The Future We Don't Want - For cities, the heat is on.

The Future We Don't Want analysis shows that, unless governments take urgent steps to cut emissions, over 1.6 billion people living in close to 1000 cities face regular, extreme heatwaves in under 30 years’ time. To put this in perspective, that is equivalent to more than 40 percent of today’s total urban population.

Today, around 200 million city-dwellers in over 350 cities live with summer1 temperature highs of over 35°C (95°F). Even at this level of exposure, heatwaves are the deadliest of all climate risks. By 2050 around 970 cities will be at least this hot, with much higher exposure in Asia, Africa and North America (see Figure 1). Average high temperatures of 35°C (95°F) will mean that heatwaves will become far more intense. Today, Egypt’s capital Cairo, for example, has summertime average high temperatures of 34˚C (93˚F). There, temperatures have reached as high as 48˚C (118˚F) during heatwaves; by 2050 this will be a lot more common occurrence across the world.

The Future We Don't Want analysis shows that Asia, and the Middle East, are already home to many cities that experience extreme temperatures. By 2050, the number of exposed cities in these regions will increase significantly with hundreds more cities at risk. The research also shows that regions that currently have few cities that deal with extreme heat, average summertime temperature highs of 35°C (95°F), will see exposure rise dramatically. Eastern China; southern, western and northern Africa; North America and parts of South America will be especially affected. Rising urban populations in these regions is partially to blame for the increased exposure; over the next 30 years 90 percent of urbanisation is expected to be concentrated in Asia and Africa alone.

A health warning for cities

Past heatwaves offer a window into the future for cities expecting temperatures to rise. Today, nearly one third of the world’s population is exposed to life-threatening heat extremes for 20 days a year or more. Events such as the 2003 heatwave in Europe, which claimed over 70,000 lives will become more frequent and severe as early as the 2040s.

People who already live in hot places will have to adapt to even longer periods of sweltering heat; while people who live in cooler cities will be exposed to levels of extreme heat to which they are unaccustomed. When adapting to climate change, cities should plan for temperatures that make it difficult and exhausting for citizens to move around outdoors, that make it impossible to work safely outdoors, and unbearable to stay indoors without air-conditioning and ventilation.

Cities with little green space are several degrees warmer than their rural surroundings as a result of the urban heat island effect. This makes urban centres more susceptible to heat extremes which can worsen air quality, cause dehydration, heat strokes, cardiovascular complications, kidney diseases, and death. The very young, the elderly, and people with pre-existing medical conditions are especially vulnerable. Heat impacts also disproportionately affect the poorest citizens who are unable to stop work during a heatwave while being more likely to work outdoors, or in poorly-ventilated factories.

In India, heatwave deaths have almost doubled over the past 20 years, leaving health services struggling to cope. During the 2016 heatwave, government hospitals received twice as many patients as usual and a record number of people were treated for heat-related illnesses such as high-grade fever, gastroenteritis, diarrhoea, and heat cramps.

Rethinking urban infrastructure

Health systems are not the only services that will be affected; cities will also have to re-think and re-build energy and transport systems. Heatwaves are already putting some cities’ energy supplies at risk. In South Korea, during a heatwave in 2013, the government had to cut air-conditioning in public buildings across Seoul, in order to stave off a country-wide power shortage. In Germany’s capital, Berlin, during a severe heatwave in 2010, temperatures reached 38˚C (100˚F), but after the air-conditioning malfunctioned on some of the city’s high-speed trains, passengers suffered temperatures of 50˚C (122˚F), forcing trains to be evacuated.

Service disruption of the sort experienced in Seoul and Berlin comes at significant economic cost and such impacts, combined with an incapacitated workforce, can cost cities billions of dollars. According to the Intergovernmental Panel on Climate Change’s most recent report, reduced labour productivity from high temperatures could reduce goods and service outputs by more than 20 percent in specific sectors such as manufacturing and construction by 2050. Another study estimates that, the economic cost of reduced productivity due to heat extremes will reach $2 trillion globally by 2030; equivalent to the GDP of India, the world’s sixth largest economy.

Responding to a hotter world

In India, where hundreds of additional cities will be exposed to extreme temperatures by 2050, the government has published a set of guidelines to help city governments prepare heat action plans. Ahmedabad was the first Indian city to develop such a policy, together with an early warning system, which issues warnings seven days before a heatwave; allowing city officials to plan their response. After the implementation of the Heat Action Plan, reports suggest that heat related deaths in the city have fallen by around 20 percent.

Spearheading this effort has been the work of the Natural Resources Defense Council (NRDC), in partnership with the Indian Institute of Public Health – Gandhinagar. Their work, supported by the Indian Meteorological Department and the National Disaster Management Authority, has helped India’s cities to better prepare for heat than ever before.

Source: C40

Region: Global