By Rud Istvan,

Scanning Google News this morning (Feb 14), headlines from the New York Times and NPR caught my eye.

NYT: “How bad is western drought? Worst in 12 centuries, study finds!”

NPR: “Study finds western megadrought worst in 1200 years!”

Both headlines refer to a new paywalled paper in Nature Climate Change (of course). Lead author Park Williams is a UCLA ‘bioclimatologist’.  I did not waste paywall money, because NPR reporter Nathan Rott provided sufficient free context on today’s NPR.org website to write this brief post on this latest ‘research news’.

The NCC paper itself appears to be decent enough. Tree ring analysis (of roof beams) from Southwestern archeology sites dating back to 800 (Chaco Canyon being an example) were spliced together with living tree ring cores to form a complete SW US regional wet/normal/dry picture spanning about 1200 years. That coniferous trees grow better annually in wet (wider rings) rather than dry (narrower rings) conditions is well established (unlike Mann’s treemometers).

The trees tell a story of 5 major Southwest US droughts since 800AD. The worst is at present; the next worst was a period lasting 23 years in the late 1500’s. To a reasonable person, this should mean these periodic western droughts have little to do with climate change. But that would not get the paper published in NCC.

So of course, there is a claimed climate change link. Williams told Rott that the present megadrought is about 1/5 climate change. NPR subtitle: “Human Caused Climate Change Contributing” “Researcher Williams said roughly one-fifth of the current megadrought can be attributed to human caused climate change. Greenhouse gas emissions are warming the world, speeding evaporation and disrupting weather patterns.” How did he arrive at that conclusion? The present trees show about 20% greater drought severity than in the late 1500’s. Sure. The difference MUST be completely climate change rather than natural variability. NYT says so. NCC says so. A bioclimatologist says so.

Williams closed the NPR interview with; “We cannot let ourselves get tricked by a few wet years into giving up on the progress we’ve been making.” By we, he must mean California. It sure isn’t India and China.  And Mauna Loa’s Keeling curve shows no CO₂ progress ever. His own regional research shows normal and wet years will return, but don’t let that trick you.

[Addendum]

I received an email from reader JT this afternoon stating:
Tree ring drought study shown wrong by the drowned forests of Fallen Leaf Lake.
And giving this link to the story and study noted above.

I believe this is the study to which JT was referring.

[End addendum-cr]