California’s Great Wilting — Lake Mead Heading Toward Rationing Line, Extreme Fire Hazard as 12.5 Million Trees Lay Dead, Agriculture Under Existential Threat
(Video provided by NASA Goddard)
7
May, 2015
According
to the California Government, Statesnowpack 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.
*
* * * *
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 California, 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.
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.
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
grain (mostly corn and wheat) 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 avacados to tomatoes to
almonds to oranges and so many more in between 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.
Links:
Hat
Tip to Andy in San Diego
Hat
Tip to Spike
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