New excuse for the “pause” of global warming #58: Colder eastern Pacific and reduced heat loss in other oceans
http://hockeyschtick.blogspot.com/2014/11/new-excuse-for-pause-of-global-warming.html
A paper published today in Geophysical Research Letters finds excuse #58 for the 18-26 year “pause” or hiatus” of global warming: Colder eastern Pacific (30% contribution) and reduced heat loss in other oceans (70% contribution). So increased heat loss in the Pacific, and decreased heat loss in the Southern and subtropical Indian Oceans & subpolar North Atlantic allegedly “explain” the “pause.” Natural ocean oscillations could explain this, but not a steady rise of greenhouse gases. According to the authors, however, “A different mechanism is important at longer timescales (1960s-present) over which the [natural] Southern Annular Mode trended upwards. In this period, increased ocean heat uptake has largely arisen from reduced heat loss associated with reduced winds over the Agulhas Return Current and southward displacement of Southern Ocean westerlies.” Surface warming hiatus caused by increased heat uptake across multiple ocean basinsS. S. Drijfhout The first decade of the twenty-first century was characterised by a hiatus in global surface warming. Using ocean model hindcasts and reanalyses we show that heat uptake between the 1990s and 2000s increased by 0.7 ± 0.3Wm−2. Approximately 30% of the increase is associated with colder sea surface temperatures in the eastern Pacific. Other basins contribute via reduced heat loss to the atmosphere, in particular the Southern and subtropical Indian Oceans (30%), and the subpolar North Atlantic (40%). A different mechanism is important at longer timescales (1960s-present) over which the Southern Annular Mode trended upwards. In this period, increased ocean heat uptake has largely arisen from reduced heat loss associated with reduced winds over the Agulhas Return Current and southward displacement of Southern Ocean westerlies.
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