[HN Gopher] Western megadrought is worst in 1,200 years, intensi...
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Western megadrought is worst in 1,200 years, intensified by climate
change
Author : lisper
Score : 36 points
Date : 2022-02-14 19:40 UTC (3 hours ago)
(HTM) web link (www.latimes.com)
(TXT) w3m dump (www.latimes.com)
| forgotmyoldacc wrote:
| I wonder why they specifically picked 22 years, as opposed to 25
| or 20.
| codetrotter wrote:
| This section of the article answers that:
|
| > Williams was part of a team that published a similar study in
| 2020. At the time, they found the drought since 2000 was the
| second-worst after the late 1500s megadrought. With widespread
| heat and dryness over the past two years, the current drought
| has passed that extreme mark.
|
| So when they first looked, it was the year 2020 and they looked
| at the period between year 2000 and 2020. And now they are
| looking at that plus the additional 2 years that has passed
| since last time they looked.
| mjfl wrote:
| warmer climates lead to much wetter climates. invariably.
| mturmon wrote:
| That's one effect.
|
| But in the western US, this effect turns out not to be the
| driver for hydrology. We've seen higher temperatures (causing
| more evapotranspiration), more highly-variable rainfall (thus,
| more precipitation lost to runoff), and less possibility for
| snow accumulation (again, causing lost precipitation due to
| faster runoff).
|
| I'm not sure where you live, but the higher temperatures and
| especially the lack of snow accumulation have been noticeable
| even to casual observers in the area.
|
| For more, see TFA, or the excellent National Climate
| Assessment. Chapter 25 covers the Southwest, and drought is the
| first topic. It has references to the literature if you're
| interested.
|
| https://nca2018.globalchange.gov/chapter/25/
|
| Just one quick excerpt:
|
| > Increased temperatures, especially the earlier occurrence of
| spring warmth, have significantly altered the water cycle in
| the Southwest region. These changes include decreases in
| snowpack and its water content, earlier peak of snow-fed
| streamflow, and increases in the proportion of rain to snow.
| These changes, attributed mainly to climate change, exacerbate
| hydrological drought.
| AnimalMuppet wrote:
| Not everywhere. Warmer climates lead to changes in wind
| patterns, which leave _some_ places drier than they were.
| mjfl wrote:
| but it increases the vapor pressure of water everywhere.
| syntaxing wrote:
| I'm not very educated in this subject, but wouldn't the West
| coast be the best place for some sort of "clean" desalination
| water plant?
| mdavis6890 wrote:
| Regarding California in particular, there is actually plenty of
| water for the residents. About 80-90% of usable water is used
| for agriculture, and the majority of that produce is exported
| from California to other countries and states. For example, all
| around the capital of Sacramento there are 1000's of acres of
| rice fields. About half the rice is exported to Asia. Appx 8%
| or so of California water is used in and around homes,
| including landscaping.
|
| It takes a gallon of water to grow a single almond, and 95%+ of
| the worlds almonds come from CA. It takes FIFTY gallons to grow
| an avocado, and 95% of the WORLD's come from CA also. These are
| not cherry-picked examples. I could have chosen dozens of other
| crops.
|
| So, in effect, California's farmers are selling roughly half of
| its water (in the form of produce) to other states and
| countries. It's a bit like Saudi Arabia in this sense, but with
| water instead of oil. Unlike oil, of course, water does
| replenish, but nevertheless the rate of export is so high that
| the aquifers are nearly empty now.
|
| Do make sure to take shorter showers though, fellow
| Californians!
| toomuchtodo wrote:
| Desalination requires enormous amounts of energy (although
| California has large amounts of solar available, ~10GW
| continuous on most sunny days per ElectricityMap.org [1]), but
| also creates a high salinity brine that is toxic to most marine
| life that must be discharged somewhere to mix with existing
| ocean water.
|
| For drinking water, it could be done (at significant cost),
| with a shift to reclaimed water for landscaping needs. But it
| is absolutely untenable for agriculture. It's also likely that
| Hoover Dam's electrical generation output will need to be
| replaced, in some part, with battery backed utility scale solar
| (as Lake Mead's water level declines below turbine intake at
| 950 feet; current water level is ~1050 feet [2]).
|
| We've known for over 100 years Western development was
| unsustainable (due to water) when the Colorado River Compact
| was originally formed [3] [4], and it was done anyway.
|
| [1] https://i.imgur.com/yIoTgJi.png (sourced from
| https://app.electricitymap.org/zone/US-CAL-
| CISO?wind=false&s...)
|
| [2] https://earthobservatory.nasa.gov/images/148758/lake-mead-
| dr...
|
| [3] https://www.usbr.gov/lc/region/pao/pdfiles/crcompct.pdf
|
| [4] https://news.ycombinator.com/item?id=27909108
| mdavis6890 wrote:
| Regarding California in particular, there is actually plenty of
| water for the residents. About 80-90% of usable water is used for
| agriculture, and the majority of that produce is exported from
| California to other countries and states. For example, all around
| the capital of Sacramento there are 1000's of acres of rice
| fields. About half the rice is exported to Asia. Appx 8% or so of
| California water is used in and around homes, including
| landscaping. It takes a gallon of water to grow a single almond,
| and 95%+ of the worlds almonds come from CA. It takes FIFTY
| gallons to grow an avocado, and 95% of the WORLD's come from CA
| also. These are not cherry-picked examples. I could have chosen
| dozens of other crops.
|
| So, in effect, California's farmers are selling roughly half of
| its water (in the form of produce) to other states and countries.
| It's a bit like Saudi Arabia in this sense, but with water
| instead of oil. Unlike oil, of course, water does replenish, but
| nevertheless the rate of export is so high that the aquifers are
| nearly empty now.
|
| Do make sure to take shorter showers though, fellow Californians!
| somewhereoutth wrote:
| And don't forget Apple changing reusable porcelain to
| 'biodegradable' plates to save on /staff costs/ water for
| washing up!
| totesraunch wrote:
| The fact that there's water for people doesn't mean the drought
| doesn't affect the state. Drought causes large amounts of dead
| trees (of which California is covered in) these dead trees
| catch fire and burn cities down. Water isn't just a consumable
| for humans
| adevx wrote:
| Pumping excessive amounts of groundwater for agriculture
| lowers the water table and may be a bigger driver for tree
| die-off:
|
| https://www.azcentral.com/in-depth/news/local/arizona-
| enviro...
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