OtagoDailyTimes, Feb. 24, 2014.
Small volcanic eruptions help explain a hiatus in global warming this century by dimming sunlight and offsetting a rise in emissions of heat-trapping gases to record highs, according to a new study.
Eruptions of at least 17 volcanoes since 2000, including Nabro in Eritrea, Kasatochi in Alaska and Merapi in Indonesia, ejected sulphur whose sun-blocking effect had been largely ignored until now by climate scientists, it said.
The pace of rising world surface temperatures has slowed since an exceptionally warm 1998, heartening those who doubt that an urgent, trillion-dollar shift to renewable energies from fossil fuels is needed to counter global warming.
Explaining the hiatus could bolster support for a U.N. climate deal, due to be agreed by almost 200 governments at a summit in Paris in late 2015 to avert ever more floods, droughts, heatwaves and rising sea levels.
“This is a complex detective story,” said Benjamin Santer of the Lawrence Livermore National Laboratory in California, lead author of the study in the journal Nature Geoscience that gives the most detailed account yet of the cooling impact of volcanoes.
“Volcanoes are part of the answer but there’s no factor that is solely responsible for the hiatus,” he told Reuters of the study by a team of U.S. and Canadian experts.