Pre-Columbian America was plagued by decades-long megadroughts

Anthony Watts writes at Watts Up With That

In the August issue of Physics Today, climate scientists Toby Ault and Scott St. George share a pair of startling research findings. Between roughly 800 and 1500 CE, the American West suffered a succession of decades-long droughts, much longer than anything we’ve endured in modern history. And statistical models suggest that, as the climate warms, such megadroughts are increasingly likely to return.


How can scientists be so sure about the duration and extent of droughts that happened long before the era of instrument-based precipitation records? As Ault and St. George explain, the annual growth rings of ancient trees contain a rich paleoclimatic record of precipitation and soil moisture patterns. The width of a tree ring gives clues as to how well nourished the tree was in a given year. The map shows four western US megadroughts predicted from tree-ring data.

Ring-width analyses provide the most complete set of data on past moisture levels. But researchers have other ways of determining those conditions. Here are four of them:

Underwater tree stumps
Archaeological artifacts
Sand-dune cores
Pollen-grain deposits

The Full article is HERE.

Here are some other views of the long-term drought;

Long Drought History

G10b Sac River Flow 30T



Sunspot Update for July 2018: The Sun Flatlines!

From Behind the Black, by Robert Zimmerman

Yesterday NOAA posted its monthly update of the solar cycle, covering sunspot activity for July 2018. As I do every month, I am posting it below, annotated to give it some context.

This might be the most significant month of solar activity that has been observed since Galileo. Except for two very short-lived and very weak sunspots that observers hardly noted, the Sun was blank for entire month of July. This has not happened since 2009, during the height of the last solar minimum.

What makes this so significant and unique is that it almost certainly signals the return of the next solar minimum, a return that comes more than a year early. The solar cycle the Sun is now completing has only been ten years long. It is also one of the weakest in more than a hundred years. This combination is unprecedented. In the past such a weak cycle required a long cycle, not a short one.

Read the full post with graphics HERE.

Robert discusses the Next Grand Minimums:

For almost a decade some solar scientists have predicted, based on the Sun’s recent behavior, that we are about to enter an era of little sunspot activity, with the possibility that we could be facing the first Grand Minimum since the Maunder Minimum in the 1600s. During that last grand minimum, named for the man who identified it, the Sun’s solar cycle produced almost no visible sunspots for decades. Though scientists think the eleven-year solar cycle was occurring, sunspot activity was so weak that the solar astronomers at the time, equipped with the very first telescopes, could not see it.

My emphasis added. There is more discussion in the text.

Three Weeks Without Sunspots

As July 17th comes to a close, the sun has been blank for 21 straight days–a remarkable 3 weeks without sunspots. To find an equal stretch of spotless suns in the historical record, you have to go back to July-August 2009 when the sun was emerging from a century-class solar minimum. We are now entering a new solar minimum, possibly as deep as the last one.


Solar minimum is a normal part of the solar cycle. Every 11 years or so, sunspot production sputters. Dark cores that produce solar flares and CMEs vanish from the solar disk, leaving the sun blank for long stretches of time. These quiet spells have been coming with regularity since the sunspot cycle was discovered in 1859.

However, not all solar minima are alike. The last one in 2008-2009 surprised observers with its depth and side-effects. Sunspot counts dropped to a 100-year low; the sun dimmed by 0.1%; Earth’s upper atmosphere collapsed, allowing space junk to accumulate; and the pressure of the solar wind flagged while cosmic rays (normally repelled by solar wind) surged to Space Age highs. These events upended the orthodox picture of solar minimum as “uneventful.”

Rest of the article at


David Archibald: June Solar Update

We have only 300 years-odd of detailed solar observations with telescopes, half that of magnetic records, half again in the radio spectrum and less than that for most modern instrument records (and 12 years of Watts Up With That to interpret it). So as the months pass our knowledge of solar activity is still growing appreciably. The evidence points to a major transition of activity in 2006 which has returned us to the solar conditions of the 19th century. 19th century-type climate is expected to follow.

Details HERE.


Sun Approaching 100 Days Without Spots*

[* Not continuous days, an accumulation  of blank sunspot days ]

2 July 2018 – “The Belgian department of solar physics research (SIDC) says we are about to touch 100; that is, a hundred days in which we do not see spots on our sun,” says Italian meteorologist Dr Carlo Testa.

During a time of few or no sunspots (a solar minimum) the Sun emits less energy than usual, says Dr Testa. “According to some scholars this situation could lead to climatic upheavals.”

Suffice it to recall, says Testa, that between 1645 and 1715 the most significant solar minimum of history, the Little Ice Age, occurred, bringing years and years marked by very strict winters that lasted until June.

Now several studies indicate that we’re headed into another Great Solar Minimum, says Testa. For some scholars this is only a hypothesis, but we are seeing small signals that support this idea: namely,the most powerful strat-warming ever recorded in mid-February, the very very unstable Spring, and finally this summer that continues to limp along.

In the immediate future Testa expects “a very limp and less hot summer than in past years,” and that the coming winter could also be affected by the solar minimum.

“What if the worst is to come?” asks Testa.

Scientists Have Found The ‘Missing Link’ From Sunspot Activity To Cosmic Rays-Clouds To Climate Change

By Kenneth Richard on 21. May 2018

Hailed as ‘the last piece of the puzzle’ in codifying our understanding of the mechanism(s) that cause climate changes, scientists are increasingly turning to Sun-modulated cosmic ray flux and cloud cover variations as the explanation for decadal- and centennial-scale global warming and cooling. In other words, climate changes are increasingly being attributed to natural variability, not anthropogenic activity.

A link to the full blog post is HERE. It is too long to re-post. Recommended reading, with references to past Grand Minimums.

Are we on the Cusp of the Next Minimum?

26 Apr 2018 – “Worldwide Wine Output Collapses To 60-Year Low, Sparks Fears Of Major Shortage,” says headline.

The Director-General of the International Organization of Vine and Wine, Jean-Marie Aurand, warned that global wine production collapsed in 2017, with a contraction of 8.6 percent compared with 2016. In fact, global wine output dropped to its lowest levels since 1957, primarily due to poor weather in the Eurozone which slashed production across the entire bloc.

In France, vinters reported “widespread damage in Bordeaux, Burgundy, and Champagne, with some losing their entire 2017 crop.

Here’s the full article:

H/T to Ice Age Now  Read the full report HERE.