Nature World: The amount of global land affected by extreme heat waves classified as three-sigma events is set to double by 2020 and quadruple by 2040 regardless of changes in the amount of carbon dioxide released into the atmosphere, a study published in Environmental Research Letters reports.
Heat waves classified as three-sigma events -- a reference to a rise in temperatures of three standard deviations above the norm -- include the one that hit Australia in 2009 and more recently the one that took place...