6 ms·

Western megadrought is worst in 1,200 years, intensified by climate change

53 points by lisper 5y ago

mdavis6890 5y ago
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!
- totesraunch 5y ago
  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 5y ago
    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-environment/2019/12/05/unregulated-pumping-arizona-groundwater-dry-wells/2425078001/ https://www.azcentral.com/in-depth/news/local/arizona-enviro...
- somewhereoutth 5y ago
  And don't forget Apple changing reusable porcelain to 'biodegradable' plates to save on /staff costs/ water for washing up!
- wobbly_bush 5y ago
  > 95%+ of the worlds almonds come from CA Does this indicate that the climate required to grow an almond is found in very few places, CA being the top of the list? In that case, there really is no alternative to not growing it (apart from abandoning it, similar to the issue some people raise with growing meat in CA and its water requirements).
- mdavis6890 5y ago
  Got a downvote or two, so I thought I'd add some references: First, I retract my numbers about 95% of world almonds and avocados coming from CA - I was typing from memory from research I did a year ago, and now I can't find sources to corroborate this. Nevertheless: https://en.wikipedia.org/wiki/Almonds_in_California https://en.wikipedia.org/wiki/Almonds_in_California "The state produces 80% of the world's almonds and 100% of the United States’ commercial supply." https://www.cdfa.ca.gov/Statistics/ https://www.cdfa.ca.gov/Statistics/ "Over a third of the country's vegetables and two-thirds of the country's fruits and nuts are grown in California." "In 2020 California's farms and ranches received $49.1 billion in cash receipts for their output." "California agricultural exports totaled $21.7 billion in 2019" https://spoonuniversity.com/lifestyle/the-problem-with-drinking-almond-milk-you-probably-never-thought-of https://spoonuniversity.com/lifestyle/the-problem-with-drink... "...between 33 and 248 gallons of water go into producing just a half-gallon of almond milk. I'll let that sink in for a second, before I remind you that 99% of almonds grown in the United States are grown in California..." https://www.truthordrought.com/almond-milk-myths https://www.truthordrought.com/almond-milk-myths "8% of CA ag water is used to grow almonds" (and keep in mind that ag water is 90% of the total usable) https://www.researchgate.net/publication/281474989_How_much_water_does_rice_use https://www.researchgate.net/publication/281474989_How_much_... "On average, about 2,500 liters of water need to be supplied (by rainfall and/or irrigation) to a rice field to produce 1 kg of rough rice." - That's 2.5L per GRAM of rice. https://news.yahoo.com/many-california-farmers-water-cut-130033782.html https://news.yahoo.com/many-california-farmers-water-cut-130... "A handful of districts supplying farmers including Gallagher are receiving nearly 2 million acre feet of water this drought year, enough to supply the city of Los Angeles for roughly four years." People like to talk about the cities being problems, or that it's the water we send down south, or whatever like that. Meanwhile, a handful of (farm) districts, in a single year, are using the equivalent of a 4-year supply of water for the entire city of LA. Wow. And yet: https://abc7news.com/san-jose-water-california-drought-conservation/10965409/ https://abc7news.com/san-jose-water-california-drought-conse... "Whaley said the [San Jose Water] company is asking customers to cutback 15-percent from their 2019 water use levels, and pay $7.13 in surcharges for every unit of water used beyond that amount."
  - amanaplanacanal 5y ago
sparker72678 5y ago
Honestly, I just found it hopeful that the megadroughts of the past in this study weren't 100 year events, but more on the order of 25ish years. (Not trying to downplay possibility of future water problems).
unethical_ban 5y ago
Question: Is the mass intake of water for ag use a cause of "water export"? Is the water used to produce alfalfa, almonds, etc. consumed by the plants and animals and shipped across the globe as part of the finished product? This would be in contrast to a slightly more closed system of water consumption and release before the ag industry took off there.
nathanaldensr 5y ago
So 1200 years ago--before there were nearly any humans on the entire continent--it was just as bad as today? Interesting.
- sparker72678 5y ago
  Isn’t that what makes this important to study? The people aren’t going away, so understudying how drought affects us is valuable.
- zorak8me 5y ago
  Just want to call out - Pre-Colombian North America had a population around 60 million.
forgotmyoldacc 5y ago
I wonder why they specifically picked 22 years, as opposed to 25 or 20.
- codetrotter 5y ago
  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.
syntaxing 5y ago
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 5y ago
  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!
  - mdavis6890 5y ago
    Got a downvote or two, so I thought I'd add some references: First, I retract my numbers about 95% of world almonds and avocados coming from CA - I was typing from memory from research I did a year ago, and now I can't find sources to corroborate this. Nevertheless: https://en.wikipedia.org/wiki/Almonds_in_California https://en.wikipedia.org/wiki/Almonds_in_California "The state produces 80% of the world's almonds and 100% of the United States’ commercial supply." https://www.cdfa.ca.gov/Statistics/ https://www.cdfa.ca.gov/Statistics/ "Over a third of the country's vegetables and two-thirds of the country's fruits and nuts are grown in California." "In 2020 California's farms and ranches received $49.1 billion in cash receipts for their output." "California agricultural exports totaled $21.7 billion in 2019" https://spoonuniversity.com/lifestyle/the-problem-with-drinking-almond-milk-you-probably-never-thought-of https://spoonuniversity.com/lifestyle/the-problem-with-drink... "...between 33 and 248 gallons of water go into producing just a half-gallon of almond milk. I'll let that sink in for a second, before I remind you that 99% of almonds grown in the United States are grown in California..." https://www.truthordrought.com/almond-milk-myths https://www.truthordrought.com/almond-milk-myths "8% of CA ag water is used to grow almonds" (and keep in mind that ag water is 90% of the total usable) https://www.researchgate.net/publication/281474989_How_much_water_does_rice_use https://www.researchgate.net/publication/281474989_How_much_... "On average, about 2,500 liters of water need to be supplied (by rainfall and/or irrigation) to a rice field to produce 1 kg of rough rice." - That's 2.5L per GRAM of rice. https://news.yahoo.com/many-california-farmers-water-cut-130033782.html https://news.yahoo.com/many-california-farmers-water-cut-130... "A handful of districts supplying farmers including Gallagher are receiving nearly 2 million acre feet of water this drought year, enough to supply the city of Los Angeles for roughly four years." People like to talk about the cities being problems, or that it's the water we send down south, or whatever like that. Meanwhile, a handful of (farm) districts, in a single year, are using the equivalent of a 4-year supply of water for the entire city of LA. Wow. And yet: https://abc7news.com/san-jose-water-california-drought-conservation/10965409/ https://abc7news.com/san-jose-water-california-drought-conse... "Whaley said the [San Jose Water] company is asking customers to cutback 15-percent from their 2019 water use levels, and pay $7.13 in surcharges for every unit of water used beyond that amount."
mjfl 5y ago
warmer climates lead to much wetter climates. invariably.
- mturmon 5y ago
  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/ 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.
- gremlinsinc 5y ago
  Living in southern Utah, I'd actually rather dry + hotter than wet + hotter...at least we avoid dying from wetbulb temps. 125 is survivable in dry heat, a death sentence if you add humidity.
- AnimalMuppet 5y ago
  Not everywhere. Warmer climates lead to changes in wind patterns, which leave some places drier than they were.
  - mjfl 5y ago
    but it increases the vapor pressure of water everywhere.

53 points by lisper 5y ago

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!

totesraunch 5y ago
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 5y ago
  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-environment/2019/12/05/unregulated-pumping-arizona-groundwater-dry-wells/2425078001/ https://www.azcentral.com/in-depth/news/local/arizona-enviro...
somewhereoutth 5y ago
And don't forget Apple changing reusable porcelain to 'biodegradable' plates to save on /staff costs/ water for washing up!
wobbly_bush 5y ago
> 95%+ of the worlds almonds come from CA Does this indicate that the climate required to grow an almond is found in very few places, CA being the top of the list? In that case, there really is no alternative to not growing it (apart from abandoning it, similar to the issue some people raise with growing meat in CA and its water requirements).
mdavis6890 5y ago
Got a downvote or two, so I thought I'd add some references: First, I retract my numbers about 95% of world almonds and avocados coming from CA - I was typing from memory from research I did a year ago, and now I can't find sources to corroborate this. Nevertheless: https://en.wikipedia.org/wiki/Almonds_in_California https://en.wikipedia.org/wiki/Almonds_in_California "The state produces 80% of the world's almonds and 100% of the United States’ commercial supply." https://www.cdfa.ca.gov/Statistics/ https://www.cdfa.ca.gov/Statistics/ "Over a third of the country's vegetables and two-thirds of the country's fruits and nuts are grown in California." "In 2020 California's farms and ranches received $49.1 billion in cash receipts for their output." "California agricultural exports totaled $21.7 billion in 2019" https://spoonuniversity.com/lifestyle/the-problem-with-drinking-almond-milk-you-probably-never-thought-of https://spoonuniversity.com/lifestyle/the-problem-with-drink... "...between 33 and 248 gallons of water go into producing just a half-gallon of almond milk. I'll let that sink in for a second, before I remind you that 99% of almonds grown in the United States are grown in California..." https://www.truthordrought.com/almond-milk-myths https://www.truthordrought.com/almond-milk-myths "8% of CA ag water is used to grow almonds" (and keep in mind that ag water is 90% of the total usable) https://www.researchgate.net/publication/281474989_How_much_water_does_rice_use https://www.researchgate.net/publication/281474989_How_much_... "On average, about 2,500 liters of water need to be supplied (by rainfall and/or irrigation) to a rice field to produce 1 kg of rough rice." - That's 2.5L per GRAM of rice. https://news.yahoo.com/many-california-farmers-water-cut-130033782.html https://news.yahoo.com/many-california-farmers-water-cut-130... "A handful of districts supplying farmers including Gallagher are receiving nearly 2 million acre feet of water this drought year, enough to supply the city of Los Angeles for roughly four years." People like to talk about the cities being problems, or that it's the water we send down south, or whatever like that. Meanwhile, a handful of (farm) districts, in a single year, are using the equivalent of a 4-year supply of water for the entire city of LA. Wow. And yet: https://abc7news.com/san-jose-water-california-drought-conservation/10965409/ https://abc7news.com/san-jose-water-california-drought-conse... "Whaley said the [San Jose Water] company is asking customers to cutback 15-percent from their 2019 water use levels, and pay $7.13 in surcharges for every unit of water used beyond that amount."
- amanaplanacanal 5y ago

sparker72678 5y ago

Honestly, I just found it hopeful that the megadroughts of the past in this study weren't 100 year events, but more on the order of 25ish years. (Not trying to downplay possibility of future water problems).

unethical_ban 5y ago

Question: Is the mass intake of water for ag use a cause of "water export"? Is the water used to produce alfalfa, almonds, etc. consumed by the plants and animals and shipped across the globe as part of the finished product? This would be in contrast to a slightly more closed system of water consumption and release before the ag industry took off there.

nathanaldensr 5y ago

So 1200 years ago--before there were nearly any humans on the entire continent--it was just as bad as today? Interesting.

sparker72678 5y ago
Isn’t that what makes this important to study? The people aren’t going away, so understudying how drought affects us is valuable.
zorak8me 5y ago
Just want to call out - Pre-Colombian North America had a population around 60 million.

forgotmyoldacc 5y ago

I wonder why they specifically picked 22 years, as opposed to 25 or 20.

codetrotter 5y ago
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.

syntaxing 5y ago

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 5y ago
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!
- mdavis6890 5y ago
  Got a downvote or two, so I thought I'd add some references: First, I retract my numbers about 95% of world almonds and avocados coming from CA - I was typing from memory from research I did a year ago, and now I can't find sources to corroborate this. Nevertheless: https://en.wikipedia.org/wiki/Almonds_in_California https://en.wikipedia.org/wiki/Almonds_in_California "The state produces 80% of the world's almonds and 100% of the United States’ commercial supply." https://www.cdfa.ca.gov/Statistics/ https://www.cdfa.ca.gov/Statistics/ "Over a third of the country's vegetables and two-thirds of the country's fruits and nuts are grown in California." "In 2020 California's farms and ranches received $49.1 billion in cash receipts for their output." "California agricultural exports totaled $21.7 billion in 2019" https://spoonuniversity.com/lifestyle/the-problem-with-drinking-almond-milk-you-probably-never-thought-of https://spoonuniversity.com/lifestyle/the-problem-with-drink... "...between 33 and 248 gallons of water go into producing just a half-gallon of almond milk. I'll let that sink in for a second, before I remind you that 99% of almonds grown in the United States are grown in California..." https://www.truthordrought.com/almond-milk-myths https://www.truthordrought.com/almond-milk-myths "8% of CA ag water is used to grow almonds" (and keep in mind that ag water is 90% of the total usable) https://www.researchgate.net/publication/281474989_How_much_water_does_rice_use https://www.researchgate.net/publication/281474989_How_much_... "On average, about 2,500 liters of water need to be supplied (by rainfall and/or irrigation) to a rice field to produce 1 kg of rough rice." - That's 2.5L per GRAM of rice. https://news.yahoo.com/many-california-farmers-water-cut-130033782.html https://news.yahoo.com/many-california-farmers-water-cut-130... "A handful of districts supplying farmers including Gallagher are receiving nearly 2 million acre feet of water this drought year, enough to supply the city of Los Angeles for roughly four years." People like to talk about the cities being problems, or that it's the water we send down south, or whatever like that. Meanwhile, a handful of (farm) districts, in a single year, are using the equivalent of a 4-year supply of water for the entire city of LA. Wow. And yet: https://abc7news.com/san-jose-water-california-drought-conservation/10965409/ https://abc7news.com/san-jose-water-california-drought-conse... "Whaley said the [San Jose Water] company is asking customers to cutback 15-percent from their 2019 water use levels, and pay $7.13 in surcharges for every unit of water used beyond that amount."

mjfl 5y ago

warmer climates lead to much wetter climates. invariably.

mturmon 5y ago
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/ 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.
gremlinsinc 5y ago
Living in southern Utah, I'd actually rather dry + hotter than wet + hotter...at least we avoid dying from wetbulb temps. 125 is survivable in dry heat, a death sentence if you add humidity.
AnimalMuppet 5y ago
Not everywhere. Warmer climates lead to changes in wind patterns, which leave some places drier than they were.
- mjfl 5y ago
  but it increases the vapor pressure of water everywhere.