To figure out what is likely to happen to Earth’s climate this century, scientists are looking 3 million years into the past.

They have concluded that the most revealing slice of time is the Pliocene Epoch, a warm, wet period between 3.15 million and 2.85 million years ago, when the world probably looked and felt much as it does now. Global temperatures and the amount of heat-trapping carbon dioxide in the atmosphere were similar to today’s climate, according to the U.S. Geological Survey.

Knowing more about the Pliocene is useful for climate modelers around the world who create sophisticated computer programs to simulate what global warming could bring to Earth.

But recreating ancient climate conditions has also given fuel to those who question human-caused global warming. In the Pliocene Epoch, there were no humans to spur carbon dioxide emissions, so the similarity in carbon dioxide levels between then and now points to natural causes, they say.

As Harry Dowsett, a USGS scientist who has made a career of studying the Pliocene, put it, this was a time “before man was able to do anything to Earth.”

Hindcasting – looking backward to project forward – relies on tools that are not regularly used in paleontology, the study of fossil evidence of past ages. Techniques like radio-carbon dating, which tracks the gradual decay of radioactive carbon, only work back to about 1 million years ago.

Instead, paleoclimatologists who study ancient climate find clues in cores drilled in sediment layers on ocean bottoms and in some leaf remains. They then examine different isotopes (atomic weights, with varying numbers of neutrons) of non-radioactive, stable carbon.

Mark Pagani, a paleoclimatologist at Yale University, described how this works: When algae in the Pliocene sucked up carbon dioxide to perform photosynthesis, they produced organic carbon with distinct isotope signatures that were sensitive to the concentration of CO2 in seawater. These signatures are preserved in fossils that can help determine how much carbon dioxide was in the atmosphere back then.

“We needed to figure out what was on the land, where the plants were growing, where the mountains were, where the sea level was, where the ice sheets were,” Dowsett said.

Using these techniques, scientists have estimated carbon dioxide levels at some locations going back as much as 150 million years, Pagani said.

The USGS homed in on the mid-Pliocene as a good analog for modern Earth’s changing climate. The agency considered data from 100 sites and a distinct period of time, making the first and only geospatial reconstruction of the Pliocene.

In the last five years, a more complete and detailed picture of the epoch has emerged.

The mid-Pliocene was about as warm as climate models predict it will be by 2100, or about 3.6 degrees F (2 degrees C) above current global mean temperatures, the Geological Survey said.

Sea levels were as much as 70 feet higher than they are now. Florida would have been a narrow strip instead of a broad peninsula, Washington, D.C., might have offered oceanfront views and much of Bangladesh would have been under water. Greenland, now covered in melting glaciers, had forests growing on its northern slope.

Animals and plants would have looked familiar to 21st century eyes, as newly formed grasslands attracted long-legged grazers. The dinosaurs were long gone, and the mountains were basically built. Two-footed ancestors of homo sapiens probably walked the Earth.

Carbon dioxide levels in the atmosphere were between 350 and 400 parts per million (that is, between 350 and 400 carbon dioxide molecules for every million molecules of air), said Pagani, who called the estimates “a pretty good ballpark figure.”

Today, the carbon dioxide concentration is similar. An April 5 reading at Hawaii’s Mauna Loa Observatory was over 394 parts per million. This figure has climbed from less than 320 ppm in 1960 and could be over 450 ppm by 2100. A graph is visible at the NOAA site http://co2now.org/.

What people care about in the 21st century, Pagani said, is how the temperature responds to rising carbon dioxide, which argues for a detailed look at the last time the Earth was as hot as projections show it will be in coming decades.

A study in the journal Nature Climate Change compared four existing climate models, and found all four are largely consistent with each other and with USGS data on the Pliocene.

But problems with simulating what could happen in the North Atlantic are significant, said Mark Chandler of NASA’s Goddard Institute for Space Studies. The models show less North Atlantic warming than occurred during the Pliocene.

“What happens to the North Atlantic in the future is going to dramatically affect the Western world,” Chandler said.

The absence of human life during the Pliocene Epoch has offered ammunition to those who question anthropogenic, or human-caused, climate change.

Patrick Michaels, a climate scientist at the libertarian CATO Institute, said Earth’s climate over time has gone through natural cycles. While he acknowledged anthropogenic climate change is occurring, Michaels said the issue is how sensitive global temperatures are to fluctuations in carbon dioxide: “It’s not the heat, it’s the sensitivity.”

“They’re absolutely right, climate changes naturally, it’s constantly changing for natural reasons,” said Maureen Raymo of Columbia University’s Lamont-Doherty Earth Observatory.

However, Raymo noted that the natural changes caused by volcanic eruptions, other geologic activities and variations in Earth’s orbit take eons to unfold. Humans have been putting additional carbon dioxide into the atmosphere through the burning of fossil fuels for only a century or so. And there is a lag between the time when carbon dioxide gets into the air and the full warming effects are felt.

Copyright 2011 Thomson Reuters. Click for restrictions.

Article source: http://usnews.msnbc.msn.com/_news/2012/04/15/11209341-climate-change-scientists-look-back-3-million-years-to-look-to-future?lite

ENERGY: Volunteers paint a roof white to reduce energy use. Gradually replacing traditional urban roofs and roads with white or lighter-colored materials would yield a cooling benefit that, over 50 years, would be the equivalent of a reduction of between 25 and 150 billion tons of carbon dioxide. (Photo: AFP)

Article source: http://www.mnn.com/earth-matters/energy/stories/global-warming-scientists-foresee-sun-reflecting-cities

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There may be more to fear from global warming than environmental changes.

According to several leading climate scientists and public health researchers, global warming will lead to higher incidence and more intense versions of disease. The direct or indirect effects of global warming might intensify the prevalence of tuberculosis, HIV/AIDS, dengue and Lyme disease, they said, but the threat of increased health risks is likely to futher motivate the public to combat global warming.

“The environmental changes wrought by global warming will undoubtedly result in major ecologic changes that will alter patterns and intensity of some infectious diseases,” said Gerald Friedland, professor of medicine and epidemiology and public health at the Yale School of Medicine.

Global warming will likely cause major population upheavals, creating crowded slums of refugees, Friedland said. Not only do areas of high population density facilitate disease transmission, but their residents are more likely to be vulnerable to disease because of malnutrition and poverty, he said. This pattern of vulnerability holds for both tuberculosis and HIV/AIDS, increasing the incidence of both the acquisition and spread of the diseases, he explained.

He said these potential effects are not surprising, since tuberculosis epidemics historically have followed major population and environmental upheavals.

By contrast, global warming may increase the infection rates of mosquito-borne diseases by creating a more mosquito-friendly habitat. Warming, and the floods associated with it, are like to increase rates of both malaria and dengue, a debilitating viral disease found in tropical areas and transmitted by mosquito bites, said Maria Diuk-Wasser, assistant professor of epidemiology at the Yale School of Public Health.

“The direct effects of temperature increase are an increase in immature mosquito development, virus development and mosquito biting rates, which increase contact rates (biting) with humans. Indirect effects are linked to how humans manage water given increased uncertainty in the water supply caused by climate change,” Diuk-Wasser said.

Global warming may affect other diseases in even more complicated ways, Diuk-Wasser said. The effect of global warming on the incidence of Lyme disease, a tick-borne chronic disease, is more difficult to examine and measure, though she said it will probably increase.

“One possible way in which temperature may limit tick populations is by increasing the length of their life cycle from two to three years in the north, where it is colder,” she said. “Climate change could be reverting that and therefore increasing production of ticks. The transmission of the Lyme bacterium is so complex, though, that it is difficult to ‘tease out’ a role of climate change.”

Diuk-Wasser added, however, that scientists do find an effect of climate change on the distribution of Lyme disease in their data, but are not yet sure of the reasons behind such results.

While the study of global warming itself is relatively new, research on the impact of global warming on disease is an even more recent endeavor that draws on the skills and expertise of a wide variety of scientists and researchers.

“The field is multi-sourced, and recently interest has been evolving among climatologists, vector biologists, disease epidemiologists, ecologists, and policymakers alike,” said Uriel Kitron, professor and chair of the environmental studies department at Emory University.

Kitron said that in order to mitigate the effects of global warming on disease, the public must turn its attention to water management and an increased understanding of the connecting between “global processes and local impact.”

Diuk-Wasser said that raising awareness about the public health effects of global warming might aid climate control efforts, because it made the potential impact of global warming more personal.

“There’s been a great interest in climate advocacy groups to look for negative effects of climate change on health, since studies have found that this motivates people to adopt measures to curb climate change,” Diuk-Wasser said.

The Yale Climate and Engery Institute recently won a grant to study the direct and indirect effects of climate change on dengue transmission in Colombia.

Article source: http://www.yaledailynews.com/news/2012/apr/11/global-warming-may-intensify-disease/

As if we needed another reason to love California, the Golden State has been named most likely to survive the tolls of climate change.

A recent study done by the Natural Resources and Defense Council highlights the best and worst states equipped with plans to combat water shortage and other problems expected to occur from globally increasing temperatures due to climate change. One of only nine, California was given top awards for an integrated and comprehensive preparedness plan that addresses all relevant water sectors and state agencies.

From snow in the Sierra Nevadas to farming in the Central Valley and the beaches of San Diego, water (and usually lack thereof) has always been an important issue for the state. According to the study, California is leading the way on addressing climate change threats.

(SCROLL DOWN FOR PHOTOS)

The entire west coast has some serious water-related problems to consider: water shortage, more frequent and intense storms, increased flooding, sea level rise, increased erosion, saltwater intrusion, and impact on marine species. Thankfully, both Oregon and Washington are likely to be saved as well, despite scientists’ dire predictions for the future.

In California, climate change could put at risk over three trillion dollars in assets and cause damages worth anywhere from seven to 47 billion dollars a year. Fortunately, the Golden State has implemented an aggressive global warming pollution reduction plan, including the California Global Warming Solutions Act signed into law in 2006 and the Water Efficiency Bill passed in 2010.

As carbon pollution continues to change our climate, its wide-ranging impacts will continue to worsen, threatening cities, towns and neighborhoods throughout the country. But many of the nation’s states are ill-equipped to deal with the major problem. Twelve states have yet to formally address climate change preparedness, and 17 have very limited programs to combat potential climate change.

The report, the first of its kind to take an in-depth look at the vulnerabilities that the entire nation faces, found that 29 states –- nearly 60 percent –- are inadequately prepared to deal with the water-related threats of global warming.

The solution? The study suggests every state needs to plan ahead like California–before it’s too late.

Curious if your out-of-state friends and family will make it? Check out the nine states most well-equipped for the big one:

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Article source: http://www.huffingtonpost.com/2012/04/08/california-climate-change-study_n_1409312.html

DURHAM — A series of global warming events called hyperthermals that occurred more than 50 million years ago had a similar origin to a much larger hyperthermal of the period, the Pelaeocene-Eocene Thermal Maximum (PETM), new research has found. The findings, published in Nature Geoscience online on April 1, represent a breakthrough in understanding the major “burp” of carbon, equivalent to burning the entire reservoir of fossil fuels on Earth, that occurred during the PETM.

“As geologists, it unnerves us that we don’t know where this huge amount of carbon released in the PETM comes from,” says Will Clyde, associate professor of Earth sciences at the University of New Hampshire and a co-author on the paper. “This is the first breakthrough we’ve had in a long time. It gives us a new understanding of the PETM.” The work confirms that the PETM was not a unique event — the result, perhaps, of a meteorite strike — but a natural part of the Earth’s carbon cycle.

Working in the Bighorn Basin region of Wyoming, a 100-mile-wide area with a semi-arid climate and stratified rocks that make it ideal for studying the PETM, Clyde and lead author Hemmo Abels of Utrecht University in the Netherlands found the first evidence of the smaller hyperthermal events on land. Previously, the only evidence of such events were from marine records.

“By finding these smaller hyperthermal events in continental records, it secures their status as global events, not just an ocean process. It means they are atmospheric events,” Clyde says.

Their findings confirm that, like the smaller hyperthermals of the era that released carbon into the atmosphere, the release of carbon in the PETM had a similar origin. In addition, the warming-to-carbon release of the PETM and the other hyperthermals are similarly scaled, which the authors interpret as an indication of a similar mechanism of carbon release during all hyperthermals, including the PETM.

“It points toward the fact that we’re dealing with the same source of carbon,” Clyde says.

Working in two areas of the Bighorn Basin just east of Yellowstone National Park — Gilmore Hill and Upper Deer Creek — Clyde and Abels sampled rock and soil to measure carbon isotope records. They then compared these continental recordings of carbon release to equivalent marine records already in existence.

During the PETM, temperatures rose between five and seven degrees Celsius in approximately 10,000 years — “a geological instant,” Clyde calls it. This rise in temperature coincided exactly with a massive global change in mammals, as land bridges opened up connecting the continents. Prior to the PETM, North America had no primates, ancient horses, or split-hoofed mammals like deer or cows.

Scientists look to the PETM for clues about the current warming of the Earth, although Clyde cautions that “the Earth 50 million years ago was very different than it is today, so it’s not a perfect analog.” While scientists still don’t fully understand the causes of these hyperthermal events, “they seem to be triggered by warming,” Clyde says. It’s possible, he says, that less dramatic warming events destabilized these large amounts of carbon, releasing them into the atmosphere where they, in turn, warmed the Earth even more.

“This work indicates that there is some part of the carbon cycle that we don’t understand, and it could accentuate global warming,” Clyde says.

The article, “Terrestrial carbon isotope excursions and biotic change during Palaeogene hyperthermals,” was published online in Nature Geoscience (www.nature.com/naturegeoscience). In addition to Clyde and Abels, co-authors were Philip Gingerich from the University of Michigan, Frederik Hilgen and Lucas Lourens from Utrecht University, Henry Fricke from Colorado College, and Gabriel Bowen from Purdue University. Clyde received funding for this work from the National Science Foundation.

Read more about Clyde’s research at Bighorn Basin here: http://www.unh.edu/news/cj_nr/2011/jul/bp11basin.cfm.

Article source: http://www.fosters.com/apps/pbcs.dll/article?AID=/20120407/GJNEWS_01/704079959&template=GreatBayRegion

“We constructed the first-ever record of global temperature spanning the end of the last ice age based on 80 proxy temperature records from around the world,” said Jeremy Shakun, a National Oceanic and Atmospheric Administration (NOAA) Climate and Global Change postdoctoral fellow at Harvard and Columbia Universities and first author of the paper. “It’s no small task to get at global mean temperature. Even for studies of the present day you need lots of locations, quality-controlled data, careful statistics. For the past 21,000 years, it’s even harder. But because the data set is large enough, these proxy data provide a reasonable estimate of global mean temperature.”

Proxy records from around the world—derived from ice cores and ocean and lake sediments — provide estimates of local surface temperature throughout history, and carbon-14 dating indicates when those temperatures occurred. For example, water molecules harboring the oxygen-18 isotope rain out faster than those containing oxygen-16 as an air mass cools, so the ratio of these isotopes in glacial ice layers tells scientists how cold it was when the snow fell. Likewise, the amount of magnesium incorporated into the shells of marine plankton depends on the temperature of the water they live in, and these shells get preserved on the seafloor when they die. The authors combined these local temperature records to produce a reconstruction of global mean temperature. Additionally, samples of ancient atmosphere are trapped as air bubbles in glaciers, providing a direct measure of carbon dioxide levels through time that could be compared to the global temperature record.

Being the first to reconstruct global mean temperatures throughout this time interval allowed the researchers to show what many suspected but none could yet prove: “This is the first paper to definitively show the role carbon dioxide played in helping to end the last ice age,” said Shakun, who co-wrote the paper with Peter Clark of Oregon State University. “We found that global temperature mirrored and generally lagged behind rising carbon dioxide during the last deglaciation, which points to carbon dioxide as the major driver of global warming.” Prior results based on Antarctic ice cores had indicated that local temperatures in Antarctica started warming before carbon dioxide began rising, which implied that carbon dioxide was a feedback to some other leading driver of warming. The delay of global temperature behind carbon dioxide found in this study, however, shows that the ice-core perspective does not apply to the globe as a whole and instead suggests that carbon dioxide was the primary driver of worldwide warming.

While the geologic record showed a remarkable correlation between carbon dioxide and global temperature, the researchers also turned to state-of-the-art model simulations to further pin down the direction of causation suggested by the temperature lag. Jaguar recently ran approximately 14 million processor hours to simulate the most recent 21,000 years of Earth’s climate. Feng He of the University of Wisconsin, Madison, a postdoctoral researcher, plugged the main forcings driving global climate over this time interval into an Intergovernmental Panel on Climate Change (IPCC)-class model called the Community Climate System Model version 3, a global climate model that couples interactions between atmosphere, oceans, lands, and sea ice. The climate science community developed the model with support from the National Science Foundation (NSF), Department of Energy (DOE), and National Aeronautics and Space Administration and used many codes developed by university researchers.

“Our model results are the first IPCC-class Coupled General Circulation Model (CGCM) simulation of such a long duration (15,000 years),” said He, who conducted the modeling with Zhengyu Liu of the University of Wisconsin-Madison and Bette Otto-Bliesner of the National Center for Atmospheric Research (NCAR). “This is of particular significance to the climate community because it shows, for the first time, that at least one of the CGCMs used to predict future climate is capable of reproducing both the timing and amplitude of climate evolution seen in the past under realistic climate forcing.”

The group ran simulations that used 4.7 million processor hours in 2009, 6.6. million in 2010, and 2.5 million in 2011. The Innovative and Novel Computational Impact on Theory and Experiment program, jointly managed by leadership computing facilities at Argonne and Oak Ridge National Laboratories, awarded the allocations.

Shaun Marcott and Alan Mix of Oregon State University analyzed data, and Andreas Schmittner, also of Oregon State, interpreted links between ocean currents and carbon dioxide. Edouard Bard of Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement provided data and expertise about radiocarbon calibration.

NSF supported this research through its Paleoclimate Program for the Paleovar Project and NCAR. The researchers used resources of the Oak Ridge Leadership Computing Facility, located in the National Center for Computational Sciences at ORNL, which is supported by DOE’s Office of Science. The paleoclimate community generated the proxy data sets and provided unpublished results of the DATED Project on retreat history of the Eurasian ice sheets. The NOAA NGDC and PANGAEA databases were also essential to this work.

Plot twist: the ‘bipolar seesaw’

As the dominant theory goes, the variation of Earth’s orbit around the sun is responsible for the growth and deterioration of glaciers because it changes insolation, or solar radiation reaching and warming an area. About 21,000 years ago the orbit of the Earth was slightly predisposed to warmer summers in the Northern Hemisphere, and the planet experienced a general warming.

Next comes a plot twist. Geologic data show that about 19,000 years ago, Northern Hemisphere glaciers began to melt, and sea levels rose. Melting glaciers dumped so much freshwater into the ocean that it slowed a system of currents that transports heat throughout the world. Called the Atlantic meridional overturning circulation (AMOC), this ocean conveyor belt is particularly important in the Atlantic where it flows northward across the equator, stealing Southern Hemisphere heat and exporting it to the Northern Hemisphere. The AMOC then sinks in the North Atlantic and returns southward in the deep ocean. A large pulse of glacial meltwater, however, can place a freshwater lid over the North Atlantic and halt this sinking, backing up the entire conveyor belt.

The simulation showed weakening of the AMOC due to the increase in glacial melt beginning about 19,000 years ago, which decreased ocean heat transport, keeping heat in the Southern Hemisphere and cooling the Northern Hemisphere. Other studies suggest this southern warming caused sea ice to retreat and shifted winds around the Southern Ocean, uncorking carbon dioxide that had previously been stored in the deep ocean and venting it to the atmosphere around 17,500 years ago. This rise in carbon dioxide then initiated worldwide warming.

The seesawing of heat between the hemispheres due to the AMOC shutdown explains why Southern Hemisphere warming led the rise in carbon dioxide while Northern Hemisphere temperatures lagged behind and reconciles these patterns with the key role played by carbon dioxide in driving global mean warming. “Differences in the deglacial temperature evolution of the Northern and Southern Hemispheres can largely be explained by variations in the strength of the Atlantic Meridional Overturning Circulation,” said He.

Before the team’s groundbreaking efforts, researchers could only simulate single time slices of Earth’s climate. Just as multiple images are stitched together to make an animation, speedy petascale supercomputers, capable of executing a quadrillion calculations each second, enable stitching together of multiple time slices to produce a continuous simulation. Liu, Otto-Bliesner, and He’s group was the first to continuously capture climate from 21,000 years ago to the present day so that scientists could compare the relationship of carbon dioxide and global mean temperature over time. The Nature article covers events up to about 6,000 years ago. The group has since extended the simulation through the present day.

“Climate model output housed at Oak Ridge is currently in the hundreds of terabytes [trillion bytes] and will soon exceed a petabyte, so you need a large facility just to accommodate the large data output,” said He. “Right now the climate model output is a top consumer of data storage in Oak Ridge. Also, [continuous simulations] definitely cannot be performed at other sites because the system needs to be quite consistent. This simulation has been run continuously for more than 3 years. Each simulation [step] depends on what happened earlier.”

To understand the relevance of the study’s finding to today, it is worth considering that carbon dioxide concentrations rose from 185 parts per million (ppm) to 260 ppm over the approximately 10,000 years during which the last ice age ended. In just the past two centuries, human activity has increased concentrations by about the same amount, reaching a carbon dioxide concentration of 392 ppm in 2011—higher than at any time in at least the last 800,000 years.

The work builds on a continuous simulation by Liu and colleagues of Earth’s climate between 21,000 and 14,000 years ago, reported in a 2009 Science article detailing the first continuous simulation of climate change during Earth’s most recent period of natural global warming. Using ORNL’s Cray X1E supercomputer named Phoenix and the even faster Cray XT system called Jaguar, the scientists used nearly a million processor hours in 2008 to run one-third of their simulation, from 21,000 years ago (the most recent glacial maximum) to 14,000 years ago (the most recent major period of natural global warming). The effort validated the ability to simulate large climate changes in the past and is critical for assessing future projections of changes, such as the fate of ocean circulation in the face of continued glacial melting in Greenland and Antarctica.

More information: Nature article: http://www.nature. … re10915.html

Provided by Oak Ridge National Laboratory (news : web)

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Article source: http://www.physorg.com/news/2012-04-carbon-dioxide-global-ice-age.html

WASHINGTON — Scientists are increasingly confident that the uptick in heat waves and heavier rainfall is linked to human-caused greenhouse-gas emissions, posing a heightened risk to the world’s population, according to two recent reports.

On Wednesday, the U.N. Intergovernmental Panel on Climate Change (IPCC) released a 594-page study suggesting that when it comes to weather observations since 1950, there has been a “change in some extremes,” which stem in part from global warming.

The report — the product of a collaboration of 220 authors from 62 countries — makes distinctions among different phenomena. It shows there is “limited to medium evidence” that climate change has contributed to changes in flooding, for example, and there is “low confidence” that long-term hurricane trends over the past 40 years have been driven by the world’s growing carbon output.

But the IPCC team projects that there is a 90 to 100 percent probability that sea level rise “will contribute to upward trends in extreme coastal high-water levels in the future.”

Chris Field, who co-chairs the IPCC’s Working Group II and serves as the director of the Carnegie Institution’s Department of Global Ecology at Stanford University, said in an interview that although many uncertainties still exist when it comes to extreme weather, “We also know the risk people face is changing as a result of climate change.”

Asking whether a particular extreme weather event can be blamed on human-caused global warming is the wrong question to ask, said Dim Coumou, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany. There’s no way to determine whether a single event was triggered by climate change, he said.

Instead, a new analysis from Coumou and a colleague, published in the journal Nature Climate Change, examines patterns of extreme weather since 2000 and asks whether the likelihood of these events was heightened by human-driven climate change.

For extreme heat waves and unusual downpours, the answer, Coumou and his colleagues found, is yes.

“The evidence is solid,” he said: Extra heat in the atmosphere from human-caused greenhouse gases has made these two types of events much more likely. The climate has already changed, and the sheer number of these events over the past decade reflects it, they find.

Linking hurricanes, tornadoes and other storms to climate change is much harder, as records for these events are poorer than temperature and rainfall records.

Coumou pointed to the 2010 heat wave in Moscow and western Russia as an example of an extreme event made much more likely by climate change. The hottest summer in 500 years of temperature records caused 15,000 deaths, shaved billions off Russia’s economic output, triggered 500 wildfires and destroyed 30 percent of the country’s grain harvest.

“We found very strong warming since 1970s in the Moscow region,” said Coumou, “and this warming has dramatically increased the chances that a record summer would occur.”

Across the United States this year so far, warm-weather records have outnumbered cold records by a factor of 12, according to the National Oceanic and Atmospheric Administration’s National Climatic Data Center.

Coumou used a “loaded dice” analogy that’s become popular with climate scientists. Rolling one six is not evidence of a loaded die. Rolling 10 in a row? Now you’re suspicious. Human-induced climate change has loaded the dice toward certain extreme events, Coumou said.

Both environmentalists and several major insurers argue policymakers must move quickly to cut carbon emissions and devise strategies to adapt to climate impacts.

“The IPCC report is yet another reminder of the pressing need to tackle climate risk in both the near and long term,” said Mark Way, head of Swiss Re’s sustainable-development activities in the Americas. “Last year in the United States, even with the absence of major hurricane impacts, the insurance industry paid out approximately $35 billion in losses due to weather-related events. Severe weather will continue to impact the economy, and society in general, until we take the necessary measures to increase our resilience.”

Although extreme weather in developed countries exacts a higher human toll than in industrialized nations, the high economic cost associated with recent U.S. disasters is shifting more of the financial burden on taxpayers.

Cynthia McHale, who runs the insurance program at the nonprofit Ceres, said the National Flood Insurance Program now has $1.2 trillion of commercial and residential assets on its books. Beyond flood risk, the risk pools backed by state guarantees known as “residual markets” grew from $55 billion in 1990 to $758 billion in 2010.

“If we continue on this path, extreme weather is certain to cause more homes and businesses to be uninsurable in the private insurance market, leaving the costs to taxpayers or individuals,” McHale said.

Last week, Lloyd’s of London posted its first pretax loss in six years, citing the costs it incurred related to natural catastrophes last year. That year now ranks as the second-most expensive on record in terms of insured disaster claims, with industry estimates ranging between $100 billion and $116 billion.

The IPCC report identifies “no regrets” strategies policymakers can pursue that reduce the risk of disasters while promoting sustainable development and climate adaptation, including early-warning systems for hurricanes and better building design and regulation to lower the impact of flash floods.

“There are lots of opportunities which pay off,” said Field, who coedited the new report.

Article source: http://seattletimes.nwsource.com/html/nationworld/2017895407_climate03.html