전세계 37개의 주요 대수층(Aquifers)이 말라가고 있어요

관련 포스트

텍사스의 극심한 지하수 고갈
지하수(대수층) 고갈로 인한 지반침하

캘리포니아의 가뭄과 정유회사, 그리고 농민

 

 

아래 그림이 전세계의 주된 37개의 Aquifer입니다.

그런데 인간의 물사용이 많아져 이상현상을 보이는 대수층이 많이 보입니다.

전체 인류 물사용량의 35%를 담당하는 것이 대수층입니다.

 

 

NASA에서 gravitational data를 조사해서 물 사용이 많아 대수층이 바로바로 채워지지 않고 말라가는 것들과

계속 잘 채워지는 것들을 지도로 표시했습니다.

(NASA 발표에 의하면 37개중 13개의 대수층의 물이 줄어드는 추세로 위험단계로 구분해야할 정도라고 합니다)

 

출처 : Environmental Science by G. Tyler Miller, Scott Spoolman (15th) (2016) National Geographic - 255page

 이렇게 많이 대수층 물을 뽑아 쓰는데 안줄어 들고 베기겠나?

 

 

 

  

위의 지도는 AGU에서 제공한 지도이고

아래 지도는 Washington Post에 나온 지도입니다.

 

 

 

 

 

이런 조사가 신문에 실리게 된 결정적인 계기는 몇년간 이어진 텍사스의 가뭄과,

최근 매우 심각한 상황을 보이는 캘리포니아의 가뭄 사태때문일 것입니다.

 

위의 지도로 볼 때 Depletion이 심각한 곳은 텍사스, 캘리포니아, 갠지즈강 중하류, 카프카스 산맥 북쪽 반건조 지역으로 보입니다.

 

이렇게 물이 줄어드는 이유로는

agriculture, growing populations, and industries such as mining
(현재 캘리포니아에서 유전에서 기름 채취를 위한 물을 정제해서
캘리포니아 농민에게 도로 팔고 있어서 문제가 된다라는 글을 얼마전에 포스팅했습니다.) 
이런 것을 원인으로 꼽고 있습니다.

 

이렇게 대수층이 줄어들어 가장 큰 고통을 겪는 곳은

가난하고, 인구밀도가 높은 지역들입니다. 이런 곳들은 지하수 이외의 대안이 없어, 물부족 사태가 나타나게 되면 사회적 혼란이 극심해질 것으로 보입니다.

 

The aquifers under the most stress are in poor, densely populated regions,
such as northwest India, Pakistan and North Africa,
where alternatives are limited and water shortages could quickly lead to instability.

 

 

 

인간들이 대수층을 남용하는 대표적인 사례를 소개합니다.

 

우리가 '리비아 대수로 사업'이란 이름으로 기억하는 사건. 영어로는 Great Man-Made River(GMR)

 

BBC news에서는 이런 제목으로 소개합니다.

 

Libya's thirst for 'fossil water'

 

리비아에는 물이 없는데, 어떻게 저런 대수로 사업을 펼칠 수 있었을까요?

대수로 사업의 물은 '대수층'에서 온 것이였습니다.

그 물은 추청컨데 약 40,000전의 것이라고 합니다. 그래서 별명이 fossil water입니다.

 

Libya is a desert country, and finding fresh water has always been a problem.

Following the Great Al-Fatah Revolution in 1969,
when an army coup led by Muammar Al Qadhafi deposed King Idris, industrialisation put even more strain on water supplies. 

 

Coastal aquifers became contaminated with sea water,
to such an extent that the water in Benghazi (Libya's second city) was undrinkable.

 

Finding a supply of fresh, clean water became a government priority.
Oil exploration in the 1950s had revealed vast aquifers beneath Libya's southern desert.

 

According to radiocarbon analysis, some of the water in the aquifers was 40,000 years old. Libyans call it "fossil water".

 

After weighing up the relative costs of desalination or transporting water from Europe,
Libyan economists decided that the cheapest option was
to construct a network of pipelines to transport water from the desert to the coastal cities,
where most Libyans live.

 

 

 

 

 

 

다음은 워싱턴포스트 기사의 원문입니다.

 

New NASA data show how the world is running out of water
By Todd C. Frankel June 16 at 2:01 PM

 

The world’s largest underground aquifers ? a source of fresh water for hundreds of millions of people ? are being depleted at alarming rates, according to new NASA satellite data that provides the most detailed picture yet of vital water reserves hidden under the Earth’s surface.

 

Twenty-one of the world’s 37 largest aquifers ? in locations from India and China to the United States and France ? have passed their sustainability tipping points, meaning more water was removed than replaced during the decade-long study period, researchers announced Tuesday. Thirteen aquifers declined at rates that put them into the most troubled category. The researchers said this indicated a long-term problem that’s likely to worsen as reliance on aquifers grows.

 

Scientists had long suspected that humans were taxing the world’s underground water supply, but the NASA data was the first detailed assessment to demonstrate that major aquifers were indeed struggling to keep pace with demands from agriculture, growing populations, and industries such as mining.

 

“The situation is quite critical,” said Jay Famiglietti, senior water scientist at NASA’s Jet Propulsion Laboratory in California and principal investigator of the University of California Irvine-led studies.

 

Underground aquifers supply 35 percent of the water used by humans worldwide. Demand is even greater in times of drought. Rain-starved California is currently tapping aquifers for 60 percent of its water use as its rivers and above-ground reservoirs dry up, a steep increase from the usual 40 percent. Some expect water from aquifers will account for virtually every drop of the state’s fresh water supply by year end.

 

The aquifers under the most stress are in poor, densely populated regions, such as northwest India, Pakistan and North Africa, where alternatives are limited and water shortages could quickly lead to instability.

 

The researchers used NASA’s GRACE satellites to take precise measurements of the world’s groundwater aquifers. The satellites detected subtle changes in the Earth’s gravitational pull, noting where the heavier weight of water exerted a greater pull on the orbiting spacecraft. Slight changes in aquifer water levels were charted over a decade, from 2003 to 2013.

 

“This has really been our first chance to see how these large reservoirs change over time,” said Gordon Grant, a research hydrologist at Oregon State University, who was not involved in the studies.

 

But the NASA satellites could not measure the total capacity of the aquifers. The size of these tucked-away water supplies remains something of a mystery. Still, the satellite data indicated that some aquifers may be much smaller than previously believed, and most estimates of aquifer reserves have “uncertainty ranges across orders of magnitude,” according to the research.

 

Aquifers can take thousands of years to fill up and only slowly recharge with water from snowmelt and rains. Now, as drilling for water has taken off across the globe, the hidden water reservoirs are being stressed.

“The water table is dropping all over the world,” Famiglietti said. “There’s not an infinite supply of water.”

[California’s water woes primed to get worse as groundwater is drained]

 

The health of the world’s aquifers varied widely, mostly dependent on how they were used. In Australia, for example, the Canning Basin in the country’s western end had the third-highest rate of depletion in the world. But the Great Artesian Basin to the east was among the healthiest.

 

The difference, the studies found, is likely attributable to heavy gold and iron ore mining and oil and gas exploration near the Canning Basin. Those are water-intensive activities.

 

The world’s most stressed aquifer ? defined as suffering rapid depletion with little or no sign of recharging ? was the Arabian Aquifer, a water source used by more than 60 million people. That was followed by the Indus Basin in India and Pakistan, then the Murzuk-Djado Basin in Libya and Niger.

 

California’s Central Valley Aquifer was the most troubled in the United States. It is being drained to irrigate farm fields, where drought has led to an explosion in the number of water wells being drilled. California only last year passed its first extensive groundwater regulations. But the new law could take two decades to take full effect.

Also running a negative balance was the Atlantic and Gulf Coastal Plains Aquifer, which stretches across the southeast coast and Florida. But three other aquifers in the middle of the country appeared to be in relatively good shape.

 

Some groundwater filters back down to aquifers, such as with field irrigation. But most of it is lost to evaporation or ends up being deposited in oceans, making it harder to use. A 2012 study by Japanese researchers attributed up to 40 percent of the observed sea-level rise in recent decades to groundwater that had been pumped out, used by humans and ended up in the ocean.

 

Famiglietti said problems with groundwater are exacerbated by global warming, which has caused the regions closest to the equator to get drier and more extreme latitudes to experience wetter and heavier rains. A self-reinforcing cycle begins. People living in mid-range latitudes not only pump more water from aquifers to contend with drier conditions, but that water ? once removed from the ground ? also then evaporates and gets recirculated to areas far north and south.

 

The studies were published Tuesday in the Water Resources Research journal.

Famiglietti said he hoped the findings would spur discussion and further research into how much groundwater is left.

“We need to get our heads together on how we manage groundwater,” he said, “because we’re running out of it.”

 

 

아래 농업 방식은

Flood irrigation입니다.