Environment & Energy

xchrom

(108,903 posts) Mon May 21, 2012, 07:06 AM May 2012

Fresh water demand driving sea-level rise faster than glacier melt

http://www.guardian.co.uk/environment/2012/may/20/world-aquifers-rising-sea-levels?intcmp=122

For three decades, Saudi Arabia has been drilling for water from underground aquifers. Engineers and farmers have tapped hidden reserves of water to grow grains, fruit and vegetables in the desert of Wadi As-Sirhan Basin. Photograph: Landsat/Nasa

Humanity's unquenchable thirst for fresh water is driving up sea levels even faster than melting glaciers, according to new research. The massive impact of the global population's growing need for water on rising sea levels is revealed in a comprehensive assessment of all the ways in which people use water.

Trillions of tonnes of water have been pumped up from deep underground reservoirs in every part of the world and then channelled into fields and pipes to keep communities fed and watered. The water then flows into the oceans, but far more quickly than the ancient aquifers are replenished by rains. The global tide would be rising even more quickly but for the fact that man-made reservoirs have, until now, held back the flow by storing huge amounts of water on land.

"The water being taken from deep wells is geologically old – there is no replenishment and so it is a one way transfer into the ocean," said sea level expert Prof Robert Nicholls, at the University of Southampton. "In the long run, I would still be more concerned about the impact of climate change, but this work shows that even if we stabilise the climate, we might still get sea level rise due to how we use water." He said the sea level would rise 10 metres or more if all the world's groundwater was pumped out, though he said removing every drop was unlikely because some aquifers contain salt water. The sea level is predicted to rise by 30-100cm by 2100, putting many coasts at risk, by increasing the number of storm surges that swamp cities.

The new research was led by Yadu Pokhrel, at the University of Tokyo, and published in Nature Geoscience. "Our study is based on a state-of-the-art model which we have extensively validated in our previous works," he said. "It suggests groundwater is a major contributor to the observed sea level rise." The team's results also neatly fill a gap scientists had identified between the rise in sea level observed by tide gauges and the contribution calculated to come from melting ice.

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Fresh water demand driving sea-level rise faster than glacier melt (Original Post) xchrom May 2012 OP

A billion is a phenonenon. It's hard for people to grasp. Each little act multiplied causes massive Gregorian May 2012 #1

The way I think the population/resource issue will play out. kristopher May 2012 #2

But isn't it notable that our low growth country uses most of the resources of any? Gregorian May 2012 #3

I realize that - it's why I underlined 'sustainable'. kristopher May 2012 #4

Gregorian

(23,867 posts)

1. A billion is a phenonenon. It's hard for people to grasp. Each little act multiplied causes massive

Reply to xchrom (Original post)

Mon May 21, 2012, 12:23 PM

May 2012

I'm working on a project that has caused me to question whether it is viable or not. It is something with a trillion things. I've had to run the numbers several times just to convince myself that what I see is really true.

Multiplicity is kind of like the penny per day exponential problem.

Each little act that each person takes has huge consequences because we are all doing it. Water, food, medical, and in the case of modern societies, driving.

In case you aren't sure what I'm rambling on about- it's population that needs to be focused on.

kristopher

(29,798 posts)

2. The way I think the population/resource issue will play out.

Reply to Gregorian (Reply #1)

Mon May 21, 2012, 12:47 PM

May 2012

There is no question that in the modern world population expansion is driven by conditions associated with undeveloped societies. We can leave aside specific reasons for this discussion.

There is no question that post industrial societies are characterized by population contraction. Again, we can leave aside specific reasons for this discussion.

There is no question that global resources critical to maintaining a human friendly ecosystem are strained and poorly understood in any comprehensive sense.

We are bringing more of the world into the sphere of societies that experience declining populations.

War, economic collapse or events like that do not accomplish the goal of altering population growth trends, over time as their effect tends to get cancelled by following rebound effects.

That makes it a race to, in sustainable fashion, bring lagging societies to a level that results in declining birth rates before we irreversibly alter our ecosystem to the point of inhabitability.

The foundation of that effort is continued acquisition of knowledge about sustainable development and deployment of those infrastructures throughout the world.

At the present time, supporting development that continues to make renewable energy more affordable for the societies struggling with massive energy poverty is one the most concrete steps you can take to help accelerate the transition to global population reduction.

Global fertility rate 2.46 / US 2.06 / Japan 1.21 / Libya 2.96

http://www.indexmundi.com/g/g.aspx?v=31&c=xx&l=en

Definition of Total fertility rate: This entry gives a figure for the average number of children that would be born per woman if all women lived to the end of their childbearing years and bore children according to a given fertility rate at each age. The total fertility rate (TFR) is a more direct measure of the level of fertility than the crude birth rate, since it refers to births per woman. This indicator shows the potential for population change in the country. A rate of two children per woman is considered the replacement rate for a population, resulting in relative stability in terms of total numbers. Rates above two children indicate populations growing in size and whose median age is declining. Higher rates may also indicate difficulties for families, in some situations, to feed and educate their children and for women to enter the labor force. Rates below two children indicate populations decreasing in size and growing older. Global fertility rates are in general decline and this trend is most pronounced in industrialized countries, especially Western Europe, where populations are projected to decline dramatically over the next 50 years.

Gregorian

(23,867 posts)

3. But isn't it notable that our low growth country uses most of the resources of any?

Reply to kristopher (Reply #2)

Mon May 21, 2012, 01:26 PM

May 2012

It is the case that as a society becomes "modern" it uses more and more of the specialty resources. And more energy per capita. The carbon footprint of all of the humans who ever lived on earth up until the time we began using the planet for it's energy resources was essentially zero.

This is a two part equation. Number of users, and what they are using. I think what we want to see is a naturally sustainable equilibrium. It seems simple at face value. But there are two scenarios that I can think of. One is that we would like the earth to last forever. That would mean that only naturally occurring resources could be used, and used in rates such that natural equilibrium is undisturbed. The other would be that we know the sun has 5 billion years of life, and whatever we use that isn't in a natural equilibrium could be used in a way that it's resource is depleted just as the solar system dies.

As it stands we are so far out of equilibrium we may not see the end of this millennium.

kristopher

(29,798 posts)

4. I realize that - it's why I underlined 'sustainable'.

Reply to Gregorian (Reply #3)

Mon May 21, 2012, 01:47 PM

May 2012

Our carbon footprint is largely an artifact of our carbon based energy system. If we can leapfrog the developing nations past that by accelerating the declining cost of renewable systems we provide a great deal of immediate quality of life benefit and ready access to modern knowledge via wireless communications. This approach already has a cost advantage where national power grids do not exist or are poorly realized.

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