Most insights come as a surprise: a burst of understanding, an elegant solution to a problem. This decade's main insight in climate science was a different breed. For 40 years, researchers had wrestled with three big questions: Is the world warming? If so, are humans behind the warming? And are natural processes likely to rein it in?

Fortunately for us, carbon monoxide (CO)—a toxic gas—is a very minor constituent of the atmosphere. It is produced by incomplete burning of fossil fuels and biomass (such as dry leaves and wood) and by the oxidation of methane and other volatile hydrocarbons in the atmosphere. 

We present a 650-year Antarctic ice core record of concentration and isotopic ratios (δ¹³C and δ¹⁸O) of atmospheric carbon monoxide. Concentrations decreased by ~25% (14 parts per billion by volume) from the mid-1300s to the 1600s then recovered completely by the late 1800s.

Estimates of Earth's climate sensitivity are uncertain, largely because of uncertainty in the long-term cloud feedback. I estimated the magnitude of the cloud feedback in response to short-term climate variations by analyzing the top-of-atmosphere radiation budget from March 2000 to February 2010. Over this period, the short-term cloud feedback had a magnitude of 0.54 T 0.74 (2s) watts

Using data for 25,780 species categorized on the International Union for Conservation of Nature (IUCN) Red List, we present an assessment of the status of the world’s vertebrates. One-fifth of species are classified as Threatened, and we show that this figure is increasing: on average, 52 species of mammals, birds and amphibians move one category closer to extinction each year. However, this overall pattern conceals the impact of conservation successes, and we show that the rate of deterioration would have been at least one-fifth as much again in the absence of these.

Quantitative scenarios are coming of age as a tool for evaluating the impact of future socioeconomic development pathways on biodiversity and ecosystem services. We analyze global terrestrial, freshwater, and marine biodiversity scenarios using a range of measures including extinctions, changes in species abundance, habitat loss, and distribution shifts, as well as comparing model projections to observations. Scenarios consistently indicate that biodiversity will continue to decline over the 21st century.

With the death of Veronica Rodrigues on 10 November, India has lost a leading figure in the resurgence of research and teaching in the biological sciences in the subcontinent. Her scientific influence was widely felt, but she was also intimately connected with fostering and advancing research in molecular biology and developmental genetics at the Tata Institute of Fundamental Research (TIFR) in Mumbai, and more recently in the inception of the landmark center of excellence at the National Centre for Biological Sciences (NCBS) in Bangalore.

In Madina village, outside Accra, Ghana, children tease each other about whose urine has a redder color. Apart from being strikingly thin, they look healthy. Yet they could be affected by Schistosoma haematobium, a parasitic disease common in Africa, where local prevalence rates can exceed 50%. Early diagnosis ensures inexpensive and effective treatment and prevents stunted growth and developmental disabilities in children and bladder cancer or other organ damage in adults (3).

In their report (Terrestrial gross carbon dioxide uptake: Global distribution and covariation with climate," 13 August, p. 834), C. Beer et al. joined others in estimating global carbon fluxes and their relationship to climate. (Letters)

A new strategy to selectively spare pregnant females has brought the Chesapeake Bay crab population back from a precipitous collapse in just 3 years.