Ancient climate change at #AGU16 – Atacama Desert may have harbored lakes, wetlands

From the paleoclimatology world, what caused such drastic climate change back then?

Marco Pfeiffer and his colleagues scan the arid Atacama Desert, where freshwater lakes and wetlands once provided refuge to South America's early settlers. CREDIT Marco Pfeiffer

Marco Pfeiffer and his colleagues scan the arid Atacama Desert, where freshwater lakes and wetlands once provided refuge to South America’s early settlers. CREDIT Marco Pfeiffer

SAN FRANCISCO — The arid Atacama Desert, thought to be a barrier to early South American settlers, may have held lakes large enough to sustain small human populations, according to new research presented here today. The lakes’ presence challenges the current understanding of the paths early settlers took to explore and settle South America, according to the researchers.

Chile’s Atacama Desert spans roughly 1,000 kilometers (600 miles) along South America’s western coast. The desert is sandwiched between two mountain ranges, which prevent water from reaching its valleys and salt flats, making it the world’s driest location outside the poles.

Now, new research shows standing water may have existed in the heart of the Atacama. Scientists recently discovered remnants of freshwater plants and animals buried in the sediment of the desert’s salt flats: the large stretches of dry, salty soil that pepper the Atacama Desert. Many of the flats span 600 to 1,000 square meters (6,400 to 10,400 square feet), though some are larger. Radiocarbon analysis showed the freshwater lakes and wetlands existed in the desert between 9,000 and 25,000 years ago, according to the researchers.

Many archeologists believe South America’s early settlers traveled from the west coast inland toward the Andean Mountains, avoiding the desert’s dry center by walking along its wetter edges. But the new findings suggest the Atacama’s ancient lakes could have provided another path through the desert, and possibly even homes for South American settlers.

“The implication is that a landscape previously thought to be uninhabitable was actually an important stepping-stone for colonization of South America,” said Marco Pfeiffer, a soil scientist at the University of California, Berkeley, and lead author of the new study. Pfeiffer will present the study’s results today at the 2016 American Geophysical Union Fall Meeting.

When Pfeiffer and his colleagues dug into the salt flats, they discovered organic material left by freshwater plants, snails and microorganisms. Radiocarbon dating suggested those organisms lived after one or more wet climate cycles, known as the Central Andean Pluvial Events.

Pfeiffer said the climate cycles likely brought rain from the Andes down to the water-starved soil of the Atacama Desert, creating the lakes and wetlands. Even populations of guanaco, the undomesticated parent of the modern llama, may have once thrived near the Atacama’s ancient water bodies, he added. When the climate cycles ended, the lakes and wetlands transitioned from fresh to saltwater before completely disappearing several thousand years later, Pfeiffer said.

Pfeiffer said the new findings could help guide future archaeological expeditions. Only three archaeological sites within the desert have been searched for evidence of human settlement, all of which stand near streams. Pfeiffer believes the Atacama Desert holds a “rich, early archaeological record remaining to be discovered and analyzed.”

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Media Q&A and presentation information

The researcher, Marco Pfeiffer, will be available to answer questions from members of the news media during a media availability from 8:30 – 9:00 a.m. PT today in the Press Conference Room, Moscone West, Room 3000. The media availability will also be streamed live over the web. Information about how to stream press conferences can be found here.

The researchers will present a poster about their work on Thursday, 15 December 2016 at the AGU Fall Meeting. (that part is for commenter “josh” – Anthony)

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66 thoughts on “Ancient climate change at #AGU16 – Atacama Desert may have harbored lakes, wetlands

    • The only news here is the timing. Maybe more recent lakes than our 1960s textbooks show. Mom trashed mine about 1970 so I can’t check.

    • YES, an old Top Gear now Grand Tour fan, Remember, Clarkson and May also drove pick-up trucks to the North Pole. First to do so.

  1. “new research shows standing water ‘may’ have existed in the heart of the Atacama salt flats” (but maybe not …so lets have some grant money), said Marco Pfeiffer, a soil scientist at the University of California, Berkeley, and lead author of the new study.
    Amazing what a University grant turns up.

    100s of yrs ago in my backward skool we was taut ALL shallow depressions with a thick crust of salt was either a dried up pond/lake/sea…. or your dinner plate.

    • Weasel words, so big in pseudo sciences. Somebody should make a program to count weasel words in articles and grade them by their usage (number of weasel words / total words or something like that). It would be an interesting statistic, I bet it would show a hockey stick over time.

      • “Weasel words” are simply a means of showing uncertainty regarding an interpretation. There’s nothing “pseudo” about geomorphology, though quite a few armchair critics have pseudo-knowledge. The statistic exists and is known as a fog index. In fact, the index tends to decline because sales and business types who hire scientists and the morons who need certainties for “policy” purposes want “firm” statements. The entire AGW thrust is based on the conversion of “could” and “might” into “is” and “will.” The problem with real-world science is that there are always gotchas, and if you don’t warn some jerk about them, and encountering one causes a problem, your competence is challenged, But if you insist on the “weasel words” and then the fool who refused to plan for alternate problems, you at least can say, “I told you it was not a certainty.”

      • Is there a ‘fog index’ for different branches of science? That would be quite interesting, too. I bet that physics is not as foggy as psychology or climastrology.

    • The point here is not that there once was water there, but when the water was there.
      Prior to the Isthmus of Panama closing, the waters off Peru were a lot warmer, so there was a lot more rain in these regions. But that was millions of years ago.
      This discovery here is that there was water there recently enough to have impacted the migration of humans into S. America.

  2. I think the news is how recently it appears the Atacama Desert was not a desert. The great confidence which attends dating in science is largely uncalled for. We can’t predict the future with computer models and we can’t date the past with any sort of precision or confidence. Science is about experiments and you can only make the necessary observations and take measurements in the present. Past and future is just educated guessing, and that is on a good day. Humility, not hubris, ought to discipline the scientific dating of the past

  3. The critical phrase in this paper is “Radiocarbon analysis showed the freshwater lakes and wetlands existed in the desert between 9,000 and 25,000 years ago.” That’s the time of late Pleistocene glaciation when pluvial lakes were present in desert areas all over the world. For example, all of the Great Basin deserts were sites of pluvial lakes because of the shifts in precipitation/evaporation ratios that occurred during the glaciation. So the author’s discovery of pluvial lake sediments in the Atacama Desert is no big deal–any glacial geologist would have predicted they would be there, just like every other desert in the world.

    • Beat me to it. Yes, as the earth went into and out of a glacial period, climatic zones shifted towards, then away from the equator. The Sahara desert had forests and rivers and huge lakes, maybe even an inland sea.

      The surprising thing is that these people find it surprising! Doesn’t anyone get a proper education any more?

    • When I walked around Lake Eyre [Australia] in 1982, I found abundant quartz and chert flakes, products of Aboriginal tool manufacture along the SE coast of the north lake. 8000? or so years ago Lake Eyre was three times its present size and full of fresh water and Aboriginal people lived and hunted [megafauna]along its shores. Now its an arid salt lake. It’ll probably return to another more humid time some time in the future. Climate is always changing and generally very slowly.

  4. Start digging around those lakes and you’re bound to come across flint or stone tools if indeed the ancient lakes were viable water sources for transients or settlers. Should be able to replace speculation with facts after some digging.

      • Money from whom and whose bucket. Grants from an anthropology or archeology department sound more appropriate than climatology.
        Digs will reveal when, where and how they lived…and when they left. But as to why they left will be speculation, but educated speculation none the less. If they left because of climate change, several thousand years ago, that kind of blows away any pretext of anthropogenic CO2 release as cause for climate change.

      • “If they left because of climate change, several thousand years ago, that kind of blows away any pretext of anthropogenic CO2 release as cause for climate change.”
        So you can bet that won’t be a published finding.
        Something else maybe, but not that.

  5. What is interesting to know, is which weather patterns (wind, pressure patterns) and which currents must have existed at the time of the lakes to create those humid conditions. Temperature will have played a role too. Did a different ‘climate motor’ exist in this part of the world during the Glacials, for example different currents?

    • Deserts on Earth occupy very specific latitudes dictated by atmospheric convective currents creating toroidal bands. These bands are symmetrically disposed about the equator. As the warm humid air from the equator rises it dumps most of its water in the tropics leaving the dry descending air to desiccate the terrain into deserts. These toroidal bands stack like donuts making the earth sort of look like the Michelin tire character. Add to this the rotation of the earth an voila you have added an east/west velocity component which accounts for the various trade wind bands that navigators have been using for centuries.
      During the glacial times these toroidal bands would be very different.

    • Wim Rost
      According to CLIMAP at the LGM 18,000 years ago. Much of the southeastern Pacific was warmer at LGM then it is today. lf this is the case then it suggests to me, that they were persistent areas of high pressure blocking over this part of the Pacific during the LGM. Just south of this SE Pacific “blob” the waters were much cooler. This suggests that there would have been a very powerful jet stream tracking to the south of this blob. Now over in the southern Atlantic there is a other “blob” of warm water SE of S America. Which again would suggest an area of persistent blocking. lf this was a persistent weather pattern during LGM Then a powerful jet stream would have tracked north over southern S America. So pushing cold Polar air up across southern S America. When this cold air meet with the warm moist air further north, Then that would have surely resulted in heavy rainfall falling over southern S America.

  6. This made me think about my adventures at say 5 years old walking around the land in Mayer AZ, the town founded by my great grandfather, Joseph Mayer. Mayer is 4,400 feet above MSL. I used to go out and collect fossils and fossilized sea shells. I remember asking my father how they got there because we were over 4,000 feet above sea level. He explained how dynamic the Earth is with moving tectonic plates and mountains constantly pushing upwards and sinking in other areas…in geological time of course. Go through the math and this shows an increase in elevation above MSL of 1 inch per 3,220 years. He always said it was silly for people to build houses and develop property close to the sea shores in most areas because of changes in the weather. The Dutch certainly knew that. That was 1958 or so. I guess Al Gore and the others yelling about sea rise missed grade school and high school geology class.

  7. Of course, the next phase will be to determine which human activities (scratch and burn farming, llama dung fires, and so on) were responsible for the climate change which resulted in desertification. No research can possibly be funded nowadays unless it contains a reference to CAGW.

  8. How about the Sahara…….this was a green paradise only 10s of thousands of years ago..it is believed it was actually warmer…..warm enough to cause a monsoon flow from the Atlantic with plenty of moisture!

      • True.

        While open, the Seaway was a nursery for whale-eating megalodon sharks during the Miocene and Pliocene. These giants went extinct at the Plio-Pleistocene boundary, when the Seaway closed.

    • Excellent link regarding that fossil whale article, but did you read some of the brilliant comments below the article? It’s comments like those that make me appreciate the caliber of people who frequent WUWT, and why I visit here every day.

  9. Since there are still salt flats in the Atacama and in neighboring Bolivia and Argentina, it’s no surprise that there were lakes there at lower elevations during the Pluvial, as elsewhere in the world. Great Salt Lake is a remnant of pluvial Lake Bonneville. During this interval, the Sahara was also green, as noted in these comments.

    The salars of this region of the Andes are the world’s main source of lithium.

    https://en.wikipedia.org/wiki/Salar_de_Atacama

    San Pedro de Atacama is one my favorite towns in Chile.

    • Si! It is an amazing place! As I tell my friends ‘I don’t need to visit Mars. I’ve spent a week in the Atacama.’ And I mean that in a good way. It really is an amazing place to see. Also, not to piss off my Chile friends, the rest of the country is equally amazing!

      • Mike,

        I tell my NH friends the truth, which is that it’s a very long trip, the beer, although German in origin, isn’t all that great, the highways lack signage, the ocean is cold (Humboldt Current straight from Antarctica), the people are snooty, Santiago is smoggy and too hot in the summer, with terrible traffic, there’s a socialist government, crime is rampant and goes unpunished, the Mapuches are on the warpath and there are frequent earthquakes, floods, tornadoes and volcanic eruptions.

  10. Take a look at the 2008 Austin conference collective published in 2008 in the journal Geomorphology, there are some good papers on this and related topics from the perspective of Quaternary geology.

  11. There is all kinds of archaeological sites in the Atacama desert. Yes, its dry and has always been dry but the very first civilization in the America’s was in this desert – Caral (pyramids and everything). Nearer to the coast but this is dated at 2600 BC.

    There are tons of other sites. This is just another climate science myth-making exercise.

  12. “Many of the flats span 600 to 1,000 square meters (6,400 to 10,400 square feet), though some are larger.”

    10,000 sq ft = 100 x 100 ft or about 30 x 30 meters. These are more the remnants of potholes or tiny ponds than large flats. Am I missing something?

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