Designing and building climate-resilient cities
As the effects of climate change intensify, cities and countries around the world are working to become more climate resilient. What challenges are they facing, and how can we build more climate-resilient cities?
Fires and floods, droughts and downpours, blizzards and cyclone bombs: the extreme weather seen around the world this year, which has killed thousands and forced millions from their homes, is in line with predictions under climate modeling of global warming.
Record temperatures have been recorded across North America and Europe, and in China, India and Pakistan, with wildfires and droughts destroying homes and livelihoods, contributing to global food shortages and disrupting business. At the same time, climate-change-related flooding and storms are destroying lives and livelihoods, driving millions from their homes in several countries around the world. Extreme winter weather across the USA paralyzed much of the country over the 2022 holiday season, leaving dozens dead.
Communities around the world are looking for and implementing solutions to improve their resilience. Here we look at what some cities are doing, both to reduce their contributions to global warming and adapt to cope with the effects today and tomorrow.
What is climate resilience?
Climate resilience is generally described as the ability to prepare for, recover from and adapt to the impacts of climate change. It is widely seen as requiring two related but separate processes: mitigation and adaptation. Mitigation refers to reducing a community’s or building’s impact on the environment, particularly in regards to climate change, by for example reducing carbon emissions. Climate adaptation refers to preparing for the existing or coming effects of climate change, by for example improving defenses against flooding or storms.
The ways communities are working to improve their climate resilience vary widely, just like the effects of extreme weather. Some cities are trying to preserve natural defenses, while others are building climate-resilient infrastructure.
The lessons we learn today will also help us build the cities of the future. First, let’s look at the effects of the extreme weather this year. It makes for grim reading.
Heatwaves and droughts
The most obvious effect of climate change is increasing temperatures. During 2022, these have led to record heatwaves across many countries and regions, with devastating results including wildfires and droughts, as well as excess deaths attributed to the heat.
Modeling of climate change has long predicted increasing temperatures, but heatwaves are becoming hotter even more quickly than researchers had feared.
Petteri Taalas, secretary-general of the World Meteorological Organization, said more frequent and more extreme heatwaves were an inevitable consequence of climate change. “In the future, these kinds of heatwaves are going to be normal. We will see stronger extremes. We have pumped so much carbon dioxide in the atmosphere that the negative trend will continue for decades,” Taalas said. “I hope that this will be a wake-up call for governments.”
Warming leads to floods
The flip side of the same coin has seen storms, heavy rains and glacial melting causing devastating floods in countries including India, the US, Pakistan and Australia. China has seen a summer of extremes, with record-breaking heatwaves and drought, as well as rainfall and flood disasters. In Pakistan, floods inundated an estimated one-third of the country, killing more than 1,500 and affecting more than 30 million people. After lashing Cuba, Hurricane Ian became the deadliest hurricane to hit Florida, killing more than 100 people.
Global warming is recognized as a major factor behind extreme rainfall and flooding. In a normal weather cycle, warm weather causes water to evaporate, creating moisture and water vapor in the air. This vapor turns into droplets, which fall as rain. As the air becomes even warmer, it can retain more and more moisture; when this then turns into rain, the resulting downpours are heavier and more intense, falling more quickly over smaller areas.
So what can countries and cities do? Philadelphia, in the United States, is an example of how a city can act both in terms of reducing its climate impact and in designing and building infrastructure to withstand climate effects, given the limitations communities face, cited by Inside Climate News.
Hurricane Ida swept through the east coast of the USA in August 2021. In Philadelphia and Pennsylvania, Ida killed four people, damaged property worth millions of dollars, and knocked out water plants. More than 80,000 households applied for emergency relief.
Even before Ida, the city knew that it needed to act to improve its climate resilience and protect itself from climate change. The Philadelphia Climate Action Playbook, released in January 2021, spells out how the city can both reduce its impact on the climate and prepare to cope with climate change’s worst effects. As well as an increased risk of hurricanes and storms, “Philly” has also had to deal with increasing temperatures and resulting effects on health.
Mitigation measures identified in the playbook include:
- Clean and lower-carbon electrical supply, including expanding solar
- Lowering municipal energy use
- Improving the energy efficiency of buildings through legislation and benchmarking
- Expanding and improving the public transit system and bike route network
- Expanding the electric vehicle charging network and updating the city’s own fleet
- Reducing city, residential and industrial waste
To cope with the effects of climate change, measures include:
- An improved stormwater and sewer overflow system
- Incorporating climate change into future city planning
- Preparing for public health risks stemming from climate change
- Convening a Flood Risk Management Task Force
- Neighborhood initiatives such as a Beat the Heat park.
Some cities are able to use their natural surroundings to protect against events such as flooding, a quality referred to as “sponginess”. Auckland, the largest city in New Zealand, was recently named as the spongiest in the world, thanks to the way it uses its natural surroundings to protect against flooding.
Parks and natural waterways act as buffers in case of flooding, protecting housing in adjacent neighborhoods. Auckland has enhanced the effects by returning some concreted waterways and wetlands to their original state.
Coping with downpours
Some effective solutions for coping with downpours and flooding can sound surprisingly simple. The Danish Water Sensitive Urban Design site features several such solutions, including a pilot in Frederiksberg, a suburb of Copenhagen. After houses along a street were flooded, the asphalt was replaced with tiles that allow the rainwater to pass through into a reservoir of gravel, rather than pooling on the surface.
Finding the right solutions
The challenges facing countries vary dramatically, and a variety of measures are being trialed or used around the planet.
Part of the World Bank, the International Finance Corporation has introduced the Building Resilience Index to help governments, developers, financial institutions, insurers and other stakeholders to identify, manage and disclose risks from environmental hazards such as storms, flooding and fires.
The World Bank reported in 2019 that investing in more resilient infrastructure could save USD 4.2 trillion, as well as reducing impacts on lives particularly in middle and low-income countries.
In its recent Practical Guide to Climate-resilient Buildings & Communities, the UN Environment Program lays out ways for communities to build to improve resilience against:
- Coastal flooding and sea-level rise
- Cyclones and strong winds
Equipping our communities for the future
The effects of climate change are being felt today in countries, cities and towns around the world. Finding the right solutions for each community is vital, and becoming increasingly urgent. By working together to identify and implement smart solutions, by building sustainable and resilient infrastructure and homes, we can slow global warming and equip our communities for the future.
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