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“It’s a rapid and catastrophic way you could completely change everything.” As Permafrost Thaws, Scientists Study the Risks

Temperature Rising

As Permafrost Thaws, Scientists Study the Risks

Katey M. Walter Anthony, a scientist, investigated a plume of methane, a greenhouse gas, at an Alaskan lake. Dr. Walter Anthony is a leading researcher in studying the escape of methane. More Photos »

By JUSTIN GILLIS

Published: December 16, 2011

FAIRBANKS, Alaska — A bubble rose through a hole in the surface of a frozen lake. It popped, followed by another, and another, as if a pot were somehow boiling in the icy depths.

Every bursting bubble sent up a puff of methane, a powerful greenhouse gas generated beneath the lake from the decay of plant debris. These plants last saw the light of day 30,000 years ago and have been locked in a deep freeze — until now.

“That’s a hot spot,” declared Katey M. Walter Anthony, a leading scientist in studying the escape of methane. A few minutes later, she leaned perilously over the edge of the ice, plunging a bottle into the water to grab a gas sample.

It was another small clue for scientists struggling to understand one of the biggest looming mysteries about the future of the earth.

Experts have long known that northern lands were a storehouse of frozen carbon, locked up in the form of leaves, roots and other organic matter trapped in icy soil — a mix that, when thawed, can produce methane and carbon dioxide, gases that trap heat and warm the planet. But they have been stunned in recent years to realize just how much organic debris is there.

A recent estimate suggests that the perennially frozen ground known as permafrost, which underlies nearly a quarter of the Northern Hemisphere, contains twice as much carbon as the entire atmosphere.

Temperatures are warming across much of that region, primarily, scientists believe, because of the rapid human release of greenhouse gases. Permafrost is warming, too. Some has already thawed, and other signs are emerging that the frozen carbon may be becoming unstable.

“It’s like broccoli in your freezer,” said Kevin Schaefer, a scientist at the National Snow and Ice Data Center in Boulder, Colo. “As long as the broccoli stays in the freezer, it’s going to be O.K. But once you take it out of the freezer and put it in the fridge, it will thaw out and eventually decay.”

If a substantial amount of the carbon should enter the atmosphere, it would intensify the planetary warming. An especially worrisome possibility is that a significant proportion will emerge not as carbon dioxide, the gas that usually forms when organic material breaks down, but as methane, produced when the breakdown occurs in lakes or wetlands. Methane is especially potent at trapping the sun’s heat, and the potential for large new methane emissions in the Arctic is one of the biggest wild cards in climate science.

Scientists have declared that understanding the problem is a major priority. The United States Department of Energy and the European Union recently committed to new projects aimed at doing so, and NASA is considering a similar plan. But researchers say the money and people devoted to the issue are still minimal compared with the risk.

For now, scientists have many more questions than answers. Preliminary computer analyses, made only recently, suggest that the Arctic and sub-Arctic regions could eventually become an annual source of carbon equal to 15 percent or so of today’s yearly emissions from human activities.

But those calculations were deliberately cautious. A recent survey drew on the expertise of 41 permafrost scientists to offer more informal projections. They estimated that if human fossil-fuel burning remained high and the planet warmed sharply, the gases from permafrost could eventually equal 35 percent of today’s annual human emissions.

The experts also said that if humanity began getting its own emissions under control soon, the greenhouse gases emerging from permafrost could be kept to a much lower level, perhaps equivalent to 10 percent of today’s human emissions.

Even at the low end, these numbers mean that the long-running international negotiations over greenhouse gases are likely to become more difficult, with less room for countries to continue burning large amounts of fossil fuels.

In the minds of most experts, the chief worry is not that the carbon in the permafrost will break down quickly — typical estimates say that will take more than a century, perhaps several — but that once the decomposition starts, it will be impossible to stop.

A troubling trend has emerged recently: Wildfires are increasing across much of the north, and early research suggests that extensive burning could lead to a more rapid thaw of permafrost.

(Page 2 of 4)

“Even if it’s 5 or 10 percent of today’s emissions, it’s exceptionally worrying, and 30 percent is humongous,” said Josep G. Canadell, a scientist in Australia who runs a global program to monitor greenhouse gases. “It will be a chronic source of emissions that will last hundreds of years.”

Rise and Fall of Permafrost

Standing on a bluff the other day, overlooking an immense river valley, A. David McGuire, a scientist from the University of Alaska, Fairbanks, sketched out two million years of the region’s history. It was the peculiar geology of western North America and eastern Siberia, he said, that caused so much plant debris to get locked in an ice box there.

These areas were not covered in glaciers during the last ice age, but the climate was frigid, with powerful winds. The winds and rivers carried immense volumes of silt and dust that settled in the lowlands of Alaska and Siberia.

A thin layer of this soil thawed on top during the summers and grasses grew, capturing carbon dioxide. In the bitter winters, grass roots, leaves and even animal parts froze before they could decompose. Layer after layer of permafrost built up.

At the peak of the ice age, 20,000 years ago, the frozen ground was more extensive than today, stretching deep into parts of the lower 48 states that were not covered by ice sheets. Climate-change contrarians like to point to that history, contending that any melting of permafrost and ice sheets today is simply the tail end of the ice age.

Citing permafrost temperatures for northern Alaska — which, though rising rapidly, remain well below freezing — an organization called the Center for the Study of Carbon Dioxide and Global Change claimed that permafrost is in “no more danger of being wiped out any time soon than it was in the days of our great-grandparents.”

But mainstream scientists, while hoping the breakdown of permafrost will indeed be slow, reject that argument. They say the climate was reasonably stable for the past 10,000 years or so, during the period when human civilization arose. Now, as people burn immense amounts of carbon in the form of fossil fuels, the planet’s temperature is rising, and the Arctic is warming twice as fast. That, scientists say, puts the remaining permafrost deposits at risk.

For several decades, researchers have been monitoring permafrost temperatures in hundreds of boreholes across the north. The temperatures have occasionally decreased in some regions for periods as long as a decade, but the overall trend has been a relentless rise, with temperatures now increasing fastest in the most northerly areas.

Thawing has been most notable at the southern margins. Across huge areas, including much of central Alaska, permafrost is hovering just below the freezing point, and is expected to start thawing in earnest as soon as the 2020s. In northern Alaska and northern Siberia, where permafrost is at least 12 degrees Fahrenheit below freezing, experts say it should take longer.

“Even in a greenhouse-warmed world, it will still get cold and dark in the Arctic in the winter,” said Mark Serreze, director of the snow and ice data center in Boulder.

Scientists need better inventories of the ancient carbon. The best estimate so far was published in 2009 by a Canadian scientist, Charles Tarnocai, and some colleagues. They calculated that there was about 1.7 trillion tons of carbon in soils of the northern regions, about 88 percent of it locked in permafrost. That is about two and a half times the amount of carbon in the atmosphere.

Philippe Ciais, a leading French scientist, wrote at the time that he was “stunned” by the estimate, a large upward revision from previous calculations.

“If, in a warmer world, bacteria decompose organic soil matter faster, releasing carbon dioxide,” Dr. Ciais wrote, “this will set up a positive feedback loop, speeding up global warming.”

(Page 3 of 4)

As a young researcher at the University of Alaska, Fairbanks, she wanted to figure out how much of that gas was escaping from lakes in areas of permafrost thaw. She was doing field work in Siberia in 2000, scattering bubble traps around various lakes in the summer, but she got almost nothing.

Plumes of Methane

Katey Walter Anthony had been told to hunt for methane, and she could not find it.

Then, that October, the lakes froze over. Plumes of methane that had been hard to spot on a choppy lake surface in summer suddenly became more visible.

“I went out on the ice, this black ice, and it looked like the starry night sky,” Dr. Walter Anthony said. “You could see these bubble clusters everywhere. I realized — ‘aha!’ — this is where all the methane is.”

When organic material comes out of the deep freeze, it is consumed by bacteria. If the material is well-aerated, bacteria that breathe oxygen will perform the breakdown, and the carbon will enter the air as carbon dioxide, the primary greenhouse gas. But in areas where oxygen is limited, like the bottom of a lake or wetland, a group of bacteria called methanogens will break down the organic material, and the carbon will emerge as methane.

Scientists are worried about both gases. They believe that most of the carbon will emerge as carbon dioxide, with only a few percent of it being converted to methane. But because methane is such a potent greenhouse gas, the 41 experts in the recent survey predicted that it would trap about as much heat as the carbon dioxide would.

Dr. Walter Anthony’s seminal discovery was that methane rose from lake bottoms not as diffuse leaks, as many scientists had long assumed, but in a handful of scattered, vigorous plumes, some of them capable of putting out many quarts of gas per day. In certain lakes they accounted for most of the emerging methane, but previous research had not taken them into consideration. That meant big upward revisions were probably needed in estimates of the amount of methane lakes might emit as permafrost thawed.

Most of the lakes Dr. Walter Anthony studies were formed by a peculiar mechanism. Permafrost that is frozen hard supports the ground surface, almost the way a concrete pillar supports a building. But when thaw begins, the ground sometimes turns to mush and the entire land surface collapses into a low-lying area, known as a thermokarst. A lake or wetland can form there, with the dark surface of the water capturing the sun’s heat and causing still more permafrost to thaw nearby.

Near thermokarst locations, trees often lean crazily because their roots are disturbed by the rapid changes in the underlying landscape, creating “drunken forests.” And the thawing, as it feeds on itself, frees up more and more ancient plant debris.

One recent day, in 11-degree weather, Dr. Walter Anthony and an assistant, Amy Strohm, dragged equipment onto two frozen thermokarst lakes near Fairbanks. The fall had been unusually warm and the ice was thin, emitting thunderous cracks — but it held. In spots, methane bubbled so vigorously it had prevented the water from freezing. Dr. Walter Anthony, six months pregnant, bent over one plume to retrieve samples.

“This is thinner ice than we like,” she said. “Don’t tell my mother-in-law! My own mother doesn’t know.”

Dr. Walter Anthony had already run chemical tests on the methane from one of the lakes, dating the carbon molecules within the gas to 30,000 years ago. She has found carbon that old emerging at numerous spots around Fairbanks, and carbon as old as 43,000 years emerging from lakes in Siberia.

“These grasses were food for mammoths during the end of the last ice age,” Dr. Walter Anthony said. “It was in the freezer for 30,000 to 40,000 years, and now the freezer door is open.”

Scientists are not sure yet whether thermokarst lakes will become more common throughout the Arctic in a warming climate, a development that could greatly accelerate permafrost thaw and methane production. But they have already started to see increases in some regions, including northernmost Alaska.

(Page 4 of 4)

“We expect increased thermokarst activity could be a very strong effect, but we don’t really know,” said Guido Grosse, another scientist at the University of Alaska, Fairbanks. He is working with Dr. Walter Anthony on precision mapping of thermokarst lakes and methane seeps, in the hope that the team can ultimately use satellites and aerial photography to detect trends.

With this kind of work still in the early stages, researchers are worried that the changes in the region may already be outrunning their ability to understand them, or to predict what will happen.

When the Tundra Burns

One day in 2007, on the plain in northern Alaska, a lightning strike set the tundra on fire.

Historically, tundra, a landscape of lichens, mosses and delicate plants, was too damp to burn. But the climate in the area is warming and drying, and fires in both the tundra and forest regions of Alaska are increasing.

The Anaktuvuk River fire burned about 400 square miles of tundra, and work on lake sediments showed that no fire of that scale had occurred in the region in at least 5,000 years.

Scientists have calculated that the fire and its aftermath sent a huge pulse of carbon into the air — as much as would be emitted in two years by a city the size of Miami. Scientists say the fire thawed the upper layer of permafrost and set off what they fear will be permanent shifts in the landscape.

Up to now, the Arctic has been absorbing carbon, on balance, and was once expected to keep doing so throughout this century. But recent analyses suggest that the permafrost thaw could turn the Arctic into a net source of carbon, possibly within a decade or two, and those studies did not account for fire.

“I maintain that the fastest way you’re going to lose permafrost and release permafrost carbon to the atmosphere is increasing fire frequency,” said Michelle C. Mack, a University of Florida scientist who is studying the Anaktuvuk fire. “It’s a rapid and catastrophic way you could completely change everything.”

The essential question scientists need to answer is whether the many factors they do not yet understand could speed the release of carbon from permafrost — or, possibly, slow it more than they expect.

For instance, nutrients released from thawing permafrost could spur denser plant growth in the Arctic, and the plants would take up some carbon dioxide. Conversely, should fires like the one at Anaktuvuk River race across warming northern landscapes, immense amounts of organic material in vegetation, soils, peat deposits and thawed permafrost could burn.

Edward A. G. Schuur, a University of Florida researcher who has done extensive field work in Alaska, is worried by the changes he already sees, including the discovery that carbon buried since before the dawn of civilization is now escaping.

“To me, it’s a spine-tingling feeling, if it’s really old carbon that hasn’t been in the air for a long time, and now it’s entering the air,” Dr. Schuur said. “That’s the fingerprint of a major disruption, and we aren’t going to be able to turn it off someday.”

“It’s a rapid and catastrophic way you could completely change everything.” As Permafrost Thaws, Scientists Study the Risks

Temperature Rising

As Permafrost Thaws, Scientists Study the Risks

Katey M. Walter Anthony, a scientist, investigated a plume of methane, a greenhouse gas, at an Alaskan lake. Dr. Walter Anthony is a leading researcher in studying the escape of methane. More Photos »

By JUSTIN GILLIS

Published: December 16, 2011

FAIRBANKS, Alaska — A bubble rose through a hole in the surface of a frozen lake. It popped, followed by another, and another, as if a pot were somehow boiling in the icy depths.

Every bursting bubble sent up a puff of methane, a powerful greenhouse gas generated beneath the lake from the decay of plant debris. These plants last saw the light of day 30,000 years ago and have been locked in a deep freeze — until now.

“That’s a hot spot,” declared Katey M. Walter Anthony, a leading scientist in studying the escape of methane. A few minutes later, she leaned perilously over the edge of the ice, plunging a bottle into the water to grab a gas sample.

It was another small clue for scientists struggling to understand one of the biggest looming mysteries about the future of the earth.

Experts have long known that northern lands were a storehouse of frozen carbon, locked up in the form of leaves, roots and other organic matter trapped in icy soil — a mix that, when thawed, can produce methane and carbon dioxide, gases that trap heat and warm the planet. But they have been stunned in recent years to realize just how much organic debris is there.

A recent estimate suggests that the perennially frozen ground known as permafrost, which underlies nearly a quarter of the Northern Hemisphere, contains twice as much carbon as the entire atmosphere.

Temperatures are warming across much of that region, primarily, scientists believe, because of the rapid human release of greenhouse gases. Permafrost is warming, too. Some has already thawed, and other signs are emerging that the frozen carbon may be becoming unstable.

“It’s like broccoli in your freezer,” said Kevin Schaefer, a scientist at the National Snow and Ice Data Center in Boulder, Colo. “As long as the broccoli stays in the freezer, it’s going to be O.K. But once you take it out of the freezer and put it in the fridge, it will thaw out and eventually decay.”

If a substantial amount of the carbon should enter the atmosphere, it would intensify the planetary warming. An especially worrisome possibility is that a significant proportion will emerge not as carbon dioxide, the gas that usually forms when organic material breaks down, but as methane, produced when the breakdown occurs in lakes or wetlands. Methane is especially potent at trapping the sun’s heat, and the potential for large new methane emissions in the Arctic is one of the biggest wild cards in climate science.

Scientists have declared that understanding the problem is a major priority. The United States Department of Energy and the European Union recently committed to new projects aimed at doing so, and NASA is considering a similar plan. But researchers say the money and people devoted to the issue are still minimal compared with the risk.

For now, scientists have many more questions than answers. Preliminary computer analyses, made only recently, suggest that the Arctic and sub-Arctic regions could eventually become an annual source of carbon equal to 15 percent or so of today’s yearly emissions from human activities.

But those calculations were deliberately cautious. A recent survey drew on the expertise of 41 permafrost scientists to offer more informal projections. They estimated that if human fossil-fuel burning remained high and the planet warmed sharply, the gases from permafrost could eventually equal 35 percent of today’s annual human emissions.

The experts also said that if humanity began getting its own emissions under control soon, the greenhouse gases emerging from permafrost could be kept to a much lower level, perhaps equivalent to 10 percent of today’s human emissions.

Even at the low end, these numbers mean that the long-running international negotiations over greenhouse gases are likely to become more difficult, with less room for countries to continue burning large amounts of fossil fuels.

In the minds of most experts, the chief worry is not that the carbon in the permafrost will break down quickly — typical estimates say that will take more than a century, perhaps several — but that once the decomposition starts, it will be impossible to stop.

A troubling trend has emerged recently: Wildfires are increasing across much of the north, and early research suggests that extensive burning could lead to a more rapid thaw of permafrost.

(Page 2 of 4)

“Even if it’s 5 or 10 percent of today’s emissions, it’s exceptionally worrying, and 30 percent is humongous,” said Josep G. Canadell, a scientist in Australia who runs a global program to monitor greenhouse gases. “It will be a chronic source of emissions that will last hundreds of years.”

Rise and Fall of Permafrost

Standing on a bluff the other day, overlooking an immense river valley, A. David McGuire, a scientist from the University of Alaska, Fairbanks, sketched out two million years of the region’s history. It was the peculiar geology of western North America and eastern Siberia, he said, that caused so much plant debris to get locked in an ice box there.

These areas were not covered in glaciers during the last ice age, but the climate was frigid, with powerful winds. The winds and rivers carried immense volumes of silt and dust that settled in the lowlands of Alaska and Siberia.

A thin layer of this soil thawed on top during the summers and grasses grew, capturing carbon dioxide. In the bitter winters, grass roots, leaves and even animal parts froze before they could decompose. Layer after layer of permafrost built up.

At the peak of the ice age, 20,000 years ago, the frozen ground was more extensive than today, stretching deep into parts of the lower 48 states that were not covered by ice sheets. Climate-change contrarians like to point to that history, contending that any melting of permafrost and ice sheets today is simply the tail end of the ice age.

Citing permafrost temperatures for northern Alaska — which, though rising rapidly, remain well below freezing — an organization called the Center for the Study of Carbon Dioxide and Global Change claimed that permafrost is in “no more danger of being wiped out any time soon than it was in the days of our great-grandparents.”

But mainstream scientists, while hoping the breakdown of permafrost will indeed be slow, reject that argument. They say the climate was reasonably stable for the past 10,000 years or so, during the period when human civilization arose. Now, as people burn immense amounts of carbon in the form of fossil fuels, the planet’s temperature is rising, and the Arctic is warming twice as fast. That, scientists say, puts the remaining permafrost deposits at risk.

For several decades, researchers have been monitoring permafrost temperatures in hundreds of boreholes across the north. The temperatures have occasionally decreased in some regions for periods as long as a decade, but the overall trend has been a relentless rise, with temperatures now increasing fastest in the most northerly areas.

Thawing has been most notable at the southern margins. Across huge areas, including much of central Alaska, permafrost is hovering just below the freezing point, and is expected to start thawing in earnest as soon as the 2020s. In northern Alaska and northern Siberia, where permafrost is at least 12 degrees Fahrenheit below freezing, experts say it should take longer.

“Even in a greenhouse-warmed world, it will still get cold and dark in the Arctic in the winter,” said Mark Serreze, director of the snow and ice data center in Boulder.

Scientists need better inventories of the ancient carbon. The best estimate so far was published in 2009 by a Canadian scientist, Charles Tarnocai, and some colleagues. They calculated that there was about 1.7 trillion tons of carbon in soils of the northern regions, about 88 percent of it locked in permafrost. That is about two and a half times the amount of carbon in the atmosphere.

Philippe Ciais, a leading French scientist, wrote at the time that he was “stunned” by the estimate, a large upward revision from previous calculations.

“If, in a warmer world, bacteria decompose organic soil matter faster, releasing carbon dioxide,” Dr. Ciais wrote, “this will set up a positive feedback loop, speeding up global warming.”

(Page 3 of 4)

As a young researcher at the University of Alaska, Fairbanks, she wanted to figure out how much of that gas was escaping from lakes in areas of permafrost thaw. She was doing field work in Siberia in 2000, scattering bubble traps around various lakes in the summer, but she got almost nothing.

Plumes of Methane

Katey Walter Anthony had been told to hunt for methane, and she could not find it.

Then, that October, the lakes froze over. Plumes of methane that had been hard to spot on a choppy lake surface in summer suddenly became more visible.

“I went out on the ice, this black ice, and it looked like the starry night sky,” Dr. Walter Anthony said. “You could see these bubble clusters everywhere. I realized — ‘aha!’ — this is where all the methane is.”

When organic material comes out of the deep freeze, it is consumed by bacteria. If the material is well-aerated, bacteria that breathe oxygen will perform the breakdown, and the carbon will enter the air as carbon dioxide, the primary greenhouse gas. But in areas where oxygen is limited, like the bottom of a lake or wetland, a group of bacteria called methanogens will break down the organic material, and the carbon will emerge as methane.

Scientists are worried about both gases. They believe that most of the carbon will emerge as carbon dioxide, with only a few percent of it being converted to methane. But because methane is such a potent greenhouse gas, the 41 experts in the recent survey predicted that it would trap about as much heat as the carbon dioxide would.

Dr. Walter Anthony’s seminal discovery was that methane rose from lake bottoms not as diffuse leaks, as many scientists had long assumed, but in a handful of scattered, vigorous plumes, some of them capable of putting out many quarts of gas per day. In certain lakes they accounted for most of the emerging methane, but previous research had not taken them into consideration. That meant big upward revisions were probably needed in estimates of the amount of methane lakes might emit as permafrost thawed.

Most of the lakes Dr. Walter Anthony studies were formed by a peculiar mechanism. Permafrost that is frozen hard supports the ground surface, almost the way a concrete pillar supports a building. But when thaw begins, the ground sometimes turns to mush and the entire land surface collapses into a low-lying area, known as a thermokarst. A lake or wetland can form there, with the dark surface of the water capturing the sun’s heat and causing still more permafrost to thaw nearby.

Near thermokarst locations, trees often lean crazily because their roots are disturbed by the rapid changes in the underlying landscape, creating “drunken forests.” And the thawing, as it feeds on itself, frees up more and more ancient plant debris.

One recent day, in 11-degree weather, Dr. Walter Anthony and an assistant, Amy Strohm, dragged equipment onto two frozen thermokarst lakes near Fairbanks. The fall had been unusually warm and the ice was thin, emitting thunderous cracks — but it held. In spots, methane bubbled so vigorously it had prevented the water from freezing. Dr. Walter Anthony, six months pregnant, bent over one plume to retrieve samples.

“This is thinner ice than we like,” she said. “Don’t tell my mother-in-law! My own mother doesn’t know.”

Dr. Walter Anthony had already run chemical tests on the methane from one of the lakes, dating the carbon molecules within the gas to 30,000 years ago. She has found carbon that old emerging at numerous spots around Fairbanks, and carbon as old as 43,000 years emerging from lakes in Siberia.

“These grasses were food for mammoths during the end of the last ice age,” Dr. Walter Anthony said. “It was in the freezer for 30,000 to 40,000 years, and now the freezer door is open.”

Scientists are not sure yet whether thermokarst lakes will become more common throughout the Arctic in a warming climate, a development that could greatly accelerate permafrost thaw and methane production. But they have already started to see increases in some regions, including northernmost Alaska.

(Page 4 of 4)

“We expect increased thermokarst activity could be a very strong effect, but we don’t really know,” said Guido Grosse, another scientist at the University of Alaska, Fairbanks. He is working with Dr. Walter Anthony on precision mapping of thermokarst lakes and methane seeps, in the hope that the team can ultimately use satellites and aerial photography to detect trends.

With this kind of work still in the early stages, researchers are worried that the changes in the region may already be outrunning their ability to understand them, or to predict what will happen.

When the Tundra Burns

One day in 2007, on the plain in northern Alaska, a lightning strike set the tundra on fire.

Historically, tundra, a landscape of lichens, mosses and delicate plants, was too damp to burn. But the climate in the area is warming and drying, and fires in both the tundra and forest regions of Alaska are increasing.

The Anaktuvuk River fire burned about 400 square miles of tundra, and work on lake sediments showed that no fire of that scale had occurred in the region in at least 5,000 years.

Scientists have calculated that the fire and its aftermath sent a huge pulse of carbon into the air — as much as would be emitted in two years by a city the size of Miami. Scientists say the fire thawed the upper layer of permafrost and set off what they fear will be permanent shifts in the landscape.

Up to now, the Arctic has been absorbing carbon, on balance, and was once expected to keep doing so throughout this century. But recent analyses suggest that the permafrost thaw could turn the Arctic into a net source of carbon, possibly within a decade or two, and those studies did not account for fire.

“I maintain that the fastest way you’re going to lose permafrost and release permafrost carbon to the atmosphere is increasing fire frequency,” said Michelle C. Mack, a University of Florida scientist who is studying the Anaktuvuk fire. “It’s a rapid and catastrophic way you could completely change everything.”

The essential question scientists need to answer is whether the many factors they do not yet understand could speed the release of carbon from permafrost — or, possibly, slow it more than they expect.

For instance, nutrients released from thawing permafrost could spur denser plant growth in the Arctic, and the plants would take up some carbon dioxide. Conversely, should fires like the one at Anaktuvuk River race across warming northern landscapes, immense amounts of organic material in vegetation, soils, peat deposits and thawed permafrost could burn.

Edward A. G. Schuur, a University of Florida researcher who has done extensive field work in Alaska, is worried by the changes he already sees, including the discovery that carbon buried since before the dawn of civilization is now escaping.

“To me, it’s a spine-tingling feeling, if it’s really old carbon that hasn’t been in the air for a long time, and now it’s entering the air,” Dr. Schuur said. “That’s the fingerprint of a major disruption, and we aren’t going to be able to turn it off someday.”

WinterBike

WinterBike

Rio de Janeiro - Aproveite o novo sistema de aluguel de bicicletas e passeie pela Cidade Maravilhosa

Recortado por belezas naturais de todos os tipos, o Rio de Janeiro é propício a passeios mais longos e contemplativos. E nada melhor para apreciar os encantos da cidade do que um bom passeio de bicicleta pelos dos 250 km de ciclovias

Recortado por belezas naturais de todos os tipos, o Rio de Janeiro é propício a passeios mais longos e contemplativos. E nada melhor para apreciar os encantos da cidade do que um bom passeio de bicicleta. Com cerca de 250 km de ciclovias, ciclofaixas e faixas compartilhadas em sua malha urbana, o Rio de Janeiro é hoje líder no Brasil em extensão de ciclovias construídas. Além de ser um ótimo exercício físico, andar de bicicleta contribui para diminuir a quantidade de carros nas ruas, o que evita a emissão de gases poluentes na atmosfera e melhora as condições de trânsito.

As ciclovias estão presentes em quase toda a orla do Rio, sendo acompanhadas pelas belas paisagens das praias cariocas. Em outros locais da cidade, como os bairros do Jardim Botânico e Gávea, há também trechos de faixas compartilhadas, nas quais as bicicletas dividem espaço com pedestres ou veículos automotores. Pontos turísticos como o Estádio do Maracanã e a Floresta da Tijuca também oferecem essas vias de transporte alternativo. Para o turista que não pode trazer sua bicicleta na mala, há várias lojas na cidade especializadas em aluguel de bicicletas, como a Bike e Lazer, em Ipanema, ou a Ciclo Port, na Barra da Tijuca. A retirada é feita no local, assim como a devolução da bicicleta. As formas de pagamento são dinheiro e cartão.

Também vale ressaltar que o Metrô Rio reserva 206 vagas para bicicletas em algumas estações e autoriza o embarque no último vagão dos trens aos sábados, domingos e feriados, sem restrição de horário. A companhia Barcas S/A também autoriza o embarque de bicicletas nos finais de semana sem cobrança extra.

Confira o que você não pode esquecer no seu passeio de bicicleta:
- Use roupas leves e confortáveis;
- Não se esqueça de passar o protetor solar, principalmente em passeios pela orla;
- Beba muita água e faça antes uma refeição leve;
- Não se esqueça da máquina fotográfica para registrar o passeio;
- Segurança também é um fator importante. Equipamentos como luvas e capacetes, além de refletores e espelhos retrovisores, são de extrema relevância para um passeio agradável.

Serviço
Bike e Lazer
• Ipanema: Rua Visconde de Pirajá 135 loja B - Tel. 2267-7778 - Próximo à Praça General Osório
• Laranjeiras: Rua das Laranjeiras 58 loja A - Tel. 2285-7941 - Próximo ao Largo do Machado.

Ciclo Port
Av. Sernambetiba, 17.610 - loja A (em frente ao posto 11) - Recreio dos Bandeirantes - Tel. 3328-7581

Fonte: Rio Guia Oficial

Rio de Janeiro - Aproveite o novo sistema de aluguel de bicicletas e passeie pela Cidade Maravilhosa

Recortado por belezas naturais de todos os tipos, o Rio de Janeiro é propício a passeios mais longos e contemplativos. E nada melhor para apreciar os encantos da cidade do que um bom passeio de bicicleta pelos dos 250 km de ciclovias

Recortado por belezas naturais de todos os tipos, o Rio de Janeiro é propício a passeios mais longos e contemplativos. E nada melhor para apreciar os encantos da cidade do que um bom passeio de bicicleta. Com cerca de 250 km de ciclovias, ciclofaixas e faixas compartilhadas em sua malha urbana, o Rio de Janeiro é hoje líder no Brasil em extensão de ciclovias construídas. Além de ser um ótimo exercício físico, andar de bicicleta contribui para diminuir a quantidade de carros nas ruas, o que evita a emissão de gases poluentes na atmosfera e melhora as condições de trânsito.

As ciclovias estão presentes em quase toda a orla do Rio, sendo acompanhadas pelas belas paisagens das praias cariocas. Em outros locais da cidade, como os bairros do Jardim Botânico e Gávea, há também trechos de faixas compartilhadas, nas quais as bicicletas dividem espaço com pedestres ou veículos automotores. Pontos turísticos como o Estádio do Maracanã e a Floresta da Tijuca também oferecem essas vias de transporte alternativo. Para o turista que não pode trazer sua bicicleta na mala, há várias lojas na cidade especializadas em aluguel de bicicletas, como a Bike e Lazer, em Ipanema, ou a Ciclo Port, na Barra da Tijuca. A retirada é feita no local, assim como a devolução da bicicleta. As formas de pagamento são dinheiro e cartão.

Também vale ressaltar que o Metrô Rio reserva 206 vagas para bicicletas em algumas estações e autoriza o embarque no último vagão dos trens aos sábados, domingos e feriados, sem restrição de horário. A companhia Barcas S/A também autoriza o embarque de bicicletas nos finais de semana sem cobrança extra.

Confira o que você não pode esquecer no seu passeio de bicicleta:
- Use roupas leves e confortáveis;
- Não se esqueça de passar o protetor solar, principalmente em passeios pela orla;
- Beba muita água e faça antes uma refeição leve;
- Não se esqueça da máquina fotográfica para registrar o passeio;
- Segurança também é um fator importante. Equipamentos como luvas e capacetes, além de refletores e espelhos retrovisores, são de extrema relevância para um passeio agradável.

Serviço
Bike e Lazer
• Ipanema: Rua Visconde de Pirajá 135 loja B - Tel. 2267-7778 - Próximo à Praça General Osório
• Laranjeiras: Rua das Laranjeiras 58 loja A - Tel. 2285-7941 - Próximo ao Largo do Machado.

Ciclo Port
Av. Sernambetiba, 17.610 - loja A (em frente ao posto 11) - Recreio dos Bandeirantes - Tel. 3328-7581

Fonte: Rio Guia Oficial

Ministros dinamarqueses se apresentam de bicicleta

Primeiro mundo é outra coisa. As ações e diferenças são vistas de forma simples, que resultam em grandes exemplos para própria sociedade. Feliz quem mora na Dinamarca, um país que vem mostrando grandes exemplos ao uso da bicicleta, começando pelos seus governantes.

No primeiro dia de trabalho do ano, a Primeira Ministra do país e todos os ministros do Partido Liberal chegaram pedalando. Um exemplo que nenhuma comitiva do mundo teria coragem de realizar.

São estas ações que fazem da Dinamarca o país número um das bicicletas, à frente da Holanda e anos luz do Brasil. Paciência!

Confira o vídeo abaixo e considere apenas os 15 segundos iniciais (chegada dos políticos com as magrelas), pois o restante faz parte da cerimônia de apresentação - tradição no país.

Ministros dinamarqueses se apresentam de bicicleta

Primeiro mundo é outra coisa. As ações e diferenças são vistas de forma simples, que resultam em grandes exemplos para própria sociedade. Feliz quem mora na Dinamarca, um país que vem mostrando grandes exemplos ao uso da bicicleta, começando pelos seus governantes.

No primeiro dia de trabalho do ano, a Primeira Ministra do país e todos os ministros do Partido Liberal chegaram pedalando. Um exemplo que nenhuma comitiva do mundo teria coragem de realizar.

São estas ações que fazem da Dinamarca o país número um das bicicletas, à frente da Holanda e anos luz do Brasil. Paciência!

Confira o vídeo abaixo e considere apenas os 15 segundos iniciais (chegada dos políticos com as magrelas), pois o restante faz parte da cerimônia de apresentação - tradição no país.

Temperature Rising - A Scientist, His Work and a Climate Reckoning

by NYtimes - KEEPING WATCH The Mauna Loa Observatory, at an altitude of 11,135 feet above sea level in Hawaii, has been continuously monitoring and collecting data related to climate change since the 1950s.


MAUNA LOA OBSERVATORY, Hawaii — Two gray machines sit inside a pair of utilitarian buildings here, sniffing the fresh breezes that blow across thousands of miles of ocean.

They make no noise. But once an hour, they spit out a number, and for decades, it has been rising relentlessly.

The first machine of this type was installed on Mauna Loa in the 1950s at the behest of Charles David Keeling, a scientist from San Diego. His resulting discovery, of the increasing level of carbon dioxide in the atmosphere, transformed the scientific understanding of humanity’s relationship with the earth. A graph of his findings is inscribed on a wall in Washington as one of the great achievements of modern science.

Yet, five years after Dr. Keeling’s death, his discovery is a focus not of celebration but of conflict. It has become the touchstone of a worldwide political debate over global warming.

When Dr. Keeling, as a young researcher, became the first person in the world to develop an accurate technique for measuring carbon dioxide in the air, the amount he discovered was 310 parts per million. That means every million pints of air, for example, contained 310 pints of carbon dioxide.

By 2005, the year he died, the number had risen to 380 parts per million. Sometime in the next few years it is expected to pass 400. Without stronger action to limit emissions, the number could pass 560 before the end of the century, double what it was before the Industrial Revolution.

The greatest question in climate science is: What will that do to the temperature of the earth?

Scientists have long known that carbon dioxide traps heat at the surface of the planet. They cite growing evidence that the inexorable rise of the gas is altering the climate in ways that threaten human welfare.

Fossil fuel emissions, they say, are like a runaway train, hurtling the world’s citizens toward a stone wall — a carbon dioxide level that, over time, will cause profound changes.

The risks include melting ice sheets, rising seas, more droughts and heat waves, more flash floods, worse storms, extinction of many plants and animals, depletion of sea life and — perhaps most important — difficulty in producing an adequate supply of food. Many of these changes are taking place at a modest level already, the scientists say, but are expected to intensify.

Reacting to such warnings, President George Bush committed the United States in 1992 to limiting its emissions of greenhouse gases, especially carbon dioxide. Scores of other nations made the same pledge, in a treaty that was long on promises and short on specifics.

But in 1998, when it came time to commit to details in a document known as the Kyoto Protocol, Congress balked. Many countries did ratify the protocol, but it had only a limited effect, and the past decade has seen little additional progress in controlling emissions.

Many countries are reluctant to commit themselves to tough emission limits, fearing that doing so will hurt economic growth. International climate talks in Cancún, Mexico, this month ended with only modest progress. The Obama administration, which came into office pledging to limit emissions in the United States, scaled back its ambitions after climate and energy legislation died in the Senate this year.

Challengers have mounted a vigorous assault on the science of climate change. Polls indicate that the public has grown more doubtful about that science. Some of the Republicans who will take control of the House of Representatives in January have promised to subject climate researchers to a season of new scrutiny.

One of them is Representative Dana Rohrabacher, Republican of California. In a recent Congressional hearing on global warming, he said, “The CO2 levels in the atmosphere are rather undramatic.”

But most scientists trained in the physics of the atmosphere have a different reaction to the increase.

“I find it shocking,” said Pieter P. Tans, who runs the government monitoring program of which the Mauna Loa Observatory is a part. “We really are in a predicament here, and it’s getting worse every year.”

As the political debate drags on, the mute gray boxes atop Mauna Loa keep spitting out their numbers, providing a reality check: not only is the carbon dioxide level rising relentlessly, but the pace of that rise is accelerating over time.

“Nature doesn’t care how hard we tried,” Jeffrey D. Sachs, the Columbia University economist, said at a recent seminar. “Nature cares how high the parts per million mount. This is running away.”

A Passion for Precision

Perhaps the biggest reason the world learned of the risk of global warming was the unusual personality of a single American scientist.

Charles David Keeling’s son Ralph remembers that when he was a child, his family bought a new home in Del Mar, Calif., north of San Diego. His father assigned him the task of edging the lawn. Dr. Keeling insisted that Ralph copy the habits of the previous owner, an Englishman who had taken pride in his garden, cutting a precise two-inch strip between the sidewalk and the grass.

Temperature Rising - A Scientist, His Work and a Climate Reckoning

by NYtimes - KEEPING WATCH The Mauna Loa Observatory, at an altitude of 11,135 feet above sea level in Hawaii, has been continuously monitoring and collecting data related to climate change since the 1950s.


MAUNA LOA OBSERVATORY, Hawaii — Two gray machines sit inside a pair of utilitarian buildings here, sniffing the fresh breezes that blow across thousands of miles of ocean.

They make no noise. But once an hour, they spit out a number, and for decades, it has been rising relentlessly.

The first machine of this type was installed on Mauna Loa in the 1950s at the behest of Charles David Keeling, a scientist from San Diego. His resulting discovery, of the increasing level of carbon dioxide in the atmosphere, transformed the scientific understanding of humanity’s relationship with the earth. A graph of his findings is inscribed on a wall in Washington as one of the great achievements of modern science.

Yet, five years after Dr. Keeling’s death, his discovery is a focus not of celebration but of conflict. It has become the touchstone of a worldwide political debate over global warming.

When Dr. Keeling, as a young researcher, became the first person in the world to develop an accurate technique for measuring carbon dioxide in the air, the amount he discovered was 310 parts per million. That means every million pints of air, for example, contained 310 pints of carbon dioxide.

By 2005, the year he died, the number had risen to 380 parts per million. Sometime in the next few years it is expected to pass 400. Without stronger action to limit emissions, the number could pass 560 before the end of the century, double what it was before the Industrial Revolution.

The greatest question in climate science is: What will that do to the temperature of the earth?

Scientists have long known that carbon dioxide traps heat at the surface of the planet. They cite growing evidence that the inexorable rise of the gas is altering the climate in ways that threaten human welfare.

Fossil fuel emissions, they say, are like a runaway train, hurtling the world’s citizens toward a stone wall — a carbon dioxide level that, over time, will cause profound changes.

The risks include melting ice sheets, rising seas, more droughts and heat waves, more flash floods, worse storms, extinction of many plants and animals, depletion of sea life and — perhaps most important — difficulty in producing an adequate supply of food. Many of these changes are taking place at a modest level already, the scientists say, but are expected to intensify.

Reacting to such warnings, President George Bush committed the United States in 1992 to limiting its emissions of greenhouse gases, especially carbon dioxide. Scores of other nations made the same pledge, in a treaty that was long on promises and short on specifics.

But in 1998, when it came time to commit to details in a document known as the Kyoto Protocol, Congress balked. Many countries did ratify the protocol, but it had only a limited effect, and the past decade has seen little additional progress in controlling emissions.

Many countries are reluctant to commit themselves to tough emission limits, fearing that doing so will hurt economic growth. International climate talks in Cancún, Mexico, this month ended with only modest progress. The Obama administration, which came into office pledging to limit emissions in the United States, scaled back its ambitions after climate and energy legislation died in the Senate this year.

Challengers have mounted a vigorous assault on the science of climate change. Polls indicate that the public has grown more doubtful about that science. Some of the Republicans who will take control of the House of Representatives in January have promised to subject climate researchers to a season of new scrutiny.

One of them is Representative Dana Rohrabacher, Republican of California. In a recent Congressional hearing on global warming, he said, “The CO2 levels in the atmosphere are rather undramatic.”

But most scientists trained in the physics of the atmosphere have a different reaction to the increase.

“I find it shocking,” said Pieter P. Tans, who runs the government monitoring program of which the Mauna Loa Observatory is a part. “We really are in a predicament here, and it’s getting worse every year.”

As the political debate drags on, the mute gray boxes atop Mauna Loa keep spitting out their numbers, providing a reality check: not only is the carbon dioxide level rising relentlessly, but the pace of that rise is accelerating over time.

“Nature doesn’t care how hard we tried,” Jeffrey D. Sachs, the Columbia University economist, said at a recent seminar. “Nature cares how high the parts per million mount. This is running away.”

A Passion for Precision

Perhaps the biggest reason the world learned of the risk of global warming was the unusual personality of a single American scientist.

Charles David Keeling’s son Ralph remembers that when he was a child, his family bought a new home in Del Mar, Calif., north of San Diego. His father assigned him the task of edging the lawn. Dr. Keeling insisted that Ralph copy the habits of the previous owner, an Englishman who had taken pride in his garden, cutting a precise two-inch strip between the sidewalk and the grass.

Temperature Rising - A Scientist, His Work and a Climate Reckoning

(Page 2 of 4)

“It took a lot of work to maintain this attractive gap,” Ralph Keeling recalled, but he said his father believed “that was just the right way to do it, and if you didn’t do that, you were cutting corners. It was a moral breach.”

Dr. Keeling was a punctilious man. It was by no means his defining trait — relatives and colleagues described a man who played a brilliant piano, loved hiking mountains and might settle a friendly argument at dinner by pulling an etymological dictionary off the shelf.

But the essence of his scientific legacy was his passion for doing things in a meticulous way. It explains why, even as challengers try to pick apart every other aspect of climate science, his half-century record of carbon dioxide measurements stands unchallenged.

By the 1950s, when Dr. Keeling was completing his scientific training, scientists had been observing the increasing use of fossil fuels and wondering whether carbon dioxide in the air was rising as a result. But nobody had been able to take accurate measurements of the gas.

As a young researcher, Dr. Keeling built instruments and developed techniques that allowed him to achieve great precision in making such measurements. Then he spent the rest of his life applying his approach.

In his earliest measurements of the air, taken in California and other parts of the West in the mid-1950s, he found that the background level for carbon dioxide was about 310 parts per million.

That discovery drew attention in Washington, and Dr. Keeling soon found himself enjoying government backing for his research. He joined the staff of the Scripps Institution of Oceanography, in the La Jolla section of San Diego, under the guidance of an esteemed scientist named Roger Revelle, and began laying plans to measure carbon dioxide around the world.

Some of the most important data came from an analyzer he placed in a government geophysical observatory that had been set up a few years earlier in a remote location: near the top of Mauna Loa, one of the volcanoes that loom over the Big Island of Hawaii.

He quickly made profound discoveries. One was that carbon dioxide oscillated slightly according to the seasons. Dr. Keeling realized the reason: most of the world’s land is in the Northern Hemisphere, and plants there were taking up carbon dioxide as they sprouted leaves and grew over the summer, then shedding it as the leaves died and decayed in the winter.

He had discovered that the earth itself was breathing.

A more ominous finding was that each year, the peak level was a little higher than the year before. Carbon dioxide was indeed rising, and quickly. That finding electrified the small community of scientists who understood its implications. Later chemical tests, by Dr. Keeling and others, proved that the increase was due to the combustion of fossil fuels.

The graph showing rising carbon dioxide levels came to be known as the Keeling Curve. Many Americans have never heard of it, but to climatologists, it is the most recognizable emblem of their science, engraved in bronze on a building at Mauna Loa and carved into a wall at the National Academy of Sciences in Washington.

By the late 1960s, a decade after Dr. Keeling began his measurements, the trend of rising carbon dioxide was undeniable, and scientists began to warn of the potential for a big increase in the temperature of the earth.

Dr. Keeling’s mentor, Dr. Revelle, moved to Harvard, where he lectured about the problem. Among the students in the 1960s who first saw the Keeling Curve displayed in Dr. Revelle’s classroom was a senator’s son from Tennessee named Albert Arnold Gore Jr., who marveled at what it could mean for the future of the planet.

Throughout much of his career, Dr. Keeling was cautious about interpreting his own measurements. He left that to other people while he concentrated on creating a record that would withstand scrutiny.

John Chin, a retired technician in Hawaii who worked closely with Dr. Keeling, recently described the painstaking steps he took, at Dr. Keeling’s behest, to ensure accuracy. Many hours were required every week just to be certain that the instruments atop Mauna Loa had not drifted out of kilter.

The golden rule was “no hanky-panky,” Mr. Chin recalled in an interview in Hilo, Hawaii. Dr. Keeling and his aides scrutinized the records closely, and if workers in Hawaii fell down on the job, Mr. Chin said, they were likely to get a call or letter: “What did you do? What happened that day?”

In later years, as the scientific evidence about climate change grew, Dr. Keeling’s interpretations became bolder, and he began to issue warnings. In an essay in 1998, he replied to claims that global warming was a myth, declaring that the real myth was that “natural resources and the ability of the earth’s habitable regions to absorb the impacts of human activities are limitless.”

Still, by the time he died, global warming had not become a major political issue. That changed in 2006, when Mr. Gore’s movie and book, both titled “An Inconvenient Truth,” brought the issue to wider public attention. The Keeling Curve was featured in both.

by NYtimes

Temperature Rising - A Scientist, His Work and a Climate Reckoning

(Page 2 of 4)

“It took a lot of work to maintain this attractive gap,” Ralph Keeling recalled, but he said his father believed “that was just the right way to do it, and if you didn’t do that, you were cutting corners. It was a moral breach.”

Dr. Keeling was a punctilious man. It was by no means his defining trait — relatives and colleagues described a man who played a brilliant piano, loved hiking mountains and might settle a friendly argument at dinner by pulling an etymological dictionary off the shelf.

But the essence of his scientific legacy was his passion for doing things in a meticulous way. It explains why, even as challengers try to pick apart every other aspect of climate science, his half-century record of carbon dioxide measurements stands unchallenged.

By the 1950s, when Dr. Keeling was completing his scientific training, scientists had been observing the increasing use of fossil fuels and wondering whether carbon dioxide in the air was rising as a result. But nobody had been able to take accurate measurements of the gas.

As a young researcher, Dr. Keeling built instruments and developed techniques that allowed him to achieve great precision in making such measurements. Then he spent the rest of his life applying his approach.

In his earliest measurements of the air, taken in California and other parts of the West in the mid-1950s, he found that the background level for carbon dioxide was about 310 parts per million.

That discovery drew attention in Washington, and Dr. Keeling soon found himself enjoying government backing for his research. He joined the staff of the Scripps Institution of Oceanography, in the La Jolla section of San Diego, under the guidance of an esteemed scientist named Roger Revelle, and began laying plans to measure carbon dioxide around the world.

Some of the most important data came from an analyzer he placed in a government geophysical observatory that had been set up a few years earlier in a remote location: near the top of Mauna Loa, one of the volcanoes that loom over the Big Island of Hawaii.

He quickly made profound discoveries. One was that carbon dioxide oscillated slightly according to the seasons. Dr. Keeling realized the reason: most of the world’s land is in the Northern Hemisphere, and plants there were taking up carbon dioxide as they sprouted leaves and grew over the summer, then shedding it as the leaves died and decayed in the winter.

He had discovered that the earth itself was breathing.

A more ominous finding was that each year, the peak level was a little higher than the year before. Carbon dioxide was indeed rising, and quickly. That finding electrified the small community of scientists who understood its implications. Later chemical tests, by Dr. Keeling and others, proved that the increase was due to the combustion of fossil fuels.

The graph showing rising carbon dioxide levels came to be known as the Keeling Curve. Many Americans have never heard of it, but to climatologists, it is the most recognizable emblem of their science, engraved in bronze on a building at Mauna Loa and carved into a wall at the National Academy of Sciences in Washington.

By the late 1960s, a decade after Dr. Keeling began his measurements, the trend of rising carbon dioxide was undeniable, and scientists began to warn of the potential for a big increase in the temperature of the earth.

Dr. Keeling’s mentor, Dr. Revelle, moved to Harvard, where he lectured about the problem. Among the students in the 1960s who first saw the Keeling Curve displayed in Dr. Revelle’s classroom was a senator’s son from Tennessee named Albert Arnold Gore Jr., who marveled at what it could mean for the future of the planet.

Throughout much of his career, Dr. Keeling was cautious about interpreting his own measurements. He left that to other people while he concentrated on creating a record that would withstand scrutiny.

John Chin, a retired technician in Hawaii who worked closely with Dr. Keeling, recently described the painstaking steps he took, at Dr. Keeling’s behest, to ensure accuracy. Many hours were required every week just to be certain that the instruments atop Mauna Loa had not drifted out of kilter.

The golden rule was “no hanky-panky,” Mr. Chin recalled in an interview in Hilo, Hawaii. Dr. Keeling and his aides scrutinized the records closely, and if workers in Hawaii fell down on the job, Mr. Chin said, they were likely to get a call or letter: “What did you do? What happened that day?”

In later years, as the scientific evidence about climate change grew, Dr. Keeling’s interpretations became bolder, and he began to issue warnings. In an essay in 1998, he replied to claims that global warming was a myth, declaring that the real myth was that “natural resources and the ability of the earth’s habitable regions to absorb the impacts of human activities are limitless.”

Still, by the time he died, global warming had not become a major political issue. That changed in 2006, when Mr. Gore’s movie and book, both titled “An Inconvenient Truth,” brought the issue to wider public attention. The Keeling Curve was featured in both.

by NYtimes

A Scientist, His Work and a Climate Reckoning

(Page 3 of 4)

In 2007, a body appointed by the United Nations declared that the scientific evidence that the earth was warming had become unequivocal, and it added that humans were almost certainly the main cause. Mr. Gore and the panel jointly won the Nobel Peace Prize.

But as action began to seem more likely, the political debate intensified, with fossil-fuel industries mobilizing to fight emission-curbing measures. Climate-change contrarians increased their attack on the science, taking advantage of the Internet to distribute their views outside the usual scientific channels.

In an interview in La Jolla, Dr. Keeling’s widow, Louise, said that if her husband had lived to see the hardening of the political battle lines over climate change, he would have been dismayed.

“He was a registered Republican,” she said. “He just didn’t think of it as a political issue at all.”

The Numbers

Not long ago, standing on a black volcanic plain two miles above the Pacific Ocean, the director of the Mauna Loa Observatory, John E. Barnes, pointed toward a high metal tower.

Samples are taken by hoses that snake to the top of the tower to ensure that only clean air is analyzed, he explained. He described other measures intended to guarantee an accurate record. Then Dr. Barnes, who works for the National Oceanic and Atmospheric Administration, displayed the hourly calculation from one of the analyzers.

It showed the amount of carbon dioxide that morning as 388 parts per million.

After Dr. Keeling had established the importance of carbon dioxide measurements, the government began making its own, in the early 1970s. Today, a NOAA monitoring program and the Scripps Institution of Oceanography program operate in parallel at Mauna Loa and other sites, with each record of measurements serving as a quality check on the other.

The Scripps program is now run by Ralph Keeling, who grew up to become a renowned atmospheric scientist in his own right and then joined the Scripps faculty. He took control of the measurement program after his father’s sudden death from a heart attack.

In an interview on the Scripps campus in La Jolla, Ralph Keeling calculated that the carbon dioxide level at Mauna Loa was likely to surpass 400 by May 2014, a sort of odometer moment in mankind’s alteration of the atmosphere.

“We’re going to race through 400 like we didn’t see it go by,” Dr. Keeling said.

What do these numbers mean?

The basic physics of the atmosphere, worked out more than a century ago, show that carbon dioxide plays a powerful role in maintaining the earth’s climate. Even though the amount in the air is tiny, the gas is so potent at trapping the sun’s heat that it effectively works as a one-way blanket, letting visible light in but stopping much of the resulting heat from escaping back to space.

Without any of the gas, the earth would most likely be a frozen wasteland — according to a recent study, its average temperature would be colder by roughly 60 degrees Fahrenheit. But scientists say humanity is now polluting the atmosphere with too much of a good thing.

In recent years, researchers have been able to put the Keeling measurements into a broader context. Bubbles of ancient air trapped by glaciers and ice sheets have been tested, and they show that over the past 800,000 years, the amount of carbon dioxide in the air oscillated between roughly 200 and 300 parts per million. Just before the Industrial Revolution, the level was about 280 parts per million and had been there for several thousand years.

That amount of the gas, in other words, produced the equable climate in which human civilization flourished.

Other studies, covering many millions of years, show a close association between carbon dioxide and the temperature of the earth. The gas seemingly played a major role in amplifying the effects of the ice ages, which were caused by wobbles in the earth’s orbit.

The geologic record suggests that as the earth began cooling, the amount of carbon dioxide fell, probably because much of it got locked up in the ocean, and that fall amplified the initial cooling. Conversely, when the orbital wobble caused the earth to begin warming, a great deal of carbon dioxide escaped from the ocean, amplifying the warming.

Richard B. Alley, a climate scientist at Pennsylvania State University, refers to carbon dioxide as the master control knob of the earth’s climate. He said that because the wobbles in the earth’s orbit were not, by themselves, big enough to cause the large changes of the ice ages, the situation made sense only when the amplification from carbon dioxide was factored in.

“What the ice ages tell us is that our physical understanding of CO2 explains what happened and nothing else does,” Dr. Alley said. “The ice ages are a very strong test of whether we’ve got it right.”

When people began burning substantial amounts of coal and oil in the 19th century, the carbon dioxide level began to rise. It is now about 40 percent higher than before the Industrial Revolution, and humans have put half the extra gas into the air since just the late 1970s. Emissions are rising so rapidly that some experts fear that the amount of the gas could double or triple before emissions are brought under control.

The earth’s history offers no exact parallel to the human combustion of fossil fuels, so scientists have struggled to calculate the effect.

by NYtimes

A Scientist, His Work and a Climate Reckoning

(Page 3 of 4)

In 2007, a body appointed by the United Nations declared that the scientific evidence that the earth was warming had become unequivocal, and it added that humans were almost certainly the main cause. Mr. Gore and the panel jointly won the Nobel Peace Prize.

But as action began to seem more likely, the political debate intensified, with fossil-fuel industries mobilizing to fight emission-curbing measures. Climate-change contrarians increased their attack on the science, taking advantage of the Internet to distribute their views outside the usual scientific channels.

In an interview in La Jolla, Dr. Keeling’s widow, Louise, said that if her husband had lived to see the hardening of the political battle lines over climate change, he would have been dismayed.

“He was a registered Republican,” she said. “He just didn’t think of it as a political issue at all.”

The Numbers

Not long ago, standing on a black volcanic plain two miles above the Pacific Ocean, the director of the Mauna Loa Observatory, John E. Barnes, pointed toward a high metal tower.

Samples are taken by hoses that snake to the top of the tower to ensure that only clean air is analyzed, he explained. He described other measures intended to guarantee an accurate record. Then Dr. Barnes, who works for the National Oceanic and Atmospheric Administration, displayed the hourly calculation from one of the analyzers.

It showed the amount of carbon dioxide that morning as 388 parts per million.

After Dr. Keeling had established the importance of carbon dioxide measurements, the government began making its own, in the early 1970s. Today, a NOAA monitoring program and the Scripps Institution of Oceanography program operate in parallel at Mauna Loa and other sites, with each record of measurements serving as a quality check on the other.

The Scripps program is now run by Ralph Keeling, who grew up to become a renowned atmospheric scientist in his own right and then joined the Scripps faculty. He took control of the measurement program after his father’s sudden death from a heart attack.

In an interview on the Scripps campus in La Jolla, Ralph Keeling calculated that the carbon dioxide level at Mauna Loa was likely to surpass 400 by May 2014, a sort of odometer moment in mankind’s alteration of the atmosphere.

“We’re going to race through 400 like we didn’t see it go by,” Dr. Keeling said.

What do these numbers mean?

The basic physics of the atmosphere, worked out more than a century ago, show that carbon dioxide plays a powerful role in maintaining the earth’s climate. Even though the amount in the air is tiny, the gas is so potent at trapping the sun’s heat that it effectively works as a one-way blanket, letting visible light in but stopping much of the resulting heat from escaping back to space.

Without any of the gas, the earth would most likely be a frozen wasteland — according to a recent study, its average temperature would be colder by roughly 60 degrees Fahrenheit. But scientists say humanity is now polluting the atmosphere with too much of a good thing.

In recent years, researchers have been able to put the Keeling measurements into a broader context. Bubbles of ancient air trapped by glaciers and ice sheets have been tested, and they show that over the past 800,000 years, the amount of carbon dioxide in the air oscillated between roughly 200 and 300 parts per million. Just before the Industrial Revolution, the level was about 280 parts per million and had been there for several thousand years.

That amount of the gas, in other words, produced the equable climate in which human civilization flourished.

Other studies, covering many millions of years, show a close association between carbon dioxide and the temperature of the earth. The gas seemingly played a major role in amplifying the effects of the ice ages, which were caused by wobbles in the earth’s orbit.

The geologic record suggests that as the earth began cooling, the amount of carbon dioxide fell, probably because much of it got locked up in the ocean, and that fall amplified the initial cooling. Conversely, when the orbital wobble caused the earth to begin warming, a great deal of carbon dioxide escaped from the ocean, amplifying the warming.

Richard B. Alley, a climate scientist at Pennsylvania State University, refers to carbon dioxide as the master control knob of the earth’s climate. He said that because the wobbles in the earth’s orbit were not, by themselves, big enough to cause the large changes of the ice ages, the situation made sense only when the amplification from carbon dioxide was factored in.

“What the ice ages tell us is that our physical understanding of CO2 explains what happened and nothing else does,” Dr. Alley said. “The ice ages are a very strong test of whether we’ve got it right.”

When people began burning substantial amounts of coal and oil in the 19th century, the carbon dioxide level began to rise. It is now about 40 percent higher than before the Industrial Revolution, and humans have put half the extra gas into the air since just the late 1970s. Emissions are rising so rapidly that some experts fear that the amount of the gas could double or triple before emissions are brought under control.

The earth’s history offers no exact parallel to the human combustion of fossil fuels, so scientists have struggled to calculate the effect.

by NYtimes