'Stadium waves' could explain lull in global warming
One of the most controversial issues emerging from the recent Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) is the failure of global climate models to predict a hiatus in warming of global surface temperatures since 1998. Several ideas have been put forward to explain this hiatus, including what the IPCC refers to as 'unpredictable climate variability' that is associated with large-scale circulation regimes in the atmosphere and ocean. The most familiar of these regimes is El Niño/La Niña, which are parts of an oscillation in the ocean-atmosphere system. On longer multi-decadal time scales, there is a network of atmospheric and oceanic circulation regimes, including the Atlantic Multidecadal Oscillation and the Pacific Decadal Oscillation.