the
growing trouble with water
Growing populations, lower crops, hydro-electricity
stress....
“The drought gripping Australia could be the worst in 1,000
years, government officials said on Tuesday, as Australia started
to draw up emergency plans to secure long-term water supplies to towns
and cities.
“The drought affecting more than half of Australia's farmlands,
already lasting more than five years, had previously been regarded
as the worst in a century.
“But officials from the Murray-Darling river basin commission
told a water summit of national and state political leaders on Tuesday
that analyses of the current prolonged drought now pointed to the
driest period in 1,000 years.”
- Africa
“ "Climate change is melting a legendary ice field
in equatorial Africa and may soon thaw it out completely, threatening
fresh water supplies to hundreds of thousands of people, a climate
expert said on Thursday.
“The fabled, snow-capped Rwenzori mountains -- dubbed the
"Mountains of the Moon" in travel brochures -- form part
of the Uganda/Democratic Republic of the Congo border and are one
of Uganda's top tourist destinations.”
- East
Africa
“Projections for rain-fed areas in East Africa -- already
suffering damaging drought and hunger -- point to potential productivity
losses of up to 33 percent in maize and more than 20 percent for
sorghum.
“Accelerated glacial melt would lead to rising sea levels
and loss of river delta systems, which coupled with low rainfall,
would threaten major food systems in South Asia and Egypt.
“ "We estimate that in the next 25 years the number
of people living in water-stressed countries will up from around
800 million to 3 billion people," the report's author Kevin
Watkins told reporters.
“ "We argue that we are heading for an entirely predictable
humanitarian catastrophe," Watkins said.”
glaciers
Glaciers act as water reserves, steadily feeding rivers
during summers.
“But a government think-tank said glaciers on the Qinghai-Tibet
plateau, which account for nearly half of China's total glacier coverage,
were shrinking at a rate of 7 percent a year, state-run Xinhua news
agency reported.” [Quoted from planetark.org]
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|
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The Mendenhall Glacier, Juneau, Alaska, in 1937
Image credit: Bradford Washburn/ Courtesy
Panopticon Gallery |
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The Mendenhall Glacier,Juneau, Alaska, in 2006
Image credit: David Arnold |
“[...] Answering those questions is far from some abstract exercise.
Were Greenland to lose its covering tomorrow, the world’s seas would
jump about 20 feet, drowning nearly every major coastal city on earth.
“Even if a disaster of this proportion is not in the cards, in
the past decade melting began to accelerate ominously. The area now
actively melting - approximately half of Greenland’s entire ice cap
- is twice what it was in 1992. The amount of fresh water entering the
ocean is triple what it was a decade ago. Last year Greenland lost 52
cubic miles of ice, according to NASA measurements, and though that
is only a tiny fraction of the ice cap’s total of nearly 600,000 cubic
miles, the rate is increasing. As the meltwater drips down to the bedrock,
it lubricates the movement of ice sheets toward the sea. The Kangerdlugssuaq
Glacier, on the island’s eastern coast, is now moving twice as fast
as it was in 2002. To the south of Kangerdlugssuaq, the Helheim Glacier
slides about 110 feet a day. Researchers reported this spring that the
speed and intensity generates noticeable earthquakes, or "glacial quakes."
And some scientists quietly worry that a dramatic collapse of the ice
cap could result in huge amounts of water draining into the ocean.”
More
on the melting of glaciers.
“Reservoirs are now at 38.9 percent of capacity and 0.1 percent
below the minimum they reached last year at the end of the worst drought
on record.
“ "This is the lowest since 1996," an Environment
Ministry spokeswoman said.
“Spain typically suffers cycles of drought -- defined as below
average rainfall -- lasting several years.
“ "The droughts of the 1980s and 1990s were more serious
than this one has been so far because they affected more of the country,"
the spokeswoman added.
“Drinking water reservoirs are now only 30.9 percent full,
compared with a 10-year average of 45.9 percent, while hydroelectric
reserves are at 55.4 percent of capacity." ”
forests
- Brazil
Reduced rainfall & deforestation in the Amazon.
“Manaus, capital of the state of Amazonas, and the entire
eastern region of the state are suffering the worst drought in more
than a century. A government scientist who calls it an "atypical"
drought says it is chiefly caused by warmer ocean temperatures.”
—
“Amazonian deforestation and fires account for more than 75
percent of Brazil's greenhouse gas emissions and place it among the
top four contributors to global climate change, Greenpeace says.”
This last is a dodgy claim, partly because it is much more complicated
than that.
mongabay.com says that the area of Amazonian deforestation since 1970 is more than
the area of France and more than twice the area of the UK.
- China
- deforestation impact on water
“In a paper soon to be published in Greenhouse
Gases and Animal Agriculture: An Update (Proceedings
of the 2nd International Conference on Greenhouse
Gases and Animal Agriculture), Khalil and his Portland
State colleague Martha J. Shearer point out that
China has produced much of the world's rice for
many decades, yet for the past 30 years, the area
devoted to rice agriculture in that country has
fallen from about 37 million hectares to a little
more than 27 million. Khalil and Shearer further
note that in these rice paddies nitrogen-based fertilizer
has to a large extent replaced animal manure or
"night soil" (human wastes). This change
in how rice is grown in China reduces the amount
of methane given off. What is more, these rice farmers
are using less water than they did before—another
change in agricultural practice that has the unintended
side benefit of reducing methane emissions.
“Clearly, it will be some time before atmospheric
scientists are able to quantify with great certainty
the changing sizes of the various sources of methane.
But as Khahil says, it's important to get at least
a crude handle on what is going on for the purpose
of shaping policy: "You don't want to try to
control something that's already going down.”
.
“[...] they note that "severe anthropogenic
deforestation has considerably reduced tropical
biomass over the past decades," suggesting
that this "reduced biomass has probably contributed
to the recent decrease in the atmospheric growth
rate of CH4 concentration." That is to say,
cutting down rain forest might have reduced the
atmospheric methane burden."”
biomass
-
Any biomass production will, over time, reach equilibrium.
Here are some alternatives concerning wood biomass
- forests.
- strip a forest and burn it. This generates more
carbon.
- strip the forest to make furniture and regrow
the forest. This way, there is less carbon.
- grow biomass (and/or process it) and you are likely
to burn fossil fuels, and make nitrogen products
which also use fossil fuels, and add nitrous oxide, another greenhouse gas.
Time factors are essential for understanding - that
is, burning a forest and regrowing it is carbon neutral
over time. A mature forest is also carbon neutral
over time.
related material
global warming |
