Climate change contributed towards the collapse of the Maya

Adam Steedman Thake in New Historican: Climate change is one of the major problems facing the world today. It is not simply a modern-day occurrence, however. Ancient populations also struggled to deal with changes in their environment.

New research has explored the devastating consequences of climate change on an ancient Maya civilisation.

Researchers have found that historic droughts in Central America matched the patterns of disruption to Maya society. Importantly, these findings provide clues regarding the longstanding questions about what role climate change had in the Maya collapse between 800 and 950 CE.

Paleoclimate records indicate a series of severe droughts occurred during this period of Maya decline. Evidence for drought, however, largely derives from the drier, less populated northern Maya Lowlands. As such, this does not explain the much more drastic societal disruption in the humid conditions of the southern Maya Lowlands.

“Our work demonstrates that the southern Maya lowlands experienced a more severe drought compared to the north,” said Mark Pagani, a Yale University professor of geology and geophysics and co-author of the study, published in the Proceedings of the National Academy of Sciences....

Mayan compass, "Chimera of the Crystal Skull," shot by Rikfriday : Xneotek.com, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license 

Archaeologists bring long-term perspective to food security and climate shock

EurekAlert via Arizona State University: What role does pre-existing vulnerabilities play for people who experience a climate shock? Does it amplify the effects of the climate shock or is effect negligible? Four Arizona State University archaeologists are looking into this as part of an international team examining how people can be most resilient to climate change when it comes to food security.

The group questioned whether vulnerability to food shortages prior to a climate shock – not the actual experience of the food shortage – is related to the scale of impact of that shock. They found a strong relationship.

The team used long-term archaeological and historical data from the North Atlantic Islands and the U.S. Southwest to form the basis of their understanding of changing dynamics in these areas. Each case in their study included information on evolving social, political and economic conditions over centuries, as well as climate data. The extended timeframe and global scope allowed them to witness changes in the context of vulnerabilities and climate challenges on a wide scale.

"The pattern is so consistent across different regions of the world experiencing substantially different climate shocks, that the role of vulnerability cannot be ignored," said Margaret Nelson, an ASU President's Professor in the School of Human Evolution and Social Change.

...Their findings support the argument for focusing on reducing vulnerabilities to climate shocks to boost resilience, which will ultimately lead to fewer required recovery efforts when crises occur. Nelson said that most often disaster management does not address vulnerabilities prior to shocks but instead focuses on returning a system to its previous condition following a disaster.

"Exposures to climate challenges and other environmental risks are not the sole causes of disasters," she says. "People have unintentionally built vulnerabilities through decisions and actions in social, political and economic realms."...

Cutthroat Castle at Hovenweep National Monument, Utah. Shot by HJPD, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license

Researchers target sea level rise to save years of archaeological evidence

Newswise via Florida State University: Prehistoric shell mounds found on some of Florida’s most pristine beaches are at risk of washing away as the sea level rises, wiping away thousands of years of archaeological evidence.

“The largest risk for these ancient treasure troves of information is sea level rise,” said Shawn Smith, a senior research associate with the Center for Ocean-Atmospheric Prediction Studies at Florida State University.

But a joint project between Smith and the National Park Service is drawing attention to the problem to hopefully minimize the impact on the state’s cultural sites. Smith and Margo Schwadron, an archaeologist with the National Park Service, have embarked on a project to examine past and future changes in climate and how we can adapt to those changes to save areas of shoreline and thus preserve cultural and archeological evidence.

“We’re kind of the pioneers in looking at the cultural focus of this issue,” Smith said, noting that most weather and ocean experts are concerned about city infrastructure for coastal areas.

To complete the project, the National Park Service awarded Smith a $30,000 grant. With that money, Smith and former Florida State University undergraduate Marcus Johnson spent hours compiling modern, colonial and paleo weather data.

The focus of their initial research is the Canaveral National Seashore and Everglades National Park, which both have prehistoric shell mounds, about 50 feet to 70 feet high. Researchers believe these shell mounds served as foundations for structures and settlements and later served as navigational landmarks during European exploration of the region....

The beach at Canaveral National Seashore, National Park Service

Cool heads likely won't prevail in a hotter, wetter world

Morgan Kelly in News at Princeton: Should climate change trigger the upsurge in heat and rainfall that scientists predict, people may face a threat just as perilous and volatile as extreme weather — each other.

Researchers from Princeton University and the University of California-Berkeley report in the journal Science that even slight spikes in temperature and precipitation have greatly increased the risk of personal violence and social upheaval throughout human history. Projected onto an Earth that is expected to warm by 2 degrees Celsius by 2050, the authors suggest that more human conflict is a likely outcome of climate change.

The researchers analyzed 60 studies from a number of disciplines — including archaeology, criminology, economics and psychology — that have explored the connection between weather and violence in various parts of the world from about 10,000 BCE to the present day. During an 18-month period, the Princeton-Berkeley researchers reviewed those studies' data — and often re-crunched raw numbers — to calculate the risk that violence would rise under hotter and wetter conditions.

They found that while climate is not the sole or primary cause of violence, it undeniably exacerbates existing social and interpersonal tension in all societies, regardless of wealth or stability. They found that 1 standard-deviation shift — the amount of change from the local norm — in heat or rainfall boosts the risk of a riot, civil war or ethnic conflict by an average of 14 percent. There is a 4 percent chance of a similarly sized upward creep in heat or rain sparking person-on-person violence such as rape, murder and assault. The researchers report that climate-change models predict an average of 2 to 4 standard-deviation shifts in global climate conditions by 2050.

..."We think that by collecting all the research together now, we're pretty clearly establishing that there is a causal relationship between the climate and human conflict," Hsiang said. "People have been skeptical up to now of an individual study here or there. But considering the body of work together, we can now show that these patterns are extremely general. It's more of the rule than the exception....

The researchers analyzed 60 studies from a number of disciplines that have explored the connection between weather and violence in various parts of the world, and throughout human history. A sampling of existing results (graphed above) show a correlation between temperature on violent personal crime and rape in the United States (A, B); drought and global civil conflict (H); temperature and the ouster of leaders worldwide (J); deviation from normal rainfall and large-scale violence in Africa (K); and global civil conflict and the intensity of El Niño (L). The darker areas indicate a stronger connection between climate and violence. Panel titles indicate the type of violence studied, the location, the unit of analysis and sample size, and the study citation. (Image by Science/AAAS)

New evidence links Mayan collapse to climate change

Voice of America: The ancient Mayan civilization, which developed a sophisticated culture in the Central American rainforests, vanished mysteriously a thousand years ago.  Now, an international team of anthropologists, archeologists, chemists and climatologists says it has identified the cause of the Mayan collapse: climate change.

To create a weather record for the past 2,000 years, the scientists analyzed a natural mineral formation called a stalagmite from a cave in Belize, using oxygen-isotope dating to determine how much rain fell on the region over the centuries. Stalagmites build up incrementally, like tree rings, as water drips through the cave ceiling, preserving an accurate climate record.

Mayan rulers commissioned stone monuments to record important events such as their rise to power, major battles, civic unrest and strategic alliances.  Pennsylvania State University Anthropology professor Douglas Kennett, the study's co-author, says the team was able to compare changes in the society documented on those monuments with their new climate timeline.

On a podcast for the journal Science, he said the team saw a relationship between rainfall levels and political stability. "The growth of Maya civilization and increases in population and levels of sophistication actually correlate with a very wet interval that spans several hundred years and the decline of the Maya actually appeared to correlate with a downturn generally in climate and climate drying," he said....

A Mayan zodiac circle, shot by theilr, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Climate change led to collapse of ancient Indus civilization

Woods Hole Oceanographic Institution: A new study combining the latest archaeological evidence with state-of-the-art geoscience technologies provides evidence that climate change was a key ingredient in the collapse of the great Indus or Harappan Civilization almost 4000 years ago. The study also resolves a long-standing debate over the source and fate of the Sarasvati, the sacred river of Hindu mythology.

Once extending more than 1 million square kilometers across the plains of the Indus River from the Arabian Sea to the Ganges, over what is now Pakistan, northwest India and eastern Afghanistan, the Indus civilization was the largest—but least known—of the first great urban cultures that also included Egypt and Mesopotamia. Like their contemporaries, the Harappans, named for one of their largest cities, lived next to rivers owing their livelihoods to the fertility of annually watered lands.

“We reconstructed the dynamic landscape of the plain where the Indus civilization developed 5200 years ago, built its cities, and slowly disintegrated between 3900 and 3000 years ago,” said Liviu Giosan, a geologist with Woods Hole Oceanographic Institution (WHOI) and lead author of the study published the week of May 28 in the Proceedings of the National Academy of Science. “Until now, speculations abounded about the links between this mysterious ancient culture and its life-giving mighty rivers.”

Today, numerous remains of the Harappan settlements are located in a vast desert region far from any flowing river. In contrast to Egypt and Mesopotamia, which have long been part of the Western classical canon, this amazingly complex culture in South Asia with a population that at its peak may have reached 10 percent of the world’s inhabitants, was completely forgotten until 1920’s. Since then, a flurry of archaeological research in Pakistan and India has uncovered a sophisticated urban culture with myriad internal trade routes and well-established sea links with Mesopotamia, standards for building construction, sanitation systems, arts and crafts, and a yet-to-be deciphered writing system...

Once extending more than 1 million square kilometers across the plains of the Indus River from the Arabian Sea to the Himalayas and the Ganges, over what is now Pakistan, northwest India and eastern Afghanistan, the Indus civilization was the largest—but least known—of the first great urban cultures that also included Egypt and Mesopotamia. Named for one of their largest cities, the Harappans relied on river floods to fuel their agricultural surpluses. Today, numerous remains of the Harappan settlements are located in a vast desert region far from any flowing river. (Liviu Giosan, Woods Hole Oceanographic Institution; Stefan Constantinescu, University of Bucharest; James P.M. Syvitski, University of Colorado.)

Universities to monitor impact of floods on UK heritage sites

The Engineer (UK): A new interdisciplinary research project will monitor and predict the impact of floods and driving rain on historic buildings to try and protect them for future generations. The risk of flooding is likely to increase owing to climate change and the effects of increased urban development. The 2007 flooding in the south west and the 2009 flood in Cumbria have shown that substantial structural damage can be caused by events such as these to heritage buildings and infrastructure.

The PARNASSUS project brings together engineers and conservationists from Bath University, archeologists from Southampton University and geographers and materials engineers from Bristol University to predict how historic structures react when subjected to flooding and driving rain.

The researchers will survey the effects of past floods and use flood and climate change modelling tools to assess the risks of future flooding for heritage sites selected by the National Trust, Historic Scotland and English Heritage. The project will investigate the effect of water saturation on the structural integrity of the buildings and measure deterioration caused by freezing and thawing.

Cold weather can cause water trapped in the masonry to expand, leading to the cracking and damaging of the structural strength of the building. Part of the study will be to assess past levels of the deterioration of sites to identify which types of buildings are most vulnerable to freeze-thaw damage….

Bodiam Castle, East Sussex, England, shot by WyrdLight-McCallum Photography www.wyrdlight.eu, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license.

Architectural impact of climate change mimicked in lab tests

The University of Bristol (UK): The architectural and structural havoc wreaked by torrential rain, flooding and fluctuating temperatures could be prevented thanks to analysis based on laboratory simulations. Through a series of tests using the combined talent of architects, scientists and engineers, experts hope to produce a clear picture of the anticipated effects of climate change on historic buildings throughout the UK, in some cases, over the next 100 years.

The initiative is part of a multi-million project aimed at preserving archaeological sites identified by the National Trust in Deer Hurst, Tewkesbury, York and Winchester, through a collaboration between the universities of Bath, Bristol and Southampton.

One of the key tests will be to assess the flooding risks using sophisticated flood and climate change modelling tools developed by the University of Bristol’s School of Geographical Sciences. The models predict the depth, extent and velocity of flooding using computer simulations, which map a range of potential flood patterns onto detailed terrain data taken at high resolution by scanning lasers, fixed to aircraft or road vehicles to enable an exact level of precision.

“Risk assessments are valuable in ensuring that resources are concentrated towards sites that are most likely to need flood protection,” said Professor Paul Bates. “What is unique about this project is the inter-disciplinary approach; working with architects and engineers will enable us to better calculate future potential damage and impact.

“We don’t know exactly how much climate is going to change in the future but we do have a range of things that might happen. Our aim is to develop predictions that will take account of the full range of possible scenarios. It’s a case of quantifying those uncertainties and identifying what action would need to be taken.”…

Windsor Castle and the River Thames from the Brocas Meadows in Eton, shot by Chris Wood, Wikimedia Commons, under the Creative Commons Attribution ShareAlike 3.0 License

Coastal castles in the UK could be moved inland

Louise Gray in the Telegraph: As sea levels threaten a number of historic properties, the government is considering ways to protect them. Historic monuments that are threatened with destruction could be moved in exceptional circumstances to a "more sustainable location", according to a consultation paper released by the Department for the Environment. Coastal defences should be improved in less severe cases and valuable assets recorded in case they are lost forever, it says.

Owners of homes which will be lost to the sea could receive grants to cover demolition and moving costs. This week the Met Office will warn of the threat of rising sea levels to Britain over the next 80 years.

…There is precedent for historic buildings to be dismantled and rebuilt elsewhere. The 17th Century Clavell Tower, at Kimmeridge Bay, Dorset was recently moved 25 metres inland at a cost of £898,000. At St Fagans National History Museum in Cardiff buildings a school, chapel, Workmen's Institute, farms and houses have been re-erected.

Hundreds of monuments around the British coast are at risk of sea level rises and erosion and could be candidates for relocation. St Michael's Mount in Cornwall which is currently reached by a causeway could become an inaccessible island, Westbury Court Garden in Gloucestershire could be flooded by the River Severn and Dunstanburgh Castle in Northumbria is under threat from erosion….

Dunstanburgh Castle, shot by Glen Bowman from Newcastle, England, Wikimedia Commons via Flickr, under Creative Commons Attribution 2.0 License

Lesson from the past for surviving climate change

E-Science News, via the University of Leicester: Research led by the University of Leicester suggests people today and in future generations should look to the past in order to mitigate the worst effects of climate change. The dangers of rising sea levels, crop failures and extreme weather were all faced by our ancestors who learnt to adapt and survive in the face of climate change.

Dr Jago Cooper, of the School of Archaeology and Ancient History at the University of Leicester, has been studying the archaeology of climate change in the Caribbean as part of a Leverhulme Early Career Fellowship. The international study involves researchers from Britain, Cuba and Canada. Dr Cooper said: "Populations in the Caribbean, from 5000 BC to AD 1492, successfully lived through a 5 meter rise in relative sea levels, marked variation in annual rainfall and periodic intensification of hurricane activity.

"This research examines the archaeological lessons that can inform current responses to the impacts of climate change in the Caribbean. I have examined the relationship between long and short-term effects of climate change and past human engagement with the geographical, ecological and meteorological consequences. A key focus of the research has been to investigate past mitigation of the impacts of climate change through the analysis of changes in settlement structures, food procurement strategies and household architecture."

…Said Dr Cooper: "We have acquired archaeological information that has then been closely correlated in space and time with the long and short-term impacts of climate change. It has then been possible to evaluate the relative advantages and disadvantages of past cultural practices in the face of environmental change and establish lessons that will contribute to contemporary mitigation strategies."

Following the end of the last Ice Age, the people of the Caribbean have had to cope with a relative sea level rise of 5m over 5,000 years. Hurricanes led to storm surges that reached inland more than ever. Groundwater became contaminated with salt and the land was waterlogged. But the researchers found that far from abandoning life by the coast and moving further inland, people continued to live by the shore- and even built houses on stilts over a lagoon…..

In the aftermath of Hurricane Gustav, waters off the southern coast of Northern Cuba were significantly churned up by the 150mph winds and 30 foot swells. Photo by NASA

Climate change casts a cloud over Britain's stately piles

The Independent (UK): They have withstood centuries of war and decay and the fluctuating fortunes of their once super-wealthy owners, but now Britain's stately homes face a potentially more destructive force: climate change. The National Trust says at least seven historic stately homes – some up to 600 years old – have been damaged by climate-change-related incidents, such as flooding, over the past five years, with repair costs running into millions of pounds.

These include 300-year-old Calke Abbey in Derbyshire, The Vyne, a 16th-century house in Hampshire, and Coughton Court, a Tudor stately home in Warwickshire, which were all damaged by flooding in 2007.

Last year heavy rainfall caused extensive damage to Cragside, a unique Victorian manor house in Northumberland built in 1870. It was the first building in the world to use hydroelectricity, and all the house's power comes from a turbine fed by a nearby stream.

Last year's heavy rainfall flooded the newly refurbished pump house, and left the ground floor under water, damaging the iron fireplaces and an early billiard table, which took months to dry out.

Floods have also destroyed some of the Trust's historic gardens – such as Westbury Court, on the River Severn, which was wiped out by salt water – as well as causing extensive damage to the Cornish village of Boscastle, which the Trust administers, in 2004. Warmer weather also means more insects, as well as algae in artificial lakes, such as at Stourhead in Wiltshire, where a mirror-like surface designed to reflect the house became a soupy sludge in 2006. Drought also means traditional plants will no longer grow….

Coughton Court, shot by Niki Walton, Wikimedia Commons, under Creative Commons Attribution ShareAlike 2.0 License

The climate peril to archaeological sites

Archaeology.org points out the impacts of climate change on vulnerable archaelogical sites, with some compelling examples: Rising sea levels are eating away at coastal sites, increased rainfall is eroding mud-brick ruins, creeping desert sands are blasting the traces of ancient civilizations, and the melting of ice is causing millennia-old organic remains to rot. "With climate change, we're feeling a sense of urgency," says University of Northern Colorado anthropologist Michael Kimball, who organized a panel discussion on climate change and archaeology at the World Archaeology Congress in Dublin last year. "It definitely focuses the mind."

For countless communities, archaeology can be a source of local identity, pride, and even income. "It may be intangible, but when a community loses its connection to history it loses something pretty important," says Kimball.

The International Panel on Climate Change (IPCC), a group of more than 1,000 experts on climate science convened by the United Nations, estimates that the world's temperature has risen about two degrees in the past century, thanks in part to an increase in carbon dioxide that traps heat in the earth's atmosphere. The consequences have already been dramatic. The world's oceans have risen four inches in that time. Weather patterns have also gotten less predictable and more extreme.

Over the next hundred years, the IPCC predicts that sea levels will rise at least another four inches. The worst-case scenario is truly frightening: a 10-degree rise in global temperatures, causing ice caps to melt and sea levels around the world to rise more than three feet.

Archaeologists can't stop global warming, but they can make dealing with it a priority. That may mean documenting sites before they disappear; in some places, simple steps like putting roofs over melting or rain-threatened areas are ways to preserve them. Action, however, must be taken soon. "Our job is not so much to talk about how to get climate change to stop," says Giovanni Boccardi, the chief of UNESCO's Asia and Pacific Unit. "While climate change is global, lots of solutions are local--and within our reach." …

From http://en.wikipedia.org/wiki/Image:Egypt.LuxorTemple.02.jpg, Pharaonic statue Photo taken by Hajor, Dec.2001. Released under cc.by.sa and/or GFDL.