The four varieties, Kizimbani, Mahonda, Kama, and Machui, have given cassava a new lease on life after the crop was devastated by the two main diseases afflicting the region: brown streak disease and mosaic disease. The diseases, which are spread by white flies, cost Africa's cassava sector more than US$1 billion in damages every year. Small-scale farmers - among the poorest in the region - bear most of the economic effects.

Cassava mosaic disease first appeared in Uganda in the mid-1980s and spread rapidly in cassava-growing areas of eastern and central Africa through the sharing of infected planting materials and via the white fly vector. Following the development and deployment of resistant and tolerant varieties and widespread awareness-raising on ways to curb the mosaic's spread, scientists, governments, non-governmental organizations, and farmers were able to bring the disease nearly under control. Then the cassava brown streak struck. This disease had been around for much longer but was confined to the coastal low-altitude areas of Eastern Africa and around Lake Malawi. From 2004, it started spreading rapidly to mid-altitude areas that were recovering from the mosaic, sending scientists back to the drawing board.

Haji Saleh, the head of Zanzibar's roots and tuber program under the Ministry of Agriculture, Livestock and Environment, says the first survey of cassava brown streak on the island was conducted in 1994 and indicated that 20 percent of the crop had disease symptoms. In a follow-up survey in 2002, the disease was found everywhere. "All the local varieties grown by the farmers were susceptible. The farmer and authorities were crying out for help," Saleh said.

Heeding the call for help, Zanzibar crop scientists in collaboration with the International Institute of Tropical Agriculture (IITA) started a breeding program to develop cassava varieties that were resistant to the two diseases. Their efforts paid off, and after only four years, four new varieties were released in 2007.

"You have to understand, cassava is a very important staple in Zanzibar, where it comes in second after rice," Saleh said. "However, it is first in terms of acreage and production with over 90 percent of farmers growing the crop. It is our food security crop as it grows in most of the agro-ecological zones including in the dry parts of the island where other crops do not perform well. So when the diseases hit, they were very devastating to the island's food security. We had to act fast."

The research team then started a rapid multiplication program, working with the farmers to spread the improved varieties on the island and beyond. "We selected pilot farmers in each district to help with the multiplication," Saleh said. "We trained them on how to grow cassava to get good yields and maintain soil fertility, and on business skills, as they were to sell the planting material as a business."

One farmer, 59-year-old Ramadhani Abdala Ame of Kianga village - a father of 10 - participated in the on-farm trials using the improved varieties. During the trials, the farmers helped the researchers select not only the best performing varieties, but also those that met farmer preferences and requirements for various uses of the crops. Ramadhani said he had given up on cassava, which was suffering from "kensa ya mhogo," or "cancer of the cassava." Infected by the brown streak disease, the crop develops a dry rot in its roots - the most economically important part of the plant - which makes it useless for consumption.

"The cassava looked good in the field, but when you harvested, the roots were rotten and useless, with all your labor and efforts going down the drain," Ramadhani said. He explained that he was given 40 cuttings of the four new varieties to test on his farm. "At that time, they did not have names, only numbers. I was amazed at their performance: the  tubers were huge, and had no disease. I selected the two I liked best that were later renamed Kizimbani and Machui."

Ramadhani said the sale of cassava roots and planting materials has made a big difference in his life. He has bought two cows to add to his stock, constructed a cowshed, and is now building a better brick and iron-sheet house for his family.

Another pilot farmer, Suleiman John Ndebe of Machui village, had also given up on cassava after 10 years of bad harvests due to the "cancer" and other pests and diseases such as mealy bug and cassava green mite. But the varieties given to him at Kizimbazi research station for testing excited him and motivated him to resume growing the crop. It's a decision he says he has not regretted.

Suleiman says his involvement in the project has turned his life around. Farming for him is now a serious business. He estimates that he makes profits of between 50 and 100 percent from his cassava, depending on the season, and his income increased more than four times. "Before the training, I did not know agriculture was a business. I did not know whether I made a profit or a loss. Now, I know how much cassava I have planted, the cost of labor and manure, how much I expect to harvest, and how much profit I will make," he said. "I am now able to save some money in the bank and my life is less stressful. I even bought a color TV to be able to follow the World Cup!"

Yet there is still a big gap to fill before all the farmers on Zanzibar can enjoy the new cassava varieties. According to Salma Omar Mohamed, a research officer with Kizimbani Research station, only some 10,000 farmers are currently growing these new varieties, out of a potential of more than 1 million. She says the business model of distributing the planting materials has excluded poor farmers who are not able to afford the materials. However, she was thankful for the strides made with funding from donors such as Alliance for a Green Revolution in Africa (AGRA), which supported the free distribution of planting materials to poor farmers under a voucher program.

Mohamed hopes they can get more such support to spread the improved varieties to all the farmers on Zanzibar and on neighboring Pemba Island, where the disease is also prevalent and penetration of the new varieties is even lower.

IITA cassava breeders report that hope is also on the way for farmers in Kenya, mainland Tanzania, and Uganda, as 15 promising cassava varieties that are suitable for the climatic conditions of these areas are in the last testing stages.

Catherine Njuguna is a communication officer with the International Institute of Tropical Agriculture (IITA) based in Dar es Salaam, Tanzania.

Visit Worldwatch's Nourishing the Planet blog to learn more about food security developments through innovations such as crop breeding.

A version of this article originally appeared on the Worldwatch Institute blog Nourishing the Planet. For permission to republish this article, please contact Juli Diamond at jdiamond@worldwatch.org.   

The following op-ed appeared in The Seattle Times.

For most Seattle residents, global hunger seems like an impossible problem to solve. Reports of famine in Niger or the thousands at risk for starvation and malnutrition in the Democratic Republic of the Congo, seem not only far away but impossible to change. A local organization, however, begs to differ.

The Seattle-based Bridges to Understanding uses digital technology to empower and connect children around the world. Students participating in the Bridges curriculum are taught to use cameras and editing software to develop stories about their community and culture. These videos, comprised of a photo slide show with a running narration, are then shared with the Bridges online community, which is made up of schools in seven countries around the world.

For many students, it's the first time they have ever even held a camera.

"At first, the prospect of designing, shooting and editing a movie seems insurmountable but then they produce these beautiful films," says Elizabeth Sewell, Bridges Program Manager at the Rural Development Foundation's (RDF) primary school in Kalleda, a small village in the Warangal district of Andhra Pradesh, India. "And then you knock down that barrier, you show them what they are capable of doing. And then they can start to approach other, larger and more institutional, problems the same way. Suddenly, in their own eyes, there are no limits to what they can achieve."

Since the 1980s, international investment in agriculture has decreased significantly. These cuts have impacted women and children the most. But in addition to making sure we reverse these trends, we need to ensure that funding is used effectively - reaching the farmers who need it most.

Who better to consult - and to equip with the tools to help out - in the global effort to combat hunger than the youth, women and farmers who will most benefit from it?

In South Africa, the organization Food and Natural Resource Policy Analysis Network is using theater to engage leaders, service providers and policymakers; encourage community participation; and research the needs of women farmers through a project called Theatre for Policy Advocacy. Popular theater personalities travel to communities in Mozambique and Malawi and stage performances using scripts based on the network's research, to engage members of the community.

After each performance, community members, women, men, youth, local leaders are engaged in facilitated dialogues. The dialogues give all community members - especially women - a chance to openly talk about the challenges they are facing without upsetting the status quo, empowering them to speak about what they need from aid groups and their community.

In Bangladesh, Burkina Faso, Mali, and other countries around the world, the Africa Rice Centre is using farmer-made instructional videos to help rice farmers share various new methods of improving rice production with each other. The strong presence of women in the videos also helps local NGOs and extension offices - which tend to be made up mostly of male agents - engage women's groups.

Projects like Bridges, Theatre for Policy Advocacy and Farmer to Farmer Training Videos - that provide a forum for those who might not otherwise have a voice - allow for the spread of important information, empowering the very people who will most benefit from, and can play the largest role in, the alleviation of global hunger and poverty.

They are ready. All they need are the tools.

Danielle Nierenberg is co-project director of the Worldwatch Institute's Nourishing the Planet Project. Molly Theobald is a research fellow at the Worldwatch Institute.

Visit Worldwatch's Nourishing the Planet blog to learn more about agricultural development in sub-Saharan Africa.

That is the story told by a new report that the Worldwatch Institute helped research and write: the Renewables Global Status Report 2010. Produced by the REN21 network of governments, NGOs, and industry associations, the report paints a remarkable picture of a booming new economic sector that has powered its way through a deep global recession, emerging stronger than ever. 

Buoyed by hundreds of new government energy policies, accelerating private investment, and myriad technology advances over the past five years, renewable energy is breaking into the mainstream of energy markets. Over the past two years, the United States and Europe have both added more power capacity from renewables than from coal, gas, and nuclear combined, according to the report. Worldwide, renewables accounted for one-third of the new generating capacity added.

Renewable energy, including hydropower, now provides 18 percent of total net electricity generation worldwide. Meanwhile, biofuels such as ethanol and biodiesel are making inroads in the transportation fuels market and are now equal to about 5 percent of world gasoline production. And in China, more than 150 million people heat at least some of their water using solar hot water systems.

The economic weight of the renewable energy sector is now large enough to attract many of the world's largest and most powerful companies, from GE and Siemens to unlikely players such as Samsung and Google. Renewable energy investment of $150 billion worldwide in 2009 was the equivalent of nearly 40 percent of annual investment in the upstream oil and gas industry, which topped $380 billion.

Changes in government policy are responsible for most of these advances. In 2009 alone, 10 national and state governments enacted policies giving renewable power generation access to the grid at prices set by policymakers, bringing the number of governments with such policies to 70. Altogether, the number of countries with policies to encourage renewable energy has increased from 55 in 2005 to 100 in 2010. 

One of the forces motivating new renewable energy policies is the desire to create new industries and jobs. Employment in the renewables sector now numbers in the hundreds of thousands in several countries. In Germany, which has led renewable energy development for more than a decade, more than 300,000 people were employed in renewables industries in 2009. This figure almost equals the number of jobs in the country's largest manufacturing sector: automobiles.

The changing geography of renewable energy is another indicator that we are entering a new era, with the growing geographic diversity boosting confidence that renewables are no longer vulnerable to political shifts in just a few countries. It is also clear that leadership is shifting decisively from Europe to Asia, with China, India, and South Korea among the countries that have stepped up their commitments to renewable energy.

This transition reflects a growing recognition within Asia itself that these oil-short countries have much to gain from the development of renewable energy in economic, environmental, and security terms. For the world as a whole, this is a momentous development, since Asian nations now lead the growth in carbon emissions. Given East Asia's dominance of low-cost global manufacturing, the region's commitment to renewable energy will almost certainly drive down the price of many renewable energy devices in the coming years.

Renewable energy is also beginning to make a dent in emissions of carbon dioxide and other greenhouse gases. In Germany, renewables displaced 109 million tons of greenhouse gases in 2009 - equivalent to 12 percent of the country's total - helping to reduce domestic emissions 29 percent from the 1990 level.

At a time when the world's energy headlines are dominated by an oil-stained Gulf of Mexico and failure of the U.S. Senate to act on climate change, renewable energy is a rare good news story. The momentum that renewables have gained in a relatively short time indicates that with modest policy changes, a very different energy system could begin to emerge over the next decade.

Our congratulations to Worldwatch Senior Fellows Janet Sawin and Eric Martinot, who co-directed the Renewables Global Status Report 2010. They and their many contributors from around the globe have provided a surprisingly clear picture of an energy economy in motion. The optimistic picture they paint offers inspiration to those who despair of the energy headlines in recent months.

Christopher Flavin is President of the Worldwatch Institute, an environmental research organization based in Washington, D.C.

For permission to republish this article, please contact Juli Diamond at jdiamond@worldwatch.org.

What is food sovereignty, and what policies and programs will help encourage it?

Food sovereignty is about communities', states', and unions' rights to shape their own food and agricultural policy. Now that may sound like a whole lot of nothing, because you're actually not making a policy demand, you're just saying that people need to be able to make their own decisions. But, actually, that's a huge thing. Because in general, particularly for smaller farmers in developing countries, and particularly for women, decisions about food and agricultural policy have never been made by them. They've always been imposed.

That's why La Via Campesina, the organization that really invented the term, says that one of the visions behind food sovereignty is that food sovereignty is about an end to all forms of violence against women. That may sound like something not at all to do with food, but of course, if we're serious about people being able to make choices about how their food comes to them and what the food system looks like, then the physical and structural violence to which women are exposed in the home, in the economy, and in society all need to be tackled. Otherwise we will continue with a situation in which 60 percent of the people going hungry today are women or girls. So food sovereignty, to boil it down, is really about power - who has it in the food system and how to redistribute it so that those who have concentrated it have it taken away from them.

In terms of specific policies, what Via Campesina is calling for is for agriculture to be removed from the World Trade Organization, which is a way again in which local countries' sovereignty is already been given away. They also call for large corporations to be booted out of agriculture. There's strong opposition to Monsanto, for example, and the way that they've been behaving in many developing countries, and many Via Campesina members are campaigning against Monsanto in their home countries.

Will another Green Revolution or more food subsidies help reduce hunger?

To answer the question, let's look at Malawi. It's the poster child for what a new Green Revolution in Africa might look like, with widespread subsidies of inorganic fertilizer for farmers. When I went there, late last year, what you found was long lines at the gasoline pump, because all Malawi's foreign exchange had been spent on importing this fossil fuel-based fertilizer. The country had bankrupted itself in order that it might be a showcase for the new Green Revolution in Africa. And of course, there are alternatives right there in Malawi, driven by farmers, invariably by women who are innovating around sustainable systems like polyculture - growing lots of crops simultaneously together, building soil fertility for the long run.

What this shows is that there are some basic incompatibilities between varieties of ways of addressing agrarian problems in Africa. Some organizations, Worldwatch included, adopt a "big tent" approach, in which solutions that keep the status quo but improve it marginally sit alongside far more radical approaches. Ultimately, you can't promote genetically modified monoculture or techniques that make large-scale commercial farming less destructive at the same time as wanting something like food sovereignty, which calls for much more of a deeper structural rethink of the way the food system operates. Food sovereignty is about democracy in our food system so that everyone gets to eat; industrial agriculture involves a food system run by technocrats for profit. At the end of the day, you can have one or the other - not both.

[Editor's Note: Worldwatch has a long history of writing about sustainable agriculture systems that encourage crop diversity and support the livelihoods of small-scale farmers. Those reports have documented evidence that genetically modified crops are not necessarily the best, most appropriate, or only available solution to agricultural challenges. Visit the Nourishing the Planet blog for a more detailed response from our team of agriculture researchers.]

How does global agricultural policy affect small-scale farmers across the world?

In general, the policies foisted on developing countries through organizations like the World Bank is that large-scale agriculture is the way to go: that small farmers are a relic of the past. They are of purely cultural significance but economically, socially, and agriculturally, they stand in the way of development. So the policies that are essentially designed to increase farm size and kick off rural populations to the cities are ones that you see in pretty much every country around the world. And yet of course, it is the poor in rural communities that are being forced to bear the brunt of these policies, and these are the communities that are least able to afford it. And again-you can never say it too often - it is on women's shoulders that the bulk of the pain of moving from agrarian society to a so-called modern industrial society, falls.

Why should American food consumers care about the fate of agricultural producers halfway across the world?

Not out of any sense of pity or charity, but because the struggles that farmers in developing countries face are very similar to the struggles that farmers in the United States face. Industrial agriculture wreaks havoc. We've seen the deaths from E. coli, we've seen industrial agriculture and the rise of BSE [mad cow disease], we've seen the massive dead-zone in the Gulf of Mexico because of the runoff from animal feeding operations flowing down the Mississippi. If you're in America and you're concerned about the quality or safety of your food, or about the consequences of the way your food is produced, then you're not alone. Those are all things that farmers elsewhere in the world are worried about, and that consumers elsewhere in the world are worried about too.

There's a proven way in which those concerns can be addressed. It is to wrench power away from the corporations that profit from low standards, from the ability to create offshore pollution, and the ability to evade the costs of defective products. So I think in the U.S., if you're at all concerned about food safety, health, obesity-any of these things-then you would want to have more control over your food system. And wanting more control over your food system is exactly what food sovereignty is about. In a globalized world, you can't have control over your food system in this country while people elsewhere don't, and this is what makes it a common struggle.

Funding for agricultural research has declined in recent decades. Where should funding for agricultural innovation and research come from?

Funding for agriculture ought to come from the places where research used to come from: the government. I don't have any stars in my eyes when I think about governments in developing countries having a ton of cash in their coffers for research into this. But governments that are net food-importing developing countries found themselves after the last food crisis in very dark times. They're keen to develop new ways of doing things.

A lot of these countries haven't had the money to be able to invest in agricultural extension and research, and so what we need are two things: one is a cancellation of the illegitimate debt that these countries have racked up with organizations like the World Bank. There's a huge debt that rich countries owe poor ones-for colonialism, for the ecological damage we have caused and continue to cause by the way we consume. Yet through the World Bank, the debt has been flipped over, and has become an agent for controlling these economies.

So we definitely need a change in the way international development and finance work. But we also need to support change within developing countries so that agricultural extension becomes something that once again is funded and is geared toward the kinds of research that is about low-carbon, that is about democratic control over resources, rather than about pushing a particular kind of product and particular kind of vision of agriculture that is ultimately unsustainable for the majority of countries in Africa.

Ronit Ridberg is a research intern with the Worldwatch Institute. Visit Worldwatch's Nourishing the Planet blog to learn more about food sovereignty and fair trade.

This article appeared in its original form on the Worldwatch blog Nourishing the Planet. For permission to republish this article, please contact Juli Diamond at jdiamond@worldwatch.org. 

On July 9, the French government released a draft plan for transportation infrastructure investments (called "avant-projet au schéma national des infrastructures de transports") over the next two decades. If the priorities hold, it will represent nothing less than an "adieu" to decades of car-centered development.

Of ?170 billion ($220 billion) in planned spending, ?85 billion-50 percent-will be allocated to high-speed rail, and ?53 billion-31 percent-to urban trams, subways, and bus lines. That's a whopping 81 percent of transportation spending for public transport! Roads and airports, by contrast, will receive only a combined 5 percent, with the remainder going to ports and waterways.

By 2020, a total of 2,300 kilometers of new high-speed rail (HSR) lines are to be built, with another 1,500 kilometers planned by 2030. (See map.) Urban mass-transit lines are to be expanded fivefold to a total of 1,800 kilometers. It is expected that the overall plan will reduce the annual carbon dioxide emissions of France's transportation sector, currently at 30 million tons, by 2 million tons.

But, as the newspaper Les Echos comments, the plan does not specify how the French government will finance the plan-through taxes, user fees, borrowing, or other measures, including the mobilization of private investments-which raises some questions about the overall viability of the plan.

Financing could also prove somewhat of an Achilles heel of ambitious Spanish plans. Spain currently has the largest high-speed rail construction program in Europe and, at 1,614 kilometers, already has the second-longest HSR track in Europe after France. Plans call for a total of 10,000 kilometers built by 2020, meaning that Spain will add more than three times the additional capacity envisioned under the already ambitious French plan by the same date.

The 2004 Strategic Plan for Infrastructures and Transport (PEIT) calls for 44 percent of total transportation investment by 2020 to be directed toward rail, primarily for expansion of the high-speed network. Between 2005 and 2020, some $152 billion is to be invested in rail, with $115 billion going to high-speed routes.

By 2010, with the country deeply mired in the global recession, the Spanish government turned to infrastructure investments, especially in rail, as a way to stimulate the economy. Its two-year Extraordinary Infrastructure Plan, rolled out in April 2010, promised to invest some $22 billion in transportation, with 70 percent going to rail and 30 percent to highways. High-speed rail tracks will see about $8 billion in new investment in 2010 alone. This latter amount is about as much as the U.S. stimulus program (ARRA) makes available for high-speed rail. Per capita, however, it's almost 7 times as much.

Given high levels of public debt, initial investments in projects will be made by construction companies and financial institutions, rather than the government. The government will begin to pay companies for their work starting in 2014, after projects are completed. Government spending is to be financed by a new tax on users of the infrastructure.

While a warm bienvenue and bienvenido is being extended to rail in these two European countries, the United States still struggles to offer its own welcome mat. The existing U.S. intercity rail network is fragmented, plans for the future are far less sweeping, and funding remains uncertain.

Gary Gardner and Michael Renner are senior researchers with the Worldwatch Institute. They can be reached at mrenner@worldwatch.org .

Designer viruses, potent new weapons, hurtling asteroids... all have the potential to obliterate humanity. So how do scientists plan for such catastrophes?

Corridors are deserted. Office doors are locked. Laboratories are quieter than usual. It can mean only one thing: conference season is upon us and it's time for scientists to shut up shop and take to the road, if only for a few days.

For more than a thousand physicists, the destination last week was the Palais de Congrès in Paris, an enormous 1970s construction of jutting concrete and angled glass. Until Wednesday, the centre will host one of the most eagerly awaited meetings on the scientific calendar. The International Conference on High Energy Physics (ICHEP) has an impressive track record as the place where new discoveries are announced, but this time around there is an extra buzz in the air.

This is the first year that physicists at the Large Hadron Collider (LHC) at Cern, the European particle physics lab near Geneva, will join researchers from other laboratories in unveiling their latest results. Talks at the meeting will cover a vast range of topics, from the performance of the LHC and other accelerators to quirks of the laws of nature and the hunt for the Higgs boson, the elusive particle said to give mass to the building blocks of nature.

One topic that will definitely not be discussed, at least not seriously, is whether the LHC might just destroy the planet. Thanks to a few vocal doomsayers and a run of unsuccessful legal cases, the exotic idea has become lodged in the public consciousness. It has probably done more to raise Cern's profile than anything in the laboratory's recent history.

Wild claims about the risks of the LHC received blanket coverage from the world's media in the run-up to the machine being switched on last year. The nature of the catastrophe took on several guises. We heard that a black hole might appear beneath the Swiss countryside and steadily devour the Earth. Maybe planet-crunching entities called "strangelets" could pop into existence and reduce our hospitable rock to a sizzling ball no wider than Lord's cricket ground. Or the universe might "collapse" into a more stable state, wiping out life here and anywhere else it might lurk in the process (see below). Each of these scenarios, and more besides, were argued by a small number of concerned individuals to be clear and present dangers to humanity.

The Large Hadron Collider is not the first particle accelerator to be framed as a doomsday machine. Particle physicists have been accused of gambling with the future of humanity since at least the 1950s, when forerunners of the LHC were being built. Mention world-ending scenarios to staff on the LHC, or its main competitor, the Tevatron at Fermilab near Chicago, and you can expect a roll of the eyes at best. Physicists have gone to great pains to explain why such fears are unfounded. The time could have been better spent by getting on with research.

Scientists have good reason to be weary of fanciful speculation over the safety of their experiments, but some academics claim there are valuable lessons to be learned from the LHC experience, ones that could save us from more realistic catastrophes before the century is out. Nick Bostrom, director of the Future of Humanity Institute at Oxford University, says that advances in fields such as weapons technology, artificial intelligence and synthetic biology (which has already given researchers the tools to create viruses from scratch) could lead to what he calls "existential threats". These are catastrophes that play out on an unprecedented scale, ones that have the potential to bring an end to the human story, either by wiping us out completely, or by "permanently and drastically destroying our future potential".

The creation of a lethal synthetic virus that kills on a global scale is but one potential risk that Bostrom highlights. Breakthroughs in physics could lead to new weapons that increase the dangers of war, he says, while advances in computing could see the advent of machines that can improve their own intelligence, and surpass that of humans. Even attempts to manipulate the atmosphere to combat global warming might backfire and trigger a global disaster.

Bostrom says the LHC should be seen as a test case, used by society to learn how to deal with events and technologies that may genuinely threaten our existence in the future. "So far, we haven't done very well, but events surrounding the LHC could stimulate us into getting our act together for next time, when the threats need to be taken more seriously," he says. "I think the danger from particle accelerators is extremely small, but there will be other areas that will cause major existential risks and we need to learn how to deal with these situations in a rational way."

Existential threats are nothing new. Schoolchildren learn that an asteroid strike wiped out three quarters of Earth's species 65m years ago and promptly ended the reign of the dinosaurs. There have been at least four other mass extinctions, each one the result of an epic natural disaster. The point that intrigues researchers such as Bostrom is that society is bad at identifying dangers such as these, and even worse at preparing for them. In an essay published in the Journal of Evolution and Technology in 2002, Bostrom expressed dismay at how little research has been done on serious threats to humanity, writing: "There is more scholarly work on the life-habits of the dung fly than on existential risks." Little has changed since, he says.

A major sticking point, says Bostrom, is that humans are doomed only to learn from direct experience. Nuclear reactors were made safer after the Chernobyl disaster in 1986. The UN drew up plans for a tsunami warning system in the Indian Ocean a year after 230,000 people died from a devastating wave in 2004. Plans to bolster flood defences around New Orleans are still being thrashed out, five years after hurricane Katrina killed nearly 2,000 and left thousands more homeless. In each case, the risks were known, but they were only acted on after the event.

"Our attitude throughout human history has been to experience events like these and then put safeguards in place," says Bostrom. "That strategy is completely futile with existential risks. By definition, you don't get to learn from experience. You only have one chance to get it right."

One approach that has been used to clarify the nature and extent of a potentially dangerous situation involves setting up a panel of experts who understand the relevant science well enough to make an informed risk assessment. In 1999, the US physicist John Marburger III was director of Brookhaven National Laboratory on Long Island, New York. The lab is home to a particle accelerator called the Relativistic Heavy Ion Collider. That summer, a puff piece on the machine in Scientific American magazine led to two letters that raised concerns over whether the machine might create a black hole or cause other untoward damage to the planet. Marburger immediately convened a panel of leading physicists to work through every doomsday scenario they could think of and assess the risk of them happening. The panel concluded the machine was safe after drawing on the fact that more violent particle collisions caused by cosmic rays slamming into planets, stars and clouds of dust and gas have occurred in nature for billions of years. At Cern, a similar safety review of the LHC, the construction of which had only just begun, reached the same conclusion.

The safety reviews at Brookhaven and Cern were largely public relations exercises. Governments never considered pulling the plug on either machine, and courts dismissed legal challenges that sought injunctions on the colliders. But the reviews highlighted what some perceived to be a shortcoming of scientific panels. They could be seen as highly partial: particle physicists ruling on the safety of particle accelerators might well have a vested interest in the projects going ahead.

Soon after the fuss broke, Francesco Calogero, an Italian physicist and former secretary general of Pugwash, an organisation that pursues ways to reduce threats to global security, championed an alternative way of deciding how risky an experiment might be. In a paper entitled, "Might a laboratory experiment destroy planet Earth?", he backed for a more adversarial approach to risk analysis. Instead of one panel of experts, there should be two. The first, the blue team, makes the case for the experiment's safety, while the red team does its best to emphasise the dangers. The two then come together and decide whose arguments are the most robust.

"It is not perfect, but I think it is the best strategy," says Calogero. "It overcomes any perceived vested interest and gives people the chance to point out arguments that are not watertight and what might go wrong."

Others argue that decisions over the fate of humanity are too important to be left to panels of scientists. Richard Posner, a US appeals court judge and author of the 2004 book Catastrophe: Risk and Response, wants an Office of Risk and Catastrophe set up in the White House. The office would be charged with identifying potentially dangerous technologies and calling in experts to inform its own risk assessments. "The problem right now is that no single government department takes responsibility for these kinds of situations," he says.

An international network of such offices could go a long way to improving global security, Posner says, but the idea is controversial. "Done well, it could be extremely valuable, but there are many ways it might end up being politicised or compromised," says Bostrom.

According to Robert Crease, head of philosophy at the State University of New York and author of the 2006 book The Philosophy of Expertise, our best hope for surviving existential threats is to train scientists as best we can and trust them to police themselves.

"You don't want a committee of people who don't have expertise trying to review the expertise of people who do. That doesn't improve matters. As soon as you set up a committee, quarrels develop over who's a member, who's best and who has what hidden agenda. It's a disaster," he says.

"The optimal course of action, the best we can do, is to improve, in each discipline, the review panels and the institutions that guarantee expertise. It boils down to trust. We don't like to rely on it, but we do every day," he adds.

For physicists meeting in Paris this week, the focus will be on discoveries rather than doomsday scenarios, and for good reason. The fears raised over particle colliders such as the LHC belong firmly in the realm of science fiction. But there are important lessons to be learned from the LHC story that go beyond particle physics. We might be faced with truly catastrophic threats before the century is out, and to deal with them we need to change our way of thinking. Instead of waiting for disaster to strike before making life safer, we have to be one step ahead. Contrary to the doomsayers' fears, the LHC might help ensure the end is never nigh.

Ending it all: the threat to the entire universe

It has been called "the ultimate ecological catastrophe", but even these strong words fail to convey the true horror and finality of a grim kind of natural disaster known to physicists as "vacuum decay".

Forget pandemic viruses that wipe out humanity, asteroid strikes that devastate life on Earth and even black holes that devour the planet. Vacuum decay leaves the entire universe not only lifeless, but without any hope of life for ever more.

Vacuum decay, which is happily only a theoretical prospect, occurs when part of the universe is knocked into a more stable state than it exists in today. This creates a bubble of "true vacuum" that expands at the speed of light. As the bubble grows, it reduces the energy locked up in the vacuum of space and rewrites the laws of nature.

In 1980, the late Harvard physicist Sidney Coleman published calculations that showed for the first time that vacuum decay was eternally terminal. He wrote: "One could always draw stoic comfort from the possibility that perhaps in the course of time the new vacuum would sustain, if not life as we know it, at least some structures capable of knowing joy. This possibility has now been eliminated."

Ian Sample's Massive: The Hunt for the God Particle is published by Virgin Books

Bad weather threatens to force fleet of ships assembled around stricken well to evacuate area

Attempts to permanently solve the problem of the Macondo oil well that has spewed more than 4m barrels of oil into the Gulf of Mexico have had to be pushed back as bad weather threatens to force the fleet of ships assembled around the stricken well to evacuate the area.

A tropical depression that formed over the Bahamas was moving in the direction of the well located off Louisiana's coast, with warnings that it could turn into a tropical storm along the west coast of Florida. The route followed by the depression is unpredictable, with weather forecasters citing a 50% chance that it reaches the Macondo well within the next two days.

The fleet of 65 ships involved in the disaster response were preparing to quit the area and head for port, though an evacuation had not yet been ordered. They include vessels being used in the monitoring of the well.

But the threat of bad weather has already delayed efforts to plug the well at its source deep beneath the sea bed. Engineers were obliged to suspend work on the first of two relief wells that are being drilled down to the source, setting back the final procedure to plug it.

They had been expecting to spend this week reinforcing the last section of the relief well with concrete, which would have allowed an attempt to plug the well with heavy mud over this weekend. Now that will be delayed.

Admiral Thad Allen, the Obama administration's point man on the disaster response, said that should the evacuation go ahead the disruption to the work at the well could last as long as two weeks.

A federal investigation panel in New Orleans continues its exploration of the causes of the disaster which began on 20 April when the Deepwater Horizon oil rig exploded. A widow of one of the 11 workers who died, Natalie Roshto, told the hearing on Thursday that he had been anxious about conditions on the rig before it went up. She said that her husband Shane had called it the oil well "from hell" and told her: "Mother Nature just doesn't want us to drill here."

Meanwhile a Senate committee has called on BP boss Tony Hayward to testify before it on whether the oil giant played any role in the release of Lockerbie bomber Abdelbaset al-Megrahi from prison in Scotland last year. It has been suggested BP lobbied for his release in the hope of securing a lucrative oil deal with Libya.

Estimated 700 people killed this year as landslides and high water levels causes billions of pounds in damage

Flooding in China this year has killed 701 people, left 347 missing and caused billions of pounds in damage, a senior Chinese official has said.

Three-quarters of China's provinces have been hit by flooding and 25 rivers have seen record high water levels, causing the worst death toll in a decade, Liu Ning, general secretary of the government's flood prevention agency, told a news conference.

Aside from the dead and missing, 645,000 houses were toppled and overall damage totalled 142.2bn yuan (£13.7bn). All the figures, Liu said, were the highest China had seen since 2000.

With the flood season far from over, this year is shaping up to be one of the most devastating since 1998, which was the worst in 50 years.

Flooding, particularly along the Yangtze river basin, has overwhelmed reservoirs, swamped towns and cities, and broken off hillsides causing landslides that have smothered communities.

Soldiers have been using bulldozers to plough through debris in search of survivors from separate landslides in Sichuan and Shaanxi provinces, while workers in other parts of the country scrambled to drain overflowing reservoirs and pile up sandbags to prevent further flooding, the official Xinhua news agency reported.

Three people were killed late on Sunday night by landslides in Lingao county in Shaanxi province that also left 17 missing, Xinhua reported. In all, flooding and landslides from rain-soaked hillsides in Shaanxi have killed 37 and left a further 97 missing.

In nearby Sichuan province rescuers searched for 13 missing people after a landslide hit Xujiaping village, burying homes and blocking roads.

Xinhua and the state broadcaster China Central Television reported that the Three Gorges Dam was dealing with its highest ever water levels when a flood crest passed the dam.

The government cited flood control along the Yangtze as one of the main reasons for the dam project that forced the relocation of 1.4 million people and cost 156bn yuan.

Just as nightmare appears over, and cap on leaking well is holding, British firm's official gives damaging testimony

? Interactive: Timeline of a disaster
? The spill in pictures

BP came under fresh attack last night amid accusations that it had ignored internal safety reports of a leak on the Deepwater Horizon rig and had not used industry best practice for avoiding oil spills.

The news comes just as BP officials were hoping that their long nightmare was starting to be over as the new cap on the leaking oil well appeared to be holding firm and working well.

There had been concerns that the cap might damage the stricken well and allow oil to burst out of the seabed. However, BP officials said there was no evidence of oil from the damaged well forcing its way through cracks in the seabed. "We do not have any anomalies or evidence that we do not have integrity [of the well]," BP's senior vice-president, Kent Wells, told reporters.

But, while the capping of the well may be going well, developments onshore continued to prove what an enormous task BP faces in trying to repair its public image. In Louisiana an investigative hearing into the leak heard testimony from a BP official who said the firm had ignored warnings ahead of the disaster.

Ronald Sepulvado, a BP well site leader, said he had reported a leak on a critical safety device at the rig to more senior company officials, but it seemed his warnings had not been passed on to the government regulating body, the Minerals Management Service.

"I assumed everything was OK, because I reported it to the team leader and he should have reported it to the MMS," he told the hearing. The leak was on a control pod connected to the blowout preventer on the rig, whose failure proved critical in causing the disaster.

A congressional committee in Washington heard testimony from Gale Norton, interior secretary under former president George W Bush. Norton said BP had ignored rules put in place in 2003. "If regulations on the books and industry best practices had been followed properly, there might not have been a blowout," she said. "It appears that BP violated all those regulations that were on the books."

BP officials know that their best hopes lie in permanently sealing the well. A relief well being dug alongside is almost finished. "The relief well is exactly where we want it," said Wells. The relief well is set to intercept the damaged well at the end of July.

But before then BP will attempt to shoot drilling mud into the damaged blowout preventer, to seal the well from the top. A previous attempt using this method failed. Wells said that the company was seeking permission to make the effort, possibly this week.

However, bad weather is building in the Caribbean and over the Atlantic, which could become a violent storm by the weekend, meteorologists said. A storm in the Gulf of Mexico could disrupt all efforts. "We certainly are going to keep a very close eye on this system," said Dan Kottlowski, a hurricane expert at the website Accuweather.

Finally plugging the well would go some way to ending the damage to BP's reputation globally. But this respite is unlikely to come soon. Mother Jones, a leftwing magazine, reported an unlisted BP phone number for politicians in California to ring for tickets to sporting events and music concerts.

The magazine said that BP had given away more than $300,000 (£196,000) worth of tickets in 10 years.

Severe flooding and rising levels to China's largest river, the Yangtze, is causing hundreds of residents in Hubei province to be evacuated

SeeSouthernForests.org provides a new way to learn about, and protect, the forests of the southern United States.

Changes over a large area are often hard to see. This can be especially true when it comes to forests where incremental forest loss often goes unnoticed until it is too late. A new website and report by the World Resources Institute seek to change this and allow people to visualize the trends and drivers of change affecting southern forests.

read more

read more

read more

Human waste may be a topic that people generally do not or prefer not to think about. However, its capture and disposal (often referred to in terms of sanitation) play a vital role in human health and development. The importance of sanitation as a basic human need has made it an international development priority and a key target in the United Nations Millennium Development Goals. Even though since 1990 the percent of the global population with access to improved sanitation has increased (see Figure 1.), lack of improved sanitation still threatens human health and development particularly in developing regions of the world.

read more

read more