That was an interesting article. Itās fascinating to see that we can measure groundwater depletion by changes in satellite velocity due to different gravity.
But Iām confused-the worst places seem to be losing around 4 cm per year of groundwater (like northern India). Even if that means 4 cm of āsolidā water (is it?) and the porosity of the soil/ārock is 10%, that would be 40 cm drop per year of the water table. If itās feasible to pump when the water level falls 100 m, that would be a 250 year supply. Of course people do pump from deeper, but that may tend to be subsidized. There were claims in the paper of much greater groundwater depletion, like 6.5 feet (2 m) per year in Yemen, but there was no citation for that.
āThe Kansas peak use arrived in 2009. But during 2012 ā one year after the last picture in this series ā its harvests had dropped by nearly 30%.ā
I quickly tried to find Kansas food production as a function of time-do you know what it was?
Since irrigation produces about 40% of total calories (I think of just crops, not including grazing which is vast majority rain fed) and about 20% of that is using unsustainable āfossilā water, that means we would lose about 8% of production after all the fossil water is depleted (if we could not produce any crop on the land without irrigation, which is pessimistic). If this occurred over 30 years, that would be about 1/ā4% per year of food production loss.
This is not an existential risk in itself, but it is one more way our civilization is unsustainably consuming limited resources and heading for a crash.
Relative to business as usual of unlimited groundwater, food prices would be higher, and we would likely have to put more of the land that used to be used for crop growth back into production, but I would not characterize it as heading for a crash.
Agua Via is a startup company developing a new atomic-scale low-energy fluid filtering technology. It could be used to purify contaminated water for human consumption and other uses, removing small-molecule and larger contaminants. It has a much smaller energy cost than reverse osmosis or distillation.
Sounds promising, not only for wastewater reclamation for irrigation/ādrinking, but could it also be used to recycle minerals?
I think the implication is that with increasing drought and loss of renewable groundwater supplies, fossil water will be drawn more intensely for use in irrigation. If drought conditions worsen globally, or groundwater suffers contamination (saltwater or pollutants) then we are headed for a crash.
The use of fossil water depends on where the water is being drawn and how renewable groundwater is replenished. Reuters has graphics on Indiaās specific water issues.
The included graphic there shows per capita water availability for India reaching close to 1000m3 (water scarcity) by 2050, with a changing slope reflecting water conservation, I presume. Since the population centers across the country face different conditions, these are averages, and some places in India will run out of water much sooner.
John Roome at World Bank Blogs has a post about Indiaās programs to arrest water losses. He offers that if trends continue, at least 25% of Indiaās agriculture will be at risk. He also suggests that Indian farmers rely on water intensive crops and growing practices, and that shifting those is part of the Indian governmentās approach to reducing water consumption.
Iām curious about water conservation here in my native California. Drought here, ground subsidence, water rationing, and legacy rights to water from outside the state, all point to ongoing problems going into the future.
That was an interesting article. Itās fascinating to see that we can measure groundwater depletion by changes in satellite velocity due to different gravity.
But Iām confused-the worst places seem to be losing around 4 cm per year of groundwater (like northern India). Even if that means 4 cm of āsolidā water (is it?) and the porosity of the soil/ārock is 10%, that would be 40 cm drop per year of the water table. If itās feasible to pump when the water level falls 100 m, that would be a 250 year supply. Of course people do pump from deeper, but that may tend to be subsidized. There were claims in the paper of much greater groundwater depletion, like 6.5 feet (2 m) per year in Yemen, but there was no citation for that.
āThe Kansas peak use arrived in 2009. But during 2012 ā one year after the last picture in this series ā its harvests had dropped by nearly 30%.ā
I quickly tried to find Kansas food production as a function of time-do you know what it was?
Since irrigation produces about 40% of total calories (I think of just crops, not including grazing which is vast majority rain fed) and about 20% of that is using unsustainable āfossilā water, that means we would lose about 8% of production after all the fossil water is depleted (if we could not produce any crop on the land without irrigation, which is pessimistic). If this occurred over 30 years, that would be about 1/ā4% per year of food production loss.
Relative to business as usual of unlimited groundwater, food prices would be higher, and we would likely have to put more of the land that used to be used for crop growth back into production, but I would not characterize it as heading for a crash.
Sounds promising, not only for wastewater reclamation for irrigation/ādrinking, but could it also be used to recycle minerals?
I think the implication is that with increasing drought and loss of renewable groundwater supplies, fossil water will be drawn more intensely for use in irrigation. If drought conditions worsen globally, or groundwater suffers contamination (saltwater or pollutants) then we are headed for a crash.
The use of fossil water depends on where the water is being drawn and how renewable groundwater is replenished. Reuters has graphics on Indiaās specific water issues. The included graphic there shows per capita water availability for India reaching close to 1000m3 (water scarcity) by 2050, with a changing slope reflecting water conservation, I presume. Since the population centers across the country face different conditions, these are averages, and some places in India will run out of water much sooner.
John Roome at World Bank Blogs has a post about Indiaās programs to arrest water losses. He offers that if trends continue, at least 25% of Indiaās agriculture will be at risk. He also suggests that Indian farmers rely on water intensive crops and growing practices, and that shifting those is part of the Indian governmentās approach to reducing water consumption.
Iām curious about water conservation here in my native California. Drought here, ground subsidence, water rationing, and legacy rights to water from outside the state, all point to ongoing problems going into the future.