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Author Topic: General Drought Stuff  (Read 67753 times)

sidd

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Re: General Drought Stuff
« Reply #200 on: November 29, 2018, 12:20:46 AM »
Sarhadi et al. find that hot and dry conditions are becoming more likely:

" anthropogenic climate forcing has doubled the joint probability of years that are  both warm and dry in the same location (relative to the 1961–1990 baseline)"

doi: 10.1126/sciadv.aau3487

open access. read all about it.

sidd

bligh8

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Re: General Drought Stuff
« Reply #201 on: December 07, 2018, 03:56:44 PM »
Climate and the Global Famine of 1876–78

Abstract

From 1875 to 1878, concurrent multiyear droughts in Asia, Brazil, and Africa, referred to as the Great Drought, caused widespread crop failures, catalyzing the so-called Global Famine, which had fatalities exceeding 50 million people and long-lasting societal consequences. Observations, paleoclimate reconstructions, and climate model simulations are used 1) to demonstrate the severity and characterize the evolution of drought across different regions, and 2) to investigate the underlying mechanisms driving its multiyear persistence. Severe or record-setting droughts occurred on continents in both hemispheres and in multiple seasons, with the “Monsoon Asia” region being the hardest hit, experiencing the single most intense and the second most expansive drought in the last 800 years. The extreme severity, duration, and extent of this global event is associated with an extraordinary combination of preceding cool tropical Pacific conditions (1870–76), a record-breaking El Niño (1877–78), a record strong Indian Ocean dipole (1877), and record warm North Atlantic Ocean (1878) conditions. Composites of historical analogs and two sets of ensemble simulations—one forced with global sea surface temperatures (SSTs) and another forced with tropical Pacific SSTs—were used to distinguish the role of the extreme conditions in different ocean basins. While the drought in most regions was largely driven by the tropical Pacific SST conditions, an extreme positive phase of the Indian Ocean dipole and warm North Atlantic SSTs, both likely aided by the strong El Niño in 1877–78, intensified and prolonged droughts in Australia and Brazil, respectively, and extended the impact to northern and southeastern Africa. Climatic conditions that caused the Great Drought and Global Famine arose from natural variability, and their recurrence, with hydrological impacts intensified by global warming, could again potentially undermine global food security.

." It was arguably the worst environmental disaster to ever befall humanity and one of the worst calamities of any sort in at least the last 150 years, with a loss of life comparable to the World Wars and the influenza epidemic of 1918/19.

"The Global Famine was initiated by severe droughts in several regions that persisted for multiple seasons between 1875 and 1878. In Fig. 1, we identify the temporal evolution of these regional droughts. The drought started in India with a failure of the 1875 winter monsoon season, and dry conditions persisted through the summer of 1877. In East Asia, the drought started in spring 1876, and the lack of rainfall persisted through summer 1878. Subsequently, droughts developed in parts of South Africa, northern Africa, and northeastern Brazil in following seasons that lasted till at least 1878. Relatively shorter but severe droughts also occurred in western Africa, Southeast Asia, and Australia between mid-1877 and 1878. Droughts in most of these regions are often associated with the occurrence of El Niño events (e.g., Kumar et al. 2006; Slingo and Annamalai 2000; Ropelewski and Halpert 1987; Wang et al. 2017; Xu et al. 2004). While previous studies (Kiladis and Diaz 1986; Aceituno et al. 2009) have identified the presence of a strong El Niño during the Great Drought, the El Niño conditions only developed in 1877 and waned in 1878. However, the drought in key areas afflicted by famines—including India, northeastern Brazil, and China—started prior to the development of the El Niño or lasted longer than its duration.


 https://doi.org/10.1175/JCLI-D-18-0159.1
« Last Edit: December 07, 2018, 08:10:10 PM by bligh8 »

SteveMDFP

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Re: General Drought Stuff
« Reply #202 on: December 07, 2018, 06:23:01 PM »
Climate and the Global Famine of 1876–78

Abstract

From 1875 to 1878, concurrent multiyear droughts in Asia, Brazil, and Africa, referred to as the Great Drought, 

Thanks for this historical review.  A disturbing cautionary tale.  One wonders how well (or poorly) the global economic system would manage a similar crisis today.  We surely don't store enough food to manage such an event adequately.  Food prices, I imagine, would rise so high that only the affluent might avoid starvation.

sidd

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Re: General Drought Stuff
« Reply #203 on: December 07, 2018, 07:42:23 PM »
The effect of the drought in 1877-1879 is gruesomely documented by Mike Davis in "Late Victorian Holocausts"

When I was a very small child I recall meeting a survivor. He was very old then. He had survived as an infant through the generosity of a local prince who made sure that the children in his little fief had something to eat. The parents were not so fortunate and died in droves.

sidd

wdmn

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Re: General Drought Stuff
« Reply #204 on: May 02, 2019, 01:05:53 AM »
Global Warming Was Already Fueling Droughts in Early 1900s, Study Shows


https://insideclimatenews.org/news/01052019/drought-climate-change-fingerprints-global-warming-20th-century-tree-rings-marvel-cook

Global warming has been fueling droughts since the early 20th Century, when soils started drying out at the same time across parts of North and Central America, Eurasia, Australia and the Mediterranean, new research shows.

The researchers say the surprising early-century findings provide the clearest signal yet that human-caused greenhouse gas emissions are changing the hydroclimate in ways that can devastate agriculture, health and livelihoods.

...

"What we're seeing is very suggestive of a role for greenhouse gases, bigger than anything we've seen previously," Marvel said. "We're not arguing here that there is a really large effect. What we're saying is, we're picking out the underlying note against the background of a symphony. That note is faint but it's definitely there. And to find it, you need to look at long-term trends and wide areas."

Darvince

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Re: General Drought Stuff
« Reply #205 on: May 02, 2019, 11:44:16 AM »
I found the paper for anyone who is curious, since the article didn't seem to have any links:
https://www.nature.com/articles/s41586-019-1149-8

Twentieth-century hydroclimate changes consistent with human influence
    Kate Marvel, Benjamin I. Cook, Céline J. W. Bonfils, Paul J. Durack, Jason E. Smerdon & A. Park Williams

Abstract
Although anthropogenic climate change is expected to have caused large shifts in temperature and rainfall, the detection of human influence on global drought has been complicated by large internal variability and the brevity of observational records. Here we address these challenges using reconstructions of the Palmer drought severity index obtained with data from tree rings that span the past millennium. We show that three distinct periods are identifiable in climate models, observations and reconstructions during the twentieth century. In recent decades (1981 to present), the signal of greenhouse gas forcing is present but not yet detectable at high confidence. Observations and reconstructions differ significantly from an expected pattern of greenhouse gas forcing around mid-century (1950–1975), coinciding with a global increase in aerosol forcing. In the first half of the century (1900–1949), however, a signal of greenhouse-gas-forced change is robustly detectable. Multiple observational datasets and reconstructions using data from tree rings confirm that human activities were probably affecting the worldwide risk of droughts as early as the beginning of the twentieth century.


As I'm just posting the paper and haven't read it, my first impression is that I'm very surprised that the relatively small run-up of temperatures to ~0.3C above preindustrial may have been enough to kick off global warming impacts.

Tor Bejnar

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Re: General Drought Stuff
« Reply #206 on: May 02, 2019, 03:58:48 PM »
I recall reading somewhere, years ago, about a detectable anthropogenic effect on climate going back about 10,000 years [well, 8,000 years].  A quick internet search finds a 2011 Nature article that supports my memory.
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Sleepy

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Re: General Drought Stuff
« Reply #207 on: May 02, 2019, 04:41:54 PM »
Pmt started a topic in 2014, Early Anthropocene.
https://forum.arctic-sea-ice.net/index.php/topic,852.0.html
There's a video lecture posted in Reply #90 with Ruddiman.
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vox_mundi

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Re: General Drought Stuff
« Reply #208 on: May 06, 2019, 01:41:43 AM »
Drought Affects Panama Canal Shipping 
https://learningenglish.voanews.com/amp/drought-affects-panama-canal-shipping/4900861.html

... Carlos Vargas is the vice president of environment and water for the Canal Authority. He said recently that Gatun — one of the largest artificial lakes in the world – was 1.4 meters below normal levels for this time of year. It has dropped more than 0.2 meters since early April. A smaller lake that also supplies the waterway, Alajuela, was 2.2 meters below usual.

“These low levels in the Panama Canal are the product of four or five months of almost zero precipitation,” Vargas told The Associated Press. “It really has been the driest dry season we’ve had in the history of the canal. The flow of rivers to the lake is down 60%.”

The Canal Authority had to restrict how deeply ships can reach below the surface. That means large ships, mainly from the United States and China, must pass through with less cargo.
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Archimid

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Re: General Drought Stuff
« Reply #209 on: May 06, 2019, 02:41:45 AM »
Its the little things that will get us. The ones no one has even thought about.
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