Switzerland 2090: oranges instead of hydroelectric

If we take immediate action to reduce carbon dioxide₂emissions, we can limit the temperature increase of Swiss rivers to 1°C between now and 2090 without significantly affecting their discharge. In turn, doing nothing threatens ecosystems and the agricultural sector and puts the country’s electricity production at risk. That is the conclusion of a study published today by EPFL in a press release.

Adrien Michel, who holds a doctorate in environmental sciences and engineering at EPFL, has published a futuristic view of the impact of global warming on Swiss rivers in the journal Hydrology and Earth System Sciences.

3 scenarios

Michel’s research identifies three possible scenarios that depend on whether greenhouse gas emissions are low, moderate or high. In the most extreme scenario, where we take no action, summer river temperatures are expected to rise by 5.5°C in the Alpine regions and 4°C in the Swiss plateaus. At the same time, the average river discharge in the mountains can decrease by 30 percent and in the lowlands by 25 percent.

glaciers

Conversely, if CO₂Emissions are reduced According to the Paris climate agreement, both the Alpine rivers and the rivers on the Swiss plateau will only warm by 1 degree Celsius by the end of the century. Drainage decreases by 5 percent in mountain basins, while remaining virtually unchanged in lowlands. In the low emissions scenario, approximately half of all remaining glaciers are preserved and glacier retreat will stabilize around 2050. In the high emissions scenario, almost all of them disappear.

Michel completed his Ph.D. in the Cryosphere Science Laboratory in the College of Architecture, Civil Engineering, and Environmental Sciences at EPFL. This is a follow-up to his retrospective study on the impact of global warming on Swiss rivers, which was published in January 2020.

More severe weather

The new study, of which Michel is the lead author, shows that extreme winter and summer events in the plateau regions will be greater in all three scenarios. In winter, increased precipitation leads to increased runoff. In summer, due to intermittent rainfall, along with a higher rate of evaporation as a result of higher temperatures, the discharge decreases. Michel relied on climate forecasts from MeteoSwiss and glacier melt data from ETH Zurich to model snow levels, runoff and river temperatures.

oranges in switzerland

“We will definitely be able to grow oranges in this part of the world,” says Michel. “But what about the rest of the biodiversity?” This study is based, of course, on how things are going now, while much about the turn of the century is still unknown. What will happen to the agriculture and energy sector? And with plants and animals in rivers, as rising temperatures hamper reproduction and increase the risk of disease in fish?

How do we ensure sufficient production of electricity if the discharge is greatly reduced? And if Switzerland decides to build new nuclear power plants or other industrial facilities, how do we keep them cool?

“People often think that water in Switzerland is an unlimited resource,” says Michel. “But by the end of this century, we may have to choose between using our rivers to water our crops and damming those rivers to produce energy.”

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