7 Ways Cities Can Prepare for the Urban Heat Island Effect


urban heat island effect

We know the earth is getting warmer. And we know the effect climate change has on people’s lives varies based on where you live. Whether your biggest concern is likely to be rising seas, drought, or more intense storms depends on the region you live in, the urban heat island effect will soon be a world-wide phenomenon.

However, one thing not as many people know is that the effect will intensify for anyone living in densely-populated areas

What is the Urban Heat Island Effect?

The urban heat island effect occurs when:

  • Natural surfaces are replaced by concrete and buildings
  • A high concentration of people all use energy
  • A high concentration of cars let off heat and exhaust
  • There is less greenery to remove carbon dioxide (CO2) from the air and provide shade
  • Tall buildings block wind movement and have reflective surfaces which multiply the sun’s effects

When you add all that up, you have a contained space that captures and magnifies the heat caused by weather conditions, making it much worse than in areas with a lower density of people.

hot city

Should You Be Concerned?

This doesn’t simply mean people in cities will be dealing with hotter days in the summer. The urban heat island effect is projected to cause some serious problems in coming years:

Significant Economic Losses

Analysts predict that the economic effects of climate change will be severe, with cities losing up to 11% of their GDP due to related costs, including:

  • The increased price of cooling in a hotter environment
  • The effects of dealing with greater air pollution and water quality issues
  • A decrease in worker productivity
  • A lower desire to be outdoors (which several industries depend on)

A Larger Contribution to Global Warming

The local effects are serious enough, but as people in cities respond to the increased heat by cranking up their ACs and using even more energy, cities will also play an outsized role in contributing to global climate change. When researchers run climate change models that take urban heat islands into effect, it adds an increase of 2°F for the most populated cities, and a global economic cost that’s 2.6 times higher than the predictions that don’t account for it.

7 Steps We Can Take to Reduce Urban Heat Island Damage

It’s not all bad news. Attacking climate change at the global level requires getting countries from all around the world to work together, which is difficult for a wide variety of reasons. Making local moves to reduce the effects of urban heat islands is much more within reach for most cities and can have a positive influence on the global problem as well.

There are a few steps highly populated cities can take to make a difference.

1. Turns roofs green

Many cities have started to turn the space available on roofs into green spaces. This solves two problems at once: it replaces the surface that absorbs heat and makes homes hotter. Plus, it adds more beautiful greenery to the city to help absorb CO2 at the same time.

green roofs to prevent urban heat island effect

2. Install more cool roofs

While green roofs are ideal, they’re not a practical replacement for all roofs. Another helpful alternative is installing cool roofs that are made of materials designed to reflect the sunlight and heat away from the building rather than capturing it. Researchers predict that cities that replace even just 20% of their current roofs with cool roofs would save 12 times the amount of what the roofs would cost, and would reduce the temperature by close to one degree.

3. Make pavement reflective

Like cool roofs, cities can install cool pavements that are made of materials that reflect heat rather than absorbing it and enhance water evaporation. This both cools the surface of the pavement itself and the air around it.

4. Plan more green spaces

Green roofs are a start, but cities can benefit from more green spaces all around. City planners should look for opportunities to add parks – even small ones – to the city to offset some of the effects of urban development.

5. Plant more trees

Where parks can’t fit, go ahead and at least add some trees. Many cities have already taken on the goal of planting large numbers of trees to help offset pollution, add shade, and improve quality of life for residents.

6. Incentivize a move toward more energy-efficient appliances

One recommendation the EPA offers for reducing heat islands is a switch to more energy-efficient appliances. This is something your average consumer can do to contribute (and a move that will save you money in energy costs), and one that cities can find ways to incentivize.

7. Install sprinklers on roofs

Roof sprinklers, which are currently used primarily in areas prone to wildfires to reduce the damage, can also be used in the fight against the urban heat island effect. The sprinklers cool the roof itself, as well as the air around it through evaporation.

Some cities are already starting to make some of these moves, but as climate change continues to worsen in the coming years, more initiatives designed to respond to and reduce urban heat islands are needed. Solutions exist; we just need to get to work implementing them.