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When It Comes to Water, We’re All Maya Now

 

Photo: Maya temple to jaguar in Guatemala
Did the Maya civilization decline due to loss of rainfall? Photo: Dennis Jarvis, Flickr Creative Commons

 

It’s possible that the stunning Maya civilization — with mastery of mathematics and astronomy, farming, water management, pyramid building and city planning — was undone by summer rain.

Not enough summer rain.

Undone, in fact, by exactly the kind of rainfall changes we ourselves are starting to experience — small shifts in rainfall that persist, and end up having an outsized impact.

The Maya dominated the Yucatan Peninsula for 600 years, and their settlement and civilization there spanned more than 1,000 years. And yet the great Maya cities collapsed and were abandoned to the jungle over a period of between 100 and 200 years. (See an interactive map of the Maya civilization.)

What happened is the subject of wide scholarly, archeological, and climatological debate — although drought has often been argued as the major source of the Mayas’ demise, a long-lasting, devastating drought.

The debate has lacked hard data, until last week.

In the journal Science, we’ve now got a graph showing precipitation over the Yucatan, during the last 200 years of Maya dominance — from the year 800 to the year 1000.

Actually, it’s not quite a graph of precipitation: It’s a graph of each year’s deviation from the typical rainfall. (We can’t reproduce the graph here because Science is a subscription-only journal.)

The years 810 to 815 were pretty wet — 10 percent more rainfall than usual. The years 820 to 840 were grim — not a single year of even average precipitation, and a cluster of years with 30 percent less rainfall than usual.

What’s so striking is that the periods of drought were relatively short, often broken by brief spikes of good rain, and the actual fall-off in rainfall seems relatively modest — 20 to 40 percent less than usual in the dry periods. In fact, over a period of 200 years, there are only a couple deep troughs reaching to 40 percent less than usual.

Could the Mayas have been undone by that kind of shift in rainfall over 100 or 150 years?

We think the catastrophic collapse of a civilization requires an equally catastrophic cause. But what if our expectation of water availability is so fixed that we lose track of it? What if small shifts in rainfall can have a surprisingly dramatic impact?

“Perhaps,” write the paper’s authors, “the magnitude of these droughts was rather modest despite the large associated environmental and societal disruptions.”

The detailed picture of Maya precipitation is the work of two paleoclimatologists, Martín Medina-Elizalde and Eelco Rohling, and they analyzed lakebed sediments and stalagmites for a mix of isotopes that revealed precipitation. Their conclusions are remarkably detailed — Medina-Elizalde and Rohling were able to tease out the difference between the rainy season precipitation of the summers and the drier season precipitation of the winters. They found that it was the summer precipitation that fell off — and that much of the fall-off may have been due to fewer hurricanes, or hurricanes of reduced intensity.

We tend to be pretty confident in our ability to see and measure what’s going on around us, to understand it, and to adjust.

It’s not certain what happened to the Maya — but one thing is true: They had sophisticated systems for accessing groundwater and for collecting, storing, and distributing rainwater. Like our own systems, the Maya systems were elaborate and fixed in place. When the rain failed to appear in the quantities they had become used to, they didn’t have the flexibility to adapt their water system to serve the millions of people who relied on it.

They had built a civilization assuming a certain quantity of water, and when 20 or 30 percent less water appeared consistently, their entire way of life, perhaps especially food cultivation, became unsustainable.

The authors themselves note, somewhat dryly, that the variations in precipitation they found during the period when Maya civilization disintegrated “are not far outside the amplitude of those preceding this time interval, when the Maya civilization flourished.” That is, the amount of rain, and the variation in that rain, wasn’t too different between dominance and destruction.

Here’s the amazing thing. We’re not actually much better off than the Mayas — except for having a wealth of data to track our own vulnerability.

Last year, rainfall in Houston, Texas, was 55 percent less than usual. How will Houston fare if that persists for a couple years?

In 2007, Atlanta received 34 percent less rain than usual — and the city almost ran out of water.

Photo: Dry Menindee in Australia
This used to be Lake Menindee in New South Wales, Australia, before years of drought. Photo: Amanda Slater, Flickr Creative Commons

 

And then there’s the story of Perth, Australia. Perth is the first western city to confront the possibility of truly running out of water. (I tell the story of Perth’s dawning realization that it was confronting a water crisis in The Big Thirst.)

The equation in Perth in 2012 is startlingly similar to that in the Yucatan Peninsula in 912.

Perth has seen average rainfall drop 20 percent over the last 25 years. Water collected by its reservoirs fell by 75 percent over that same period.

Why?

Because the reservoirs were built assuming a certain amount, and location, of rainfall. As one Perth official put it, “All of a sudden, it looked like we’d built our reservoirs in the wrong place.”

For a chilling bar graph of what it looks like when a city looks water disaster in the eye, nothing matches the simple chart Perth’s water utility has put up online.

The crisis Perth confronted in the late 1990s, and avoided, was identical to that faced by Maya water managers — except Perth mustered the leadership and vision to fix its water problems.

Most metropolitan areas would be in a similar crisis if their long-term water availability suddenly dropped 20 percent — not to say 30 or 40 percent. Our municipal water systems have no more nimble adaptability than those of the Maya. Indeed, during the brutal 10-year drought in Australia, many big reservoirs were down to 30 or 20 or 10 percent capacity — there is nothing more ominous than a city-sized reservoir that is 80 percent empty.

The lesson of the Maya and the lesson of Perth are the same. Our water assumptions are just that: assumptions. We should be building municipal water cultures that have flexibility, multiple sources, the ability to re-use water, the ability to conserve.

Real strategic thinking about water isn’t about a new water treatment plant, or a plan to replace aging water mains. It’s about knowing what you’ll do if you’re suddenly faced with a 10 or 20 percent loss of available water, permanently.

Being ready for that kind of shift would change how we all think about water — from factory managers to dads doing the dishes.

In fact, we are all Maya.

 

Charles Fishman is an award-winning investigative journalist and New York Times bestselling author who has spent the last four years traveling the world to understand and explain water issues. He is the author of The Big Thirst.

Comments

  1. nachaliz
    boston
    June 5, 2013, 11:56 am

    mmm

  2. [...] Adventures When It Comes to Water, We’re All Maya Now is from National [...]

  3. Scott Miller
    New York
    March 8, 2012, 1:35 am

    While climate and weather plays a profound role in shaping human cultures, the type of ecological determinism presented in this article is inappropriately reductive and is frowned upon by professional historians. While waning access to resources exacerbates tensions within and between societies, it is the choices of people (driven as they are by world-view, social and political institutions, etc) that, at the end of the day, determine whether human groups persist or perish in periods of hardship. Presenting ecological research in this manner makes human actors the puppets of ecological systems, limiting human agency. It also obscures the fact that the Maya civilization did not collapse in the two centuries after 800. Some centers in the most drought-prone lowland zones, such as Uxmal and Labna were indeed abandoned. Others, such as Chichen and Tulum, rose in prominence during and after the end of the Classical Period, remaining powerful cultural centers up until, and in some cases even after, the Spanish Conquest.

  4. Peter Vos
    South Africa
    March 4, 2012, 3:29 am

    Be nice to see details of human population graphs alongside those rainfall lapses. We seem hardwired to ignore the fact the earth and all its resources are finite, so continue to breed well beyond the point of habitat overshoot.

  5. Frank Norton
    San Francisco, CA USA
    March 2, 2012, 5:10 pm

    The high property valuse in The City of San Francisco are determined by the Hetch Hechy water system that is fed from the Hetch Hetchy Resavour near the Yosemte Valley, some 300 miles away up in the Sierra Mountains. There are conservationists that want to drain the Hetch Hetchy resavour and return the valley to its natural state. This year the snows have been mostly absent , but lower resavour lakes are mostly filled. Guess what the property prices would be in San Francisco if there were insufficient water ariving from the mountain snows.

  6. [...] in North Georgia. There’s not enough water (the Chattahoochee is not much of a river). Here’s an interesting article about why the 404 may go the way of the Maya. This entry was posted in Antiquity, Archaeology, The South by crankyprofessor. Bookmark the [...]

  7. [...] ourselves are starting to experience � small shifts in rainfall that persist,�Source:http://newswatch.nationalgeographic.com/2012/03/01/maya-drought-rainfall/ Posted by anacrismerino at [...]

  8. MICHAEL
    MENINDEE
    March 2, 2012, 6:19 am

    the photo you have of menindee lakes is a few years old that lake is now full and the darling river which runs into this lake is in flood

  9. David Zetland
    March 1, 2012, 10:26 am

    Well, not exactly. The Maya depended on water to grow food. The people of Perth do not. Most of their water use is voluntary (you mention in your book that they STILL have irrigated lawns). Perth is not in trouble — unless water managers continue to help citizens waste water on lawns today that they will want to drink tomorrow.