Why cities will sense climate change faster and harder

In 1950, only 30 percent of the world’s population lived in urban areas; Today it’s 56 percent, and is expected to rise to 68 percent by 2050. In less than 30 years, three out of four major cities in the world will have a climate very different from what they designed their infrastructure for. If these urban areas do not adapt to climate change, millions of people are at risk.

For cities in temperate latitudes, climate change means more heat waves and shorter cold seasons. For cities located in subtropical and tropical latitudes, this means wetter rainy seasons and warmer dry seasons. Most coastal cities – anywhere – are threatened by sea level rise.

All over the world, cities will face a much greater chance of extreme weather events. Depending on its location, this includes heavy snowfall, severe droughts, water shortages, heat waves, larger floods, more wildfires, severe storms, and longer storm seasons. The most vulnerable populations will bear the heaviest costs: the elderly, the poor, and others who lack the wealth and political connections to protect themselves.

new climate system

Severe weather isn’t the only concern. Study from 2019 520 cities around the world have predicted that even if countries limit temperature rise to 2°C above pre-industrial conditions, climate zones around the world will shift hundreds of miles north by 2050. This would result in 77 percent of cities Those studied experience significant change in their climate systems throughout the year.

For example, the study authors predicted that by mid-century the climate in London would be similar to that of modern Barcelona. In short, in less than 30 years, three out of four major cities in the world will have a climate very different from what the urban form and infrastructure were designed for. A similar study examining the effects of climate change on more than 570 European cities predicted that within 30 years they would face an entirely new climate system – one characterized by more heat waves, droughts and increased flood risks.

Cities generate more than 70 percent of global greenhouse gas emissions, mainly from building heating and cooling and the presence of cars, trucks, and other vehicles.

very slow

Urbanization also makes people more vulnerable to the effects of climate change. For example, as cities expand, people are removing vegetation, which can increase the risk of flooding and sea level rise. They also create sealing surfaces that do not absorb water, such as roads and buildings. This increases flood risk and produces urban heat islands.

At best, urban infrastructure built for past climate regimes and less severe weather events can be modified at a rate of about 3 percent per year. At this rate, which is difficult to maintain even for the world’s richest cities, it will take decades to make cities more sustainable and resilient. The most vulnerable city-dwellers live in the developing world’s fast-growing cities such as Dhaka, Bangladesh, Lagos, Nigeria and Manila in the Philippines, where local governments rarely have the resources to make the expensive changes needed.

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