California to Experience More Extreme Droughts, Inundations due to Climate Change

In the future, the Pacific Ocean's temperature cycles could disrupt more than just December fishing. A study published in Nature Communications suggests that the weather patterns known as El Nino and La Nina could lead to at least a doubling of extreme droughts and floods in California later this century.

The study shows more frequent extreme events are likely to occur. Other research shows the Golden State's average precipitation increasing gradually, but not enough to account for the occurrence of extreme events. A better understanding of what gives rise to El Nino and La Nina cycles -- together known as El Nino-Southern Oscillation -- might help California predict and prepare for more frequent droughts and floods in the coming century.

"Wet and dry years in California are linked to El Nino and La Nina. That relationship is getting stronger," said atmospheric scientist Jin-Ho Yoon of the Department of Energy's Pacific Northwest National Laboratory. "Our study shows that ENSO will be exhibiting increasing control over California weather."

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Amazon Region Expected to Have More Frequent, Extreme Droughts and Extreme Rains

A new paper co-authored by WHRC scientists Philip Duffy and Paulo Brando evaluates the accuracy of current climate models and uses them to project future drought and wet periods in the Amazon. They conclude that the whole of the Amazon will confront more hydrological extremes, and that most of the region will experience much more frequent and extensive drought. These changes would have profound implications for forest structure, composition, biomass, and carbon emissions.

According to Dr. Duffy, "Historically, the main source of CO2 emissions from Amazon forests has been direct human action, especially deforestation. However, in the future, climate change may cause large emissions that result from changes in the large-scale environment rather than from direct human action, and hence are much more difficult to control. This study, based on 35 climate models, suggests that future climate change will increase the frequency and geographic extent of meteorological drought in most of Amazon. This may contribute to forest degradation and increased emissions of CO2 to the atmosphere, amplifying global warming."

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Not Drought Shamed yet

It was a pretty picture.  However, walking through chunks of Orinda and Lafayette, I've noticed some folks and businesses are still watering like they did before the drought.  Not cool, guys.  Not cool at all.

Recurrent Droughts in the Black Sea Region During the Miocene Neogene

Recurrent phases of drought in the upper Miocene of the Black Sea region

Authors:

Vasiliev et al

Abstract:

Since the Miocene the Black Sea proved to be highly sensitive to fluctuations in the hydrological cycle because of its recurrent restricted connections with the open ocean and the location between the dry Mediterranean and more humid higher northern latitudes. Although the Black Sea formed one of the foci of the 1975 Deep Sea Drilling Project Leg 42B, robust tools to reconstruct past changes in its hydrological cycle were lacking at that time. Here we revisit the sedimentary succession (Hole 380A) and determined compound-specific carbon (δ13C) hydrogen isotope ratios (δD) of terrestrial and aquatic biomarkers to investigate changes in the hydrological budget of the Black Sea during the late Miocene. The δ13C and δD isotopic composition of n-alkanes as well as alkenones and palynology indicate large environmental changes in the Black Sea and/or in the sources of the water entering the Black Sea during the late Miocene. The δD of alkenones, showing an enrichment of more than 80 ‰ at the end of the Miocene, implies a major shift in basin hydrology, possibly resulting in severely increased salinity. These changes in δD composition of the alkenones coincide with both with sharp shifts in reconstructed sea surface temperature and palynological assemblages. Two intervals with negative water budget were identified, most likely caused by enhanced evaporation. The older and longer dry/evaporative phase predates the Maeotian/Pontian boundary (regional stages) at ~ 6.1 Ma. The younger drying phase corresponds to the Messinian salinity crisis. This shift to highly evaporative conditions is related to a similar shift previously observed in a Messinian (Pontian) sedimentary succession from the Taman peninsula (Russia). These recurrent dry phases likely reflect regional climatic shifts over a significantly larger area around the Black Sea area during the upper Miocene.

California's Drought Tied to Climate Change, Could be Very Frequent in the Future

The atmospheric conditions associated with the unprecedented drought currently afflicting California are "very likely" linked to human-caused climate change, Stanford scientists say.

In a new study, a team led by Stanford climate scientist Noah Diffenbaugh used a novel combination of computer simulations and statistical techniques to show that a persistent region of high atmospheric pressure hovering over the Pacific Ocean that diverted storms away from California was much more likely to form in the presence of modern greenhouse gas concentrations.

The research, published on Sept. 29 as a supplement to this month's issue of the Bulletin of the American Meteorological Society, is one of the most comprehensive studies to investigate the link between climate change and California's ongoing drought.

"Our research finds that extreme atmospheric high pressure in this region—which is strongly linked to unusually low precipitation in California—is much more likely to occur today than prior to the human emission of greenhouse gases that began during the Industrial Revolution in the 1800s," said Diffenbaugh, associate professor of Environmental Earth System Science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment.

The exceptional drought currently crippling California is by some metrics the worst in state history. Combined with unusually warm temperatures and stagnant air conditions, the lack of precipitation has triggered a dangerous increase in wildfires and incidents of air pollution across the state. A recent report estimated that the water shortage would result in direct and indirect agricultural losses of at least $2.2 billion, and lead to the loss of more than 17,000 seasonal and part-time jobs in 2014 alone. Such impacts prompted California Governor Jerry Brown to declare a drought emergency, and the federal government to designate all 58 California counties as "natural disaster areas."

Scientists agree that the immediate cause of the drought is a particularly stubborn "blocking ridge" over the northeastern Pacific –popularly known as the Ridiculously Resilient Ridge, or "Triple R"–that prevented winter storms from reaching California during the 2013 and 2014 rainy seasons.

Blocking ridges are regions of high atmospheric pressure that disrupt typical wind patterns in the atmosphere. "Winds respond to the spatial distribution of atmospheric pressure," said Daniel Swain, a graduate student in Diffenbaugh's lab and lead author of the study. "We have seen this amazingly persistent region of high pressure over the northeastern Pacific for many months now, which has substantially altered atmospheric flow and kept California largely dry."

Blocking ridges occur periodically at temperature latitudes, but the Triple R was exceptional for both its size and longevity. While it dissipated briefly during the summer months of 2013, it returned even stronger by fall 2013 and persisted through much of the winter, which is normally California's "wet season." "At its peak in January 2014, the Triple R extended from the subtropical Pacific between California and Hawaii to the coast of the Arctic Ocean north of Alaska," said Swain, who coined the term "ridiculously resilient ridge" last fall to highlight the unusually persistent nature of the offshore blocking ridge.

Like a large boulder that has tumbled into a narrow stream, the Triple R diverted the flow of high-speed air currents known as the jet stream far to the north, causing Pacific storms to bypass not only California, but also Oregon and Washington. As a result, rain and snow that would normally fall on the West Coast were instead re-routed to Alaska and as far north as the Arctic Circle.

An important question for scientists and decision-makers has been whether human-caused climate change has influenced the conditions responsible for California's drought. Given the important role of the Triple R, Diffenbaugh's team set out to measure the probability of such extreme ridging events. The team first assessed the rarity of the Triple R in the context of the 20th century historical record. They found that the combined persistence and intensity of the Triple R in 2013 was unrivaled by any event since 1948, which is when comprehensive information about the circulation of the atmosphere is first available.

To more directly address the question of whether climate change played a role in the probability of the 2013 event, the team collaborated with Bala Rajaratnam, assistant professor of Statistics and of Environmental Earth System Science, and an affiliated faculty of the Woods Institute for the Environment. Rajaratnam and his graduate students Michael Tsiang and Matz Haugen applied advanced statistical techniques to a large suite of climate model simulations. Using the Triple R as a benchmark, the group compared geopotential heights–an atmospheric property related to pressure– between two sets of climate model experiments. One set mirrored the present climate, in which the atmosphere is growing increasingly warm due to human emissions of carbon dioxide and other greenhouse gases. In the other set of experiments, greenhouse gases were kept at a level similar to those that existed just prior to the Industrial Revolution.

The interdisciplinary research team found that the extreme geopotential heights associated with the Triple R in 2013 were at least three times as likely to occur in the present climate as in the preindustrial climate. They also found that such extreme values are consistently tied to unusually low precipitation in California, and the formation of atmospheric ridges over the northeastern Pacific.

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MegaDrought Almost Certain for American Southwest With Global Warming

Due to global warming, scientists say, the chances of the southwestern United States experiencing a decade long drought is at least 50 percent, and the chances of a "megadrought" – one that lasts over 30 years – ranges from 20 to 50 percent over the next century.

The study by Cornell University, University of Arizona and U.S. Geological Survey researchers will be published in a forthcoming issue of the American Meteorological Society's Journal of Climate.

"For the southwestern U.S., I'm not optimistic about avoiding real megadroughts," said Toby Ault, Cornell assistant professor of earth and atmospheric sciences and lead author of the paper. "As we add greenhouse gases into the atmosphere – and we haven't put the brakes on stopping this – we are weighting the dice for megadrought conditions."

As of mid-August, most of California sits in a D4 "exceptional drought," which is in the most severe category. Oregon, Arizona, New Mexico, Oklahoma and Texas also loiter between moderate and exceptional drought. Ault says climatologists don't know whether the severe western and southwestern drought will continue, but he said, "With ongoing climate change, this is a glimpse of things to come. It's a preview of our future."

Ault said that the West and Southwest must look for mitigation strategies to cope with looming long-drought scenarios. "This will be worse than anything seen during the last 2,000 years and would pose unprecedented challenges to water resources in the region," he said.

In computer models, while California, Arizona and New Mexico will likely face drought, the researchers show the chances for drought in parts of Washington, Montana and Idaho may decrease.

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Just How Bad the California Drought is

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New Mexico's Horrible Drought: Climate Change or the Return of the Cycle Which Killed the Anasazi

Scientists in the West have a particular way of walking a landscape and divining its secrets: They kick a toe into loamy soil or drag a boot heel across the desert's crust, leaning down to squint at the tiny excavation.

Try that maneuver in New Mexico these days and it yields nothing but bad news in a puff of dust.

Across the West, changes in the climate are taking a toll. Almost 87% of the region is in a drought.

Nevada is removing wild horses and stocks of cattle from federal rangelands, Wyoming is seeding clouds as part of a long-term "weather modification program," officials in Colorado say the state's southeastern plains are experiencing Dust Bowl conditions, and the entire western U.S. has been beset by more frequent and ferocious wildfires across an ever-more combustible landscape.

But nowhere is it worse than in New Mexico. In this parched state, the question is no longer how much worse it can get but whether it will ever get better — and, ominously, whether collapsing ecosystems can recover even if it does.

The statistics are sobering: All of New Mexico is officially in a drought, and three-quarters of it is categorized as severe or exceptional. Reservoir storage statewide is 17% of normal, lowest in the West. Residents of some towns subsist on trucked-in water, and others are drilling deep wells costing $100,000 or more to sink and still more to operate.

For Noel: Return of the Lost Church

In Venezuela. I'll answer your question soon, Noel. Promise.