Friday, April 17, 2015

California Dry

Anyone who has been paying attention to the news here in the US knows about the current extreme drought in California and all the problems that it's causing. My daughter who lives in Long Beach said in a message some weeks ago, "Remember back in 2010 when it rained and rained here and we had that flood that drowned both our cars and totaled them? I miss those days - can we have them back?"

The New York Times has an excellent article that puts California's current situation in historical perspective. Climatic reconstruction shows that over the last 2,000 years, California has had two "megadroughts" that have been centuries in length. It's far too soon to know if this is the beginning of another megadrought, but if you will please click to enlarge the chart above you can see that California has been more dry than wet over the last two millennia. If you look at the two megadroughts on the chart you'll see they correlate with the Medieval Climatic Anomaly that was one of the causal factors in the Anasazi/Ancestral Pueblo abandonment of the Northern Southwest. Even in the archaeological record here in the Front Range, we see a population crash in the late 13th Century.

At a Society for California Archaeology conference 10+ years ago, I attended a paper that presented much the same data. An observation made by that presenter was that the period of European discovery and colonization of California pretty much correlates with the wettest period in the region in the last 2,000 years. You can see that yourself on this chart. Our society's view of what's "normal climate" in California is hopelessly skewed.

The early anthropologists and archaeologists who worked in California in the late 19th and early 20th Century didn't have access to these environmental reconstructions and assumed the past climate was much like today.  Their assumptions about past Indian behavior were that they were living in this "paradise" full of easily obtainable wild food, and were just able to coast along. Now we know that wasn't the case, and a volume of papers demonstrating that was titled, Prehistoric California: Archaeology and the Myth of Paradise.

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