As Austria experienced record-breaking temperatures on 4 August 2026, with more than 50 weather stations reporting all-time highs, IIASA Director General and SITCA Co-Founder Professor Hans Joachim Schellnhuber joined Austrian public radio Ö1's Mittagsjournal to discuss what these extremes mean for the future, as well as why society must prepare for a much hotter climate.

Reflecting on the unprecedented heat, Schellnhuber cautioned against viewing the current summer as an isolated event. "This day and this summer may well go down as the coolest of this century," he said, noting that climate projections indicate temperatures as high as 45°C could become commonplace in Vienna within the next two to three decades if global warming continues on its current trajectory.

During the interview, Schellnhuber emphasized that the world has already reached approximately 1.5°C of global warming above pre-industrial levels, which is the first critical threshold identified in the Paris Agreement. While existing national climate commitments would still lead to around 2.7°C of warming by the end of the century if fully implemented, he warned that weakening climate ambitions in many countries makes a rise of around 3°C increasingly likely. Across continental regions, warming could reach approximately 5°C, with cities experiencing temperature increases of up to 8°C.

Schellnhuber stressed that adaptation and mitigation must go hand in hand. While he acknowledged that air conditioning is becoming increasingly necessary, particularly for vulnerable groups and in schools. He cautioned that it cannot be the primary solution. Air conditioning redistributes heat outdoors, intensifying urban heat islands and making public spaces even less comfortable during heat waves. Instead, Schellnhuber highlighted the vital role of nature-based solutions. Expanding urban green spaces, planting trees, and removing impervious surfaces can significantly reduce temperatures in cities. Studies have shown that the temperature difference between densely built-up areas and green, vegetated spaces can reach as much as 20°C, demonstrating the substantial cooling effect of urban nature.

The interview also focused on the role of the built environment in addressing climate change. Schellnhuber argued that replacing carbon-intensive construction materials such as concrete with sustainably sourced timber and other bio-based materials offers a powerful opportunity to reduce emissions while storing carbon. Combined with greener urban design, transforming the construction sector could turn one of today's largest sources of greenhouse gas emissions into a key contributor to climate solutions.

The interview underscores IIASA's commitment to providing science-based insights that help policymakers and society respond to the accelerating impacts of climate change. As extreme heat becomes more frequent across Europe, integrated solutions that combine ambitious emissions reductions with climate-resilient urban planning will be essential to protecting communities and ensuring a livable future.