By Kenneth Richard on 14. June 2021
Scientists continue to publish new drought reconstructions indicating there were far more frequent and severe drought periods in the past several thousand years than anything observed in the modern period.
A new study (Berg and McColl, 2021) indicates there has long been “qualitatively incorrect” estimates of the impact modern and future warming has on drought trends and dryland expansion because atmospheric aridity is “not an accurate proxy of the future extent of drylands.” Consequently, the authors suggest there will be “no global drylands expansion under greenhouse warming, contrary to previous claims based on atmospheric aridity.”
Indeed, instead of being driven by increasing greenhouse gas concentrations and warming, droughts along the western coast of the United States are “predominantly [84%] driven by internal atmospheric variability” and cooling sea surface temperatures (Baek et al., 2021).
Image Source: Baek et al., 2021
Many new drought reconstructions even indicate the modern period has recorded no increasing drought trends relative to the last few thousand years.
“The periods 1931-1938 and 1909-1917 were the longest and most severe wet and dry periods.”
Image Source: Zhu et al., 2021
“Despite its significant recent impacts, the 2000s drought is ranked as only the sixth driest run in the CHU reconstruction, is only half or less the duration of the 1700s, early 1900s, and 1950s droughts, and has a magnitude (running SWE total of years with snowpack below the mean) 50–75% less severe than these others.”
“The magnitude of the 1950s drought in the WSR reconstruction is only 67% of the magnitude of the highest-ranking droughts in the same record, 1818–1834 and 1728–1744.”
“The 20th century has less frequent and long dry or wet periods. … Our findings are also consistent with studies that document pre-instrumental droughts that have been more intense or longer-lasting than dry periods of the 20th century (Woodhouse and Overpeck, 1998, Novak, 2007).”
Image Source: Brice et al., 2021
“For the final reconstruction, the instrumental target data are adjusted to provide realistic estimates of high-elevation summer rainfall back to 729 CE. The reconstruction contains substantially more low-frequency variability than other high-resolution hydroclimate records from the eastern Mediterranean including extended dry periods from 1,350 to 1,379 CE (39 ± 4.5 mm) and 913 to 942 (40 ± 8.4 mm), and moist periods from 862 to 891 (86 ± 11 mm) and 1,522 to 1,551 (80 ± 3.5 mm), relative to the long-term mean of 61 mm. The most recent 30-year period from 1986 to 2015 is characterized by above average June–July precipitation (73 ± 2 mm).”
Image Source: Esper et al., 2021
“1774 (SPEI -3.11) and 1787 (SPEI +2.13) being the driest and the wettest years, respectively.”
“The five year mean of reconstructed SPEI revealed droughts in 1818–1822, 1798–1802, 1813–1817, 1793–1797, 1958–1962.”
Image Source: Yadava et al., 2021
“Results showed that years with high drought magnitude ranged from 1920−22, 1926−29, 1942−46 and 1947−51 with values corresponding to 2.2, 3.2, 3.4 and 2.6, respectively while years with low drought magnitude ranged from 1930−31, 1988−89 and 2001−02 with values as 0.2, 0.12 and 0.15, respectively.”
“The longest droughts occurred from 1926−29, 1937−41, 1942−46, 1947−51, 1952−56, and 1958−61 with values in years as 3, 4, 4, 4, 4, and 3 years, respectively, while the shortest droughts occurred in time period of 1 year and ranged from 1930−31, 1964−65, 1979−80, 1981−82, 1983−84, 1988−89, 1991−92, 1993−94, 1996−97 and 2001−02.”
The IPCC’s AR4 report Chapter 10 Page 750 says:
Mean Precipitation … Globally averaged mean water vapour, evaporation and precipitation are projected to increase.
Hardly a recipe for drought.
So…the earth was cooler therefore less humid, more water was froze up in glaciers and icecaps, the pole icecaps were larger insuring both less evaporation and continued lower temperatures…and there were more frequent and worse droughts?
Don’t get all sciency….WE’RE ALL GOING TO DIE BECAUSE OF WARMING!
It doesn’t take a PhD in the hard sciences to understand that a warming earth automatically results in a wetter atmosphere. It’s the most basics of physics and chemistry that dictates that result. Cold eras in earth’s geologic history have always been dry eras .. and vice versa.
Not only dry…but much windier.
But but but, “climate change” means hotter hots, colder colds, dryer drys, and wetter wets. Because carbon magic.
Hmmm… we have these studies that say, “Never mind the drought alarmism.”
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Then we have the ever-astute YSM (Yellow Stream Media) saying, “Never mind those studies. Drought! Drought!”
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And on the topic of drought, we recently had our own dear Loydo saying, “Temperature! Temperature!”
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Hard to say where Loydo will come down on this post about drought. “Pine Island! Pine Island!” maybe?
Place your bets, ladies and gentlemen.
Put me down for $5 on Pine Island.
LOL!
$5 on Polar Bears.
The Poor Poley Bears!!!
One would think that the the Kuroshio current, also known as the Black or Japan Current or the Black Stream, which is the equivalent of the Atlantic’s Gulf stream would have a lot to do with how moisture is funnelled off the North Pacific into North America and would be a huge influence whether California is getting an atmospheric river, or it gets moved north into the Pacific North West from Oregon to British Columbia/Alaska. Along with the Hadley Cell that sets up the jet stream for delivery of weather to the western North America, which fluctuates a tiny amount hither and thither and you get a drought there and a flood here. Or vice versa.
Let’s ask Cliff Mass.
The region you comment upon is Cliff’s area of weather specialty.
Anyone interested in how bad a drought can get is invited to visit the Casa Grande Ruins National Monument.
A small editorial point on the headline:
“Several More New Studies Show Drought Is Now Less Common And Severe Than Centuries, Millennia Ago” is a bit awkward, consider: New Studies Show Drought Less Common And Milder Than Past Centuries, Millennia.
One of my favorite demonstrations of prior droughts is at Lake Tahoe. The natural rim level of Tahoe is 6,223 feet asl. C14 dating of submerged tree remnants, at a depth of 6,212 feet asl, shows an age of 5,510 years before present, more or less a mid-Holocene temperature high. So a drought that produces 11 feet of lowering of Lake Tahoe is normal. Can you imagine the headlines if Lake Tahoe dried up to historic, mid-Holocene levels? The Tahoe mansion/boat crowd screams if the lake level even get close to the dammed level, because their boats are sitting in the sand, tied to the dock, and tens of feet from the water.
There is at least one thing the WUWT original posts about droughts not being unique skips mentioning. That is the population of the immediate drought area(s) are greater than before; which to those alive makes the situation more than an academic subject. If we expand the human interest to include drought area(s) productive food capability an even greater population than during previous extreme droughts is being adversely impacted.
…and right on cue, check out what The Economist has to say about droughts in the American West.
What is rather alarming is the possibility of another 39 year drought in Australia, which appears to have occurred between 1174 and 1212 AD, according to ice core analyses at Law Dome in Antarctica.
“Vance et al. set out to produce “the first millennial-length Australian drought record.” In doing so, they utilized climate records from the Law Dome ice core in East Antarctica to reconstruct a 1,000 year record of the Interdecadal Pacific Oscillation that they then combined with an eastern Australian rainfall proxy (also derived from the Law Dome site) from which they were able to identify historic megadroughts (defined as more than 5 years of below average rainfall).”
“Lasting 39 years (1174-1212 AD), this unparalleled drought was the exclamation point on a uniquely dry period in which 80 out of 111 concurrent years (over the period 1102-1212 AD) persisted in drought.”
https://www.cato.org/blog/1000-year-history-eastern-australia-megadroughts-how-do-they-compare-recent-occurrence-big-dry
It’s pretty clear from the data that Dansgaard–Oeschger events (also known as Bond Events) are associated with global cooling and extensive drought.
Warming is associated with wetter conditions, which is logical since absolute humidity increases with temperature – so the atmosphere has an increased carrying capacity for water vapor as the temperature rises.
The longest Australia drought of 39 years, estimated from proxy records, occurred during the Medieval Warm Period when temperatures were probably above current temperatures, although we can’t be certain about that.
However, a numbers of research papers have provided evidence from proxy sources that the MWP was a global phenomenon which affected the Southern Hemisphere, including Australia and New Zealand, although the precise timing of temperature rises in different regions around the planet would obviously have varied significantly.