4 ms·

Please show the math and sources, I would love to see the sauce.

by TrainedMonkey 3y ago

bongodongobob 3y ago
Me too because that sounds impossible to calculate.
- ajb 3y ago
  What difficulty do you see? It's not going to be enough to appreciably change the ocean area, so isn't it just volume divided by the area of the ocean?
  - bongodongobob 3y ago
    Permeability, amount of precipitation, land usage, evaporation, avg temperature, temperature variation, soil composition, erosion, wells, flood plain, wetland, etc.
  - hinkley 3y ago
    I think it would be 1) how accurate are aquifer and coastline topography measures (1 mm wouldn’t be far off but what about a meter? That’s a lot of inundation). And 2) how much has subsidence permanently decreased the carrying capacity of aquifers? It could be a thing where only 50% of what is extracted can be returned. Either theoretically or safely (eg, earthquakes).
    - ajb 3y ago
      Makes sense, thanks.
Loggias 3y ago
[dead]
hinkley 3y ago
There’s a calculator that works out how many acre feet of water it takes to raise the ocean level, and the UN has estimates on total global aquifer depletion. There were a couple ways to calculate it. I’ll see if I can reproduce my work.
hinkley 3y ago
OK, I am finding that my memory was faulty here. Global aquifer depletion isn’t equivalent to 1 mm of ocean volume. It’s equivalent to 3 mm of ocean volume per year (2010: https://www.ngwa.org/what-is-groundwater/About-groundwater/facts-about-global-groundwater-usage https://www.ngwa.org/what-is-groundwater/About-groundwater/f...) Groundwater is the world’s most extracted raw material with withdrawal rates currently in the estimated range of 982 km3 /yea Surface area of the ocean: 361,000,000 km² 1,000,000 mm per kilometer means 361 km³ per millimeter of sea level, ignoring inundation. The USGS estimates that just the US has lost 1000 km³ from 1900-2008, most recently (2008) at rate of 25 km³ per year which is at least another 400, so let’s call it 1400 km³ which is almost 4 mm. Just for the United States. I can no longer find the studies that estimated global depletion of aquifers. I don’t know if my queries changed or SEO rotted the search engines. But if it’s anything like the US, (2.5% a year) then we are over 40,000 km³ globally. Which is about 10 centimeters of sea level rise we could mitigate if we could refill all of the world’s aquifers. I know California has been experimenting with this, but we know with boil orders that untreated water made it into the water supply. What happens when the same thing happens with groundwater injection wells?

Please show the math and sources, I would love to see the sauce.

bongodongobob 3y ago

Me too because that sounds impossible to calculate.

ajb 3y ago
What difficulty do you see? It's not going to be enough to appreciably change the ocean area, so isn't it just volume divided by the area of the ocean?
- bongodongobob 3y ago
  Permeability, amount of precipitation, land usage, evaporation, avg temperature, temperature variation, soil composition, erosion, wells, flood plain, wetland, etc.
- hinkley 3y ago
  I think it would be 1) how accurate are aquifer and coastline topography measures (1 mm wouldn’t be far off but what about a meter? That’s a lot of inundation). And 2) how much has subsidence permanently decreased the carrying capacity of aquifers? It could be a thing where only 50% of what is extracted can be returned. Either theoretically or safely (eg, earthquakes).
  - ajb 3y ago
    Makes sense, thanks.

Loggias 3y ago

[dead]

hinkley 3y ago

There’s a calculator that works out how many acre feet of water it takes to raise the ocean level, and the UN has estimates on total global aquifer depletion. There were a couple ways to calculate it. I’ll see if I can reproduce my work.

hinkley 3y ago

OK, I am finding that my memory was faulty here. Global aquifer depletion isn’t equivalent to 1 mm of ocean volume. It’s equivalent to 3 mm of ocean volume per year (2010: https://www.ngwa.org/what-is-groundwater/About-groundwater/facts-about-global-groundwater-usage https://www.ngwa.org/what-is-groundwater/About-groundwater/f...) Groundwater is the world’s most extracted raw material with withdrawal rates currently in the estimated range of 982 km3 /yea Surface area of the ocean: 361,000,000 km² 1,000,000 mm per kilometer means 361 km³ per millimeter of sea level, ignoring inundation. The USGS estimates that just the US has lost 1000 km³ from 1900-2008, most recently (2008) at rate of 25 km³ per year which is at least another 400, so let’s call it 1400 km³ which is almost 4 mm. Just for the United States. I can no longer find the studies that estimated global depletion of aquifers. I don’t know if my queries changed or SEO rotted the search engines. But if it’s anything like the US, (2.5% a year) then we are over 40,000 km³ globally. Which is about 10 centimeters of sea level rise we could mitigate if we could refill all of the world’s aquifers. I know California has been experimenting with this, but we know with boil orders that untreated water made it into the water supply. What happens when the same thing happens with groundwater injection wells?