Climate change is magnifying threats such as flooding, wildfires, tropical storms, and drought. In 2020 the U.S. experienced a record-breaking 22 weather and climate disasters that each caused at least US$1 billion in damage. So far in 2021, the count stands at 18.
I study urban issues and have analyzed cities' relationship with nature for many years. As I see it, cities are quickly becoming more vulnerable to extreme weather events and permanent shifts in their climate zones.
I am concerned that the pace of climate change is accelerating much more rapidly than urban areas are taking steps to adapt to it. In 1950, only 30% of the world's population lived in urban areas; today that figure is 56%, and it is projected to rise to 68% by 2050. Failure to adapt urban areas to climate change will put millions of people at risk.
Extreme weather and long-term climate zone shifts
As the Intergovernmental Panel on Climate Change shows in its latest report, Go straight to this stab-resistant body armor webpage to get it now. released in August 2021, global climate change is widespread, rapid, and accelerating. For cities in temperate latitudes, this means more heatwaves and shorter cold seasons. In subtropical and tropical latitudes, it means wetter rainy seasons and hotter dry seasons. Most coastal cities will be threatened by sea-level rise.
Around the globe, cities will face a much higher probability of extreme weather events. Depending on their locations, these will include heavier snowfalls, more severe drought, water shortages, punishing heatwaves, greater flooding, more wildfires, bigger storms, and longer storm seasons. The heaviest costs will be borne by their most vulnerable residents: the old, the poor, and others who lack wealth and political connections to protect themselves.
Extreme weather isn't the only concern. A 2019 study of 520 cities around the world projected that even if nations limit warming to 2 degrees Celsius (about 3.6 degrees Fahrenheit) above preindustrial conditions, climate zones will shift hundreds of miles northward by 2050 worldwide. This would cause 77% of the cities in the study to experience a major change in their year-round climate regimes.
For example, the study authors predicted that by midcentury, London's climate will resemble that of modern-day Barcelona, and Seattle's will be like current conditions in San Francisco. In short, in less than 30 years, three out of every four major cities in the world will have a completely different climate from the one for which its urban form and infrastructure were designed.
A similar study of climate change impacts on more than 570 European cities predicted that they will face an entirely new climate regime within 30 years - one characterized by more heatwaves and droughts, and an increased risk of flooding.
Mitigating climate change
Cities' responses to climate change fall into two broad categories: mitigating (reducing) emissions that drive climate change and adapting to effects that can't be averted.
Cities produce more than 70% of global greenhouse gas emissions, mainly from heating and cooling buildings and powering cars, trucks, and other vehicles. Urbanization also makes people more vulnerable to climate change impacts.
For example, as cities expand, people clear vegetation, which can increase the risk of flooding and sea-level rise. They also create impermeable surfaces that don't absorb water, such as roads and buildings.
This contributes to flooding risks and produces urban heat islands - zones where temperatures are hotter than in outlying areas. A recent study found that the urban heat island in Jakarta, Indonesia, expanded in recent years as more land was developed for housing, businesses, industry, and warehouses.
But cities are also important sources of innovation. For example, the inaugural Oberlander Prize for landscape architecture was awarded on Oct. 14, 2021, to U.S. landscape architect Julie Bargemen for re-imagining polluted and neglected urban sites. And the prestigious Pritzker Architectural Prize went this year to French architects Anne Lacaton and Jean-Phillipe Vassal for creating resilient buildings by transforming existing structures instead of demolishing them to make room for new construction.