COLOURFUL BACTERIA PUT THE SPOTLIGHT ON POLLUTION
Cleanup crews may soon have a better way to spot contamination: colourful bacteria.
Pollution from oil spills and the like can linger for many years and chemicals such as naphthalene are rarely visible. So crews have to use other chemicals – sometimes harsh and expensive ones, such as carbon tetrachloride – to pinpoint areas in need of decontamination.
But bacteria engineered to change colour in response to specific chemical pollutants would be much cheaper, easier, cleaner and safer, scientists told a meeting of the Society for General Microbiology in Dublin last week.
The scientists tested their microbial sensors out on an oil spill in the North Sea. “We found that our sensors worked extremely well – and we also found the residue from numerous other old spills in the area,” says Jan Van der Meer, a microbiology professor at the University of Lausanne in Switzerland.
Moreover, he says the biosensor bacteria could be adapted for other uses, such as measuring arsenic contamination in rice (a major problem in Bangladesh).
WASTE NOT, WANT NOT
They say one man’s trash is another man’s treasure – and it is true even of human waste.
San Antonio, Tex., announced last week that it would become the first U.S. city to sell methane gas harvested from human “biosolids” on a commercial scale.
Though the source is quite different from a natural gas well, methane processed from human sewage is chemically identical to conventional gas fuel, so it can be used by existing power plants. The city estimates that it will be able to use 90 per cent of municipal sewage to create 1.5 million cubic feet of gas a day.
“Biogas” created from burning organic matter – such as manure, agricultural waste, discarded food and wood pulp – is already being used worldwide. For example, cow waste powers buses in Sweden and provides energy for more than a million people in Nepal.
Creating biogas from human waste may be particularly useful for developing countries such as India, where open-air defecation is common and a major health hazard. The United Nations named 2008 the International Year of Sanitation to highlight the fact that 2.6 billion people worldwide have nowhere safe and clean to go to the bathroom.
LIGHTER ON TOP
If all the cities in tropical and temperate climates required roofs and pavement to be tinted white, it would have the same effect on global warming as cutting 44 billion tonnes of greenhouse-gas emissions, the Global Climate Change Conference in Sacramento was told last week. That amount – more than the whole world pumps out in a year – would be worth about $1,100-billion (U.S.), based on the current price of carbon-offset credits.
The research, conducted by scientists at the Lawrence Berkeley National Laboratory in California, will be published in an upcoming issue of the journal Climatic Change.
Unlike other proposals to “geo-engineer” the climate, such as seeding oceans with iron to fertilize algae spawns (risking a collapse of the food chain) or spraying sulphur into the skies to block sunlight (but also precipitating acid rain), this idea is not controversial. And the concept is simple: White surfaces reflect more sunlight back to space than dark surfaces.
Moreover, buildings with white roofs are cooler, cutting the amount of energy used for air conditioning by about 20 per cent, as well as reducing air pollution from power plants and making cities less smoggy. The Berkeley scientists estimate that white roofs would result in energy savings of $1-billion (U.S.) a year in the United States alone.
California has mandated since 2005 that flat roofs be white and next year will require retrofitted and new sloped roofs to be “cool-coloured” (about half as reflective as pure white).
But white roofs and pavement made of a material more reflective than asphalt, such as concrete, will not solve our climatic problems on their own. Research leader Hashem Akbari notes that global greenhouse-gas emissions are still rising and a project of this scale would offset the estimated growth for only 11 years. “This plan basically buys us time to slow the rate of our emissions growth until we find permanent solutions to emit less and remove some of the carbon that we have dumped into the atmosphere.”
GREENPEACE WINS FIGHT
Protesters in Britain appear to have scored a major legal victory against energy companies and their government.
A jury cleared six Greenpeace activists last week of causing criminal damage to a coal-fired power plant in southeast England. Last October, they scaled one of the plant’s smokestacks and scrawled “GORDON” on it in protest against government plans to build new coal-fired plants. They had intended to write, “Gordon, bin it” – a demand aimed at Prime Minister Gordon Brown.
The graffiti cost $60,000 to remove from the plant, which emits 20,000 tonnes of carbon dioxide each day, as much as the world’s 30 least-polluting countries.
The protesters admitted causing property damage, but mounted a “lawful-excuse defence,” arguing that they acted to prevent even greater property damage from climate change. Among the witnesses were James Hansen, a leading climate-change expert and a scientist with the U.S. National Aeronautics and Space Administration, who said the Kingsnorth plant alone would wipe out 400 species, and Aqq aluk Lynge, vice-president of the Inuit Circumpolar Conference, who described the difficulties Inuit communities face because of unpredictable weather and loss of the species they hunt.
This defence “is novel to me,” says Will Amos, a staff lawyer at the uOttawa-Ecojustice Environmental Law Clinic. While there is speculation that many more activists will use the same argument, “it would be hard to predict a floodgate scenario,” he says. “However, as property damages directly related to climate change increases, it would be unreasonable not to expect greater civil disobedience where governments are seen as not acting.”