World's Major Cities Face 25% Increase In Extremely Hot Days Since The 1990s

Recent analysis indicates that the world's largest capital cities are experiencing a 25% increase in extremely hot days annually compared to the 1990s. The International Institute For Environment and Development (IIED) conducted this study in 2024, focusing on extreme heat trends in the 20 most populous capitals over three decades, from 1994 to 2023. This research highlights a significant rise in days with temperatures reaching 35°C or higher.

The updated analysis now includes data from 40 capitals and incorporates the latest temperature records from 2024, which was declared the hottest year by the World Meteorological Organisation. Cities like Washington DC, Madrid, Tokyo, and Beijing have all seen an increase in hot days as climate change worsens. The IIED's findings show that from 1994-2003, there were about 1,062 days annually exceeding 35°C across these capitals. This number rose to an average of 1,335 days between 2015 and 2024.

Globally, this trend is evident with cities like Rome and Beijing witnessing a doubling of such hot days. Manila experienced a tripling of these occurrences. In Madrid, the average number of days above 35°C increased from 25 to 47 annually. Even London, known for its cooler climate, saw its days over 30°C double.

Anna Walnycki, an IIED researcher, expressed concern over governments' slow response to rising global temperatures. "Global temperatures are rising faster than governments probably expected and definitely faster than they seem to be reacting," she stated. She warned that without adaptation measures, millions living in urban areas could face increasingly harsh conditions due to the urban heat island effect.

The situation is particularly dire for low-income or unplanned communities in the global south. These areas often have lower-quality housing and are more vulnerable to extreme heat impacts. Walnycki noted that one-third of city dwellers globally reside in slums or informal settlements.

Fossil Fuels and Climate Change

The intensification of heatwaves is largely attributed to global warming driven by fossil fuel consumption. Despite the urgent need for emissions reductions—by at least 45% by 2030—to meet the Paris Agreement's goal of limiting global temperature rise to below 1.5°C above preindustrial levels, emissions continue to climb.

This ongoing increase in fossil fuel emissions exacerbates the climate crisis, making extreme weather events more frequent and severe. Addressing these challenges requires immediate action from governments worldwide to mitigate further damage and protect vulnerable populations.

The findings underscore the urgent need for comprehensive strategies to combat climate change effects on urban environments globally. As temperatures continue to rise, proactive measures are essential to safeguard communities against escalating heat risks.

With inputs from WAM