(Video provided by NASA Goddard)
According to the California Government, State snowpack levels are now at 1 percent of average. That’s not just the lowest ever recorded. That’s about as close to zero as one can get without actually hitting zero.
“I don’t think the American public has gripped in its gut what could happen. We’re looking at a scenario where there’s no more agriculture in California.” — Stephen Chu in a public press release six years ago.
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Southwest megadrought. For more than 20 years now, climate models have been indicating rising risk of severe, multi-decade drought for this region of the US as a result of human-caused global warming. For years, we’ve watched the warnings mount. And for years we’ve watched as climates for that region grew drier and drier.
Warming seeped into the region, driving snow packs higher, or off the mountains entirely. Critical stores through dry summer months, these zones of mountain snow and ice serve as aquifers for human beings, shrubs and trees, and local animals alike. Their dwindling alone left the region more vulnerable to drought conditions.
But further-reaching changes — warming in the nearby ocean, and a recession of sea ice in the Arctic — also tilted the odds toward drought. Heating in the near shore waters of the Northeastern Pacific served as a kind of barrier to storm systems running across the wide ocean. Loss of sea ice in the Bering, Chukchi and Beaufort Seas provided a heat stress to that Arctic region. The net result was conditions that preferentially enabled the development of dry high pressure systems along the North American West Coast. A condition many have come to call — the Ridiculously Resilient Ridge.
As the climate continues to warm, these conditions — local, regional, and global — enforce a kind of tilting toward drier and drier conditions. Conditions that models show may result in worse droughts than even the one we are seeing now. Droughts that last, not for four years, but for ten years, twenty years, thirty years or more. It’s a problem we’re just starting to deal with now. But if you think this is bad, warm the world by another 0.5 C, or 1 C, or 2 C and you probably really don’t want to see what’s in store.
For according to a February article in National Geographic and based on studies published by NASA, Columbia University and Cornell:
The chances of a 35-year or longer “megadrought” striking the Southwest and central Great Plains by 2100 are above 80 percent if the world stays on its current trajectory of greenhouse gas emissions.
California Hitting Water Limits
But the current drought, though not yet a ‘megadrought,’ is more than bad enough. Aptly called epic, the powerful and ongoing lock on California moisture has wrung out aquifers, pushed snowpacks to below 1 percent of usual levels for springtime, greatly depleted ground water supplies, and forced an additional 25 percent water rationing across the state.
Stresses to water supplies — not only for California, but for many other states as well — are mounting. Key Aquifers, like Lake Mead in Northern Arizona, are hitting levels where downstream rationing may be required. A shock that would send impacts rippling on through the entire US Southwestern water supply.
(Nearly 50 percent of California is now under the most severe drought conditions we have a measure for. A total of more than 37 million people in California alone are impacted by drought at this time. Image source: US Drought Monitor.)
Expert climate spotter Andy in San Diego has been providing situation discussion in this forum on the drought there for weeks. Of particular concern are water levels at Lake Mead — which are fast approaching the line where water rationing to various locations across the Southwest goes into effect as a requirement by law.
Yesterday, Andy noted in discussion here that:
Lake Mead is at 1078.79. [Approximately] 4 ft from the start of cutoffs. It appears Arizona gets [rationed] first at 1075 in some documentation, Nevada in others. Outflows from Mead were … shut off Saturday & Sunday. Starting Saturday, outflows from Lake Powell were cranked up by about 1000 [cubic feet per second]. … At this point, inflows to Powell are being sent downstream to Mead immediately. I see a bit of gambling here hoping for decent inflows to Powell in Late May through early July. Unfortunately, snow pack above Powell is pretty much non existent. Powell is at ~44% full pool. Mead is at ~38%. This will be an interesting summer, it appears that all of the Hail Mary’s have been used for 2015 already. (some edits for clarity)
Since Andy’s update yesterday, Lake Mead levels had fallen further to 1078.55 feet — just 3.5 feet above levels where rationing requirements begin.
12.5 Million Dead Trees Could Fuel Epic Fire Season
As key US aquifers hover over mandatory rationing levels, impacts to wildlife across California are growing more and more extreme. Anyone having watched Neil DeGrasse Tyson’s amazing Cosmos series may have noted dessicated, browned grasses and fields in the background of some shots. The reason for this is that many of Tyson’s narrations were filmed on location in California. And, at the time — in 2014 — California’s epic drought was really starting to bite deep.
How deep had not yet become apparent. But new reports out yesterday began to shed light on what is an amazingly stark situation.
According features in the Washington Post and elsewhere, more than 12.5 million trees perished in California alone last year due to extreme drought conditions. Encompassing more than 1 million acres, it’s a swath of forest the size of Rhode Island — now filled with withered trees. Key plants necessary for a variety of life and land supports including moistening the air, anchoring the soil, and providing homes for communities of creatures.
(USDA photo shows swaths of dead trees in California pine forest. Image source USDA via CBS Local.)
Research indicated that not only did the heat and drought stress the trees. But the warm conditions favored the invasion of tree-devouring beetles. Wood-devouring insects that thrive in the hot, dry conditions put in place by the ongoing drought.
The dead trees are bad enough. But put them smack dab in the worst drought on record for California and they are an extreme fire hazard.
Since late 2013, fire season has never really ended for California. It’s flared and dwindled, but wildfire burning has continued regardless of season due to both extreme heat and drying. Summer months are the worst times, though, and this year’s very extreme conditions has California fire planners very worried.
At issue are all the millions and millions of dead trees. Sitting in the sun, dried and wrung of all moisture, they’re essentially large stacks of kindling. Fuels that could rapidly ignite given even the smallest spark.
Cambria, Calif. is under an emergency fire declaration. There’s no actual fire, no smoke, but here’s the situation broken down by Cambria Fire Chief Mark Miller. If a fire started today under the circumstances that exist……In the first 20 minutes, it would be six acres, and there would be two houses involved.
US Agriculture Under Threat
But not only is California now a fire-vulnerable land of browned, snowless mountains, rapidly dwindling water supplies, and dessicated, dying, beetle devoured plant life. It is a place that hosts the heart of US produce production. A vital source of food for the US and for the world that is now under threat.
Central Valley California, according to a new report in Think Progress, is the production hub for more than 90 percent of the United States’ fresh fruits and vegetables. It’s a condition that arose from a combination of slick marketing, a host of unique micro-climates suited to practically every form of vegetable, and a domination of (mostly corn and soy) mono-cropping throughout the productive regions of the Central US. Essentially, mono-cropping in the plains drove the majority of produce farmers to the West Coast.
And, as result, most of the fresh vegetables Americans enjoy are all grown from one basket. A basket that is now baking under a merciless California sun. Everything from lettuce to avocados to tomatoes to almonds to oranges, and so many more, are now at risk.
(The majority of California agriculture is irrigation-based — supplied by aqueducts like the one shown above. Aqueducts like this one also add flood risk due to enhanced potential of extreme rainfall events due atmospheric heating combined with land subsidence due to ground water depletion. Image source: Public Herald.)
Fully 80 percent of California’s water supply goes to food growers. It’s a stream of vital water that proceeds from California aquifers to farmers and then directly to your dinner table. A stream that Governor Jerry Brown has refused to cut at any cost. But despite increasingly draconian water rationing to other sectors, farms are still feeling a hit. In 2014, nearly 500,000 acres of cropland lay fallow. A number that could more than double by the end of this year. With so much of California’s water evaporating, with so many wells running dry, even water protected for farm use takes a hit.
In this way, ongoing drought in California is a direct threat to US food security. A fact that hasn’t been missed by food experts like John Ikerd who recommend a widespread re-localization of produce production to add resiliency to the US food supply in the face of growing climate challenges.
But the fact that we may need such a reorganization, together with the fact that the current California drought is an early, easier outlier of what is to come, highlights our vulnerability. Warming of the Earth System is already shocking the US and global food system to such a degree that it is calling into question the future of US produce production.
Strong El Nino is No Cure
Among many, hopes are that a strong El Nino may deliver a drought-breaking flood of moisture by the end of this year. And while there is growing indication that a monster El Nino may be developing in the Pacific, such an event would be no cure for poor climate-changed California. In fact, such an event could produce floods that further impact agriculture — stripping denuded landscapes and flushing vital soil nutrients down streams and into a eutrophying ocean.
The ground there is baked, subsided. The pores in the earth closed up, creating a tablet effect for water ponding. The fires have stripped trees and brush from hillsides, resulting in landslide hazard.
And the kind of rainfall a 2.5 to 3 C anomaly event (that some models are indicating) could generate would be extraordinary (especially when we add in the extra atmospheric moisture loading from overall human heating of 0.9 to 1 C above 1880).
For California, it looks like the option for ending epic drought is epic flood. And, with human caused warming, more drought will almost certainly follow any flood.
Hat Tip to Andy in San Diego
Hat Tip to Spike