Thursday 8 April 2010
Biofuel Production Puts Pressure On Water
Robert M. Thorson
April 8, 2010
This is a story about robbing Peter to pay Paul — the taking of water to feed the opiate of energy independence.March 11, a freight train rumbles through the woods of Windham. Light rain falls, snow melts, the ground softens and the track bends. At 3 a.m., four railroad tanker cars carrying 120,000 gallons of flammable liquid ethanol derail above the Shetucket River. The alarm system goes off. "What the ... ?" one crew member says to another, or so I imagine. The train squeaks to a halt and the men walk back with their flashlights to investigate. Three cars are tipped and overturned. The men return to the train, notify the dispatcher and continue their trip to Providence. When first hearing this story, I embellished it in my mind as a slow-motion train wreck between our nation's energy policy moving in one direction, and its water policy moving in the other. In the aftermath of 9/11, biofuels were touted as a magic bullet of national energy independence. The calculations were computed, the studies were done, the lobbyists lobbied and Congress passed the Energy Independence and Security Act of 2007. The act mandates a fivefold increase in domestic ethanol production by 2022, with about half that goal met by 2015 with corn-based ethanol. The U.S. began subsidizing biofuel plant construction throughout the cornbelt. Also in the time since 9/11: Snowpacks diminished. Droughts threatened. Fires burned. The water levels in the Great Lakes and countless smaller ones dropped, a trend recently (and temporarily?) reversed by the unusual weather of the last two years. Meanwhile, the climate modelers firmed up their predictions that the water supply in the American heartland is on a downward trend.And now, the slow-motion train wreck. "In short, an increased reliance on biofuel trades an oil problem for a water problem." That's a quote from a recent report ominously titled "Another Biofuels Drawback: The Demand for Irrigation." It summarizes two recent studies by Argonne National Laboratory containing some stunning numbers. It takes between 10 and 324 gallons of water to create a single gallon of ethanol (with an average of 98), depending on the geography and proportion of irrigation. This transfer will increase U.S. water demand by about 1.4 trillion gallons per year, practically all from the corn-belt states. Other energy sectors also require staggering amounts of water.Worst is irrigated soybean biodiesel, which takes between 3.6 million and 7.2 million gallons of water to produce a single megawatt hour of electricity. In comparison, oil shale extraction requires only 44 to 171 gallons per megawatt, and petroleum extraction only 2.6 to10.4 gallons. U.S. water consumption for energy development is predicted to rise by two thirds to about 10 billion gallons per day by 2030. Approximately half that increase will be for rising population and the other half for legally mandated biofuel conversions. Over that period, the proportion of land being irrigated for biofuels will rise dramatically from 3 percent to 20 percent. Any leftover water will drain to the Gulf of Mexico, carrying with it the excess nutrients and pesticides that were needed to grow enough corn to produce enough fuel to meet the mandates to make us feel good about energy independence. As a result, the Mississippi River stagnates, the bayous breathe more laboriously and the low-oxygen dead zone beneath the Gulf enlarges. Meanwhile, petroleum-diesel train engines haul ethanol tankers eastward under cover of night. An accident occurs, tankers tip, an innocent freshwater resource is threatened, and dozens of large vehicles — fire, ambulance, police, troopers, hazmat teams, regulators, press, television — all powered by fossil fuels, come to investigate. I wonder if they saw what was taking place behind the scenes on that dark night. •Robert M. Thorson is a professor of geology at the University of Connecticut's College of Liberal Arts and Sciences and a member of The Courant's Place Board of Contributors. His column appears every other Thursday. He can be reached at profthorson@yahoo.com.
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Energy Efficiency on the World Stage
The place where all the concerns and possibilities of the coming New Energy economy meet is called Energy Efficiency. Energy Efficiency offers a faster and more accessible path to meeting rapidly rising energy demand, providing energy security in an ever more dangerous world and addressing global climate change. It also offers jobs the sluggish economy urgently needs and the energy-cost savings that can fund the buildout of New Energy.
Despite the highest hopes of New Energy advocates and developers, installed capacity growth on a big enough scale to meet unchecked rising world energy demand in the near term could only happen with a massive and sustained commitment. Such a commitment will not come in industrial societies where Old Energy's vested interests refuse to give way.
In the absence of such a massive commitment, Energy Efficiency is the necessary and best alternative. Energy Vision Update 2010; Towards a More Energy Efficient World describes the world’s renewed commitment to Energy Efficiency, the most redeeming feature of an otherwise disappointing December international climate change summit in Copenhagen.
The fastest, cheapest way to make the biggest impact on the available domestic energy supply is with negawatts, the label energy visionary Amory Lovins gave to getting more output with less energy. Closing the efficiency gap between available and cost-effective options and the wasteful way energy is presently used will not only reduce the pressure on world resources; it will also save money, an estimated $2-to-$4 for every dollar spent. Those are dollars that can be invested in New Energy infrastructure. (Such a deal!)
Even the most pessimistic scenarios about recovery and growth in Western industrial economies nevertheless foresee rising energy consumption around the world. Demand will be driven by, if nothing else, the continuing march out of poverty and into the middle class of billions of people in India, China, Brazil, Indonesia, Korea and Southeast Asia.
But even if the world had not already had enough of oil tanker spills and deadly coal mine disasters, it is becoming clear the Old Energy infrastructure - even augmented by the rapidly expanding capacities of the New Energies - cannot fully meet predicted levels of near-term demand without a complimentary expansion of Energy Efficiency tools and capabilities.
Happily, the advance of Energy Efficiency is happening around the world without the need for international agreements or leadership from the U.S. Senate (neither of which, it would seem, is within reach on this or any important topic). China is building new, high voltage transmission. South Korea is pioneering Smart Grid technology. And the entrepreneuers of silicon vallies from Massachusetts and California to Bangalore, their high tech toy sales dwindling and the realization rising that a world without adequate electricity is not one in which they can prosper, are turning with all their desperate passion to Energy Efficiency.
Hope, with springtime, is in the air.
This post is based on Energy Vision Update 2010; Towards a More Energy Efficient World (March 2010, World Economic Forum with IHS Cambridge Energy Research Associates)
Despite the highest hopes of New Energy advocates and developers, installed capacity growth on a big enough scale to meet unchecked rising world energy demand in the near term could only happen with a massive and sustained commitment. Such a commitment will not come in industrial societies where Old Energy's vested interests refuse to give way.
In the absence of such a massive commitment, Energy Efficiency is the necessary and best alternative. Energy Vision Update 2010; Towards a More Energy Efficient World describes the world’s renewed commitment to Energy Efficiency, the most redeeming feature of an otherwise disappointing December international climate change summit in Copenhagen.
The fastest, cheapest way to make the biggest impact on the available domestic energy supply is with negawatts, the label energy visionary Amory Lovins gave to getting more output with less energy. Closing the efficiency gap between available and cost-effective options and the wasteful way energy is presently used will not only reduce the pressure on world resources; it will also save money, an estimated $2-to-$4 for every dollar spent. Those are dollars that can be invested in New Energy infrastructure. (Such a deal!)
Even the most pessimistic scenarios about recovery and growth in Western industrial economies nevertheless foresee rising energy consumption around the world. Demand will be driven by, if nothing else, the continuing march out of poverty and into the middle class of billions of people in India, China, Brazil, Indonesia, Korea and Southeast Asia.
But even if the world had not already had enough of oil tanker spills and deadly coal mine disasters, it is becoming clear the Old Energy infrastructure - even augmented by the rapidly expanding capacities of the New Energies - cannot fully meet predicted levels of near-term demand without a complimentary expansion of Energy Efficiency tools and capabilities.
Happily, the advance of Energy Efficiency is happening around the world without the need for international agreements or leadership from the U.S. Senate (neither of which, it would seem, is within reach on this or any important topic). China is building new, high voltage transmission. South Korea is pioneering Smart Grid technology. And the entrepreneuers of silicon vallies from Massachusetts and California to Bangalore, their high tech toy sales dwindling and the realization rising that a world without adequate electricity is not one in which they can prosper, are turning with all their desperate passion to Energy Efficiency.
Hope, with springtime, is in the air.
This post is based on Energy Vision Update 2010; Towards a More Energy Efficient World (March 2010, World Economic Forum with IHS Cambridge Energy Research Associates)
Microbelt: An Extremely Efficient Palm Sized Wind Turbine
April 7, 2010
Humdinger, a Hawaii based startup, has developed a small wind turbine called Microbelt that is supposedly 10 times more efficient at generating wind energy than other systems of the same size. The palm sized Microbelt uses an aeroelastic flutter and vibration of a membrane instead of a turbine to generate power. The device is inexpensive and the company aims to use it for powering building monitoring and transit monitoring sensors, replacing the need for expensive batteries.
Humdinger Microbelt
Humdinger, a Hawaii based startup, has developed a small wind turbine called Microbelt that is supposedly 10 times more efficient at generating wind energy than other systems of the same size. The palm sized Microbelt uses an aeroelastic flutter and vibration of a membrane instead of a turbine to generate power. The device is inexpensive and the company aims to use it for powering building monitoring and transit monitoring sensors, replacing the need for expensive batteries.
Humdinger Microbelt
AES Solar Energy Closes on €173 Million Project Financing for 43 MW Photovoltaic Project in Italy
Arlington, VA Posted on April 7th, 2010
A total of five banks participated in this financing: Société Générale (as Documentation, Technical & Modeling Bank and Hedging Coordinator), Unicredit Mediocredito Centrale (as Documentation Bank), BNP Paribas (as Insurance Bank), Crédit Agricole Corporate and Investment Bank and Dexia Crediop (as Agent). SACE is taking this opportunity to step up its involvement in financing solar PV projects, participating via providing a guarantee for a portion of Société Générale's commitment. The facilities cover approximately 85% of estimated project costs at completion and the final maturity date is 18 years post construction.Massimiliano Battisti, a Managing Director at Société Générale, one of the coordinating banks in this transaction remarked, "While the Italian regulatory environment makes solar PV a highly attractive investment, its dynamics make innovative financing solutions necessary. This poses a significant barrier to entry for less sophisticated investors. In this environment we believe that it is very important to have partners like AES Solar who are among the most experienced sponsors in this sector, as they have both the industry and the financial expertise as well as the ability to understand the subtleties of the local market to enable them to successfully deliver the project."Construction on the project is underway and the project is expected to reach commercialoperation by the end of 2010, qualifying it for a 20-year regulated feed-in tariff under the"Conto Energia" scheme. CSM will use First Solar thin film panels.The addition of the 43 MW CSM will more than double the global operating portfolio of AES Solar, which currently includes 38 MW across France, Greece and Spain.
About AES SolarAES Solar Energy Ltd, (AES Solar) is a joint venture between The AES Corporation and Riverstone Holdings LLC, formed to develop, own and operate utility-scale photovoltaic solar installations around the world. AES Solar currently has 38 MW in operations ininvestments in the midstream, exploration & production, oilfield services, power and renewable sectors of the energy industry. With offices in New York, London and Houston, the firm has committed approximately $13 billion to 66 investments in North America, Latin America, Europe and Asia. For more information, visit www.riverstonellc.com.
About The AES CorporationThe AES Corporation (NYSE: AES) is a Fortune 500 global power company with generation and distribution businesses. Through its diverse portfolio of thermal and renewable fuel sources, AES safely provides affordable and sustainable energy in 29 countries. AES’ workforce of 27,000 people is committed to operational excellence and meeting the world's changing power needs. AES’ 2009 revenues were $14 billion and it owns and manages $40 billion in total assets. To learn more, please visit www.aes.com.
A total of five banks participated in this financing: Société Générale (as Documentation, Technical & Modeling Bank and Hedging Coordinator), Unicredit Mediocredito Centrale (as Documentation Bank), BNP Paribas (as Insurance Bank), Crédit Agricole Corporate and Investment Bank and Dexia Crediop (as Agent). SACE is taking this opportunity to step up its involvement in financing solar PV projects, participating via providing a guarantee for a portion of Société Générale's commitment. The facilities cover approximately 85% of estimated project costs at completion and the final maturity date is 18 years post construction.Massimiliano Battisti, a Managing Director at Société Générale, one of the coordinating banks in this transaction remarked, "While the Italian regulatory environment makes solar PV a highly attractive investment, its dynamics make innovative financing solutions necessary. This poses a significant barrier to entry for less sophisticated investors. In this environment we believe that it is very important to have partners like AES Solar who are among the most experienced sponsors in this sector, as they have both the industry and the financial expertise as well as the ability to understand the subtleties of the local market to enable them to successfully deliver the project."Construction on the project is underway and the project is expected to reach commercialoperation by the end of 2010, qualifying it for a 20-year regulated feed-in tariff under the"Conto Energia" scheme. CSM will use First Solar thin film panels.The addition of the 43 MW CSM will more than double the global operating portfolio of AES Solar, which currently includes 38 MW across France, Greece and Spain.
About AES SolarAES Solar Energy Ltd, (AES Solar) is a joint venture between The AES Corporation and Riverstone Holdings LLC, formed to develop, own and operate utility-scale photovoltaic solar installations around the world. AES Solar currently has 38 MW in operations ininvestments in the midstream, exploration & production, oilfield services, power and renewable sectors of the energy industry. With offices in New York, London and Houston, the firm has committed approximately $13 billion to 66 investments in North America, Latin America, Europe and Asia. For more information, visit www.riverstonellc.com.
About The AES CorporationThe AES Corporation (NYSE: AES) is a Fortune 500 global power company with generation and distribution businesses. Through its diverse portfolio of thermal and renewable fuel sources, AES safely provides affordable and sustainable energy in 29 countries. AES’ workforce of 27,000 people is committed to operational excellence and meeting the world's changing power needs. AES’ 2009 revenues were $14 billion and it owns and manages $40 billion in total assets. To learn more, please visit www.aes.com.
Vauxhall’s new electric car range
08 April 2010
GM is planning more extended-range electric vehicles (E-REV) for Europe, including models positioned above and below the Ampera, according to Opel-Vauxhall boss Nick Reilly.
Each car will have its own distinctive styling, as hinted at by the Vauxhall Flextreme GTE concept unveiled at Geneva. The two cars will be based on the next-generation Corsa platform and the Insignia’s Epsilon platform, but the modifications required to accommodate the E-REV drivetrain more than justifies unique styling for each car, says Reilly. It will create two parallel ranges for GM Europe in the largest market segments.
Reilly also said that the next Ampera will have a battery pack designed to last significantly less than the 10 years of the current car’s, and that it will be configured for easy removal and replacement.
The current car’s battery is difficult to remove because of how it is protected from crash damage. But new construction methods have prompted a change of strategy, as has the realisation that the cost of a battery change on a 10-year-old car may not be economically viable given the car’s likely value.
GM also plans to offer buyers different batteries, with a range of powerpacks at different prices. The aim is to reduce the price of E-REV models; the large battery pack of the current Ampera will account for a high proportion of its price.
Most of the first batch of Amperas, built in the US and on sale in the middle of 2011, have already been sold to European governments and fleets.
The decision on where to build European Amperas will be made in a year’s time and will be determined, in part, on the level of incentives offered in the countries being considered. At the moment, Britain’s Ellesmere Port plant is well placed because today’s government is planning electric car incentives that would take £5000 off the list price of an Ampera.
GM is planning more extended-range electric vehicles (E-REV) for Europe, including models positioned above and below the Ampera, according to Opel-Vauxhall boss Nick Reilly.
Each car will have its own distinctive styling, as hinted at by the Vauxhall Flextreme GTE concept unveiled at Geneva. The two cars will be based on the next-generation Corsa platform and the Insignia’s Epsilon platform, but the modifications required to accommodate the E-REV drivetrain more than justifies unique styling for each car, says Reilly. It will create two parallel ranges for GM Europe in the largest market segments.
Reilly also said that the next Ampera will have a battery pack designed to last significantly less than the 10 years of the current car’s, and that it will be configured for easy removal and replacement.
The current car’s battery is difficult to remove because of how it is protected from crash damage. But new construction methods have prompted a change of strategy, as has the realisation that the cost of a battery change on a 10-year-old car may not be economically viable given the car’s likely value.
GM also plans to offer buyers different batteries, with a range of powerpacks at different prices. The aim is to reduce the price of E-REV models; the large battery pack of the current Ampera will account for a high proportion of its price.
Most of the first batch of Amperas, built in the US and on sale in the middle of 2011, have already been sold to European governments and fleets.
The decision on where to build European Amperas will be made in a year’s time and will be determined, in part, on the level of incentives offered in the countries being considered. At the moment, Britain’s Ellesmere Port plant is well placed because today’s government is planning electric car incentives that would take £5000 off the list price of an Ampera.
Daimler, Renault to Team Up On Small Car, Hybrid and Electric Vehicle Technology
BY Ariel SchwartzTue Apr 6, 2010
Sign number one that automakers are serious about making the transition to hybrid and electric vehicles: They're teaming up to share technology. Daimler and the Renault-Nissan Alliance are expected to announce a global partnership tomorrow that will allow the companies to share technology and development costs for small cars, hybrids, and EVs. So why are they sharing such precious information?
Bloomberg explains that the automakers are crunched for cash and racing to reach emissions standards--like the newly implemented greenhouse gas emissions standards in the U.S. and the strict E.U. rules. In an interview with Bloomberg, one automotive analyst went so far as to say that the alliance is actually being forced by the E.U. standards. Because without selling large amounts of small cars (or EVs), carmakers can't possibly reach CO2 targets.
In practical terms, the alliance means that Daimler and Renault will share technology for gasoline, diesel, fuel cell, hybrid, and electric engines, as well as development costs for all vehicles. Eventually, Mercedes-Benz (a division of Daimler) could supply transmissions and engines to Nissan's Infiniti brand, and the Renault Twingo and Daimler Smart car may share components. On the consumer side of things, the alliance could bring lower cost efficient vehicles to the mainstream--that is, of course, if Renault and Daimler work faster together than they do separately.
Sign number one that automakers are serious about making the transition to hybrid and electric vehicles: They're teaming up to share technology. Daimler and the Renault-Nissan Alliance are expected to announce a global partnership tomorrow that will allow the companies to share technology and development costs for small cars, hybrids, and EVs. So why are they sharing such precious information?
Bloomberg explains that the automakers are crunched for cash and racing to reach emissions standards--like the newly implemented greenhouse gas emissions standards in the U.S. and the strict E.U. rules. In an interview with Bloomberg, one automotive analyst went so far as to say that the alliance is actually being forced by the E.U. standards. Because without selling large amounts of small cars (or EVs), carmakers can't possibly reach CO2 targets.
In practical terms, the alliance means that Daimler and Renault will share technology for gasoline, diesel, fuel cell, hybrid, and electric engines, as well as development costs for all vehicles. Eventually, Mercedes-Benz (a division of Daimler) could supply transmissions and engines to Nissan's Infiniti brand, and the Renault Twingo and Daimler Smart car may share components. On the consumer side of things, the alliance could bring lower cost efficient vehicles to the mainstream--that is, of course, if Renault and Daimler work faster together than they do separately.
Faint young sun paradox explained by Stanford – greenhouse effect not involved
7 04 2010
Early Earth stayed warm because its ocean absorbed more sunlight; greenhouse gases were not involved, Stanford researchers say.
From a Stanford University News press release.
Researchers have long wondered why water on Earth was not frozen during the early days of the planet, when the sun emanated only 70 to 75 percent as much energy as it does today. Some theorize that high levels of greenhouse gases in the atmosphere, the same mechanism cited in global warming today, were key. But new research involving Stanford scientists has a different explanation: The oceans, much larger than today, absorbed enough heat from the sun to avoid turning into ice.
BY LOUIS BERGERON
Four billion years ago, our then stripling sun radiated only 70 to 75 percent as much energy as it does today. Other things on Earth being equal, with so little energy reaching the planet’s surface, all water on the planet should been have frozen. But ancient rocks hold ample evidence that the early Earth was awash in liquid water – a planetary ocean of it. So something must have compensated for the reduced solar output and kept Earth’s water wet.
To explain this apparent paradox, a popular theory holds there must have been higher concentrations of greenhouse gases in the atmosphere, most likely carbon dioxide, which would have helped retain a greater proportion of the solar energy that arrived.
But a team of earth scientists including researchers from Stanford have analyzed the mineral content of 3.8-billion-year-old marine rocks from Greenland and concluded otherwise.
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide,” said Dennis Bird, professor of geological and environmental sciences.
Instead, the team proposes that the vast global ocean of early Earth absorbed a greater percentage of the incoming solar energy than today’s oceans, enough to ward off a frozen planet. Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.
The study is detailed in a paper published in the April 1 issue of Nature. Bird and Norman Sleep, a professor of geophysics, are among the four authors. The lead author is Minik Rosing, a geology professor at the Natural History Museum of Denmark, University of Copenhagen, and a former Allan Cox Visiting Professor at Stanford’s School of Earth Sciences.
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Another key component of the theory is in the clouds. “Not all clouds are the same,” Bird said.
Clouds reflect sunlight back into space to a degree, cooling Earth, but how effective they are depends on the number of tiny particles available to serve as nuclei around which the water droplets can condense. An abundance of nuclei means more droplets of a smaller size, which makes for a denser cloud and a greater reflectivity, or albedo, on the part of the cloud.
Most nuclei today are generated by plants or algae and promote the formation of numerous small droplets. But plants and algae didn’t flourish until much later in Earth’s history, so their contribution of potential nuclei to the early atmosphere circa 4 billion years ago would have been minimal. The few nuclei that might have been available would likely have come from erosion of rock on the small, rare landmasses of the day and would have caused larger droplets that were essentially transparent to the solar energy that came in to Earth, according to Bird.
“We put together some models that demonstrate, with the slow continental growth and with a limited amount of clouds, you could keep water above freezing throughout geologic history,” Bird said.
“What this shows is that there is no faint early sun paradox,” said Sleep.
The modeling work was done with climate modeler Christian Bjerrum, a professor in the Department of Geography and Geology, University of Copenhagen, also a co-author of the Nature paper.
The rocks that the team analyzed are a type of marine sedimentary rock called a banded iron formation.
Video: These rocks, billions of years old, tell a new story about the evolution of early Earth, Stanford researchers say.
“Any rock carries a memory of the environment in which it formed,” Rosing said. “These ancient rocks that are about 3.8 billion years old, they actually carry a memory of the composition of the ocean and atmosphere at the time when they were deposited.”
Another constraint on early carbon dioxide levels came from life itself.
In the days before photosynthetic organisms spread across the globe, most life forms were methanogens, single-celled organisms that consumed hydrogen and carbon dioxide and produced methane as a digestive byproduct.
But to thrive, methanogens need a balanced diet. If the concentration of either of their foodstuffs veers too far below their preferred proportions, methanogens won’t survive. Their dietary restrictions, specifically the minimum concentration of hydrogen, provided another constraint on the concentration of carbon dioxide in the atmosphere, and it falls well below the level needed for a greenhouse effect sufficient to compensate for a weak early sun.
“The conclusion from all this is that we can’t solve a faint sun paradox and also satisfy the geologic and metabolic constraints by having high carbon dioxide values,” Bird said.
But the theory of a lower Earthly albedo meets those constraints.
“The lower albedo counterbalanced the fainter sun and provided Earth with clement conditions without the need for dramatically higher concentrations of greenhouse gasses in the atmosphere,” Rosing said.
Early Earth stayed warm because its ocean absorbed more sunlight; greenhouse gases were not involved, Stanford researchers say.
From a Stanford University News press release.
Researchers have long wondered why water on Earth was not frozen during the early days of the planet, when the sun emanated only 70 to 75 percent as much energy as it does today. Some theorize that high levels of greenhouse gases in the atmosphere, the same mechanism cited in global warming today, were key. But new research involving Stanford scientists has a different explanation: The oceans, much larger than today, absorbed enough heat from the sun to avoid turning into ice.
BY LOUIS BERGERON
Four billion years ago, our then stripling sun radiated only 70 to 75 percent as much energy as it does today. Other things on Earth being equal, with so little energy reaching the planet’s surface, all water on the planet should been have frozen. But ancient rocks hold ample evidence that the early Earth was awash in liquid water – a planetary ocean of it. So something must have compensated for the reduced solar output and kept Earth’s water wet.
To explain this apparent paradox, a popular theory holds there must have been higher concentrations of greenhouse gases in the atmosphere, most likely carbon dioxide, which would have helped retain a greater proportion of the solar energy that arrived.
But a team of earth scientists including researchers from Stanford have analyzed the mineral content of 3.8-billion-year-old marine rocks from Greenland and concluded otherwise.
“There is no geologic evidence in these rocks for really high concentrations of a greenhouse gas like carbon dioxide,” said Dennis Bird, professor of geological and environmental sciences.
Instead, the team proposes that the vast global ocean of early Earth absorbed a greater percentage of the incoming solar energy than today’s oceans, enough to ward off a frozen planet. Because the first landmasses that formed on Earth were small – mere islands in the planetary sea – a far greater proportion of the surface of was covered with water than today.
The study is detailed in a paper published in the April 1 issue of Nature. Bird and Norman Sleep, a professor of geophysics, are among the four authors. The lead author is Minik Rosing, a geology professor at the Natural History Museum of Denmark, University of Copenhagen, and a former Allan Cox Visiting Professor at Stanford’s School of Earth Sciences.
The crux of the theory is that because oceans are darker than continents, particularly before plants and soils covered landmasses, seas absorb more sunlight.
“It’s the same phenomenon you will experience if you drive to Wal-Mart on a hot day and step out of your car onto the asphalt,” Bird said. “It’s really hot walking across the blacktop until you get onto the white concrete sidewalk.”
Another key component of the theory is in the clouds. “Not all clouds are the same,” Bird said.
Clouds reflect sunlight back into space to a degree, cooling Earth, but how effective they are depends on the number of tiny particles available to serve as nuclei around which the water droplets can condense. An abundance of nuclei means more droplets of a smaller size, which makes for a denser cloud and a greater reflectivity, or albedo, on the part of the cloud.
Most nuclei today are generated by plants or algae and promote the formation of numerous small droplets. But plants and algae didn’t flourish until much later in Earth’s history, so their contribution of potential nuclei to the early atmosphere circa 4 billion years ago would have been minimal. The few nuclei that might have been available would likely have come from erosion of rock on the small, rare landmasses of the day and would have caused larger droplets that were essentially transparent to the solar energy that came in to Earth, according to Bird.
“We put together some models that demonstrate, with the slow continental growth and with a limited amount of clouds, you could keep water above freezing throughout geologic history,” Bird said.
“What this shows is that there is no faint early sun paradox,” said Sleep.
The modeling work was done with climate modeler Christian Bjerrum, a professor in the Department of Geography and Geology, University of Copenhagen, also a co-author of the Nature paper.
The rocks that the team analyzed are a type of marine sedimentary rock called a banded iron formation.
Video: These rocks, billions of years old, tell a new story about the evolution of early Earth, Stanford researchers say.
“Any rock carries a memory of the environment in which it formed,” Rosing said. “These ancient rocks that are about 3.8 billion years old, they actually carry a memory of the composition of the ocean and atmosphere at the time when they were deposited.”
Another constraint on early carbon dioxide levels came from life itself.
In the days before photosynthetic organisms spread across the globe, most life forms were methanogens, single-celled organisms that consumed hydrogen and carbon dioxide and produced methane as a digestive byproduct.
But to thrive, methanogens need a balanced diet. If the concentration of either of their foodstuffs veers too far below their preferred proportions, methanogens won’t survive. Their dietary restrictions, specifically the minimum concentration of hydrogen, provided another constraint on the concentration of carbon dioxide in the atmosphere, and it falls well below the level needed for a greenhouse effect sufficient to compensate for a weak early sun.
“The conclusion from all this is that we can’t solve a faint sun paradox and also satisfy the geologic and metabolic constraints by having high carbon dioxide values,” Bird said.
But the theory of a lower Earthly albedo meets those constraints.
“The lower albedo counterbalanced the fainter sun and provided Earth with clement conditions without the need for dramatically higher concentrations of greenhouse gasses in the atmosphere,” Rosing said.
Tokyo kicks off carbon trading scheme
Japanese metropolis launches Asia's first emissions cap-and-trade scheme
BusinessGreen.com Staff, BusinessGreen, 07 Apr 2010
Plans for a national Japanese emissions trading scheme may still be mired in confusion, but that has not stopped Tokyo winning the race to launch Asia's first carbon trading initiative.
The city last week kicked off its long-awaited carbon trading scheme, which will require 1,400 of Tokyo's most energy and carbon intensive organisations to meet legally binding emission targets modeled on those used in Europe's cap-and-trade scheme.
During the first phase of the scheme, which runs up to 2014, participating organisations will have to cut their carbon emissions by six per cent.
Those that fail to operate within their emission caps will from 2011 be required to purchase emission allowances to cover any excess emissions, or alternatively invest in renewable energy certificates or offset credits issued by smaller businesses or branch offices. However, under the rules of the scheme, credits issued outside of Tokyo can not exceed a third of the emission cuts required of participating organisations.
Those firms that fail to comply with the new rules will face fines and could also be named and shamed by the government. According to local reports, organisations that do not operate within their caps will also be ordered to cut emissions by 1.3 times the amount they failed to reduce emissions during the first phase of the scheme.
City officials said that in the long term the aim was to cut the metropolis' carbon emissions by 25 per cent on 2000 levels by 2020.
Yuki Arata, the director for emissions trading at the Tokyo metropolitan government's environment bureau, told news agency AFP that the scheme was also intended to work as a "model for the Japanese government".
Last month, the national government controversially delayed a decision on how to roll out its planned cap-and-trade scheme, approving a draft version of its climate change bill that failed to finalise the details on how the scheme will work.
While the government remains committed to implementing a cap-and-trade scheme and to cutting emissions by 25 per cent by 2020, it has delayed until after this summer's election its decision on whether to impose absolute or carbon-intensity caps through the scheme and is also yet to finalise how targets will be imposed on different industries.
BusinessGreen.com Staff, BusinessGreen, 07 Apr 2010
Plans for a national Japanese emissions trading scheme may still be mired in confusion, but that has not stopped Tokyo winning the race to launch Asia's first carbon trading initiative.
The city last week kicked off its long-awaited carbon trading scheme, which will require 1,400 of Tokyo's most energy and carbon intensive organisations to meet legally binding emission targets modeled on those used in Europe's cap-and-trade scheme.
During the first phase of the scheme, which runs up to 2014, participating organisations will have to cut their carbon emissions by six per cent.
Those that fail to operate within their emission caps will from 2011 be required to purchase emission allowances to cover any excess emissions, or alternatively invest in renewable energy certificates or offset credits issued by smaller businesses or branch offices. However, under the rules of the scheme, credits issued outside of Tokyo can not exceed a third of the emission cuts required of participating organisations.
Those firms that fail to comply with the new rules will face fines and could also be named and shamed by the government. According to local reports, organisations that do not operate within their caps will also be ordered to cut emissions by 1.3 times the amount they failed to reduce emissions during the first phase of the scheme.
City officials said that in the long term the aim was to cut the metropolis' carbon emissions by 25 per cent on 2000 levels by 2020.
Yuki Arata, the director for emissions trading at the Tokyo metropolitan government's environment bureau, told news agency AFP that the scheme was also intended to work as a "model for the Japanese government".
Last month, the national government controversially delayed a decision on how to roll out its planned cap-and-trade scheme, approving a draft version of its climate change bill that failed to finalise the details on how the scheme will work.
While the government remains committed to implementing a cap-and-trade scheme and to cutting emissions by 25 per cent by 2020, it has delayed until after this summer's election its decision on whether to impose absolute or carbon-intensity caps through the scheme and is also yet to finalise how targets will be imposed on different industries.
Plants flower five days earlier for every degree of global warming
Plants in Britain are flowering earlier today than at any period since records began, according to data collected by ordinary gardeners over 250 years.
By Louise Gray, Environment CorrespondentPublished: 4:07PM BST 07 Apr 2010
In an example of "citizen science", researchers looked at more than 400,000 records collected by Victorian vicars, dog walkers and the viewers of the BBC series Springwatch.
The records, that go back to 1753, were divided into 25 year periods in order to compare the average flowering time as the weather changed from year to year. More than 400 species were recorded, from spring blooms like daffodils to summer plants like ivy.
In recent times, from 1985 to 2009, flowers came up on the 20th May, earlier than during any other period.
In the coldest 25-year period, from 1835 to 1859, plants bloomed almost two weeks later around 3rd June. In even the warmest period compared to today, from 1910 to 1934, plants came up two days later on 22nd May.
The figures, analysed by scientists from around the world including Cambridge University, found that on average plants flower five days earlier for every 1 degree C (1.8 degree F) rise in temperature.
The result, published in the Proceedings of the Royal Society B, is the first time that scientists have managed to calculate how many days earlier the average plant will flower as the temperature increases.
The study of how plants react to the climate, known as "phenology", is important because of the knock-on effect for other species. For example pollinators such as bees and butterflies may struggle if flowers bloom early and are over quickly, threatening animals further up the food chain and even humans.
Researchers hope the results will help to work out a "global index" showing how many days earlier plants will flower around the world as the temperature warms, so it is possible to protect certain species.
Richard Smithers, Woodland Trust Senior Conservation Adviser and one of the authors of the paper, said the study showed how climate change is already affecting Britain.
"It is hard to make climate change real for people - they see a winter like this and do not believe it. This makes it very real for people. The natural world is our canary in the cage. It does show what is happening and the fact that plants flower five days earlier for every 1C of temperature rise and the fact that the last 25 years was earlier than any other period since 1753 should tell people a great deal," he said.
By Louise Gray, Environment CorrespondentPublished: 4:07PM BST 07 Apr 2010
In an example of "citizen science", researchers looked at more than 400,000 records collected by Victorian vicars, dog walkers and the viewers of the BBC series Springwatch.
The records, that go back to 1753, were divided into 25 year periods in order to compare the average flowering time as the weather changed from year to year. More than 400 species were recorded, from spring blooms like daffodils to summer plants like ivy.
In recent times, from 1985 to 2009, flowers came up on the 20th May, earlier than during any other period.
In the coldest 25-year period, from 1835 to 1859, plants bloomed almost two weeks later around 3rd June. In even the warmest period compared to today, from 1910 to 1934, plants came up two days later on 22nd May.
The figures, analysed by scientists from around the world including Cambridge University, found that on average plants flower five days earlier for every 1 degree C (1.8 degree F) rise in temperature.
The result, published in the Proceedings of the Royal Society B, is the first time that scientists have managed to calculate how many days earlier the average plant will flower as the temperature increases.
The study of how plants react to the climate, known as "phenology", is important because of the knock-on effect for other species. For example pollinators such as bees and butterflies may struggle if flowers bloom early and are over quickly, threatening animals further up the food chain and even humans.
Researchers hope the results will help to work out a "global index" showing how many days earlier plants will flower around the world as the temperature warms, so it is possible to protect certain species.
Richard Smithers, Woodland Trust Senior Conservation Adviser and one of the authors of the paper, said the study showed how climate change is already affecting Britain.
"It is hard to make climate change real for people - they see a winter like this and do not believe it. This makes it very real for people. The natural world is our canary in the cage. It does show what is happening and the fact that plants flower five days earlier for every 1C of temperature rise and the fact that the last 25 years was earlier than any other period since 1753 should tell people a great deal," he said.
Arctic winter ice recovers slightly despite record year low, scientists say
Figures from the National Snow and Ice Data Centre indicate six or seven- year low over past three decades
Juliette Jowit
guardian.co.uk, Wednesday 7 April 2010 10.05 BST
The melting Arctic ice cap recovered slightly over the last winter, but scientists warned that it was still one of the worst years on record.
The twice yearly figures published by the National Snow and Ice Data Centre of the winter high and summer low for the Arctic sea ice is seen as a powerful indicator of global warming.
Last night the US organisation released the data for the winter of 2009-10 showing the maximum extent reached on 31 March was 5.89m square miles (15.25m sq km). This was 250,000 square miles (650,000 sq km) below the 1979 to 2000 average for March when measurements are taken for winter sea ice. The rate of decline for March over the 1978 to 2010 period is 2.6% per decade, according to NSIDC data. Arctic sea ice reflects sunlight, keeping the polar regions cool and moderating global climate.
NSIDC said there had been some recovery in the amount of ice that was two years old or more, from last year's previous record low.
However, the spread of the ice, though higher than in some recent very bad years, was still low compared to past decades. "I think it's the sixth or seventh lowest maximum out of the previous 32 years," said Walt Meier, a research scientist at NSIDC.
Looking ahead to the other key annual figure - the lowest extent of sea ice at the end of the summer melting season - Meier said this year was also expected to be historically low, depending on temperatures and winds which blow the ice around, and sometimes out of the Arctic Sea into the warmer Atlantic and Pacific currents.
"I would say [it's going to be] low, perhaps one of the lowest, but not approaching 2007," said Meier, referring to the record lows that year when the Arctic lost an area of ice the size of Alaska in one year. "Given the amount of thin ice we know we're going to be low, it's just a matter of how low."
Last month, Japanese scientists reported in the journal Geophysical Research Letters that winds rather than climate change had been responsible for around one-third of the steep downward trend in sea ice extent in the region since 1979. The study did not question global warming is also melting ice in the Arctic, but it could raise doubts about high-profile claims that the region has passed a climate "tipping point" that could see ice loss sharply accelerate in coming years.
Last week the Catlin Arctic Survey leader Ann Daniels wrote for the Guardian about the ice seen by the team of three explorers trekking across the Arctic in "incredibly strong north winds" to measure ocean acidification linked to greenhouse gases. "We've also been seeing vast areas of open water and very thin ice — it's the first time any of us have experienced anything quite like this on such a large scale," wrote Daniels. "The way the ice is behaving is simply the strangest we have ever seen."
Juliette Jowit
guardian.co.uk, Wednesday 7 April 2010 10.05 BST
The melting Arctic ice cap recovered slightly over the last winter, but scientists warned that it was still one of the worst years on record.
The twice yearly figures published by the National Snow and Ice Data Centre of the winter high and summer low for the Arctic sea ice is seen as a powerful indicator of global warming.
Last night the US organisation released the data for the winter of 2009-10 showing the maximum extent reached on 31 March was 5.89m square miles (15.25m sq km). This was 250,000 square miles (650,000 sq km) below the 1979 to 2000 average for March when measurements are taken for winter sea ice. The rate of decline for March over the 1978 to 2010 period is 2.6% per decade, according to NSIDC data. Arctic sea ice reflects sunlight, keeping the polar regions cool and moderating global climate.
NSIDC said there had been some recovery in the amount of ice that was two years old or more, from last year's previous record low.
However, the spread of the ice, though higher than in some recent very bad years, was still low compared to past decades. "I think it's the sixth or seventh lowest maximum out of the previous 32 years," said Walt Meier, a research scientist at NSIDC.
Looking ahead to the other key annual figure - the lowest extent of sea ice at the end of the summer melting season - Meier said this year was also expected to be historically low, depending on temperatures and winds which blow the ice around, and sometimes out of the Arctic Sea into the warmer Atlantic and Pacific currents.
"I would say [it's going to be] low, perhaps one of the lowest, but not approaching 2007," said Meier, referring to the record lows that year when the Arctic lost an area of ice the size of Alaska in one year. "Given the amount of thin ice we know we're going to be low, it's just a matter of how low."
Last month, Japanese scientists reported in the journal Geophysical Research Letters that winds rather than climate change had been responsible for around one-third of the steep downward trend in sea ice extent in the region since 1979. The study did not question global warming is also melting ice in the Arctic, but it could raise doubts about high-profile claims that the region has passed a climate "tipping point" that could see ice loss sharply accelerate in coming years.
Last week the Catlin Arctic Survey leader Ann Daniels wrote for the Guardian about the ice seen by the team of three explorers trekking across the Arctic in "incredibly strong north winds" to measure ocean acidification linked to greenhouse gases. "We've also been seeing vast areas of open water and very thin ice — it's the first time any of us have experienced anything quite like this on such a large scale," wrote Daniels. "The way the ice is behaving is simply the strangest we have ever seen."
Drought turns southern China into arid plain
The government has embarked on a massive rain-making operation, firing thousands of cloud-seeding rockets into the sky
It is hard to imagine a less fitting environment for a mollusc than the arid plain of Damoguzhen in south-west China.
There is not a drop of water in sight. The baked and fissured earth resembles an ancient desert. Yet shellfish are scattered here in their thousands; all so recently perished that shriveled, blackened bodies are still visible inside cracked, opened shells.
Far out of water, the aquatic animals are not the advance guard of evolutionary progress; but the victims of a drought that has devastated their habitat and now threatens the livelihoods of millions of people in surrounding regions. The Chinese government is so worried about the drought that it has embarked on a massive rain-making operation, involving firing thousands of shells and rockets into the sky to seed clouds.
Until last summer, Damoguzhen was home to a lake that stretched across a mile-wide expanse of water in Yunnan, a southern Chinese province famed for its mighty rivers, moist climate and beautiful views.
Today, it joins 310 reservoirs, 580 rivers and 3,600 pools that have been baked dry by a once-in-a-century drought that is evaporating drinking supplies, devastating crops and stirring up political tensions over dam construction, monoculture plantations and cross-border water management in south-east Asia. Linking specific weather events to human-caused climate change is impossible, but the drought is consistent with what climate scientists expect to see more of in future.
Hardest hit are local farmers such as Ying Yuexian, who has seen her tobacco and rice crop shrivel up over a six-month period that has seen record high temperatures and half the usual amount of rain.
"In February, the water dried up completely," said the 34-year-old, surveying the parched expanse where she once fished. "It turned into this overnight." Instead of drawing water from the lake, she now scrapes soil from its cracked bed in the hope that the nutrients can replenish the earth on her sun-blasted farmland.
Her husband, Zhu Chongqing, estimates that the family's annual income will halve this year and the situation could get worse because the wet season is not due for another month. "We are waiting for the rain. We dare not plant rice or tobacco before that, but the drought continues" he said. "I've never experienced anything like this."
It is a similar story across the region. Older villagers say reservoirs and irrigation channels are dry for the first time in their lives. Mountain communities have to walk hours each day to secure drinking supplies. Rationing has been introduced in many areas, affecting more than 20 million people, 15m animals and 2m hectares of farmland.
With its mighty rivers and steep gorges, south-west China is the world's biggest hydro-electric powerhouse, but reservoir levels have fallen so low this year that 60% of dams report a decline in electricity output. This forces industrial estates and cities to burn more coal and emit more carbon to make up the shortfall.
Commodity values are also rising. In the giant rubber plantations of Xishuangbanna, farmers report a sharp fall in production that has pushed up prices by 40%.
"Less water means less rubber," said Zhang Xiaoping a rubber farmer. "In a good year, I can collect 80kg a day from these 300 trees, but I am down to half that now."
According to local media, sugar prices are up 10% because of the impact on cane fields. Rice and broad beans are also more expensive.
Wildlife is threatened because Yunnan - one of the most biodiverse regions on earth - is a last refuge for many species that are extinct elsewhere. Conservationists say birds have migrated, elephants moved to new territory and many big mammals are ranging further to secure water. Reptiles and plants are most vulnerable.
"We are hearing stories from nature reserves that amphibians are dying," said Wu Yusong of the Worldwide Fund for Nature's Yunnan office. "We are still in the process of monitoring the situation but we know that half the agricultural crops in this region cannot be harvested this year so we can imagine that other plants will be also be similarly affected."
The government says it has earmarked more than 7 billion yuan (£700m) for relief projects, mobilised 7,600 water trucks and dug 180,000 wells to alleviate the impact.
It has also launched a massive weather modification operation. In a single week, the authorities fired over 10,000 silver nitrate shells and over 1,000 rockets into the clouds to induce rain, according to Zheng Guoguang, head of the China Meteorological Administration.
Short bursts of rain have mitigated the problem in some areas, but the overall picture remains grim and the causes contentious.
On stretches of the Mekong river, water levels are at 50-year lows, spurring criticism from downstream nations that China's hydropower expansion has siphoned off supplies that should be preserved for drinking water and fishing.
At the first summit this week of the Mekong River Commission, which comprises Thailand, Cambodia, Laos and Vietnam, the Chinese vice minister, Song Tao, insisted climate change rather than his country was to blame.
"Statistics show that the recent drought that hit the whole river basin is attributable to the extreme dry weather, and the water level decline of the Mekong River has nothing to do with hydropower development," he said.
But environment activists inside China say dams and other forms of accelerated development are taking an excessive ecological toll. "Dams and plantations are not to blame for the extreme weather, but they worsen the impact of the drought and the competition for water resources," said Yang Yong, an explorer and geologist. "The government now realises the problems and should reconsider its plans for water resource management."
"In recent years, the focus of dam construction has been on power generation, but we have neglected the needs of flood prevention and irrigation," said Wang Yongchen of Green Earth Volunteers.
The drought has also raised fresh doubts about the wisdom of China's biggest hydro-engineering project, the South-North water diversion scheme, which is designed to channel billions of tonnes to arid northern cities such as Beijing and Tianjin.
This made sense while the south enjoyed more abundant water resources, but climatologists are now warning that north and south China could suffer simultaneous droughts.
The National Climate Centre estimates 10 downpours will be needed to alleviate the water shortage in the south. This is not forecast for at least another month.
With the prospect of prolonged dry spells in the future, Liu Ning, vice-minister of water resources, told local media it may be necessary to move people from the most vulnerable areas.
"They can go to cities, or places with more water. If droughts continue for several more years, we think we can use the nation's power to relocate them to other provinces."
• Additional reporting by Chen Shi and Cui Zheng
It is hard to imagine a less fitting environment for a mollusc than the arid plain of Damoguzhen in south-west China.
There is not a drop of water in sight. The baked and fissured earth resembles an ancient desert. Yet shellfish are scattered here in their thousands; all so recently perished that shriveled, blackened bodies are still visible inside cracked, opened shells.
Far out of water, the aquatic animals are not the advance guard of evolutionary progress; but the victims of a drought that has devastated their habitat and now threatens the livelihoods of millions of people in surrounding regions. The Chinese government is so worried about the drought that it has embarked on a massive rain-making operation, involving firing thousands of shells and rockets into the sky to seed clouds.
Until last summer, Damoguzhen was home to a lake that stretched across a mile-wide expanse of water in Yunnan, a southern Chinese province famed for its mighty rivers, moist climate and beautiful views.
Today, it joins 310 reservoirs, 580 rivers and 3,600 pools that have been baked dry by a once-in-a-century drought that is evaporating drinking supplies, devastating crops and stirring up political tensions over dam construction, monoculture plantations and cross-border water management in south-east Asia. Linking specific weather events to human-caused climate change is impossible, but the drought is consistent with what climate scientists expect to see more of in future.
Hardest hit are local farmers such as Ying Yuexian, who has seen her tobacco and rice crop shrivel up over a six-month period that has seen record high temperatures and half the usual amount of rain.
"In February, the water dried up completely," said the 34-year-old, surveying the parched expanse where she once fished. "It turned into this overnight." Instead of drawing water from the lake, she now scrapes soil from its cracked bed in the hope that the nutrients can replenish the earth on her sun-blasted farmland.
Her husband, Zhu Chongqing, estimates that the family's annual income will halve this year and the situation could get worse because the wet season is not due for another month. "We are waiting for the rain. We dare not plant rice or tobacco before that, but the drought continues" he said. "I've never experienced anything like this."
It is a similar story across the region. Older villagers say reservoirs and irrigation channels are dry for the first time in their lives. Mountain communities have to walk hours each day to secure drinking supplies. Rationing has been introduced in many areas, affecting more than 20 million people, 15m animals and 2m hectares of farmland.
With its mighty rivers and steep gorges, south-west China is the world's biggest hydro-electric powerhouse, but reservoir levels have fallen so low this year that 60% of dams report a decline in electricity output. This forces industrial estates and cities to burn more coal and emit more carbon to make up the shortfall.
Commodity values are also rising. In the giant rubber plantations of Xishuangbanna, farmers report a sharp fall in production that has pushed up prices by 40%.
"Less water means less rubber," said Zhang Xiaoping a rubber farmer. "In a good year, I can collect 80kg a day from these 300 trees, but I am down to half that now."
According to local media, sugar prices are up 10% because of the impact on cane fields. Rice and broad beans are also more expensive.
Wildlife is threatened because Yunnan - one of the most biodiverse regions on earth - is a last refuge for many species that are extinct elsewhere. Conservationists say birds have migrated, elephants moved to new territory and many big mammals are ranging further to secure water. Reptiles and plants are most vulnerable.
"We are hearing stories from nature reserves that amphibians are dying," said Wu Yusong of the Worldwide Fund for Nature's Yunnan office. "We are still in the process of monitoring the situation but we know that half the agricultural crops in this region cannot be harvested this year so we can imagine that other plants will be also be similarly affected."
The government says it has earmarked more than 7 billion yuan (£700m) for relief projects, mobilised 7,600 water trucks and dug 180,000 wells to alleviate the impact.
It has also launched a massive weather modification operation. In a single week, the authorities fired over 10,000 silver nitrate shells and over 1,000 rockets into the clouds to induce rain, according to Zheng Guoguang, head of the China Meteorological Administration.
Short bursts of rain have mitigated the problem in some areas, but the overall picture remains grim and the causes contentious.
On stretches of the Mekong river, water levels are at 50-year lows, spurring criticism from downstream nations that China's hydropower expansion has siphoned off supplies that should be preserved for drinking water and fishing.
At the first summit this week of the Mekong River Commission, which comprises Thailand, Cambodia, Laos and Vietnam, the Chinese vice minister, Song Tao, insisted climate change rather than his country was to blame.
"Statistics show that the recent drought that hit the whole river basin is attributable to the extreme dry weather, and the water level decline of the Mekong River has nothing to do with hydropower development," he said.
But environment activists inside China say dams and other forms of accelerated development are taking an excessive ecological toll. "Dams and plantations are not to blame for the extreme weather, but they worsen the impact of the drought and the competition for water resources," said Yang Yong, an explorer and geologist. "The government now realises the problems and should reconsider its plans for water resource management."
"In recent years, the focus of dam construction has been on power generation, but we have neglected the needs of flood prevention and irrigation," said Wang Yongchen of Green Earth Volunteers.
The drought has also raised fresh doubts about the wisdom of China's biggest hydro-engineering project, the South-North water diversion scheme, which is designed to channel billions of tonnes to arid northern cities such as Beijing and Tianjin.
This made sense while the south enjoyed more abundant water resources, but climatologists are now warning that north and south China could suffer simultaneous droughts.
The National Climate Centre estimates 10 downpours will be needed to alleviate the water shortage in the south. This is not forecast for at least another month.
With the prospect of prolonged dry spells in the future, Liu Ning, vice-minister of water resources, told local media it may be necessary to move people from the most vulnerable areas.
"They can go to cities, or places with more water. If droughts continue for several more years, we think we can use the nation's power to relocate them to other provinces."
• Additional reporting by Chen Shi and Cui Zheng
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