Global emissions of carbon dioxide (CO₂) – the main cause of global warming – increased by 3% last year, reaching an all-time high of 34 billion tonnes in 2011. In China, the world's most populous country, average emissions of CO₂ increased by 9% to 7.2 tonnes per capita. China is now within the range of 6 to 19 tonnes per capita emissions of the major industrialised countries. In the European Union, CO₂ emissions dropped by 3% to 7.5 tonnes per capita. The United States remain one of the largest emitters of CO₂, with 17.3 tones per capita, despite a decline due to the recession in 2008-2009, high oil prices and an increased share of natural gas. These are the main findings of the annual report 'Trends in global CO₂ emissions', released today by the European Commission's Joint Research Centre (JRC) and the Netherlands Environmental Assessment Agency (PBL).

Anyone who has looked at the jagged recording of the electrical activity of a single neuron in the brain must have wondered how any useful information could be extracted from such a frazzled signal.

Not all adult stem cells are created equal. Some are busy regenerating worn out or damaged tissues, while their quieter brethren serve as a strategic back-up crew that only steps in when demand shoots up. Now, researchers at the Stowers Institute for Medical Research have identified an important molecular cue that keeps quiescent mouse hematopoietic (or blood-forming) stem cells from proliferating when their services are not needed.