Cities, home to half the world’s population, face a myriad of climate change risks (flooding, sea inundation, heat waves, droughts..etc) according to a report by the UN’s Intergovernmental Panel on Climate Change (IPCC) published on Monday. Here are the main ones:
- Climate risks are increasing for the 4.2 billion people living in cities, as well as for buildings and infrastructure.
- The main threats are “heat stress” – when temperatures exceed what the human body can tolerate – and flooding, as well as the consequences of climate-related disasters that can affect the supply of food, water, and other essential resources.
- It is estimated that by the year 2050, the urban population is expected to grow by 2.5 billion people, especially in areas that are particularly vulnerable to climate change, on coastlines in Africa, Asia, and small islands.
- More than a billion people living in low-lying coastal areas could be flooded by 2050 as climate change leads to rising sea levels, more frequent and heavier rainfall, and more powerful tropical storms.
- If the average global temperature rises 2°C above pre-industrial levels, damage to infrastructure could cost $4.2 trillion by 2100.
- Between half and three-quarters of the world’s population, mainly in cities, could face unbearable conditions of extreme heat and high humidity by 2100, depending on the degree of global warming. The threat is particularly acute in tropical regions.
- Heat waves could reduce working capacity by 20% by 2050 in the hottest months.
- Urban areas prone to floods and droughts could more than double between 2000 and 2030.
- Another 350 million people could suffer from water shortages if global temperatures rise by 1.5°C, and 410.7 million at 2°C.
- For many cities, the threat is multiple. Of the 571 cities analyzed in Europe, more than 100 are exposed to two or more climate change impacts.
The challenge of adapting urban space
- If global warming reaches 2 to 2.5°C, at least 25 megacities will be affected by sea level rise.
- A sea level rise of 15 cm would be enough to increase the number of people exposed to 100-year floods by about 20 percent.
- Ports and airports built on land at sea level are likely to be flooded. At 2°C warming, 338 airports would be under water.
- With urbanization in Asia, the continent’s cities are “very vulnerable” to future flooding. In Indonesia, the risk of flooding will increase by up to 120% between 2000 and 2030.
- This increased risk for coastal cities and small islands will lead to a need to plan for population relocation.
- An additional 122 million people will live in extreme poverty by 2030 under a scenario where inequalities will increase.
- In urban areas, the most socially and economically marginalized residents and communities will be hardest hit.
- The number of people living in coastal settlements could increase if states fail to reduce poverty and inequality.
- Energy-intensive urban development makes them even more vulnerable to climate change and dependent on fossil fuels.
- Adaptation to climate change in urban areas is essential for the health and well-being of the majority of the world’s population.
- According to the report, the phenomenon of “climate gentrification” means that poor communities will be replaced by wealthier populations in less vulnerable areas.
- Setting efficiency standards for buildings and rethinking urban planning, such as pedestrian zones, can increase the effectiveness of adaptation measures.
- Nature-based solutions such as trees, green roofs, and parks can absorb excess water during heavy rains, are effective, promote health, and create jobs if implemented on a large scale.
- The human body will not be able to adapt to certain extreme weather conditions, leading to “irreversible” consequences.