42% of Sea Level rise due to human water use?

[NTL2009]

I was surprised to see this in a 'pop science' article a few years ago ("Ask Marilyn"), but quickly found the source, which appeared reputable (to me). But I have not seen any follow up. I finally got back to it.

https://www.nature.com/articles/ngeo1476

... We find that, together, unsustainable groundwater use, artificial reservoir water impoundment, climate-driven changes in terrestrial water storage and the loss of water from closed basins have contributed a sea-level rise of about 0.77 mm yr−1 between 1961 and 2003, about 42% of the observed sea-level rise. We note that, of these components, the unsustainable use of groundwater represents the largest contribution. ...

To stay within forum guidelines, please stay away from the "Global Warming" comparison aspect of this - I'm really only interested in evaluating if this information seems reasonable on its own.

On one hand, I can understand that we pump water from the ground for irrigation, in large enough quantities to affect the levels of these natural aquifers. And we also use lake/river water for personal and industrial use, and apparently much of this finds a more direct route to the oceans?

https://water.usgs.gov/edu/gwdepletion.html

some excerpts:

... Groundwater pumping by Baton Rouge, Louisiana, increased more than tenfold between the 1930s and 1970, resulting in groundwater-level declines of approximately 200 feet.
In the Houston, Texas, area, extensive groundwater pumping to support economic and population growth has caused water-level declines of approximately 400 feet ...

The Memphis, Tennessee area is one of the largest metropolitan areas in the world that relies exclusively on groundwater for municipal supply. Large withdrawals have caused regional water-level declines of up to 70 feet. ...

High Plains - The High Plains aquifer (which includes the Ogallala aquifer) underlies parts of eight States and has been intensively developed for irrigation. Since pre-development, water levels have declined more than 100 feet in some areas and the saturated thickness has been reduced by more than half in others.

Pacific Northwest - Groundwater development of the Columbia River Basalt aquifer of Washington and Oregon for irrigation, public-supply, and industrial uses has caused water-level declines of more than 100 feet in several areas.

Desert Southwest - Increased groundwater pumping to support population growth in south-central Arizona (including the Tucson and Phoenix areas) has resulted in water-level declines of between 300 and 500 feet in much of the area. Land subsidence was first noticed in the 1940s and subsequently as much as 12.5 feet of subsidence has been measured. Additionally, lowering of the water table has resulted in the loss of stream-side vegetation.

But the oceans are also massive, does this make sense? And is there something we could/should be doing about it? Related, I'm also concerned about the lowering of these aquifers, and what affect that could have on our ability to produce food in the future. And if this appears valid, I'm curious as to why this has not received more attention.

 

[phinds]

... But the oceans are also massive ...

I agree that that fact engenders skepticism about those figures.

 

[Rive]

the oceans are also massive, does this make sense?

Feels so weird that it asks a look into the methodology, but the article is actually behind a paywall (at least I can't access it).
Anyway, those groundwater declines alone makes me feel bad, without even checking the other part. Sounds like a desert in making.

 

[johnbbahm]

I think I would have to take issue with the level that ground water has declined.
If the ground water dropped by 30 feet anywhere, many wells would no longer function.
I am in the Houston area, and there are many layers of water, the first being at only about 20 feet,
and there are many underwater former sand pits, attesting to this.
The good water is down at around 400 feet, or deeper.
A friend is on well water an went to 400 feet, the way I understand it, each deeper layer has been in the ground longer,
the shallow layers, smell bad, the deeper the layer the better the water.

 

[Bystander]

Aquifer recharge rate studies are, as of ~ 10 a ago, countable on the fingers of one hand; human pumping rates from aquifers, again as of 10 a, were ~ 3x10³km³/a plus or minus half a decimal order of magnitude for the "lower forty-eight." Elsewhere in the world, who knows?

take issue with the level that ground water has declined.

https://en.wikipedia.org/wiki/Ogallala_Aquifer

Edit: 10 cm rise ~ 3x10⁴km³.

 

[gmax137]

wiki says the water surface area of Earth is 361 132 000 km^2. For the given 0.77 mm/year rise, that would be 2.8E11 m^3 per year. (did I do that right?). If I divide that by the 7 billion population I get 40 m^3 per year per person. Or 110 liters per day (30 US gallons). That's alot, but it isn't so high that it fails the giggle test. So... "maybe"

 

[willem2]

Aquifer recharge rate studies are, as of ~ 10 a ago, countable on the fingers of one hand; human pumping rates from aquifers, again as of 10 a, were ~ 3x10³km³/a plus or minus half a decimal order of magnitude for the "lower forty-eight." Elsewhere in the world, who knows?
https://en.wikipedia.org/wiki/Ogallala_Aquifer

Edit: 10 cm rise ~ 3x10⁴km³.

Theis figure seems way off. 3*10^3 km³ per year is 300mm of water per year for the entire US. According to the wikipedia article on the Ogallala Aquifer, the total extraction is only 312 km³. If you divide this by the surface area of the oceans, the result is only 0.8 mm. Extraction in other places may be a lot larger. Lake Aral has lost about 1000 km^3 since 1960, so about 2.5 mm, and that's just from the water in the lake, not the groundwater.
Since the 0.77 mm/year from 1961 to 2003 given in the arcticle is only 30 mm, this seems plausible. ​

 

[NTL2009]

wiki says the water surface area of Earth is 361 132 000 km^2. For the given 0.77 mm/year rise, that would be 2.8E11 m^3 per year. (did I do that right?). If I divide that by the 7 billion population I get 40 m^3 per year per person. Or 110 liters per day (30 US gallons). That's a lot, but it isn't so high that it fails the giggle test. So... "maybe"

I independently came up with similar figures, so they are either right, or we are wrong together!

The 110 L/day doesn't sound so high when you consider the amount of water required to produce the food we eat, that we are ultimately responsible for. This article lists L required to produce common foods:

https://www.theguardian.com/news/datablog/2013/jan/10/how-much-water-food-production-waste

At the lower end of the list, a single egg is 196 L, going up to chicken, pork, beef at 4,000~15,000 L/kg. If you add up a days meals, it would be quite a lot. But not all of that is pumped water (I don't think?), but certainly a good % is in many/most cases.

Hmmm, I grew up on a farm in the Midwest USA, we 'finished' cattle - taking them from ~ 500# to slaughter weight of ~ 1100# (rough numbers, going from long ago memory about details I didn't care that much about, but close enough). We didn't irrigate our crops, and I'm reading that a steer will consume ~ 15 G (OK, try this in L/kg) ~ 60 L/day, and estimate ~ 1 year to finish, that's ~ 22,000 L. A 500 kg steer might finish out (meat minus bones, etc) ~ 200 kg, so that's 110 L/kg, a long way from 15,000. Of course, other areas will need to irrigate crops, and there is more water in the processing, transport, etc.

But it still seems not hard to get to the 110 L/day mark for human water usage for food on average. A single almond requires over 1 gallon of water, And I think almost all of that is from irrigation.

 

[kcaldwel]

Interesting... I just happened to think of these two relevant recent article, where two basins in California have subsided up to 60mm, and parts of Jakarta falling by 2.5m (!) in 10 years, both from ground water removal:

https://phys.org/news/2018-08-animation-based-satellite-southern-california.html

https://www.bbc.com/news/world-asia-44636934

 

[NTL2009]

I think I would have to take issue with the level that ground water has declined.
If the ground water dropped by 30 feet anywhere, many wells would no longer function. ...

I think those numbers refer to the deep wells (I'm assuming they need to go deep for the large quantities they need for irrigation), so they may have little affect on the shallow wells.

Feels so weird that it asks a look into the methodology, but the article is actually behind a paywall (at least I can't access it).
Anyway, those groundwater declines alone makes me feel bad, without even checking the other part. Sounds like a desert in making.

Well, I don't have access either. That's why I'm asking - why is that weird? I thought someone here who has more insight into this field might have other sources, or could expand/debunk upon what I found. But it seems the numbers aren't out of whack, based on what we've put together so far?

Yes, the desert in the making aspect is scary. I'm not a "doom and gloom" person, but I find it pretty unsettling. We seem to be becoming more and more dependent on irrigation to feed the masses, and it is a waning resource. Maybe technology can stay ahead of the game, but food on a large scale is hard to do in green houses, or other water savings ways.

 

[Nik_2213]

IMHO, there are further complications.
IIRC, although much of Nile delta is subsiding due combination of compaction, water extraction, gas & oil extraction etc, some parts are rising, apparently due second-order isostatic effects. Downside is such rises may not keep pace with sea-level changes, and they would not accommodate the many folk displaced from flooded regions...