Science Linking Drought to Global Warming Remains Matter of Dispute - longstanding prediction that wet areas of the world will get wetter in a warming climate, even as the dry ones get drier.

By JUSTIN GILLISFEB. 16, 2014   NYtimes.com

In delivering aid to drought-stricken California last week, President Obama and his aides cited the state as an example of what could be in store for much of the rest of the country as human-caused climate change intensifies.

But in doing so, they were pushing at the boundaries of scientific knowledge about the relationship between climate change and drought. While a trend of increasing drought that may be linked to global warming has been documented in some regions, including parts of the Mediterranean and in the Southwestern United States, there is no scientific consensus yet that it is a worldwide phenomenon. Nor is there definitive evidence that it is causing California’s problems.

In fact, the most recent computer projections suggest that as the world warms, California should get wetter, not drier, in the winter, when the state gets the bulk of its precipitation. That has prompted some of the leading experts to suggest that climate change most likely had little role in causing the drought.

“I’m pretty sure the severity of this thing is due to natural variability,” said Richard Seager, a climate scientist who studies water issues at the Lamont-Doherty Earth Observatory of Columbia University.

To be sure, 2013 was the driest year in 119 years of record keeping in California. But extreme droughts have happened in the state before, and the experts say this one bears a notable resemblance to some of those, including a crippling drought in 1976 and 1977.

Over all, drought seems to be decreasing in the central United States and certain other parts of the world, though that is entirely consistent with the longstanding prediction that wet areas of the world will get wetter in a warming climate, even as the dry ones get drier.

What may be different about this drought is that, whatever the cause, the effects appear to have been made worse by climatic warming. And in making that case last week, scientists said, the administration was on solid ground.

California has been warming along with most regions of the United States, and temperatures in recent months have been markedly higher than during the 1976-77 drought. In fact, for some of the state’s most important agricultural regions, summer lasted practically into January, with high temperatures of 10 or 15 degrees above normal on some days.

The consequence, scientists say, has been that any moisture the state does get evaporates more rapidly, intensifying the effects of the drought on agriculture in particular. “We are going through a pattern we’ve seen before, but we’re doing it in a warmer environment,” said Michael Anderson, the California state climatologist.

The White House science adviser, John P. Holdren, said in a briefing last week: “Scientifically, no single episode of extreme weather, no storm, no flood, no drought can be said to have been caused by global climate change. But the global climate has now been so extensively impacted by the human-caused buildup of greenhouse gases that weather practically everywhere is being influenced by climate change.”

The drought eased a bit with heavy rains in Northern California this month, but many major reservoirs have only half the water expected for this time of year. “I think the situation is still pretty severe,” said Prof. Alex Hall, who studies climate at the University of California, Los Angeles.

California gets much of its water from snow in the winter along the western slopes of the Sierra Nevada. That means 38 million people and a $45 billion agricultural economy are critically dependent on about five heavy storms a year.

Dry Western States

Rain and snow in California have been so minimal over the last three years that 95 percent of the state is in drought. Neighboring states like Nevada have also been hard-hit.

If a ridge of high atmospheric pressure develops off the California coast, it can easily push moisture-bearing winds to the north, so that the water falls closer to Seattle than Sacramento. Just such a ridge has been parked off California for much of the last three years.

A decade ago, scientists at the University of California, Santa Cruz, published a tantalizing set of papers that predicted a greater likelihood of such a ridge. The lead researcher, Jacob O. Sewall, harnessed substantial computing power to run forecasts of what would happen in a future climate after a substantial melting of sea ice in the Arctic. The ice is already melting because of fast-rising temperatures in the region that many scientists attribute to human emissions.

Dr. Sewall expected some sort of disturbance in the circulation of the atmosphere, but he and his adviser, Lisa Cirbus Sloan, were not prepared for the answer they received. “The surprise jumped out that, wow, all of a sudden it got a whole lot drier in the western part of North America,” Dr. Sewall recalled.

His first study on the question was published in 2004, and was based on conditions that were expected by midcentury. Arctic sea ice then fell much faster than expected, hitting a record low in 2007 and then another record low in 2012.

He and several other scientists said the loss of ice has allowed extra heat to escape from the Arctic Ocean into the atmosphere in the fall and early winter, disturbing weather patterns over vast distances. That, they said, has made extreme weather events of all kinds more likely in the Northern Hemisphere, possibly including winter extremes like the cold blasts hitting the East Coast these days.

At the same time, the California drought, now in its third year, bears a striking resemblance to the atmospheric pattern predicted in Dr. Sewall’s computer analysis.

The resemblance is so uncanny that Dr. Sewall, who now works at Kutztown University in Pennsylvania, suspects an element of coincidence, but he also calls the correlation “frightening.” If this kind of drought has indeed become more likely for California, that means the state — where some towns are now worried about running out of drinking water — is getting a glimpse of its future.

Since his studies were published, other research has come to somewhat different conclusions. Many of those studies have found a likelihood that climate change will indeed cause the American West to dry out, but by an entirely different mechanism — the arrival of more dry air from the tropics. And the most recent batch of studies predicts that effect will not really apply to the western slope of the Sierra. Climate projections show that the area should get somewhat more moisture in the winter, not less.

It may take years to resolve the scientific uncertainty. But with California’s growing population, the state faces increasing pressure to resolve tensions involved in apportioning its water among city dwellers, farmers, industry and an environment under increasing strain from global warming.

Dr. Seager of Columbia University pointed out that much of the Southwestern United States had been in a drought of fluctuating severity for 15 years. In some areas, moreover, the warmer climate is causing winter precipitation to fall as rain rather than snow, meaning less melting snowpack to help parched states through the hotter summers.

“It all adds up across the Southwest to an increasingly stressed water system,” he said. “That’s what they might as well get ready for.”

UK floods: Swollen Thames threatens thousands of homes

by BBC.com

Thousands of homes along the River Thames are threatened with flooding as water levels continue to rise.

Fourteen severe flood warnings are in place in Berkshire and Surrey, while two remain in Somerset.

Amid criticism of Environment Agency head Lord Smith, PM David Cameron - who is in flood-hit Dorset - said it was not the time to change personnel.

A minister will answer an urgent question put by Labour in the Commons on the flooding crisis later.

Speaking from Portland, off the Dorset coast, Mr Cameron said: "I am only interested in one thing and that is making sure that everything government can do is being done and will go on being done to help people through this difficult time.

"There will be time later on to talk about things. Right now everybody's got to focus on the job in hand."

Mr Cameron's comments follow a deepening political row.

Speaking earlier, Lord Smith said his staff knew "100 times" more about flooding than any politician and pointed out that they were bound by rules laid down by government.

He has insisted again he will not resign.

Communities Secretary Eric Pickles previously said ministers had been given bad advice by the Environment Agency over river dredging.

Meanwhile, Environment Secretary Owen Paterson and Mr Pickles are thought to be at odds over the performance of the Environment Agency.

No 10 did not deny Mr Paterson had complained about his colleague, who is standing in for him after he had an eye operation, but said both were doing an "excellent job".

Earlier, Deputy Prime Minister Nick Clegg, who was in Burrowbridge in Somerset on Monday, said dredging should have been done over the last few years but added: "I don't think now is the time to point the finger of blame."

Among other developments:

• Environment Agency has issued 14 severe warnings - meaning "danger to life" - along the River Thames, in areas including Staines, Chertsey and Datchet
• Two severe warning are in place for the south-west of England in Salt Moor and East Lyng, in Somerset
• Large parts of Worcester city centre could be closed for a weekbecause of flooding, the county council has said. Twenty-nine flood warnings remain in place across Herefordshire and Worcestershire
• An earth bank has been built to protect the town of Bridgwater, on the edge of the Somerset Levels, from flooding
• Dyfed Powys police have found a body in their search for a kayaker who went missing on the River Usk on Sunday
• A meeting of the emergency Cobra committee will take place later. Mr Cameron will take part by phone from the South West.
• Essex County Council says it is releasing £1m of emergency funds to tackle road flooding across the county

Major incident

Homes in the Berkshire village of Datchet are underwater and thousands more along the lower River Thames are threatened by flooding.

Thames Valley Police have declared a "major incident" in the east of the county.

Howard Davidson, from the Environment Agency said he expects conditions in Berkshire to deteriorate as more rain falls over the coming days.

"We have issued flood warnings from Datchet down to Shepperton, and we urge people to take heed of the flood warnings. We are anticipating another three or four inches on the Thames over the next 24 hours."

Councillor Colin Rayner, from the Royal Borough of Windsor and Maidenhead, said: "We need help here. We need the police, we need the Army. We've got 50 volunteers here, we've got the vulnerable people out of their homes, now we need to get everyone else out."

One resident in Colnbrook, Berkshire, Asif Khan told the BBC: "The whole street is under water. We've got water coming through our house now, it's got above the air brick level. Our garage is completely flooded. The fridge just went bang. It's something out of a horror movie. So we're now going to take two small kids somehow through the street to the car which we've parked on the other road, and go to our in-laws."

Another resident Paul Palmer, who lives in the village of Hurst told BBC Radio Berkshire: "I've lived here for 44 years and I've never known anything like it. Every entrance, every exit to Hurst is flooded now. We've had no use of our toilets since Friday morning, our sewers are completely blocked and it's starting to back up into the toilet. The council won't offer an emergency toilet unless you're a council tenant. It's like going back to the dark ages. You'd think they could get at least one chemical toilet cubicle at the local village hall or something."

Several Thames gauges are showing their highest levels since being installed in the 1980s and 90s.

Severe delays

The flooding has also caused severe delays on several train lines, National Rail said.

Robin Gisby, managing director of Network Rail, said his team were watching "several hundred" sites across England carefully.

"What I think is really significant, and it has got worse overnight, is Oxford down to the Thames Valley through Didcot, Reading, Maidenhead and into Paddington.

"This isn't now just flooding, this is groundwater. The land is so saturated we have got water rising up, just as much as flowing on to it. So it is difficult."

The main rail route into Devon and Cornwall via Bridgwater remains cut off because of problems caused by flooding and storm damage.

The line from Paddington to Exeter via Newbury is expected to reopen later following a drop in flood water levels at Athelney.

The line from Waterloo to Exeter via Yeovil, closed due to a landslip at Crewkerne on Saturday, has reopened.

More than 300 less serious warnings and alerts have been issued by the Environment Agency, mostly in southern England and the Midlands.

The Met Office has no rain warnings in place for Monday, but it is warning of ice across much of the UK.

But forecasters say another area of low pressure is expected to reach the UK on Monday night and into Tuesday, bringing more heavy rain.

Peter Sloss, of the BBC Weather Centre, said Monday would be the "driest day of the week" but he warned there would be 20-40mm (1-2in) of rain for many areas by the end of Thursday.

He said some showers would be wintry, with snow likely on higher ground in Wales, Scotland, Northern Ireland and northern England.

Sistema Cantareira corre risco de secar, mostra estudo.

Estadão.com.br

 

Especialista da Unicamp alerta para a possibilidade de se entrar em período histórico de pouca chuva
CAMPINAS - O aumento do volume máximo de água produzido pelo Sistema Cantareira – que abastece 47% da Grande São Paulo –, a partir de 2004, agravou a situação de esvaziamento de represas, até chegar a um atípico verão sem chuva. Criados em 1974, os reservatórios do Cantareira chegaram ao pior nível (20,3% da capacidade) neste mês.
Um estudo feito pelo especialista em hidrologia Antônio Carlos Zuffo, professor da Universidade Estadual de Campinas (Unicamp), indica que o aumento de produção do sistema desconsiderou períodos históricos de pouca chuva. O Cantareira começou a ser construído com base em um período de poucas precipitações – que durou de 1935 a 1969. Nas duas décadas seguintes, no entanto, o volume de precipitações aumentou e a vazão subiu até 30%. "Com base nesse período de mais chuva, quando foi renovada a outorga, em 2004, elevou-se a capacidade de produção do Cantareira, porque viram que ele chegou a fornecer até 7 mil litros de água por segundo a mais."

Oficialmente, a partir de 2004 a Companhia de Saneamento Básico do Estado de São Paulo (Sabesp), que opera o sistema, recebeu da Agência Nacional de Águas (ANA) e do Departamento de Águas e Energia Elétrica (DAEE) autorização para aumentar o volume de produção de 33 mil litros de água por segundo para 36 mil litros.

Risco. Observando as chuvas desde 1910, o estudo da Unicamp indica que o Estado pode ter entrado em um longo período, de 30 a 40 anos, com precipitações abaixo da média dos anos anteriores. Isso vai colocar o Cantareira em colapso, caso não seja redimensionada sua capacidade de produção.

As conclusões do estudo, encomendado para o Consórcio das Bacias dos Rios Piracicaba, Capivari e Jundiaí, entidade que representa 73 cidades do interior de onde é retirada a água do sistema, foram apresentadas em junho. "Sem novos sistemas, vamos ter de conviver por 10 a 15 anos com os racionamentos, se tivermos entrado em um longo período de seca", afirma Zuffo.

Segundo o professor, estudiosos em hidrologia consideram a existência de dois fenômenos, denominados José e Noé – referências bíblicas aos períodos cíclicos de fartura precedidos pela seca no Egito e ao dilúvio, respectivamente. São fenômenos cíclicos e de longa duração em que fases de precipitações mais elevadas – como nos verões de 1982/83 e 1975/76 – são sucedidas por períodos de seca.

Para o especialista, o Sudeste entrou nesse longo período de baixas precipitações. "O problema é que o clima não obedece a interesse político. O que vão fazer se o Cantareira deixar de produzir os 7 mil litros por segundo a mais da época de mais chuvas?"

O diretor-presidente da ANA, Vicente Andreu, afirma que os cálculos do sistema foram feitos considerando uma margem de risco de 5%. Mas que, sem essa elevação, não teria havido aumento de oferta de água.

Nas propostas para a segunda renovação da outorga, que será assinada neste ano, a Sabesp solicitou que o volume total de água produzida pelo Cantareira para os próximos dez anos suba para 40 mil litros por segundo. "Se essa vazão for autorizada, terão vendido o ovo sem saber se a galinha vai botá-lo. Quem garante que vai chover nessa proporção?", indaga Zuffo.

Severe Drought Has U.S. West Fearing Worst - “We are on track for having the worst drought in 500 years”

 NYtimes
By ADAM NAGOURNEY and IAN LOVETTFEB. 1, 2014

LOS ANGELES — The punishing drought that has swept California is now threatening the state’s drinking water supply.

With no sign of rain, 17 rural communities providing water to 40,000 people are in danger of running out within 60 to 120 days. State officials said that the number was likely to rise in the months ahead after the State Water Project, the main municipal water distribution system, announced on Friday that it did not have enough water to supplement the dwindling supplies of local agencies that provide water to an additional 25 million people. It is first time the project has turned off its spigot in its 54-year history.

State officials said they were moving to put emergency plans in place. In the worst case, they said drinking water would have to be brought by truck into parched communities and additional wells would have to be drilled to draw on groundwater. The deteriorating situation would likely mean imposing mandatory water conservation measures on homeowners and businesses, who have already been asked to voluntarily reduce their water use by 20 percent.

 “Every day this drought goes on we are going to have to tighten the screws on what people are doing” said Gov. Jerry Brown, who was governor during the last major drought here, in 1976-77.

This latest development has underscored the urgency of a drought that has already produced parched fields, starving livestock, and pockets of smog.

“We are on track for having the worst drought in 500 years,” said B. Lynn Ingram, a professor of earth and planetary sciences at the University of California, Berkeley.

Already the drought, technically in its third year, is forcing big shifts in behavior. Farmers in Nevada said they had given up on even planting, while ranchers in Northern California and New Mexico said they were being forced to sell off cattle as fields that should be four feet high with grass are a blanket of brown and stunted stalks.

Fishing and camping in much of California has been outlawed, to protect endangered salmon and guard against fires. Many people said they had already begun to cut back drastically on taking showers, washing their car and watering their lawns.

Rain and snow showers brought relief in parts of the state at the week’s end — people emerging from a movie theater in West Hollywood on Thursday evening broke into applause upon seeing rain splattering on the sidewalk — but they were nowhere near enough to make up for record-long dry stretches, officials said.

“I have experienced a really long career in this area, and my worry meter has never been this high,” said Tim Quinn, executive director of theAssociation of California Water Agencies, a statewide coalition. “We are talking historical drought conditions, no supplies of water in many parts of the state. My industry’s job is to try to make sure that these kind of things never happen. And they are happening.”

Officials are girding for the kind of geographical, cultural and economic battles that have long plagued a part of the country that is defined by a lack of water: between farmers and environmentalists, urban and rural users, and the northern and southern regions of this state.

“We do have a politics of finger-pointing and blame whenever there is a problem,” said Mr. Brown. “And we have a problem, so there is going to be a tendency to blame people.” President Obama called him last week to check on the drought situation and express his concern.

Tom Vilsack, secretary of the federal Agriculture Department, said in an interview that his agency’s ability to help farmers absorb the shock, with subsidies to buy food for cattle, had been undercut by the long deadlock in Congress over extending the farm bill, which finally seemed to be resolved last week.

Mr. Vilsack called the drought in California a “deep concern,” and a warning sign of trouble ahead for much of the West.

“That’s why it’s important for us to take climate change seriously,” he said. “If we don’t do the research, if we don’t have the financial assistance, if we don’t have the conservation resources, there’s very little we can do to help these farmers.”

The crisis is unfolding in ways expected and unexpected. Near Sacramento, the low level of streams has brought out prospectors, sifting for flecks of gold in slow-running waters. To the west, the heavy water demand of growers of medical marijuana — six gallons per plant per day during a 150-day period— is drawing down streams where salmon and other endangered fish species spawn.

“Every pickup truck has a water tank in the back,” said Scott Bauer, a coho salmon recovery coordinator with the California Department of Fish and Wildlife. “There is a potential to lose whole runs of fish.”

Without rain to scrub the air, pollution in the Los Angeles basin, which has declined over the past decade, has returned to dangerous levels, as evident from the brown-tinged air. Homeowners have been instructed to stop burning wood in their fireplaces.

In the San Joaquin Valley, federal limits for particulate matter were breached for most of December and January. Schools used flags to signal when children should play indoors.

“One of the concerns is that as concentrations get higher, it affects not only the people who are most susceptible, but healthy people as well,” said Karen Magliano, assistant chief of the air quality planning division of the state’s Air Resources Board.

The impact has been particularly severe on farmers and ranchers. “I have friends with the ground torn out, all ready to go,” said Darrell Pursel, who farms just south of Yerington, Nev. “But what are you going to plant? At this moment, it looks like we’re not going to have any water. Unless we get a lot of rain, I know I won’t be planting anything.”

The University of California Cooperative Extension held a drought survival session last week in Browns Valley, about 60 miles north of Sacramento, drawing hundreds of ranchers in person and online. “We have people coming from six or seven hours away,” said Jeffrey James, who ran the session.

Dan Macon, 46, a rancher in Auburn, Calif., said the situation was “as bad as I have ever experienced. Most of our range lands are essentially out of feed.”

With each parched sunrise, a sense of alarm is rising amid signs that this is a drought that comes along only every few centuries. Sacramento had gone 52 days without water, and Albuquerque had gone 42 days without rain or snow as of Saturday.

The snowpack in the Sierra Nevada, which supplies much of California with water during the dry season, was at just 12 percent of normal last week, reflecting the lack of rain or snow in December and January.

“When we don’t have rainfall in our biggest two months, you really are starting off bad,” said Dar Mims, a meteorologist with the Air Resources Board.

Even as officials move into action, people who have lived through droughts before — albeit none as severe as this — said they were doing triage in their gardens (water the oak tree, not the lawn) and taking classic “stop-start-stop-start” shower.

Jacob Battersby, a producer in Oakland, said he began cutting back even before the voluntary restrictions were announced.

“My wife and I both enjoy gardening,” he wrote in an email. “ ‘Sorry, plants. You will be getting none to drink this winter.’ ”

Industry Awakens to Threat of Climate Change

By NYtimes.com

WASHINGTON — Coca-Cola has always been more focused on its economic bottom line than on global warming, but when the company lost a lucrative operating license in India because of a serious water shortage there in 2004, things began to change.

Today, after a decade of increasing damage to Coke’s balance sheet as global droughts dried up the water needed to produce its soda, the company has embraced the idea of climate change as an economically disruptive force.

“Increased droughts, more unpredictable variability, 100-year floods every two years,” said Jeffrey Seabright, Coke’s vice president for environment and water resources, listing the problems that he said were also disrupting the company’s supply of sugar cane and sugar beets, as well as citrus for its fruit juices. “When we look at our most essential ingredients, we see those events as threats.”

Coke reflects a growing view among American business leaders and mainstream economists who see global warming as a force that contributes to lower gross domestic products, higher food and commodity costs, broken supply chains and increased financial risk. Their position is at striking odds with the longstanding argument, advanced by the coal industry and others, that policies to curb carbon emissions are more economically harmful than the impact of climate change.

“The bottom line is that the policies will increase the cost of carbon and electricity,” said Roger Bezdek, an economist who produced a report for the coal lobby that was released this week. “Even the most conservative estimates peg the social benefit of carbon-based fuels as 50 times greater than its supposed social cost.”

Some tycoons are no longer listening.

At the Swiss resort of Davos, corporate leaders and politicians gathered for the annual four-day World Economic Forum will devote all of Friday to panels and talks on the threat of climate change. The emphasis will be less about saving polar bears and more about promoting economic self-interest.

In Philadelphia this month, the American Economic Association inaugurated its new president, William D. Nordhaus, a Yale economist and one of the world’s foremost experts on the economics of climate change.

“There is clearly a growing recognition of this in the broader academic economic community,” said Mr. Nordhaus, who has spent decades researching the economic impacts of both climate change and of policies intended to mitigate climate change.

In Washington, the World Bank president, Jim Yong Kim, has put climate change at the center of the bank’s mission, citing global warming as the chief contributor to rising global poverty rates and falling G.D.P.’s in developing nations. In Europe, the Organization for Economic Cooperation and Development, the Paris-based club of 34 industrialized nations, has begun to warn of the steep costs of increased carbon pollution.

Nike, which has more than 700 factories in 49 countries, many in Southeast Asia, is also speaking out because of extreme weather that is disrupting its supply chain. In 2008, floods temporarily shut down four Nike factories in Thailand, and the company remains concerned about rising droughts in regions that produce cotton, which the company uses in its athletic clothes.

“That puts less cotton on the market, the price goes up, and you have market volatility,” said Hannah Jones, the company’s vice president for sustainability and innovation. Nike has already reported the impact of climate change on water supplies on its financial risk disclosure forms to the Securities and Exchange Commission.

Both Nike and Coke are responding internally: Coke uses water-conservation technologies and Nike is using more synthetic material that is less dependent on weather conditions. At Davos and in global capitals, the companies are also lobbying governments to enact environmentally friendly policies.

But the ideas are a tough sell in countries like China and India, where cheap coal-powered energy is lifting the economies and helping to raise millions of people out of poverty. Even in Europe, officials have begun to balk at the cost of environmental policies: On Wednesday, the European Union scaled back its climate change and renewable energy commitments, as high energy costs, declining industrial competitiveness and a recognition that the economy is unlikely to rebound soon caused European policy makers to question the short-term economic trade-offs of climate policy.

What this article just reconfirms, is that corporate greed, and not peoples lives, is the ruling factor in mitigating , or not, the effects...

In the United States, the rich can afford to weigh in. The California hedge-fund billionaire Thomas F. Steyer, who has used millions from his own fortune to support political candidates who favor climate policy, is working with Michael R. Bloomberg, the former New York mayor, and Henry M. Paulson Jr., a former Treasury secretary in the George W. Bush administration, to commission an economic study on the financial risks associated with climate change. The study, titled “Risky Business,” aims to assess the potential impacts of climate change by region and by sector across the American economy.

“This study is about one thing, the economics,” Mr. Paulson said in an interview, adding that “business leaders are not adequately focused on the economic impact of climate change.”

Also consulting on the “Risky Business” report is Robert E. Rubin, a former Treasury secretary in the Clinton administration. “There are a lot of really significant, monumental issues facing the global economy, but this supersedes all else,” Mr. Rubin said in an interview. “To make meaningful headway in the economics community and the business community, you’ve got to make it concrete.”

Last fall, the governments of seven countries — Colombia, Ethiopia, Indonesia, South Korea, Norway, Sweden and Britain — created the Global Commission on the Economy and Climate and jointly began another study on how governments and businesses can address climate risks to better achieve economic growth. That study and the one commissioned by Mr. Steyer and others are being published this fall, just before a major United Nations meeting on climate change.

Although many Republicans oppose the idea of a price or tax on carbon pollution, some conservative economists endorse the idea. Among them are Arthur B. Laffer, senior economic adviser to President Ronald Reagan; the Harvard economist N. Gregory Mankiw, who was economic adviser to Mitt Romney’s presidential campaign; and Douglas Holtz-Eakin, the head of the American Action Forum, a conservative think tank, and an economic adviser to the 2008 presidential campaign of Senator John McCain, the Arizona Republican.

“There’s no question that if we get substantial changes in atmospheric temperatures, as all the evidence suggests, that it’s going to contribute to sea-level rise,” Mr. Holtz-Eakin said. “There will be agriculture and economic effects — it’s inescapable.” He added, “I’d be shocked if people supported anything other than a carbon tax — that’s how economists think about it.”