~Salek, Ishmael, and Beekeepa, separately

Intercultural jam session. © BY GARRETT PALM. ALL RIGHTS RESERVED.

Editor’s note: Correspondent Garrett Palm recently traveled in West Africa, volunteering at the Festival Au Desert. This is the third installment of his story.  Read part one: Travel: Green tea and music videos in Mali, and part two: Travel: Along the Niger River. More photos at Palm’s Flickr feed.

Tuareg gather at the Festival in the Desert. © BY GARRETT PALM. ALL RIGHTS RESERVED.

Story and photos by Garrett Palm

Arriving at the port of Korioumé outside of Tombouctou was a shock. The boatmen all told us different times for our arrival. We pulled in a few hours before any of their guesses. The plank of wood over the muddy bank bowed under our weight, after 30-some hours of being well-fed with capitaine, a local fish straight out of the river, served with beet and potato salads.

One other penasse pulled to shore at the scraggly port, consisting of a few mud huts. Three other Westerners waited for their driver (they were early, too). I approached them to ask where they were from — Southeast side of Portland, Oregon. I called over the other Portlander on our boat, owner of a world music record label. They were part of a group of eight from Portland, including a family with two young kids in kindergarten and first grade. So far, every American I met in Africa was from Portland.

Why does Portland have its people everywhere? Brooklyn, where I recently lived, is full of Oregonians. We all love our home and talk about how we miss it, so we weren’t driven away by boredom. Portland just produces people who are curious about the world.

The moment we got off the penasse the hard sell began. Craftsmen came straight to every white face, holding up  jewelry or hats,  asking what you think a good price would be. There was some of that in Bamako, and more in Mopti, but it was non-stop in Tombouctou. The vendors do not accept “no, merci” for an answer, no matter how many times you repeat it.

Cadeaux! Cadeaux! © BY GARRETT PALM. ALL RIGHTS RESERVED.

We stayed the night in a secured hotel. The army had not yet arrived to the area so we had to rely on our security. The city felt safe and no one was worried. A small crowd of locals appeared outside our gate, apparently to welcome us and say hello.

We slept on mattresses on the floor. It was my second (and so far last) night indoors in Africa. Since I’ve been here I’ve spent two nights and one meal indoors. The rest of my time in Africa has been entirely outdoors, often sleeping in tents.

In the desert. © BY GARRETT PALM. ALL RIGHTS RESERVED.

The next day we began working on the Festival in the Desert, two kilometers outside  town in the sand dunes of the Sahara. My job was to welcome and register all the ticket buying visitors to the festival.

Traditionally, the Tuareg tribes gathered this time of year to meet, discuss disputes, trade, and play music together. Nomadic tribes travel for weeks by camel to reach the festival. Eleven years ago a group formalized the occasion and invited foreigners. Usually the festival attracts 700-1,000 foreigners. This year, due to a potential terrorist threat from the Al Qaeda in the Islamic Maghreb (AQIM), the numbers were down. I checked in just 150 foreigners. That drop in tourists meant that the craftsmen who make their living once a year off of the 1,000 people now had to get it out of 150.

A caravan of Tuareg arrives at the Festival in the Desert. © BY GARRETT PALM. ALL RIGHTS RESERVED

Everywhere I went I was followed by these craftsmen who just wanted a minute of my time to drink tea and look at their work. Even when I was running around trying to organize an event for the festival, they wanted me to stop. Each one of them became a friend first. Even people I met on the road in Mopti, and the night in Tombouctou, suddenly leveraged this friendship to sell me what they had.

As the festival went on they became more desperate to make sales. Many of us volunteers took time during the day to hide in our tent in peace. I was never sure what interaction was real and what was just to sell me something. It’s possible they wanted to be my friend and sell me their jewelry, not be my friend to sell me their jewelry.

It wasn’t just craftsmen we hid from but kids as well. Every toubob (tourist) was constantly surrounded by children and craftsmen. The children all ask for cadeaux or bic or bonbon, gifts or pens or candy. They won’t let people be alone until they get a gift. Instead of going to school, they chase the tourists who have the money and food. Tourists give them gifts to be left alone or because they think it helps the kids, but it just encourages them to harass more tourists and it takes them away from studying or learning skills.

Please don’t give cadeaux when traveling. Give needed materials or money to school headmasters or local NGOs.

When I wasn’t being hunted for my wallet, the festival was a great time. Welcoming all the tourists allowed me to meet people from all over the world. I was recognized later, back in Bamako, from my front desk stint in Tombouctou. The best represented country was, surprisingly, America. Most travelers I’ve met here are from Europe, but for some reason many Americans came out to the desert. Next was Italy, then France.

After everyone was checked in, I was assigned to put together a group from around the world to go on stage to show that the whole world is here in the Sahara, and that we stand with the Tuaregs against AQIM. I went from camp to camp, getting someone from each nationality to commit. The event was broadcast live on Malian TV. I was introduced as coming from the country of Barack Obama which got a huge cheer. Obama is immensely popular here. His face and name are on many t-shirts, bags, and posters.

African moonrise. © BY GARRETT PALM. ALL RIGHTS RESERVED.

My journey to the desert was for the music, and the concerts were the highlight of the festival.

My life changed in Colorado my first summer out of college, and the music of West Africa was a part of that change. Ali Farke Toure’s album with Ry Cooder, Talking Timbuktu, lead the way. The Niger Delta blues he played – dusty, slow, atmospheric songs of the desert – became my mind-expanding drug. His music became a way to connect with the high desert landscape I lived in at the time and to reconnect with it when I left. His son performed a tribute to his father with a band of all stars.

The headliner of the festival was Tinariwen, a Tuareg band that has recently gained international recognition. They started as rebels fighting the Malian government. Tuaregs are a musical group of nomads. They travel by night and play music in their tents during the hot days. Tinariwen trained with the military in Algeria to fight the Malian government. While they were there they were introduced to electric guitars. Tuareg rock and roll was born.

The crowd grooves to one of the performers. © BY GARRETT PALM. ALL RIGHTS RESERVED.

At one point U2′s Bono joined Tinariwen to sing with them — Bono “of Youtube” as the festival announcer said. Most of the locals weren’t terribly excited to have him onstage, and all he did was scream-sing “viva Timbuktu” and “viva Tinariwen” over the song which did not mesh with the music at all. He watched the rest of the night from the back. It was strange seeing him there.

The surprise performer of the weekend was Koudede, a musician from Niger. The other Portlander on our boat up the Niger discovered him and signed him to his label, and this was his first big show. The music was perfect, danceable West African. Listen here. I danced so much with the Tuaregs that they gave me an honorary Tuareg name: Mohammed Jackson.

One Tuareg boy gave me his fancy indigo turban. It turned my skin blue. My nickname with the other volunteers became Smurf Neck. I’m not a trained dancer beside a few ballet classes as a kid and growing up learning to dance to Michael Jackson from my dad. I do, however, have the skill of making a fool of myself. To me the main skill you need to dance is a lack of self-importance. Dancing is supposed to be freeing. If you worry about how you look you won’t dance.

http://www.flickr.com/photos/gpalm/sets/72157629005973015/show/

The encampment du benevole (volunteer’s camp) was right behind the stage. We slept in the sand after the shows ended around 2 or 3. The food was sandy couscous or rice with oily cabbage. Everything I brought with me is now covered in sand. The sand of the Sahara is finer than the beach sand I’m used to. This makes it softer, but also more intrusive.

At the edge of the festival, on the dunes past the dunes circling the site, was the Malian military. Their flatbed trucks with large Gatling guns attached to the backs stood watch over us all. Every few hours WW II-era fighter planes did low flyovers. It felt like an airshow. At the front desk we set up a tent next to ours for the anticipated tourist check-in spillover (I have no idea how they expected me to check in 1,000 people). When the tourists didn’t show, the front gate guards moved in and took naps with their wooden Tommy guns at their sides.

At the end of the festival most of us volunteers climbed aboard the penasse back to Mopti and slept.

More light snow, then clearing by Saturday evening.

Upslope storm hammers areas east of the Continental Divide

By Summit Voice

SUMMIT COUNTY — One of the biggest snowstorms in recent memory dropped more than 4 feet of snow in a few spots along the Front Range, but left the high country mostly high and dry, with just a few inches reported at most mountain ski areas.

The exceptions are Eldora, reporting 31 inches for the 48-hour storm total, Echo Mountain, with an amazing 55 inches in 48 hours, as well as some of the areas in the San Juans, including Telluride (8 inches), Wolf Creek (9 inches) and Purgatory (12 inches).

An avalanche warning for the Front Range has expired, but the Colorado Avalanche Information Center cautions that the new snow will result in widespread avalanche activity in areas where more than 12 inches accumulated.

Some of the central mountain areas also picked up decent totals, with 9 inches at Monarch and 6 inches at Snowmass. Other areas picked up between 2 and 4 inches in the past couple of days.

The storm set up in a classic upslope pattern, with low pressure spinning across southern Colorado, dragging moisture northward and pushing up against the eastern face of the mountains, snarling traffic, closing schools and government offices, slowing operations at Denver International Airport and giving Denver weather forecasters a chance to show off their winter weather wear.

A few Front Range snow totals include 45 inches at Jamestown (Boulder County), 50 inches at Pinecliffe in Gilpin County and 21 inches in Boulder. You can see all the snow totals at this National Weather Service web page.

The full NWS winter weather briefing page is online here.

Most experts agree that, given existing resouces, it would all but impossible to stop an Arctic oil spill on the scale of the Deepwater Horizon disaster. U.S. COAST GUARD PHOTO.

Conservation group advocates for an international Arctic response plan

By Summit Voice

SUMMIT COUNTY — With oil drilling activities in the American Arctic on the horizon, concerns are mounting about the lack emergency response capabilities, as well as information about environmental conditions in the  area.

A new report by the Center for American Progress highlights some of those concerns, pointing out that several federal agencies have called for more studies of baseline environmental conditions.  Oil spill cleanup experts also say more resources are needed for the U.S. Coast Guard to fulfill its mission in the region.

The report also explains that even the well-developed infrastructure and abundance of trained personnel in the Gulf of Mexico couldn’t prevent the Deepwater Horizon tragedy — and the country’s Arctic response capabilities pale by comparison.

Drilling for oil in the Arctic should not be pursued without adequate safeguards in place. If the Deepwater Horizon disaster had any lessons to offer, it’s that the importance of preparedness cannot be overstated. That’s why the report strongly recommend specific actions be taken by the federal government, by Congress, and by Shell and other companies before beginning exploratory drilling in the Arctic.

Recommendations in the report include:

• Ensure adequate response capabilities are in place before drilling operations commence
• Require and oversee oil spill response drills in the Arctic that prove the assertions made in company drilling plans prior to plan approval
• Engage other Arctic nations in developing an international oil spill response agreement that includes an Arctic Ocean drilling management plan
• Appropriate adequate funds for the Coast Guard to carry out its mission in the Arctic, including increasing our icebreaking capability
• Significantly increase the liability cap (currently $75 million) for oil companies in violation of drilling safety rules

Mexican gray wolf. PHOTO COURTESY USFWS.

The latest wolf-location map from Arizona and New Mexico.

By Summit Voice

SUMMIT COUNTY — Taking a small step away from the brink of extinction, the Mexican gray wolf population grew for the second year in a row.

According to the latest census there are now 26 wolves in New Mexico and 32 wolves in Arizona. Most importantly for the success of the recovery program, the number of breeding pairs increased from just two in each of the preceding annual counts to six in 2011.

That increase came despite the fact that the massive Wallow Fire in Arizona burned through inportant denning habitat.

Federal officials say continued collaboration and reduction in livestock losses is key to developing the social acceptance needed for successful long-term recovery.

“Building public tolerance by those who live on the land and must coexist with the wolf is so very important to the success of Mexican wolf recovery in Arizona,” said  Arizona Game and Fish Department director Larry Voyles.

The latest wolf census  shows that 18 pups born during 2011 have survived, boosting the total population to 58, up from 42 just a couple of years ago. There may be other pups living in the wild that weren’t detected in the surveys, according to the U.S. Fish and Wildlife Service. Previous annual reports are online here.

“Eight more wolves in the wild than the previous year is a step back from the edge of extinction,” said Michael Robinson of the Center for Biological Diversity. “And that’s happy news. Of course, six breeding pairs is still perilously low — and that low number is due, in part, to the Obama administration’s slowdown in releasing wolves into the wild.”

“Building public tolerance by those who live on the land and must coexist with the wolf is so very important to the success of Mexican wolf recovery in Arizona,” Voyles said. “To that end, we have seen an increase in numbers this past year, even with Arizona’s largest wildfire, the Wallow, which burned through three packs’ denning areas during the time pups were being born and raised.”

By the recovery program’s original 1998 blueprint, the population was projected to reach 102 wolves by 2006, including 18 breeding pairs. No recovery goal has yet been established for the Mexican wolf; a recovery team is now working on creating such a goal.

The U.S. Fish and Wildlife Service released just two wolves into the wild in 2011. Both released wolves had been captured in past years.

In total, during the past five years, just 11 captured wolves have been released into the wild, while dozens of other once-wild wolves still languish in captivity. Only a single wolf has been released from the captive-breeding pool (i.e. an animal not originally captured from the wild) over the past five years, and that was in 2008.

Nine wolves are known to have died in 2011, including two illegally shot, one apparently killed by a vehicle, one shot by the government, one struck by lightning and four whose causes of death have not been released.

“Restoring wolves to the wild helps restore the balance of nature in the Southwest,” said Robinson. “More wolves means stronger and more alert elk and deer, more leftover meals for badgers and bears, and healthier streamsides as elk spend less time eating willow shoots.”

The town square in Brignoles, France.

SUMMIT COUNTY — There are always some semantics involved when it comes to determining what, exactly, a village is. The dictionary is not much help, most often describing a village as “bigger than a hamlet, smaller than a town.” Can anyone name an actual “hamlet,” please? In the end, I think village-ness is more a state of mind that anything else …

Cassis, a classic French fishing village.

A village house.

The village VW.

Tiled roofs in a French village.

This cabin is all that remains of a once-thriving mining village.

A medieval village clings to a hillside in Albania.

Mountain village.

Local Summit County readers will recognize this village!

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Avalanche danger has climbed into the red zone in Colorado's Front Range mountains.

Big and dangerous slides likely near and above treeline

By Summit Voice

SUMMIT COUNTY — Heavy snow in Colorado’s Front Range mountains east of the Continental Divide has prompted an avalanche warning from the Colorado Avalanche Information Center. The warning, effective through 12 p.m. Feb. 4, covers the area from the Wyoming border all the way to the Pikes Peak area, west of Colorado Springs.

Rapid accumulations of new snow will “overwhelm a weak snowpack,” the forecasters said, explaining that the storm will trigger a natural avalanche cycle and it will also be very easy for backcountry travelers to trigger slides in the backcountry.

Avalanches are possible on slopes below treeline and above treeline, there is a potential for large and dangerous avalanches. The tender snowpack can be triggered from a distance and even from low-angled slopes below and away from avalanche paths.

From the CAIC site:

“Over the last few weeks, several parties have been caught on low angle terrain when they triggered avalanches several hundred feet above them. North to east winds will drift the new snow into some unusual places near and above treeline. The old snow surface is a highly variable mix of crusts and facets. Expect some very poor bonding, and fresh wind slabs and storm slabs will be easy to trigger.”

Brown-capped rosy finch. PHOTO COURTESY DOMINIC SHERONY VIA THE CREATIVE COMMONS.

‘Extremophile’ rosy finches thrive where other birds perish

*Editor’s note: Have a bird question? Send it our way or leave it in the comment box and we’ll try and get it answered for you.

By Max Wood

SUMMIT COUNTY — Birding in the winter in Summit County, Colorado may fail to puff up your year list with sheer numbers of species, but both amateur and professional birders are bound to come away with a few good-quality birds with a little effort.

Of the species that stay in Summit County in the winter, the most exciting, in my opinion, are three species of rosy-finches. Two of them, the brown-capped rosy-finch (Leucosticte australis) and the black rosy-finch (Leucosticte atrata), are reliably found each winter in Summit County. The gray-crowned rosy-finch (Leucosticte tephrocotis) is a ‘sometimes’ visitor to the Rocky Mountains during the winter months. Of the three, only the brown-capped rosy-finch breeds in Colorado.

Rosy-finches are extremophiles, thriving in environments where most species perish. Rosy-finches live and breed in the alpine. They can be found in the summer months high up on mountain tops or in high northern latitudes above the tree line where they forage on insects found on the permanent snowfields. They build their nests in cracks and holes on cliff faces. Rosy-finches have additional sacks for food storage in their bills, which allow them to range up to 4 kilometers in the barren alpine environment to in search of food for their nestlings.

Rosy-finches are mostly altitudinal migrants, mostly descending in elevation to find more favorable conditions in the winter, similar to Clark’s Nutcrackers. All of the Rosy-finches spend winter farther south than their breeding range, but only a short distance (200-450 km). Rosy-finches search out areas that are free of snow, where they often congregate in large flocks before heading back up to their high elevation homes as soon as conditions allow, often as early as April.

The three rosy-finch species found in Summit County are very similar in appearance. They are all medium sized (6.25 inches in length) finches with strong, triangular bills. They differ mostly in the color pattern of the feathers on their heads, though they also average darker or lighter in their overall body color. At least two of the species have been spotted at North Peak of Keystone Ski Area this January, where there had been a feeder they were visiting. Though the feeder was removed, the birds are still seen visiting the spot occasionally.

I thank you for the exciting opportunity to share my knowledge of and passion for birds with the online Summit Voice community.

Max Wood is an ornithologist with a Master’s degree, specializing in restoration treatments fore resident and migrant songbirds. He has conducted a wide variety of research projects ranging from migration monitoring to spot-mapping breeding songbirds.  I am a writer for http://www.yourbirdoasis.com a retailer of bird feeders, bird houses, bird baths and an essential resource for burgeoning and expert birders alike.

Sierra Yellow-legged frog. PHOTO COURTESY USFWS.

Non-native trout, pesticide drift and fungal disease seen as primary threats

By Summit Voice

SUMMIT COUNTY —Two species of rare frogs native to high-elevation lakes in California’s Sierra Nevada will get protection under the state’s Endangered Species Act.

The California Fish and Game Commission voted unanimously this week to designate Sierra mountain yellow-legged frogs as threatened and southern mountain yellow-legged frogs as endangered.

“With formal state protection, California can start recovering an important part of mountain ecosystems to bring back formerly abundant amphibians,” said Jeff Miller at the Center for Biological Diversity, which petitioned for state protection in 2010. “Taking out exotic trout and getting rid of pollutants to restore mountain yellow-legged frogs will have ripple effects beyond these species — it’ll help to heal some of the damaged high-elevation habitats of the Sierras and Southern California mountains.”

Just a few decades ago, mountain yellow-legged frogs were abundant around many of the Sierra’s alpine lakes. Tadpoles must survive up to four freezing winters at the bottom of deep lakes before metamorphosing. These hardy frogs are vulnerable to predation by introduced trout and diseases that may be exacerbated by pesticides; other threats are habitat changes caused by water developments, climate change and livestock grazing. More than half of frog populations found in 1995 have now gone extinct.

The new state listing makes it unlawful to “take” (defined as killing, harming or capturing) frogs without state authorization. The Center has twice sued the California Department of Fish and Game to force evaluation of the environmental impacts of the state’s fish-stocking program, which introduces exotic trout into the high-elevation habitats where species such as the mountain-yellow-legged frog evolved without aquatic predators. The Department is recommending no trout stocking in the state without a fish management plan, and no further stocking of trout in areas that would conflict with protecting yellow-legged frogs.

Widespread stocking of nonnative trout in high-elevation Sierra lakes has been a primary cause of the species’ decline. Introduced trout eat tadpoles and juvenile frogs and change the food web of the aquatic ecosystems on which the native frogs depend.

Since 2000, the National Park Service and Forest Service have begun removing nonnative trout from some high Sierra lakes on federal lands in an attempt to restore yellow-legged frog populations. The state has taken some steps to reduce trout stocking in areas with endangered frogs; 113 high-elevation lakes in California have been dropped from the stocking program to protect frogs and an additional 504 have been dropped to protect other native species, such as endemic trout. Fish and Game also has 63 ongoing nonnative fish removal projects and is translocating frogs to repopulate former habitats.

Recent research has linked pesticides that drift from agricultural areas in the Central Valley to declines of native amphibians in the Sierra Nevada. Pesticides and other pollutants can directly kill frogs and also act as environmental stressors that render amphibians more susceptible to diseases, including a chytrid fungus that has recently ravaged many yellow-legged frog populations.

Mismanagement of national forest lands has degraded frog habitat where livestock grazing, logging, water diversions, off-road vehicles and recreational activity are allowed in frog habitat. Rapid climate change has brought warmer temperatures, decreases in runoff, shifts in winter precipitation in the Sierra from snow to rain, and habitat changes that are rendering frog populations more vulnerable to drought-related extinction events.

Shrinking Arctic sea ice is affecting mid-latitude weather patterns. PHOTO COURTESY ALFRED WEGENER INSTITUTE.

Warmer Arctic temps weaken westerlies that bring warm, moist air to the continent

By Summit Voice

SUMMIT COUNTY — German scientists say they’ve found more evidence showing links between declining Arctic sea ice and shifting weather patterns, with cold, snowy winters more likely in Europe following summers when Arctic sea ice is low.

The researchers from the Alfred Wegener Institute for Polar and Marine Research say shrinking summertime sea ice cover changes the air pressure zones in the Arctic atmosphere, slowing westerly winds that usually transport relatively warm and moist air toward Europe.

If there is a particularly large-scale melt of Arctic sea ice in summer, as observed in recent years, two important effects are intensified. Firstly, the retreat of the  ice leaves a darker ocean to warm up more in summer from  solar radiation.

Secondly, the diminished ice cover can no longer prevent the heat stored in the ocean from being released into the atmosphere. As a result of the decreased sea ice cover the air is warmed more than it used to be, particularly in autumn and winter, because during this period the ocean is warmer than the atmosphere.

“These higher temperatures can be proven by current measurements from the Arctic regions,” said Ralf Jaiser, lead author of the publication from the Research Unit Potsdam of the Alfred Wegener Institute.

The warming of the air near the ground leads to rising movements and the atmosphere becomes less stable.

“We have analysed the complex non-linear processes behind this destabilisation and have shown how these altered conditions in the Arctic influence the typical circulation and air pressure patterns,” Jaiser explained.

One of these patterns is the air pressure difference between the Arctic and mid-latitudes: The so-called Arctic oscillation involving the Azores high and Iceland low.

If the pressure difference is high, it generates a strong westerly wind, carrying warm and humid Atlantic air masses to Europe. Without the westerlies, cold Arctic air can penetrate down through to Europe, as was the case during the last two winters.

Model calculations show that the air pressure difference with decreased sea ice cover in the Arctic summer is weakened in the following winter, enabling Arctic cold to push down to mid-latitudes.

Early this winter, that scenario did not develop in Europe, as mild temperatures dominated. But the recent and persisent outbreak of Polar air over the continent signals a return to those conditions.

“Many other factors naturally play a role in the complex climate system of our Earth which overlap in part. Our results explain the mechanisms of how regional changes in the Arctic sea ice cover have a global impact and their effects over a period from late summer to winter,” Jaiser said.

“Other mechanisms are linked, for example, with the snow cover in Siberia or tropical influences. The interactions between these influential factors will be the subject matter of future research work and therefore represent a factor of uncertainty in forecasts,” he concluded.

“Our work contributes to reducing the existing uncertainties of the global climate model and developing more credible regional climate scenarios – an important foundation to enable people to adjust to the altered conditions,” explains Prof. Dr. Klaus Dethloff, Head of the Atmospheric Circulation Section at the Research Unit Potsdam of the Alfred Wegener Institute.

Could forest-clearing in beetle-killed stands tilt regional climate toward dry conditions?

New research tracks rainfall patterns in Central America 

By Summit Voice

SUMMIT COUNTY — As if the pine beetle outbreak weren’t bad enough, there’s new evidence to suggest that widespread forest clearing can change precipitation patterns on regional scale, tilting climate toward drought conditions.

The findings by NASA climatologist Ben Cook suggest ancient Meso-American civilizations of the Mayans and Aztecs likely amplified droughts in the Yucatán Peninsula and southern and central Mexico by clearing rainforests to make room for pastures and farmland.

Converting forest to farmland can increase the reflectivity, or albedo, of the land surface in ways that affect precipitation patterns.

“Farmland and pastures absorb slightly less energy from the sun than the rainforest because their surfaces tend to be lighter and more reflective,” Cook said. “This means that there’s less energy available for convection and precipitation.”

Cook and colleagues reached their conclusions by comparing Central American rainfall patterns from pre-Columbian (before 1492 C.E.) and post-Columbian periods. The pre-Columbian era saw widespread deforestation on the Yucatán Peninsula and throughout southern and central Mexico. During the post-Columbian period, forests regenerated as native populations declined and farmlands and pastures were abandoned.

The results are unmistakable: Precipitation levels declined by a considerable amount — generally 10 to 20 percent — when deforestation was widespread. Precipitation records from stalagmites, a type of cave formation affected by moisture levels that paleoclimatologists use to deduce past climate trends, in the Yucatán agree well with Cook’s model results.

The effect is most noticeable over the Yucatán Peninsula and southern Mexico, areas that overlapped with the centers of the Mayan and Aztec civilizations and had high levels of deforestation and the most densely concentrated populations. Rainfall levels declined, for example, by as much as 20 percent over parts of the Yucatán Peninsula between 800 C.E. and 950 C.E.

Cook’s study supports previous research that suggests drought, amplified by deforestation, was a key factor in the rapid collapse of the Mayan empire around 950 C.E.

During the peak of Mayan civilization between the years 800 and 950, the land cover reconstruction Cook based his modeling on indicates that the Maya had left only a tiny percentage of the forests on the Yucatán Peninsula intact.

But after Europeans decimated native populations, natural vegetation covered nearly all of the Yucatán. In modern times, deforestation has altered some areas near the coast, but a large majority of the peninsula’s forests remain intact.

“I wouldn’t argue that deforestation causes drought or that it’s entirely responsible for the decline of the Maya, but our results do show that deforestation can bias the climate toward drought and that about half of the dryness in the pre-Colonial period was the result of deforestation,” Cook said.

Cook presented his research in early December at the annual meeting of the American Geophysican Union in San Francisco, where other researchers discussed significant droughts that affected the Northeast, including a three-year dry spell in the 1960s that had major impacts on the region.

New studies by NASA paleoclimatologist Dorothy Peteet shows that far more severe droughts have occurred in the Northeast — at least three major dry spells have hit region in the last 6,000 years.

The longest, which corresponds with a span of time known as the Medieval Warm Period, lasted some 500 years and began around 850. The other two took place more than 5,000 years ago. They were shorter, only about 20 to 40 years, but likely more severe.

Peteet analyzed sediment cores collected from several tidal marshes in the Hudson River Valley to gain an understanding of historic precipitation patterns. Using X-ray fluorescence spectroscopy they search for characteristic elements — such as bromine and calcium — that are more likely to occur at the marsh during droughts.

“People don’t generally think about the Northeast as an area that can experience drought, but there’s geologic evidence that shows major droughts can and do occur,” Peteet said. “It’s something scientists can’t ignore. What we’re finding in these sediment cores has big implications for the region.”

Fresh water from the Hudson River and salty water from the Atlantic Ocean were both predominant in Piermont Marsh at different time periods, but saltwater moves upriver during dry periods as the amount of fresh water entering the marsh declines. Peteet’s team detected extremely high levels of both bromine and calcium, both of them indicators of the presence of saltwater and the existence of drought, in sections of the sediment cores corresponding to 5,745 and 5,480 years ago.

During the Medieval Warm Period, the researchers also found striking increases in the abundance of certain types of pollen species, especially pine and hickory, that indicate a dry climate. Before the Medieval Warm Period, in contrast, there were more oaks, which thrive wetter conditions. They also found a thick layer of charcoal demonstrating that wildfires, which are more frequent during droughts, were common during the Medieval Warm Period.

“We still need to do more research before we can say with confidence how widespread or frequent droughts in the Northeast have been,” Peteet said.

There are some gaps in the cores Peteet’s team studied that she plans to investigate in greater detail. She also expects to expand the scope of the project to other marshes and estuaries in the Northeast and to collaborate with climate modelers to begin teasing out the factors that cause droughts to occur in the region.