July 24 2017 read full Washington Post article here

Even if we meet our most ambitious climate goal — keeping global temperatures within a strict 1.5 degrees Celsius (or 2.7 degree Fahrenheit) of their preindustrial levels — there will still be consequences, scientists say. And they’ll last for years after we stop emitting carbon dioxide into the atmosphere.

New research suggests that extreme El Niño events — which can cause intense rainfall, flooding and other severe weather events in certain parts of the world — will occur more and more often as long as humans continue producing greenhouse gas emissions. And even if we’re able to stabilize the global climate at the 1.5-degree threshold, the study concludes, these events will continue to increase in frequency for up to another 100 years afterward. The findings were published Monday in the journal Nature Climate Change.

It was really a surprise that what we find is after we reach 1.5 degrees Celsius and stabilize world temperatures, the frequency of extreme El Niño continued to increase for another century,” said Wenju Cai, a chief research scientist at Australia’s Commonwealth Scientific and Industrial Research Organization and one of the study’s lead authors. “We were expecting that the risk would stabilize.” …

…The models suggested that by the time we hit the 1.5-degree mark, the frequency of extreme El Niño will have doubled from its preindustrial level of about five events every 100 years to about 10. This increase will occur steadily over time, the researchers note, meaning that any additional increase in carbon dioxide in the future will lead to an increased risk of an extreme event

…The researchers noted that the same results did not hold true for La Niña events, which often produce the opposite effects of El Niño. While previous research has suggested that more intense warming scenarios may lead to more frequent La Niña events as well, the milder climate trajectory in this study did not produce any significant changes.

Trenberth, who was not involved with the research, still has concerns about the models used in the research, which he says are “the same flawed models used before.” He argues that the models do a poor job of capturing some of the impacts of El Niño events — even “regular” ones — and the way they’re influenced by temperature and moisture in the atmosphere….