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Scientists predict 600% increase in deadly heat waves in Israel by 2100

Extreme weather lasting all summer is projected to drive an 11-fold leap in mortality rates by the end of the century

Ibex on a cliff at sunrise in Israel. Photo by iStock

By Ruth Schuster February 28, 2023

This article originally appeared on Haaretz, and was reprinted here with permission. Sign up here to get Haaretz’s free Daily Brief newsletter delivered to your inbox.

The number of extreme heat waves in Israel is expected to leap sevenfold or 600 percent a year by 2100, with temperature differentials of up to 10 degrees Celsius (18 degrees Fahrenheit) that could last not days but months. Mortality from heat stress is projected to jump more than tenfold, according to a new study examining climate change in the East Mediterranean.

Compared with 40-degree differentials during polar heat waves, Israelis might think we have been spared the worst climate change extremes. But regional heat waves here have also been getting longer, hotter and more frequent.

The data relate to the Eastern Mediterranean: Egypt, Israel, Syria, Jordan and southern Turkey, explains lead researcher Assaf Hochman of Hebrew University. Their projections are based on the “8.5 high-emissions” scenario (the concentration of carbon that delivers global warming at an average of 8.5 watts per square meter across the planet), which is the trajectory Earth is on. Greenhouse gas emissions are still increasing, not diminishing.

Even now, the changes are palpable and taking a lethal turn. Winter never arrived in Israel this year; the pole and Middle East are the two areas warming the fastest, he says. (Climate change in Israel is somewhat mitigated relative to the North Pole because proximity to the Mediterranean Sea helps diminish the extremes, Hochman notes.)

Heat waves in Israel are already causing about 30 deaths annually. The study foresees that figure rising 11-fold by the year 2100, to 330 heat-related deaths each year. That is the conservative estimate based on linear extrapolation from the local death statistics, Hochman says. If the progression is not linear but exponential, deaths could be far higher.

If that sounds implausible, consider that heat waves in Europe are estimated to have killed 20,000 people last year. One single heat wave in 2003 is estimated to have killed somewhere between 30,000 to 75,000 Europeans. A heat wave in Russia in 2005 caused 55,000 deaths.

That 2003 summer blast was the warmest Europe had known for about 500 years, at just 1.5 degrees Celsius above average for the period. Every year since has been hotter.

Heat waves are defined as abnormally hot weather over an extended period. How bad could it get? A study from 2014 predicted a 6 to 10 degree differential and heat waves lasting as long as 40 days. Actually, in the 8.5 scenario for the East Mediterranean, a single heat wave could last all summer, Hochman warns. That’s not a heat wave, that’s a heat tsunami.

As for the temperature differential, crucially their new model doesn’t look at temperature alone but “heat stress”: It factors in humidity, wind intensity and the “marine inversion base” – which all boil down to how badly we suffer from the heat. The more humid the weather, the harder it is for our sweat to evaporate and cool us down, and the easier it is to develop heatstroke.

In the hot spot

The East Mediterranean is considered a climate change hot spot because it lies between temperate and arid climates, rendering it particularly vulnerable to small changes in the global circulation systems, Hochman explains. Also, heat waves in the region are already lasting longer than in the past: a 2010 paper found their duration had jumped between 600 to 800 percent from 1960 to 2010.

Extreme temperatures affect not only our well-being and mortality rates, but infrastructure, animals and agriculture. Just for one example, an electricity plant drawing water to cool its machinery will have to halt operations if the water gets too warm – this is already happening with some European nuclear plants. Or plants are banned from releasing their own heated water back into the environment, which is already overheated.

The point is that relying on air-conditioning to escape heat stress is not a sustainable strategy. The desalination plants on which Israel relies to relieve drought stress also rely on electric power.

Even if emissions were to stop right now, the climate would take time to “digest” the carbon dioxide already released into the atmosphere. More heating is in the cards, based on climatological analyses going back millions of years. And in any case, global emissions are still increasing.

This week, the new environment minister, Idit Silman, met with climate deniers – but Israel cannot fairly be pilloried on its lonesome for denial. Denialism is declining, but it isn’t dead and Israel is in good company.

Now this study underscores the urgency of recognizing the problems Israel, the region and the world face, and preparing not only for sea level rise and the Mediterranean encroaching into the Hula valley, but for significant intensification of life-threatening heat stress – starting in our lifetimes

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