• Climate change creates maddening 'weather whiplash'

    Office of Missouri Gov. Jay Nixon via Reuters

    Flooding is seen along the Mississippi River near LaGrange, Missouri, in this April 21, handout photo courtesy of the Missouri Governor's Office.

    By Larry O'Hanlon
    Discovery News

    The term "weather whiplash" is being invoked to describe the drought-flood cycles beginning to take over the Mississippi and Missouri rivers.

    The cause of the maddening weather extremes and their huge and varied consequences is none other than climate change, according to a new report by the climate science communication organization Climate Nexus, and backed by climate researchers.

    "In some parts of the world, including the 1.2 million square miles comprising the Mississippi River Basin, climate change can manifest as alternating periods of 'feast or famine' -- wide swings of extremes such as flooding and drought," the report reads.

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    The term "weather whiplash" was first invoked to describe this effect by science writer Andrew Freedman in 2009. But now climate scientists are using the term, and pointing to the current floods, in the Midwest as the classic case.

    "I'm using it now to describe the longer term kind of flooding-drying cycles," said meteorologist Jeff Masters, co-founder and director meteorology at the Weather Underground. "It's pretty amazing. It used to be only one in three years were flood years. Now it's almost every year."

    The whiplash has become especially painful in river towns where just a few months ago dredging was needed to keep goods afloat and keep communities alive. Now sandbags are the only thing holding back the rivers from flooding the very same towns.

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    The physical reason for the extremes is that as the atmosphere gets hotter, it holds more water and so is capable of generating more extreme rainfall events, Masters explained. On the other hand, it’s harder to separate water from warmer air, which means drier seasons get drier.

    We do expect to see both drought and floods in a hotter atmosphere Masters told Discovery News. "The models say the wet areas are going to get wetter and dry areas drier."

    And since climate change is global, the whiplash isn’t only happening in North America.

    "In the U.S. of course, it is going from floods in 2011 (Missouri through Ohio River Valley to New England, flooding Mississippi and Missouri) to widespread drought in 2012 and back to floods in 2013," said climate researcher Kevin Trenberth of the National Center for Atmospheric Research. "But it's much worse in Australia: a nine-year drought then floods mid-2010 to mid-2011 and then back to drought and record heat in Jan(uary) this year."

    Nor can the pattern be expected to get any better, say climate scientists.

    "Society and its infrastructure were designed for the climate of the past, not for the rapidly changing climate of the present or the future," reads the Climate Nexus report, quoting from the 2013 National Climate Assessment. "Climate change, once considered an issue for a distance future, has moved firmly into the present. Impacts related to climate change are already evident in many sectors and are expected to become increasingly challenging across the nation throughout this century and beyond."

  • Drought blamed for demise of Mayans

    Andrea Dailey at Longwood University

    This silkscreen shows dates in the Maya Long Count Calendar and a sacred calendar called the Tzolk'in. The silkscreen is based on carvings found in Quirigua, Guatemala.

    By Stephanie Pappas
    LiveScience

    The Mayan apocalypse may have been a bust, but a century-old understanding of the calendar that spawned the doomsday rumors appears to be right on.

    In a new study, scientists used modern methods to double-check the match between the Mayan Long Count calendar and the modern European calendar. Understanding how the two coincide is important, because research on the rise and fall of the Maya suggests that climate change spelled their doom. To be certain of that link, however, researchers have to be able to match carved Maya historical records with dates in the modern calendar.

    Linking the two calendars is no picnic. The Long Count calendar is essentially a cyclical count of days, known as k'in. The k'in are counted in 20-day cycles called winal or uinal, which in turn are catalogd in 360-day cycles called tuns. Twenty tuns make a 7,200-day k'atun (about 20 years), and 20 k'atuns then make a b'ak'tun. [Images: Mayan Calendar Carvings]

    Each b'ak'tun is 144,000 days long, representing a little less than 400 years. It was the ending of one of these b'ak'tuns that led to rumors of the end of the world on Dec. 21, 2012. 

    Tracking time
    This base-20 Long Count calendar fell into disuse in the Maya empire before Spanish explorers arrived in South and Central America in the 1500s. That means there are few historical records that can be used to link the Long Count with European methods of tracking time.

    In 1905, a researcher named Joseph Goodman proposed a conversion formula, later added to by other researchers and renamed the Goodman-Martinez-Thompson (GMT) correlation. The GMT correlation is based on a few historical texts as well as astronomical data. In 1960, University of Pennsylvania researchers carried out radiocarbon dating of two wooden lintels from Tikal, Guatemala, a major Maya city. The dating uses isotopes, or molecular variations, in organic material to determine age. In this case, it seemed to confirm the GMT correlation. 

    But dating technology has come a long way in five decades, and Pennsylvania State University archaeologist Douglas Kennett wanted to be sure the dates were accurate.

    "When looking at how climate affects the rise and fall of the Maya, I began to question how accurately the two calendars correlated using those methods," Kennett said in a statement.

    Confirming the calendar
    To find out, Kennett and his colleagues re-radiocarbon dated a lintel beam previously supposed to be carved sometime between A.D. 695 and 712. They used the tree rings still visible in the carved wood as well as carbon isotopes to determine the beam's age.

    The analysis pegged the lintel's carving at around A.D. 658-696, an overlap that backs up the original GMT correlation estimates. The two estimates are even more likely to match up when you consider that 10 to 15 years of wood growth were likely removed from the lintel during carving, the researchers wrote Thursday in the journal Scientific Reports.

    This particular lintel carving celebrates the defeat of Tick'aak K'ahk', king of the nearby city of Calakmul, by Tikal's leader Jasaw Chan K'awiil. The new study confirms previous suspicions that this victory occurred in A.D. 695, 13 years after Jasaw Chan K'awiil ascended to the throne. 

    "These events and those recorded at cities throughout the Maya lowlands can now be harmonized with greater assurance to other environmental, climatic and archaeological datasets," the researchers wrote, adding that the confirmation further supports the theory that climate change and drought contributed to the Maya's rise and fall.

    Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook and Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Isn't that the pits: Weather creates olive oil shortage

    Rich Pedroncelli / AP file

    Spain is the world's largest producer of olive oil, making almost half the global supply, according to the Guardian. But Spain was one of several olive-producing countries hammered by a drought that swept across southern Europe in the summer of 2012.

    By Marc Lallanilla
    LiveScience

    Erratic weather, including a devastating drought in Europe and a freak hailstorm in Australia, has left the world with a looming shortage of olive oil.

    In spring of 2012, a late frost hit Spain in the middle of the olive's flowering season, according to the Huffington Post. As a result, Spanish olive trees produced fewer fruits, and those olives the trees did produce were smaller and yielded less oil.

    Spain is the world's largest producer of olive oil, making almost half the global supply, according to the Guardian. But Spain was one of several olive-producing countries hammered by a drought that swept across southern Europe in the summer of 2012.

    While olive growers in Greece, Turkey, Italy and Tunisia all suffered from the drought, none reported losses like the staggering 60 percent drop in olive production that hit Spanish growers, according to the Daily Mail.

    These factors — combined with a severe hailstorm that destroyed roughly 6 percent of Australia's olive crop, according to Australia's ABC.net news service — have left restaurants and food manufacturers worldwide in a tight spot.

    Not only will the olive oil shortage raise prices, but it's also expected to increase the already-rampant illegal doctoring of olive oil, the Daily Mail reports. In 2011, two businessmen in Spain were found guilty of selling extra-virgin olive oil that was, in fact, 75 percent sunflower oil, a cheaper substitute.

    The market for olive oil has grown rapidly in recent years as food scientists have touted the product's health benefits. Studies have shown that the oil can improve cholesterol levels, and it's an important component of the Mediterranean diet, frequently cited as one of the most healthful ways of eating.

    Email Marc Lallanilla or follow him @MarcLallanilla. Follow LiveScience on Twitter @livescience, Facebook & Google+. Original article on LiveScience.com.

    Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

  • Australia drought may have led to demise of aboriginal culture

    By Tia Ghose
    LiveScience

    A 1,500-year drought in Australia may have led to the demise of an ancient aboriginal culture, a new study suggests.

    The results, published Nov. 28 in the journal Geophysical Research Letters, show that geological traces of a mega-drought in the northwest Kimberley region of Western Australia coincide with a gap and transition in the region's rock art style. The finding suggests that the people who lived prior to the drought, called the Gwion, either left the region or dramatically altered their culture as a result of the drought, and a new culture called the Wanjinda eventually took its place.

    "There is this significant gap in rock art. A possible reason for that is that the climate at that time changed so markedly that the artists who produced the Gwion art moved on from the Kimberley region," said study co-author Hamish McGowan, a climatologist at the University of Queensland in Australia.

    But not everyone agrees with that interpretation. While the evidence for a drought is very convincing, archaeological sites show continuous occupation during that time, said Peter Veth, an archaeologist at the University of Western Australia who is an expert in the Kimberley's rock art and was not involved in the study.

    "They reconfigure themselves on the land and often do portray things quite differently, but I don't see it as a different people," Veth told LiveScience.

    Ancient inhabitants
    Aboriginal cultures have inhabited Northwest Australia for the past roughly 45,000 years, McGowan said. But at least 17,000 years ago during the Pleistocene Era, a culture called the Gwion began depicting aspects of their life on the rocks in the region. The Gwion art depicted some extinct animals (such as a marsupial lion that went extinct during the last ice age) but also groups of slim figures in what look like ancient celebrations. [ Image Gallery: Europe's Oldest Rock Art ]

    But between 5,000 and 7,000 years ago, traces of the Gwion rock art disappeared, and it wasn't until around 4,000 years ago when a new style of rock-art painting called the Wandjina, which depicts round faces with big eyes, emerged. It is still practiced today.

    Pollen record
    To understand why the rock art changed, McGowan and his colleagues analyzed sediments drilled from Black Springs, Australia. They found that around 6,300 years ago, the type of pollen started to change, suggesting a transition from a lush environment to one characterized by scrubby forests and open grasslands. The sediments also show an increase in dust, suggesting much drier conditions.

    The results painted a picture of an ancient mega-drought that roughly coincided with the disappearance of Gwion art, McGowan said.

    "The northwest of Australia can undergo very substantive natural changes in climate, which in the past have severely impacted aboriginal society," he told LiveScience, adding the climate change and disappearance of Gwion art suggest these people left the region.

    But while it's likely that the drought radically altered the local societies, the rock art from the area isn't dated well enough to make conclusions about the complete disappearance of the culture, Veth said.

    What's more, archaeological evidence suggests the area was continuously occupied, he told LiveScience. For instance, archaeologists find very similar stone tools throughout the drought, Veth said.

    "They have identified a very interesting climate episode and it does seem to correlate with this switch — and that's the word I would use — a switch in the way people are portraying art," he said.

    Follow LiveScience on Twitter @livescience. We're also on Facebook  and Google+.

  • NOAA: 2012 was warmest year ever for US, second most 'extreme'

    Last year was one for the history books, as a long-term warming trend brought two record highs for each record low between 2000 and 2010. And even more concerning, in the past year there were five record highs for each low recorded. NBC's Anne Thompson reports.

    By Elizabeth Chuck, Staff Writer, NBC News

    If you found yourself bundling up in scarves, hats, and long underwear less than usual last year, you weren't alone: 2012 was the warmest year on record in the contiguous United States, according to scientists with The National Oceanic and Atmospheric Administration.


    The average temperature for 2012 was 55.3 degrees Fahrenheit, 3.2 degrees above normal and a full degree higher than the previous warmest year recorded -- 1998 -- NOAA said in its report Tuesday. All 48 states in the contiguous U.S. had above-average annual temperatures last year, including 19 that broke annual records, from Connecticut through Utah.

    “We’re taking quite a large step,” said Jake Crouch, a climate scientist from the NOAA National Climatic Data Center, which has recorded temperatures in the contiguous U.S. for the past 118 years.

    It was also a historic year for "extreme" weather, scientists with the federal agency said. With 11 disasters that surpassed $1 billion in losses, including Superstorm Sandy, Hurricane Isaac, and tornadoes across the Great Plains, Texas, and the Southeast and Ohio Valley, NOAA said 2012 was second only to 1998 in the agency's "extreme" weather index.

    A long-term warming trend for the U.S., combined with drought and a northerly jet stream, led to the record heat, explained Crouch. 

    "During the winter season, the jet stream tended to stay further north of the U.S.-Canadian border, so that limited colder outbreaks in the country. It also limited precipitation. So that led to a warm and dry winter season, and that persisted through the spring," he said. 

    Matt Rourke / AP file

    People play in water from an open fire hydrant during the afternoon heat on July 18, 2012, in Philadelphia. July was the hottest month ever on record in the contiguous U.S.

    "That warm and dry spring and winter laid the groundwork for the drought we had this summer... . When we have drought, it tends to drive daytime temperatures upward."

    The unprecedented warm weather wasn't contained to the United States.

    A corresponding rise in global temperatures prompted the World Meteorological Organization to call the rate at which the Arctic sea ice was melting "alarming" in its Nov. 28, 2012, report.

    “The extent of Arctic sea ice reached a new record low. The alarming rate of its melt this year highlighted the far-reaching changes taking place on Earth’s oceans and biosphere. Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records,” World Meteorological Organization Secretary-General Michel Jarraud said.

    Each year since 2001 has been among the warmest on record worldwide, with 2012 likely to "be no exception despite the cooling influence of La Niña early in the year," the report added.

    'Horrible' sea level rise of more than 3 feet plausible by 2100, experts say 

    Watch NBC's special coverage of the 2012 drought 

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    NOAA expects to have global data for 2012 sometime in the coming weeks, but Crouch said scientists already know with certainty "it's going to be in the top ten" warmest years ever.

    Adding to the extremes: 2012 was the driest year on record for the U.S., with 26.57 inches of average precipitation -- 2.57 inches below average. Those dry conditions created an ideal environment for wildfires in the West, which charred 9.2 million acres -- the third highest amount ever recorded, NOAA said Tuesday.

    Other notable climate activity from 2012:

    • Snowpack totals across the Central and Southern Rockies were less than half normal.
    • July was the hottest month ever on record in the contiguous U.S.
    • Tornado activity was concentrated toward the beginning of the season, with large outbreaks in March and April in the Ohio Valley and Central Plains, but the final 2012 tornado count will likely be less than 1,000 -- the least since 2002. "The factors behind that are kind of related to what was going on with the drought. We didn't have these large storm systems moving through the country, so that limited precipitation, and that also limited severe weather outbreaks," Crouch said. What made this year so high on the extreme weather index were cyclones, hurricanes, and the heat, he said.
    • Alaska was cooler and slightly wetter than average, and had a record-cold January. "Their January temperatures were 14 degrees below average. Many locations in Alaska had temperatures 30 degrees below zero," Crouch said, adding that Anchorage, Alaska, set a new snow record.
    • Hawaii experienced growing drought conditions, with 47.4 percent of the state experiencing moderate-to-exceptional drought at the beginning of 2012 and 63.3 percent at the end of the year. Alaska and Hawaii were not included in the bulk of NOAA's 2012 report because of terrain issues, and because scientists don't have records dating back as far as states in the contiguous U.S.

    While NOAA made no meteorological forecasts for 2013, Crouch said the drought was going to continue to be an issue.

    "The drought got a lot of attention this summer when it was having impacts on agriculture. More than 60 percent of the country is still in drought," he said. "And if things don't change, the drought is going to continue to be a big story in 2013."

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