, who often exploit slave labour, stood to gain from the new rules.

Faced with a vocal campaign against the measure, Lula hit back, accusing “the NGOS [of]… not telling the truth.”

In the decision, which came late on Thursday, Lula vetoed two of the most divisive sections of the bill – giving private businesses and absentee landowners the right to regularise their lands. But the Brazilian president gave the green light to one of the most controversial clauses, which will give new landowners the right to resell their properties after three years.

Europe refuses to get soil on its hands

UK Guardian
David Cronin
Wednesday, June 24, 2009

The other evening I had an experience of mundane magic. At the early age of 38, I ate the first vegetable that I had grown all by myself. It was a humble scallion yet on my tongue it had a tang of pride and achievement.

How many of the EU’s environment ministers who will gather in Luxembourg this Thursday produce their own food? I’m not asking that question because I think that my success story with organic scallions suddenly gives me greener credentials than the political masters of this continent. I ask it because I doubt that many of them feel any emotional connection to soil, judging by the cavalier way they disregard it.

Three years ago, the European commission proposed a legal framework for soil protection. Three years later, it is at risk of being consigned to the compost heap as a small but powerful group of EU governments are refusing to approve it. Britain, France, Germany, Austria and the Netherlands are all opposed to the plan, claiming either that implementing it would be too onerous or that soil is a matter best left for national administrations.

The reasons cited for rejecting the blueprint are spurious. Far from being too onerous, the proposal does not go far enough in obliging governments to protect a resource that none of us can live without. Politicians or civil servants from regions with poor soil quality have no reason to fear that Brussels bureaucrats will ambush them with subpoenas. Instead of urgent action, the law would simply require governments to identify areas afflicted by such problems as soil erosion and salinisation (the accumulation of salt) and to compile an inventory of contaminated sites, along with plans to rehabilitate such land.

The soil protection saga is a troubling testament to how the EU’s approach to the environment suffers from compartmentalised thinking. Whereas binding laws have been introduced on air and water, the union lacks similar rules on soil. Any clever child would be able to tell you that all these things are intimately connected. But allegedly well-educated officials and politicians can’t grasp that it’s foolish to try to protect one while neglecting the others.

Britain’s reluctance to endorse the plan offers yet another example of how hollow the rhetoric of Tony Blair and Gordon Brown’s governments on climate change has been. Cared for properly, soil can act as a carbon “sink”, absorbing about one-fifth of all man-made emissions of carbon dioxide. When soil is damaged, however, the pattern is reversed and rather than soaking up CO2, it releases it. Each year British soil loses about 0.6% of its organic matter and the resulting increase in CO2 emissions would be roughly equivalent to putting an extra five million cars on the road. This problem has been acute for several decades: between 1980 and 1995 British soil lost 18% of its organic matter. In 2004, the Environment Agency stated that the degradation caused to soil in England and Wales due to such factors as intensive agriculture and mismanagement of forests (during road construction and harvesting) was unsustainable.

Across the EU, thousands of sites have been polluted because of reckless industrial practices; nobody is sure of the full extent of this damage as there is a paucity of data about soil. The commission, meanwhile, reckons that soil degradation deprives the EU economy of €38bn per annum and that’s probably a conservative estimate.

Soil cannot be shielded from further deterioration by token gestures. A comprehensive and effective strategy would have to grapple with reforms of agricultural and industrial policy and a more sensible attitude to waste management (as I’ve learned from my limited experiments in the garden, composting can be of vital importance in keeping soil fertile). Not only does that strategy seem distant, though, our governments also can’t even agree on minimal rules. It is difficult not to despair.

Cows bred to burp less will help reduce potent greenhouse gas and tackle global warming

UK Daily Mail

Wednesday, June 24, 2009

A prototype cow which burps less is being bred in a breakthrough that could reduce a big source of the greenhouse gases responsible for global warming.

The farm animals are responsible for nearly three-quarters of total methane emissions.

Most of the gas comes from bovine burps, which are 20 times more potent than carbon dioxide as a greenhouse gas.

Stephen Moore, a professor at the University of Alberta in Canada, is examining the genes responsible for methane produced from the animal’s four stomachs in order to breed more efficient, environmentally friendly cows.

He completed tests using traditional techniques to breed efficient animals that produce 25 per cent less methane than less efficient animals.

‘We are working on producing diagnostic markers (clues to medical causes) for efficient animals,’ said Moore.

‘We are looking at the next generation of technologies that will enable us to determine the genetics of an animal through a blood test or testing some hairs that you might pluck from the animal.’

Farmers could shrink their cattle’s ecological footprint by breeding cows that grow faster, so reducing the time spent standing in fields. Cattle could also be bred to become more efficient in converting feed into muscle and producing less methane and waste, said Moore.

Another method already being used to reduce methane emissions is feeding livestock a diet higher in energy and rich in edible oils, which ferment less than grass or low-quality feed.

New Hampshire-based Stonyfield Farm, an organic yogurt producer in which Groupe Danone holds a majority stake, reduced emissions from their cows on an average of 12 percent by adding alfalfa, flax or hemp to livestock feed on a small number of its farms.

‘If every U.S. dairy farmer reduced emissions by 12 per cent it would be equal to about half a million cars being taken off the road,’ said Nancy Hirshberg, vice president of Stonyfield’s Natural Resources department.

More work needs to be done before the long-term impact is known. Professor Moore’s study was published earlier this year in the Journal of Animal Science.

Reviving American Chestnut Trees May Mitigate Climate Change

ScienceDaily

Monday, June 15, 2009

A Purdue University study shows that introducing a new hybrid of the American chestnut tree would not only bring back the all-but-extinct species, but also put a dent in the amount of carbon in the Earth’s atmosphere.

Douglass Jacobs, an associate professor of forestry and natural resources, found that American chestnuts grow much faster and larger than other hardwood species, allowing them to sequester more carbon than other trees over the same period. And since American chestnut trees are more often used for high-quality hardwood products such as furniture, they hold the carbon longer than wood used for paper or other low-grade materials.

“Maintaining or increasing forest cover has been identified as an important way to slow climate change,” said Jacobs, whose paper was published in the June issue of the journal Forest Ecology and Management. “The American chestnut is an incredibly fast-growing tree. Generally the faster a tree grows, the more carbon it is able to sequester. And when these trees are harvested and processed, the carbon can be stored in the hardwood products for decades, maybe longer.”

At the beginning of the last century, the chestnut blight, caused by a fungus, rapidly spread throughout the American chestnut’s natural range, which extended from southern New England and New York southwest to Alabama. About 50 years ago, the species was nearly gone.

New efforts to hybridize remaining American chestnuts with blight-resistant Chinese chestnuts have resulted in a species that is about 94 percent American chestnut with the protection found in the Chinese species. Jacobs said those new trees could be ready to plant in the next decade, either in existing forests or former agricultural fields that are being returned to forested land.

“We’re really quite close to having a blight-resistant hybrid that can be reintroduced into eastern forests,” Jacobs said. “But because American chestnut has been absent from our forests for so long now, we really don’t know much about the species at all.”

Jacobs studied four sites in southwestern Wisconsin that were unaffected by the blight because they are so far from the tree’s natural range. He compared the American chestnut directly against black walnut and northern red oak at several different ages, and also cross-referenced his results to other studies using quaking aspen, red pine and white pine in the same region.

In each case the American chestnut grew faster, having as much as three times more aboveground biomass than other species at the same point of development. American chestnut also sequestered more carbon than all the others. The only exception was black walnut on one site, but the American chestnut absorbed more carbon on the other study sites.

“Each tree has about the same percentage of its biomass made up of carbon, but the fact that the American chestnut grows faster and larger means it stores more carbon in a shorter amount of time,” Jacobs said.

Jacobs said trees absorb about one-sixth of the carbon emitted globally each year. Increasing the amount that can be absorbed annually could make a considerable difference in slowing climate change, he said.

“This is not the only answer,” Jacobs said. “We need to rely less on fossil fuels and develop alternate forms of energy, but increasing the number of American chestnuts, which store more carbon, can help slow the release of carbon into the atmosphere.”

Carbon dioxide is considered a major greenhouse gas, responsible for rising global temperatures.

Jacobs said that since this study looked at aboveground carbon sequestration, future studies would seek to understand more about how forests that contain American chestnuts store carbon below the ground. The Stry Foundation, Electric Power Research Institute, and Hardwood Tree Improvement and Regeneration Center funded the research.

U.N.: Nature Best at Handling Climate Change

FoxNews.com

Saturday, June 6, 2009

AMSTERDAM — Nature’s way is best for controlling the gases responsible for climate change, the U.N. Environment Program said in a report Friday.

The report said better management of forests, more careful agricultural practices and the restoration of peatlands could soak up significant amounts of carbon dioxide, the most common of the gases blamed for global warming.

“We need to move toward a comprehensive policy framework for addressing ecosystems,” said co-author Barney Dickson, releasing the report at the U.N. climate negotiations in Bonn, Germany.

The event was Webcast worldwide.

Millions of dollars are being invested in research on capturing and burying carbon emissions from power stations, but investing in ecosystems could achieve cheaper results, the report said.

It also would have the added effects of preserving biodiversity, improving water supplies and boosting livelihoods.

Halving deforestation by mid-century and maintaining that lower rate for another 50 years would save the equivalent of five years of carbon emissions at the current level, said Dickson, the agency’s head of climate change and biodiversity.

The loss of peatlands, mainly drained for palm oil and pulp wood plantations in Southeast Asia, contributes 8 percent of global carbon emissions. China could capture about 5 percent of its carbon emissions from burning fossil fuels by returning straw to croplands, it said.

Agriculture has the largest potential for storing carbon if farmers use better techniques, such as avoiding turning over the soil and using natural compost and manure rather than chemical fertilizers, it said.

Report: Agriculture holds the key to solving global warming

Green Right Now
Barbara Kessler
Wednesday, 3 June, 2009

Agriculture, so often cited as a factor in global decline – for claiming natural grasslands that store carbon, soil erosion and pesticide runoff – could become a big part of the solution to global warming, according to a hopeful report by Worldwatch Institute released today.

Innovations in food production and land use that are ready to be put to work could reduce greenhouse gas emissions equivalent to roughly 25 percent of global fossil fuel emissions and be managed to reduce carbon already in the atmosphere as well, according to WWI and Ecoagriculture Partners.

Carbon capture technology remains unproven and will take a decade at least to put into operation. By contrast, agricultural and land use management practices that are ready today could be employed to sequester carbon through photosynthesis by growing and sustaining more plants.

To understand how and why the agricultural approach to climate change must be a part of the solution, the public first needs to recognize that the world must “go negative” with carbon emissions – producing fewer than it churns out to reach the necessary reductions by 2050, said Sara Scherr, co-author with Sajal Sthapit of the report, Mitigating Climate Change Through Food and Land Use.

Policymakers must go beyond improving energy efficiency and scaling up renewables and add ways to pull down emissions from forestry and agriculture operations.

More than 30 percent of all human-caused greenhouse gases are linked to agriculture and land use, notes the report, which rivals the combined emissions of the transportation and industry sectors.

The report outlines five ways to reduce and sequester carbon using farming strategies:

* Enriching soil carbon. Soil, the third largest carbon pool on Earth’s surface, can be managed to reduce greenhouse gas emissions by minimizing tillage, cutting use of nitrogen fertilizers, and preventing erosion. Soils can store a vast amount of additional carbon by building up organic matter and by burying carbon in the form of biochar (biomass burned in a low-oxygen environment).

* Farming with perennials. Two-thirds of all arable land is used to grow annual grains, but there is large potential to substitute these with perennial trees, shrubs, palms, and grasses that produce food, livestock feed, and fuel. These perennials maintain and develop their roots and branches over many years, storing carbon in the vegetation and soil.

* Climate-friendly livestock production. Livestock accounts for nearly half of all greenhouse gas emissions from agriculture and land use. Innovations such as rotational grazing, manure management, methane capture for biogas production, and improved feeds and feed additives can reduce livestock-related emissions.

* Protecting natural habitat. Deforestation, land clearing, and forest and grassland fires are major sources of greenhouse gas emissions. Incentives are needed to encourage farmers, ranchers, and foresters to maintain natural forest and grassland habitats through product certification, payments for climate services, securing tenure rights, and community fire control.

* Restoring degraded watersheds and range lands. Restoring vegetation on vast areas of degraded land can reduce greenhouse gas emissions while making land productive again, protecting critical watersheds, and alleviating rural poverty.

China to Invest $14.6 Billion in Wind Power by 2010

Bloomberg News
John Liu
Tuesday, June 2, 2009

China, the world’s second-biggest energy consumer, will invest about 100 billion yuan ($14.6 billion) to more than double its wind power capacity by 2010 from last year, a government official said.

The country’s wind power capacity will rise to 30,000 megawatts from 12,000 megawatts, Shi Lishan, deputy director of renewable energy at the National Energy Administration, said in Rudong city in the eastern province of Jiangsu today. China’s wind power capacity was the fourth-largest in the world last year, according to Shi.

Investment in alternative energy may exceed 2 trillion yuan by 2020, the National Development and Reform Commission, China’s top economic planner, said in 2007. Wind power is “vital” as it is the cheapest form of renewable energy, Shi said. About 80 percent of the country’s power is produced from coal.

“The on-grid price for wind power is about 0.5 to 0.6 yuan per kilowatt-hour compared with about 0.2 to 0.4 yuan per kilowatt-hour for coal,” Shi told reporters.

China Longyuan Electric Power Group, which accounts for about a quarter of the nation’s wind-power capacity, plans to boost capacity to 6,000 megawatts by next year and to 20,000 megawatts by 2020, Vice President Huang Qun told reporters.

Longyuan, the renewable-energy unit of China Guodian Corp., one of the country’s five state power producers, was capable of generating 2,630 megawatts of electricity using wind turbines last year, he said.

Huang was accompanying a delegation of media, industry and government representatives on a tour of the 100-megawatt Rudong wind farm operated by Longyuan.

Government Spending

The government has allocated 210 billion yuan for energy- saving and carbon-reduction projects under its 4 trillion-yuan economic stimulus package, the planning commission said in May.

China is separately drafting a long-term plan to develop renewable energy to replace coal and oil with cleaner-burning fuels. Details will be released “soon,” Han Wenke, head of energy research at the commission, said last month.

The stimulus plan will accelerate the upgrading of power grids, Shi said today. There will be no new preferential policies for wind power projects, he said.

The Asian nation became the world’s biggest emitter of greenhouse gases from burning fossil fuels in 2006, followed by the U.S., Russia, India and Japan, according to U.S. Department of Energy data on Bloomberg.

Private Investment

China Resources Power Holdings Co., the third-biggest Hong Kong-listed mainland electricity supplier by market value, said today it received government approval for two wind projects in Gansu and Guangdong provinces totaling 221 megawatts in capacity.

It will cost about 8,000 yuan to add 1 kilowatt of wind capacity in China, about 30 to 50 percent less expensive than in Europe, Shi said.

“It normally takes 10 years for local developers to see returns on their investments in wind farms,” Chen Tao, an adviser at China Energy Conservation Wind Power Investment Co., said by mobile phone from Beijing.

The world’s third-largest economy will increase its wind power capacity by fivefold to 100,000 megawatts by 2020 from at least 20,000 megawatts next year to help fight climate change, Zhang Guobao, director of the energy administration, said May 26.

About five megawatts is sufficient to power about 1,000 households in China on average, Hu Zhaoguang, vice president of the State Power Economic Research Institute, said by telephone from Beijing today.

China could pass Europe, Japan and the U.S. to become the world’s biggest renewable energy consumer by 2010, Washington- based researcher WorldWatch Institute said in November 2007.

Water from Melting Greenland Ice Sheath May Impact Northeast US Coast

ENN

Thursday, May 28, 2009

New research by the National Center for Atmospheric Research points to the possibility that water from the melting Greenland Ice Sheath could change oceanic circulation in the North Atlantic, in a way that would raise sea levels off the Northeast by about eight inches more than the average global sea level rise that is expected with global warming.

Results of the study are being published this week in Geophysical Research Letters. They suggest that moderate to high rates of ice melt from Greenland may shift ocean circulation by about 2100, causing sea levels off the northeast coast of North America to rise by about 30 to 51 centimeters (12 to 20 inches) more than other coastal areas.

The research builds on recent reports that have found that sea level rise could adversely affect North America, and its findings suggest that the situation is even more urgent than previously believed.

“If the Greenland melt continues to accelerate, we could see significant impacts this century on the northeast U.S. coast from the resulting sea level rise,” says scientist Aixue Hu, the paper’s lead author. Hu is at the National Center for Atmospheric Research (NCAR) in Boulder, Colo. “Major northeastern cities are directly in the path of the greatest rise.”
To assess the impact of Greenland ice melt on ocean circulation, Hu and his coauthors used the Community Climate System Model, an NCAR-based computer model that simulates global climate.

They considered three scenarios: the melt rate continuing to increase by 7 percent a year, as has been the case in recent years, or the melt rate slowing down to an increase of either 1 or 3 percent a year.

If Greenland’s melt rate slows down to a 3 percent annual increase, the study team’s computer simulations indicate that the runoff from its ice sheet could alter ocean circulation in a way that would direct about a foot of water toward the northeast coast of North America by 2100.

This would be on top of the average global sea level rise expected as a result of global warming. Although the study team did not try to estimate that mean global sea level rise, their simulations indicated that melt from Greenland alone under the 3 percent scenario could raise sea levels by an average of 53 centimeters (21 inches).

If the annual increase in the melt rate dropped to 1 percent, the runoff would not raise northeastern sea levels by more than the 8 inches found in the earlier study in Nature Geoscience.

But if the melt rate continued at its present 7 percent increase per year through 2050 and then leveled off, the study suggests that the northeast coast could see as much as 51 centimeters (20 inches) of sea level rise above a global average that could be several feet.

While this scenario is considered unlikely, the science of oceanic circulation modeling is a rapidly developing field, and future efforts will undoubtedly produce addtitional scenarios to consider.

Climate Change Odds Much Worse Than Thought

Science Daily

Wednesday, May 20, 2009

The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth’s climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago – and could be even worse than that.

The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well – such as the degree of economic growth, with its associated energy use, in different countries.

Study co-author Ronald Prinn, the co-director of the Joint Program and director of MIT’s Center for Global Change Science, says that, regarding global warming, it is important “to base our opinions and policies on the peer-reviewed science,” he says. And in the peer-reviewed literature, the MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems. “In that sense, our work is unique,” he says.

The new projections, published this month in the American Meteorological Society’s Journal of Climate, indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the 2003 study of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.

Prinn says these and a variety of other changes based on new measurements and new analyses changed the odds on what could be expected in this century in the “no policy” scenarios – that is, where there are no policies in place that specifically induce reductions in greenhouse gas emissions. Overall, the changes “unfortunately largely summed up all in the same direction,” he says. “Overall, they stacked up so they caused more projected global warming.”

While the outcomes in the “no policy” projections now look much worse than before, there is less change from previous work in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions. Without action, “there is significantly more risk than we previously estimated,” Prinn says. “This increases the urgency for significant policy action.”

To illustrate the range of probabilities revealed by the 400 simulations, Prinn and the team produced a “roulette wheel” that reflects the latest relative odds of various levels of temperature rise. The wheel provides a very graphic representation of just how serious the potential climate impacts are.

“There’s no way the world can or should take these risks,” Prinn says. And the odds indicated by this modeling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur, for example, if increased temperatures caused a large-scale melting of permafrost in arctic regions and subsequent release of large quantities of methane, a very potent greenhouse gas. Including that feedback “is just going to make it worse,” Prinn says.

The lead author of the paper describing the new projections is Andrei Sokolov, research scientist in the Joint Program. Other authors, besides Sokolov and Prinn, include Peter H. Stone, Chris E. Forest, Sergey Paltsev, Adam Schlosser, Stephanie Dutkiewicz, John Reilly, Marcus Sarofim, Chien Wang and Henry D. Jacoby, all of the MIT Joint Program on the Science and Policy of Global Change, as well as Mort Webster of MIT’s Engineering Systems Division and D. Kicklighter, B. Felzer and J. Melillo of the Marine Biological Laboratory at Woods Hole.

Prinn stresses that the computer models are built to match the known conditions, processes and past history of the relevant human and natural systems, and the researchers are therefore dependent on the accuracy of this current knowledge. Beyond this, “we do the research, and let the results fall where they may,” he says. Since there are so many uncertainties, especially with regard to what human beings will choose to do and how large the climate response will be, “we don’t pretend we can do it accurately. Instead, we do these 400 runs and look at the spread of the odds.”

Because vehicles last for years, and buildings and powerplants last for decades, it is essential to start making major changes through adoption of significant national and international policies as soon as possible, Prinn says. “The least-cost option to lower the risk is to start now and steadily transform the global energy system over the coming decades to low or zero greenhouse gas-emitting technologies.”

This work was supported in part by grants from the Office of Science of the U.S. Dept. of Energy, and by the industrial and foundation sponsors of the MIT Joint Program on the Science and Policy of Global Change.