This past September was the hottest in Israeli history, in keeping with the global trend of this year being the hottest on record. That sizzling month was followed by the usual autumn rainy season – which itself has been behaving very unusually.
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With the climate change conference COP21 kicking off in Paris, it begs the question: Is Israel’s recent extreme weather the result of normal fluctuations or as a result of global warming?
“Rain in the south has been hundreds of percent more than the average for this time of year,” says Prof. Daniel Rosenfeld of the Hebrew University of Jerusalem’s Institute of Earth Sciences. “In northern Israel, the trend is the opposite. I would define it as weather fluctuation – this is an ‘El Niño year.’ But things might not have reached such extreme levels if not superimposed on the general trend of climate change.”
El Niño, named for the Christ Child, has been a factor boosting temperatures worldwide this winter. It is characterized by the Pacific Ocean sea surface warming compared with its average temperature. For an anomaly, it’s pretty common, happening at irregular intervals of anywhere from two to seven years, and lasting nine months to two years in a row.
The upshot of El Niño is changes in weather patterns absolutely everywhere, including over Israel. Hence the hot summer – an effect possibly amplified by climate change, Rosenfeld points out – and the unusually rainy autumn in Israel’s south.
Suddenly, a river runs through it
Northern Israel has received only 70 percent of its average precipitation this winter. The level of Lake Kinneret – a key source of freshwater for Israel – remains perilously close to the “danger line” below which the national water utility is prohibited from pumping from it.
Meanwhile, the normally arid south has been pounded with rain. Soaked surfers inundated social media sites with scenes of garbage cans sailing down rivers that used to be streets from Kfar Sava to Ashkelon. And after a sunny weekend, more rain began on Monday – but at least this time it’s nationwide.
The patterns observed this season comply with the long-term forecasts for Israel and the region for global warming and climate change: Northern Israel, starting from the catchment area of the Sea of Galilee and going northward toward Islamic State territory in Syria, is getting drier. That is exactly as predicted in climate change models, and by Rosenfeld himself in his November 2012 paper “The Arctic Oscillation, Climate Change and the Effects on Precipitation in Israel,” written with meteorologist Amir Givati of the Israel Hydrological Service and published in the Atmospheric Research journal.
They also predicted then that southern Israel, including the Negev Desert, will get a little wetter. That has panned out so far – though, as Rosenfeld notes, the south isn’t a little wetter this winter, it’s a lot wetter.
In fact, some scientists ascribe destabilization in the Middle East and North Africa, and the rise of ISIS in parts of Syria and Iraq, to climate change causing extreme drought. A leading geostrategist, Arnon Soffer of the University of Haifa, even predicts that Europe may face not tens of thousands but hundreds of millions of refugees as the Middle East and North Africa become uninhabitable.
Short-term weather forecasting is an art at best, given the enormous number of parameters, let alone forecasting for the season. But based on the existence of El Niño this fall, we can probably expect a lot more rain this winter in Israel. “This correlation isn’t so strong that it’s absolute,” Rosenfeld cautions. “But the chances are good."