The role of climate change in the development and demise of Classic Maya civilization (300 to 1000 C.E.) remains controversial because of the absence of well-dated climate and archaeological sequences. We present a precisely dated subannual climate record for the past 2000 years from Yok Balum Cave, Belize. From comparison of this record with historical events compiled from well-dated stone monuments, we propose that anomalously high rainfall favored unprecedented population expansion and the proliferation of political centers between 440 and 660 C.E.

The observed presence of water vapor convectively injected deep into the stratosphere over the United States can fundamentally change the catalytic chlorine/bromine free-radical chemistry of the lower stratosphere by shifting total available inorganic chlorine into the catalytically active free-radical form, ClO. This chemical shift markedly affects total ozone loss rates and makes the catalytic system extraordinarily sensitive to convective injection into the mid-latitude lower stratosphere in summer.

The observed presence of water vapor convectively injected deep into the stratosphere over the United States fundamentally changes the catalytic chlorine/bromine free radical chemistry of the lower stratosphere by shifting total available inorganic chlorine into the catalytically active free-radical form, ClO. This chemical shift markedly affects total ozone loss rates and makes the catalytic system extraordinarily sensitive to convective injection into the mid-latitude lower stratosphere in summer.

Fundamental thermodynamics and climate models suggest that dry regions will become drier and wet regions will become wetter in response to warming. Efforts to detect this long-term response in sparse surface observations of rainfall and evaporation remain ambiguous. We show that ocean salinity patterns express an identifiable fingerprint of an intensifying water cycle. Our 50-year observed global surface salinity changes, combined with changes from global climate models, present robust evidence of an intensified global water cycle at a rate of 8 ± 5% per degree of surface warming.

India’s science: Excellence unrecognized. (Letters)

The Montreal Protocol is perhaps the most successful international environmental treaty, responsible for global phaseout of the consumption and production of ozone-depleting substances (ODSs), e.g., chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Hydrofluorocarbons (HFCs), which do not destroy stratospheric ozone, were considered long-term substitutes for ODSs and are not controlled by the Montreal Protocol. Because most HFCs are potent greenhouse gases (GHGs), they are included in the Kyoto Protocol.

At the Indian Science Congress last month, Prime Minister Manmohan Singh pledged to hike R&D expenditures from around $3 billion last year to $8 billion in 2017. The windfall is meant to turbocharge initiatives to create elite research institutions, bring expatriate Indian scientists home, enrich science education, and equip smart new laboratories. Included in this push is South Asia's first biosafety level–4 lab for handling the most dangerous pathogens, slated to be up and running this spring.

Indian Prime Minister Manmohan Singh plans to increase the government's R&D spending and create incentives for the private sector to increase spending on science and technology as well.

The Open Source Drug Discovery network's army of volunteers is building a kind of Wikipedia on tuberculosis, which is the leading cause of death in India for those in the prime of life.

In 1905, Sir William Osler, the most influential physician of his time, stepped down from the medical faculty of Johns Hopkins University at the age of 55. At his farewell, he emphasized that the “effective, moving, vitalizing work of the world is done between the ages of 25 and 40—these 15 golden years of plenty.” Many of us, who are old but still active like myself, may like to strongly disagree. But the power of the creative prime in this age group is irrefutable.