Claim: Climate change ‘may’ be responsible for the abrupt collapse of Tibetan civilization around 2000BC

If we have another grand minimum and temperatures cool, farmers will have to adjust the crops that they grow. This is one example of how the climate has an impact on food supplies.

Watts Up With That?

From Washington State University: Closing the Case on an Ancient Archeological Mystery

Solving 4,000-year-old mystery helps WSU archeologist find useful resource for a warmer future

Barley cultivation in Jiuzhaigou National Park hasn’t changed much in nearly 2,000 years. The park is located in the Min Shan mountain range, Northern Sichuan in South Western China. Credit: Washington State University

PULLMAN, Wash.–Climate change may be responsible for the abrupt collapse of civilization on the fringes of the Tibetan Plateau around 2000 B.C.

WSU archaeologist Jade D’Alpoim Guedes and an international team of researchers found that cooling global temperatures at the end of the Holocene Climatic Optimum, a 4,000 year period of warm weather, would have made it impossible for ancient people on the Tibetan Plateau to cultivate millet, their primary food source.

Guedes’ team’s research recently was published online in the Proceedings of the National Academy of Sciences. Her results provide…

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California Drought Report #10

Reblogged from Sierra Foothill Commentary my local politics blog.

Sierra Foothill Commentary

The New York Times: In California, a Wet Era May Be Ending

The drought, now in its fourth year, is by many measures the worst since the state began keeping records of temperature and precipitation in the 1800s. And with a population now close to 39 million and a thirsty, $50 billion agricultural industry, California has been affected more by this drought than by any previous one.

But scientists say that in the more ancient past, California and the Southwest occasionally had even worse droughts — so-called megadroughts — that lasted decades. At least in parts of California, in two cases in the last 1,200 years, these dry spells lingered for up to two centuries.

The new normal, scientists say, may in fact be an old one.

Source New York Times

After introducing history the writer starts blabbering about global warming, which is not relevant to historic droughts that resulted…

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The Large Cliff Top Pueblos at Mesa Verde, Colorado and Treeflow Data from Lees Ferry, Arizona

“It is interesting to note that the Colorado River discharge increased during the Medieval Warm Period and declined during the Little Ice Age.”

Watts Up With That?

Guest essay by Samuel I Outcalt

The Data: The major tourist attractions at Mesa Verde National Park (near Cortez, Colorado) are the large cliff top pueblos inhabited by the Anasazi between 1128 and 1273 AD. To explore the relationship between the Anasazi occupancy of these large pueblos and climate change a 101 year center weighted moving average filter was applied to the Annual Treeflow Discharge Estimate of the Colorado River at Lees Ferry, Arizona (180 miles due west). These discharge estimates were calculated using the parameters derived from the linear regression of annual modern stream discharge [dependent variable] and modern regional tree ring data sets [independent variables].

The regression parameters were then used to estimate stream discharge at the gage site for length of the tree ring records. The explained variance of the tree ring data sets used in this reconstruction varied between 57% and 77%. The reconstruction is…

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NOAA ENSO Model Now Forecasting a Supercalifragilistic El Niño for 2015/16 Season

Watts Up With That?

Guest Post by Bob Tisdale

First: Congratulations to the teeny-tiny 2014/15 El Niño. It’s now official. NOAA included it as an “official warm event” on their Oceanic NINO Index this week.

NOAA’s CFS.v2 model (dated April 9, 2015, source here) is now forecasting a strong El Niño for this upcoming ENSO season, or as blogger Alec, aka Daffy Duck called it, “a supercalifragilistic el nino” when he brought the forecast to my attention here. See Figure 1. That forecast is noticeably higher than the one that shows up on page 25 of the NOAA weekly ENSO update, which was dated April 4^th.

Figure 1

If you live in California and are hoping for drought relief, I wouldn’t get my hopes up just yet. It’s still (boreal) springtime, and ENSO forecasts have a hurdle called the “spring prediction barrier”. Basically, El Nino forecasts have a bad…

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