Big Changes Underway in the Climate System?
September 2015 - The Earth's global average surface climate is primarily determined by the exchange of energy between the atmosphere, the oceans and space. However, changes in regional climate are often governed by changes in the circulation of the atmosphere and ocean. These form coherent patterns like the El Niño Southern Oscillation (ENSO) fluctuations in tropical East Pacific sea surface temperature and sea level pressure, or the North Atlantic Oscillation variations in the strength of the westerlies over the North Atlantic. A fluctuation in any one of these can temporarily exacerbate or counter the effects of global climate change in affected regions. Some of these patterns of climate variability fluctuate over years and decades and can even affect global average surface temperature, as appears to have occurred in recent years with changes in the Pacific implicated in the slowdown in the rate of global surface warming.
In the article linked below we examine the latest behaviour of some of these key climate patterns. We begin with the year-to-year changes in the El Niño Southern Oscillation and look across timescales to potential multi-decadal changes in the Atlantic and Pacific. We use our latest global observations and initialised climate predictions from months to years ahead to assess whether rapid shifts are imminent or already underway. Changes in these key climate patterns could have pronounced effects on regional climate worldwide and temporarily alter the rate of global warming.