Vienna Cannot Escape the Heat - Cooling Measures Are Not Enough

The rising temperatures in the summer months pose increasing challenges for cities like Vienna. A research team from the University of Natural Resources and Life Sciences (BOKU) analyzed the effectiveness of different cooling measures in the Greater Vienna urban areas as part of the Imp-DroP project (Impact of longer Drought Periods on Climate in Greater Vienna). The result: Despite comprehensive strategies, the temperature increase can only be limitedly mitigated.

Cities are particularly susceptible to heat – due to dense construction, sealed surfaces, and lack of greenery, they store heat during the day and cool down slowly at night. Additionally, man-made heat sources such as traffic or air conditioning have an amplifying effect. In densely built-up neighborhoods, so-called urban heat islands are created with significantly higher temperatures.

Cooling strategies analyzed at four locations in Vienna

Project leader Philipp Weihs and his team examined various cooling strategies: watering of green roofs and parks, reduction of anthropogenic heat, and the use of photovoltaics on green roofs. The effect was analyzed at four measurement locations in Vienna – including the AKH and the Schönbrunn Horticultural School – using sensors and models.

The model simulations show: An optimally watered green infrastructure can bring temperature reductions of up to three degrees Celsius in certain areas. Citywide, the potential cooling effect averages around 1.5 degrees. But according to Weihs, this is not enough: "Even with the full utilization of all available adaptation measures, the cooling effect is not sufficient to fully compensate for the expected warming – even if the Paris climate target is met."

Measures against heat are not enough

A central problem remains water availability. While the Vienna high spring pipelines deliver up to 375,000 cubic meters of water daily, around 630,000 cubic meters would be needed during heat waves for comprehensive watering. Therefore, supply solely through high spring water is not possible.

In addition to evaporative cooling, other urban factors were also analyzed. Particularly heat sources such as industry, traffic, and building cooling contribute significantly to heating. The researchers see potential in the local use of photovoltaics on green roofs: This could not only reduce energy demand but also locally reduce the temperature by up to 1.5 degrees.

(Red)

This article has been automatically translated, read the original article here.