Some scientists have argued from observations that global warming will alter clouds in ways that will largely counter warming by greenhouse gases. But the overwhelming majority of climate scientists sides with the models, which show clouds changing in ways that amplify warming, not dampen it. Whom to believe? To help sort it out, a climate researcher looked at the example of El Niño and La Niña, naturally occurring weather patterns that cause warming (El Niño) and cooling (La Niña) in the tropical Pacific and around the globe.

In January, entomologists will start deploying a strange bacterium called Wolbachia pipientis in an attempt to halt disease transmission by mosquitoes. Their target is Aedes aegypti, the mosquito that transmits dengue, a human viral disease that causes crippling joint and muscle pains. Recent studies have shown that infection with Wolbachia makes mosquitoes resistant to the dengue virus. Now, a team at the University of Queensland in Brisbane, Australia, wants to test whether they can spread Wolbachia in the wild by setting free small numbers of mosquitoes infected with the microbe.

In 2003, a geneticist used DNA markers called microsatellites to show that a fishing vessel had violated its quota by catching too many cod from the North Sea. It was a rare victory against the massive problem of illegal fishing. For technical reasons, however, microsatellite tests for identifying the local origins of caught fish haven't been widely adopted.

Nine years ago, a small group of infectious-disease experts gambled on an unorthodox strategy to make a much-needed—and affordable—vaccine for Africa. Last Monday in Burkina Faso, it paid off in spades with the kickoff of a massive campaign to immunize 20 million people in three African countries against deadly meningococcal meningitis by the end of December.

Close to two-thirds of the world's poorest people live in rural areas. Eradication of rural poverty depends on increased access to goods, services, and information, targets detailed in the United Nations Millennium Development Goals. However, alleviating poverty is hindered by two interlinked phenomena: lack of access to improved energy services and worsening environmental shocks due to climate change. Mitigating climate change, increasing energy access, and alleviating rural poverty can all be complementary, their overlap defining an energy-poverty-climate nexus.

In his news story "Is there a road ahead for cellulosic ethanol?" (Special section on Scaling up Alternative Energy, 13 August, p. 784), R. F. Service identifies factors contributing to fading enthusiasm for cellulosic ethanol and observes that policy-makers' decisions this year could shape the nascent U.S. biofuels industry for decades. It is critical at this time to distinguish the fundamental from the ephemeral and to base policy on the former rather than the latter. (Letters)

Over the past decade, biologists working in Ecuador's Yasuni National Park and the adjoining Waorani Ethnic Reserve, a 17,000-kilometer section of the Amazon Basin that was designated a UNESCO Biosphere Reserve in 1989, have documented Yasuni's remarkable biodiversity, providing evidence that its forest has the highest number of species on the planet, including an unprecedented core where there are overlapping world richness records for amphibians, reptiles, bats, and trees.

Transgenic maize engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has become widely adopted in U.S. agriculture. In 2009, Bt maize was planted on more than 22.2 million hectares, constituting 63% of the U.S. crop.

Genetically engineered crops represent one of the most controversial and rapidly adopted technologies in the history of agriculture. First grown commercially in 1996, transgenic crops covered 135 million hectares (ha) in 25 countries during 2009.

Fungal degradation of plant biomass may provide insights for improving cellulosic biofuel production. We show that the model cellulolytic fungus Neurospora crassa relies on a high-affinity cellodextrin transport system for rapid growth on cellulose. Reconstitution of the N. crassa cellodextrin transport system in Saccharomyces cerevisiae promotes efficient growth of this yeast on cellodextrins. In simultaneous saccharification and fermentation experiments, the engineered yeast strains more rapidly convert cellulose to ethanol when compared with yeast lacking this system.