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Friday, November 12, 2010

Nuclear Winter: Nuclear War would be an Unprecedented Human Catastrophe - by Carl Sagan - 2010-11-09


Nuclear Winter: Nuclear War would be an Unprecedented Human Catastrophe
- by Carl Sagan - 2010-11-09
Even small nuclear wars can have devastating climatic effects...
 

Arabs face severe water crisis by 2015

Lebanon, once considered to have an abundance of water, is threatened with acute shortages as the Arab world lurches toward severe water scarcity as early as 2015. For Lebanon, which has long neglected to take measures to conserve and manage its water resources, the crisis couldn't come at a worse time: The government is gripped by political crisis that many fear could lead to renewed civil war; the decision-making process has been paralyzed; and a 10-year water plan adopted in 2002 has ground to a halt.
The Cabinet, burdened with a $54 billion public debt, decided recently to delay all discussion on a proposal by Water and Energy Minister Jibran Bassil to build 11 dams on Lebanon's several rivers.
Fadi Comair, general director of hydraulic and electrical resources, says that enlisting the private sector is the only way to solve the worsening water problem.
"We cannot implement infrastructure projects if the private sector does not intervene," he told The Daily Star, Lebanon's English language newspaper. "Without the private sector we can do nothing."
Comair, lashing out at the sectarian divisions that plague Lebanon, declared: "If politicians in our country had any ethics they would have taken care of such projects instead of attacking each other on TV every day."
The World Bank recently urged major investment in Lebanon's ramshackle water infrastructure while noting that the tiny country's water resources are equivalent to 49,830 cubic feet per capita, one of the highest in the Middle East and North Africa.
Other states in the arid region can only watch in wonder as Lebanon's government ignores a problem most would gladly take on if they had the same water resources.
The Arab world has 5 percent of the world's population -- an estimated 360 million people -- but only 1.4 percent of the planet's renewable fresh water supply.
By 2025, the Arab population will likely total around 568 million, gravely stretching shrinking natural water resources.
By the end of the century, the report noted, climate change will mean a 25 percent decrease in precipitation and a matching increase in evaporation rates.
The wealthier Arab states, primarily the oil producers of the Persian Gulf that have no rivers and little rainfall, rely heavily on desalination plants. They account for half the world's desalination capacity, a costly undertaking. Other states, including Egypt and Jordan, plan to develop nuclear power to drive such plants.
But that will take years to achieve. And even in the Arabian Peninsula, water consumption is rising as the population swells.
Water use there now exceeds renewable sources, Sweden's Stockholm International Water Institute says, and that situation is unlikely to change anytime soon.
In the meantime, a November report by the Arab Forum for Environment and Development said that in less than five years from now Arabs will have to get by on around 7,650 cubic feet of water a year each. That's less than 1-10th of the world average of 196,800 cubic feet of water per capita.
"The Arab world is already living a water crisis that will only get worse with inaction," the report said.
Thirteen Arab states are among the 19 in the world most affected by water scarcity and citizens of eight of those Arab countries have to survive on less than 7,060 cubic feet of water per year.
"Without fundamental changes in policies and practices, the situation will get worse, with drastic social, political and economic ramifications," the Arab Forum warned.
Limited resources mean water in the region plays a strategic role in national security, foreign policy and domestic stability.
Agriculture is a major drain on renewable water supplies because of irrigation and that could lead to states going to war over water resources in a region where sectarian and ethnic conflict as well as intrastate tensions are rife.
"Analysts, academics and diplomats remain divided over whether or not water will cause a war within the region, but they do agree on one thing: it will become an increasingly important and scarce resource in the coming decades," The Middle East Economic Digest observed recently.
Yemen, the Arab world's poorest state which is gripped by terrorism, civil strife and a collapsing economy, could be a case in point. It's expected to run out of water in the next few years.http://www.terradaily.com/reports/Arabs_face_severe_water_crisis_by_2015_999.html
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Invasive grass threatens U.S. grazing land


An invasive species of "devil" weed in range lands in the western United States could make millions of acres of grazing land worthless, researchers say. Researchers at Oregon State University say the weed knows as medusahead has growth advantages over most other grass species that could allow it to continue to spread across much of the West and disrupt native ecosystems, a university release said Thursday.
Their study comparing the "relative growth rate" of this invasive annual grass to that of other competing species in natural field conditions found that medusahead has a faster growth rate, a longer period of growth and produced more total biomass than any native grasses.
"Medusahead is now spreading at about 12 percent a year over 17 western states," Seema Mangla, a researcher in the OSU College of Forestry, said. "Once established, it's very hard to get rid of.
"It displaces native grasses and even other invasive species that animals can still eat," she said.
"This is a devil species," she said.
Native to the Mediterranean region, medusahead was imported to the United States in the late 1880s.
The sharp and twisting points on the tips of medusahead can injure animals and give the plant its name, based on the female monster in Greek mythology who had hair composed of writhing snakes.
The plant takes up other soil resources and its deep root system soaks up limited moisture. It creates fuel for wildfires, is virtually inedible and prevents many other plants from germinating, researchers say.
Experts at the Oregon Department of Agriculture say once land is invaded by medusahead, it becomes largely worthless, incapable of supporting native animals, birds or livestock.http://www.seeddaily.com/reports/Invasive_grass_threatens_US_grazing_land_999.html
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Wednesday, November 10, 2010

New Shipping Lanes in Melting Arctic Will Accelerate Global Warming

http://www.truth-out.org/new-shipping-lanes-melting-arctic-will-accelerate-global-warming65005
Lisa Song, Solve Climate: "In the next few decades, a warming Arctic will open up shorter shipping routes, potentially reducing the amount of fuel needed to travel between ports. But the increased amount of soot in the atmosphere could further accelerate the region's climate change, and the shorter distances won't generate enough fuel savings to offset the impact. Those are the key findings of a recent study published in the journal Atmospheric Chemistry and Physics. This new study is the first systematic analysis of how Arctic shipping could affect local climate."
Read the Article
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Modeling Glacier Fed Water Dependency




The researchers investigated the whole river basin region of certain glaciers in the Himalayas, the Andes, the Caucasus Mountains, Siberia, North America and New Zealand. Credit: Uni Innsbruck
http://www.terradaily.com/reports/Modeling_Glacier_Fed_Water_Dependency_999.html Innsbruck, Austria (SPX) Nov 09, 2010 Glaciers of large mountain regions contribute, to some extent considerably, to the water supply of certain populated areas. However, in a recent study conducted by Innsbruck glaciologists and climatologists it has been shown that there are important regional differences. The results of the study are published in the scientific journal Proceedings of the National Academy of Sciences (PNAS). In their recently published study the glaciologists and climatologists, headed by Prof. Georg Kaser and Dr. Ben Marzeion from the Institute of Geography of the University of Innsbruck, have demonstrated that the contribution potential of glaciers to the water supply of populated areas varies regionally.
The scientists gathered data on the amount of precipitation on certain glaciers and calculated when the water is discharged and available in populated areas.
"There is a big difference in whether the water is discharged in an arid period or in a period, when there usually is a lot of precipitation, e.g. in monsoon regions in Asia," explains Ben Marzeion.
"And there are regions, for instance around the Aral Sea, where precipitation happens in the mountain regions in winter. The glacier melt water runoff in summer is vital for the population living in this area."
The Innsbruck researchers modeled estimates that show human dependence on glacier melt in a certain region. They demonstrate that high-mountain communities are highly dependent on glacier melt water but the population density is usually relatively low in these regions.
"The impact is a lot more dramatic in mid latitude river basins, where the population density is a lot higher and glacier melt still contributes to the available water reservoir to a large extent," the climatologists explain.
Regional differences The incentive of the study was the widespread discussion about the impact of climate change on water availability in highly populated regions. "In the last few years numbers have been named that do not pass a closer examination," says glaciologist and climatologist Georg Kaser. "It is an exaggeration when it is claimed that the melting of glaciers endangers the water supply of 2 billion people."
With their study the Innsbruck scientists want to draw attention to the considerable regional differences regarding the problem of future water supply. "By all means, the expected climatic development may have detrimental effects for smaller high-mountain communities."
The data for the study was obtained from the World Glacier Inventory, global temperature and precipitation data and the Global Digital Elevation Model. The researchers investigated the whole river basin region of certain glaciers in the Himalayas, the Andes, the Caucasus Mountains, Siberia, North America and New Zealand.
"In principle, this is a simple research approach, which, nevertheless, provides us with important arguments for a more differentiated discussion in climate research," says Georg Kaser, who is pleased about the results of the study, which has been published in the renowned scientific journal Proceedings of the National Academy of Sciences (PNAS).
"With regard to the next report issued by the Intergovernmental Panel on Climate Change (IPCC), our data can be seen as the basis for regionally more precise estimations and they show that the impact of the expected climate change may be higher in some regions than in others," says Kaiser
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Fish stocks dwindle as trawlers empty Asia's seas




http://www.terradaily.com/reports/Fish_stocks_dwindle_as_trawlers_empty_Asias_seas_999.html Penang, Malaysia (AFP) Nov 10, 2010 Overfishing in Southeast Asian seas has left garoupas and sea bass in dire straits, searching for mates on denuded seabeds, according to experts alarmed by ever-declining catches. Marine scientists and fishermen say that popular fish species -- especially the large and valuable ones -- have been caught indiscriminately, causing numbers to plunge dramatically.
For big fish "finding a mate is a difficult task. They have to swim a long distance to find one," said Edward Allison from the World Fish Center in Malaysia's northern resort island of Penang.
One of the culprits is bottom trawling, which involves dragging huge, heavy nets along the sea floor. Large metal plates and rubber wheels attached to the nets move along the bottom and crush nearly everything in their path.
Allison said the habitat for young fish, or fry, is also shrinking because the mangrove swamps which provide food and protection are being obliterated by coastal development including tourist resorts.
Demand for top-quality seafood, from Southeast Asian nations themselves and from Hong Kong and China, is another major factor behind the emptying of the seas.
According to World Fish data, there were 10 times more fish in the Gulf of Thailand in 1965 than 30 years later.
In Malaysia the decline was between 80 and 90 percent while in the Philippines it is estimated that there was a 46-78 percent dropoff in fish stocks.
There is little data from other countries without the resources to carry out the studies, but World Fish believes the rate of decline in those three countries is reflected across Southeast Asia.
In Tanjung Karang, a fishing village in central Malaysia on the banks of the murky Tengi river which flows into the Malacca Strait, coastal fishermen are gloomy as they come ashore to sell their daily catch.
After spending four hours at sea Kamarul Nizam, 35, managed to net only a few kilos of small prawns and cheap catfish. He sells them to Gan Soon Heng, a wholesaler who has been in the business for more than two decades.
Sitting in his wooden shop on the banks of the Tengi, Gan gives Kamarul about 30 dollars -- meagre pay for a hard day's work, as half is eaten up in costs.
Gan shows off a 37 kilo (81 pound) stingray, a 12 kilo garoupa and a long Spanish mackerel.
"Such a big stingray is rare. Even the 12 kilo garoupa is considered small. Twenty years ago you could catch much bigger fishes. Now you only get small ones," he said as he pointed to a few palm-sized stingrays lying in an icebox.
Tiew Kian Hap, 44, has fished the Malacca Strait for three decades, trawling for giant stingray, redfish and black pomfret.
"If we catch them we can make a profit. But their numbers now are much less. Also there are a lot of fishing boats out there hunting for them too," he said.
Instead, he mostly hauls in tiddlers that go to make belachan, a strong-smelling fish paste that is a vital ingredient in some popular Malaysian dishes.
Tiew lamented the lack of enforcement that sees big trawlers encroach close to the shore, wiping out the fry that, if left undisturbed, would grow into a valuable catch.
"Popular fishes like kambong or mackerel which we hope to catch get wiped out because even the small ones -- one to two inches -- are caught when their nets sweep the ocean floor," he said.
"There is no point reporting it because no action is taken."
Another fisherman, Ong Chee Hooi, 33, said the decline had been sharp in the past five years, and that even the mud crabs that used to be plentiful in the mangroves were disappearing.
"Their numbers have fallen. Factories and houses put up by the coast are polluting the water and this is killing the mangrove swamps," he said.
Allison said the use of dynamite and cyanide to fish in coral reefs, common in Indonesia and the Philippines, also poses a serious threat.
He urged enforcement authorities to adopt conservation measures such as encouraging the use of hook and line traps that net only targeted fish, and aquaculture to produce popular species.
"The aquatic system is quite resilient and they can recover if we can remove some of the pressures. What is needed is the political will and motivation to do so," he said.
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Climate Change Assessments

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Tuesday, November 9, 2010

$5 Trillion: The Cost Each Year of Rainforest Destruction



British researchers set out the economic impact of species destruction -- and their findings are changing world's approach to global warming. READ MORE
By Matt Chorley / Independent UK

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Biofuel worse for climate than fossil fuel: study

Biofuel worse for climate than fossil fuel: study

European plans to promote biofuels will drive farmers to convert 69,000 square km of wild land into fields and plantatons, depriving the poor of food and accelerating climate change, a report warned on Monday.

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Biofuels Fallacy: Why Burning Plants Instead of Fossil Fuels Won't Save the Climate The quest to replace black fuels with green fuels is just another resource and land grab by big corporations.

The quest to replace black fuels with green fuels is just another resource and land grab by big corporations. READ MORE
Jeff Conant: You and your colleagues at ETC Group are strong advocates of taking what I would call a reasoned approach to the deployment of new technologies; you're best known for having led the charge for a global ban on the infamous Terminator Seed, and you've just had a tremendous victory by winning a global moratorium on geoengineering experiments (see last week's piece on AlterNet). Now, you're releasing a report on another impending technological concern: synthetic biology.
Jim Thomas: The report is called "The New Biomassters: Synthetic Biology and the Next Assault on Biodiversity and Livelihoods." It's an exposé and argument against the new "bioeconomy" most OECD countries are now promoting as the next (supposedly "green") wave of industrial production -- switching from fossil fuels to biological material (biomass) as the key feedstock of the economy. As such, it encompasses biofuels, burning biomass for electricity, and using biomass for chemicals, plastics and other materials formerly sourced from petroleum. More at:

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Monday, November 8, 2010

The International Space Weather Initiative by Dr. Tony Phillips for NASA Science News




Although space weather is usually associated with Earth's polar regions--think, "Northern Lights"--the equator can be just as interesting. For example, there is a phenomenon in Earth's upper atmosphere called the "equatorial anomaly." It is, essentially, a fountain of ionization that circles the globe once a day, always keeping its spout toward the sun. During solar storms, the equatorial anomaly can intensify and shape-shift, bending GPS signals in unexpected ways and making normal radio communications impossible.
http://www.spacedaily.com/reports/The_International_Space_Weather_Initiative_999.html Huntsville AL (SPX) Nov 09, 2010 Prompted by a recent increase in solar activity, more than a hundred researchers and government officials are converging on Helwan, Egypt, to discuss a matter of global importance: storms from the sun. The "First Workshop of the International Space Weather Initiative (ISWI)" meets Nov. 6th through 10th and is convened by the United Nations, the National Aeronautics and Space Administration (NASA), and the Japan Aerospace Exploration Agency (JAXA).
"Strong solar storms can knock out power, disable satellites, and scramble GPS," says meeting organizer and ISWI executive director Joe Davila of NASA's Goddard Space Flight Center. "This meeting will help us prepare for the next big event."
A key problem organizers hope to solve is a gap - many gaps, actually - in storm coverage around our planet. When a big storm is underway, waves of ionization ripple through Earth's upper atmosphere, electric currents flow through the topsoil, and the whole planet's magnetic field begins to shake.
"These are global phenomena," says Davila, "so we need to be able to monitor them all around the world."
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Climate scientists plan campaign against global warming skeptics


The American Geophysical Union plans to announce that 700 researchers have agreed to speak out on the issue. Other scientists plan a pushback against congressional conservatives who have vowed to kill regulations on greenhouse gas emissions.

Global warming
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Report Reveals Forces Destroying Atlantic Bluefin Tuna By ANDREW C. REVKIN


A powerful and innovative international journalistic effort has revealed the web of interests — from boat captains to European government agencies to fish auctions — behind the devastation of  Atlantic bluefin tuna.

I encourage you to explore the reporting by the International Consortium of Investigative Journalists and a companion documentary by  Television for the Environment. (Also known by its lower-case acronym, tve, the nonprofit documentary unit was created in 1984 by WWF, known in the United States as the World Wildlife Fund, the United Nations Environment Program and the Britain’s Central TV). Here’s a video summary:
http://www.youtube.com/watch?v=jC2snB6db5Q&feature=player_embedded
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Der Spiegel: Geologists Warning Of “Mega-Eruption”

Der Spiegel: Geologists Warning Of “Mega-Eruption”http://www.spiegel.de/wissenschaft/natur/0,1518,727092,00.html

Germany's Der Spiegel reports on the growling-ever-louder Indonesian Merapi volcano in an article titled: Geologists Warning of Mega-Eruption of Merapi.
The Merapi eruptions are becoming more violent – and the big bang could be just ahead. The Indonesian volcano has been spewing 800°C ash clouds for days.
Indonesia's volcanoes (Wikipedia)
According to Der Spiegel, 122 people have been killed, most on Friday. “Merapi is among the most dangerous volcanoes,” says geo-scientist Volker Steinbach of the German Federal Administration for Geoscience and Raw Materials (BGR). Der Spiegel adds:
Friday’s eruption is its worst this decade, says the chief geologist of the Energy Administration, Raden Sukhyiar, in the “Jakarta Post”. The biggest known eruptions occurred in 1006, 1369, 1786, 1822, 1872 – destroying a large number of villages – and 1930 when 1300 people perished.
Investigations of the volcano have revealed that an unprecedented Magma reservoir lurks underneath it, says Birger Lühr, a volcano researcher at the GFZ in Potsdam, Germany.
A rough estimate indicates that there is three times more magma than what was ejected by the Indonesian volcano Tambora in 1815 – the biggest eruption in the last 10,000 years, which led to a cooling of the climate globally.
Geoscientists aren’t sure what to make of this huge magma reservoir. As Der Spiegel reports, they are hesitant to make predictions of catastrophe (That’s only done in climate science, even though the odds are far less).
Word of a ‘mega-eruption’ is making the rounds among scientists. But apparently they are avoiding the use of the word to avoid being labelled preachers of disasters. ‘We can only speculate what the volcano will do,’ says Birger Lühr. Merapi is hardly predictable.
Merapi in 2005 (Wikipedia)
History shows, however, that volcanoes in Indonesia have a worrisome potential for catastrophic eruptions. Nature cannot be controlled. It can only be coped with.

 

Cost of Green Power Makes Projects Tougher Sell By MATTHEW L. WALD and TOM ZELLER Jr.

http://www.nytimes.com/2010/11/08/science/earth/08fossil.html?_r=1

Sunday, November 7, 2010

Volcanoes Have Shifted Asian Rainfall



Large, explosive volcanoes such as Indonesia's Merapi (erupting here in 2006) have the potential to change weather patterns if their eruptions are big enough.
http://www.terradaily.com/reports/Volcanoes_Have_Shifted_Asian_Rainfall_999.html New York NY (SPX) Nov 08, 2010 Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air. Some suspect that extended "volcanic winters" from gigantic blowups helped kill off dinosaurs and Neanderthals. In the summer following Indonesia's 1815 Tambora eruption, frost wrecked crops as far off as New England, and the 1991 blowout of the Philippines' Mount Pinatubo lowered average global temperatures by 0.7 degrees F-enough to mask the effects of manmade greenhouse gases for a year or so.
Now, scientists have shown that eruptions also affect rainfall over the Asian monsoon region, where seasonal storms water crops for nearly half of earth's population.
Tree-ring researchers at Columbia University's Lamont-Doherty Earth Observatory showed that big eruptions tend to dry up much of central Asia, but bring more rain to southeast Asian countries including Vietnam, Laos, Cambodia, Thailand and Myanmar-the opposite of what many climate models predict. Their paper appears in an advance online version of the journal Geophysical Research Letters.
The growth rings of some tree species can be correlated with rainfall, and the observatory's Tree Ring Lab used rings from some 300 sites across Asia to measure the effects of 54 eruptions going back about 800 years.
The data came from Lamont's new 1,000-year tree-ring atlas of Asian weather, which has already produced evidence of long, devastating droughts; the researchers also have done a prior study of volcanic cooling in the tropics.
"We might think of the study of the solid earth and the atmosphere as two different things, but really everything in the system is interconnected," said Kevin Anchukaitis, the study's lead author. "Volcanoes can be important players in climate over time."
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River Flows Across US Altered By Land And Water Management



Flows are altered by a variety of land- and water-management activities, including reservoirs, diversions, subsurface tile drains, groundwater withdrawals, wastewater inputs, and impervious surfaces, such as parking lots, sidewalks and roads.
http://www.terradaily.com/reports/River_Flows_Across_US_Altered_By_Land_And_Water_Management_999.html Washington DC (SPX) Nov 08, 2010 The amount of water flowing in streams and rivers has been significantly altered in nearly 90 percent of waters that were assessed in a new nationwide USGS study. Flow alterations are a primary contributor to degraded river ecosystems and loss of native species. "This USGS assessment provides the most geographically extensive analysis to date of stream flow alteration," said Bill Werkheiser, USGS Associate Director for Water.
"Findings show the pervasiveness of stream flow alteration resulting from land and water management, the significant impact of altered stream flow on aquatic organisms, and the importance of considering this factor for sustaining and restoring the health of the Nation's streams and ecosystems."
Flows are altered by a variety of land- and water-management activities, including reservoirs, diversions, subsurface tile drains, groundwater withdrawals, wastewater inputs, and impervious surfaces, such as parking lots, sidewalks and roads.
"Altered river flows lead to the loss of native fish and invertebrate species whose survival and reproduction are tightly linked to specific flow conditions," said Daren Carlisle, USGS ecologist and lead scientist on this study.
"These consequences can also affect water quality, recreational opportunities and the maintenance of sport fish populations."
For example, in streams with severely diminished flow, native trout, a popular sport fish that requires fast-flowing streams with gravel bottoms, are replaced by less desirable non-native species, such as carp. Overall, the USGS study indicated that streams with diminished flow contained aquatic communities that prefer slow moving currents more characteristic of lake or pond habitats.
"Management practices related to water demand continue to alter stream flows in many places," said Jeff Ostermiller, Water Quality Manager with the Utah Division of Water Quality.
"Understanding the ecological effects of these flow alterations helps water managers develop effective strategies to ensure that water remains sufficiently clean and abundant to support fisheries and recreation opportunities, while simultaneously supporting economic development."
Annual and seasonal cycles of water flows - particularly the low and high flows - shape ecological processes in rivers and streams. An adequate minimum flow is important to maintain suitable water conditions and habitat for fish and other aquatic life. High flows are important because they replenish floodplains and flush out accumulated sediment that can degrade habitat.
"While this study provided the first, national assessment of flow alteration, focused studies within specific geographic regions will provide a better understanding of the ecological effects of altered stream flows, which can be more effectively applied to local water management challenges," said Carlisle.
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Time For A Rain Dance




File image.
http://www.terradaily.com/reports/Time_For_A_Rain_Dance_999.html Tel Aviv, Israel (SPX) Nov 08, 2010 In many areas of the world, including California's Mojave Desert, rain is a precious and rare resource. To encourage rainfall, scientists use "cloud seeding," a weather modification process designed to increase precipitation amounts by dispersing chemicals into the clouds. But research now reveals that the common practice of cloud seeding with materials such as silver iodide and frozen carbon dioxide may not be as effective as it had been hoped.
In the most comprehensive reassessment of the effects of cloud seeding over the past fifty years, new findings from Prof. Pinhas Alpert, Prof. Zev Levin and Dr. Noam Halfon of Tel Aviv University's Department of Geophysics and Planetary Sciences have dispelled the myth that seeding is an effective mechanism for precipitation enhancement.
The findings were recently reported in Atmospheric Research.
Throwing seeds into the wind During the course of his study, Prof. Alpert and his colleagues looked over fifty years' worth of data on cloud seeding, with an emphasis on the effects of seeding on rainfall amounts in a target area over the Sea of Galilee in the north of Israel.
The research team used a comprehensive rainfall database and compared statistics from periods of seeding and non-seeding, as well as the amounts of precipitation in adjacent non-seeded areas.
"By comparing rainfall statistics with periods of seeding, we were able to show that increments of rainfall happened by chance," says Prof. Alpert. "For the first time, we were able to explain the increases in rainfall through changing weather patterns" instead of the use of cloud seeding.
Most notable was a six year period of increased rainfall, originally thought to be a product of successful cloud seeding. Prof. Alpert and his fellow researchers showed that this increase corresponded with a specific type of cyclones which are consistent with increased rainfall over the mountainous regions.
They observed that a similarly significant rain enhancement over the Judean Mountains, an area which was not the subject of seeding.
The researchers concluded that changing weather patterns were responsible for the higher amount of precipitation during these years. Their research method may be useful in the investigation of cloud seeding in the U.S. and other regions.
Considering the alternatives Despite being relatively expensive, there are more than 80 cloud seeding projects around the world, according to a recent World Meteorological Organization report. In Beijing, China, for example, Prof. Alpert notes, a large amount of chemical particles were introduced to the clouds to inhibit precipitation - a process called "overseeding" - to limit rainfall during the 2008 Olympics.
Seeding is also used in the Sierra Mountains of California and in Wyoming to try to increase precipitation in the mountains, thus increasing water levels in reservoirs. However, he says, there is no proof that this method is successful.
The only probable place where cloud seeding could be successful, Alpert says, is when seeding is performed on orographic clouds, which develop over mountains and have a short lifespan. In this type of cloud, seeding could serve to accelerate the formation of precipitation.
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