Blog Post By Jona Elwell

On World Cities Day Today, How Trees Are Key to Sustainable and Resilient Cities

October 31 is a big day. Yes it’s Halloween (do you have a tree themed costume?) but it is also World Cities Day! Declared by the UN in 2014, World Cities Day is a way to promote the international communities growing interest in urbanization and the needs to address current and future concerns.

(Loic Pritchett/Washington Post)

Right now more than half the world lives in cities – that number is expected to jump to 68% by 2050. This is an issue that hits home too. More than 80% of Americans live in urban areas.

Even more concerning? The rise of ‘megacities’ – cities with more than 10 million inhabitants. In only 12 years it is estimated there will be 43 megacities.

As more and more of the earth’s inhabitants live cities it is imperative that sustainable development adapts and grows as well. Many countries will face challenges in meeting the needs of their growing urban populations, including the increasing rate and repercussions of climate change. In coming decades, building resilience will be essential urban policy and a smart investment for cities.

(Loic Pritchett/Washington Post)

This year alone we’ve seen the effects of the California wildfires, record breaking hurricane damage in San Juan, PR, Houston, TX and along the Florida Panhandle, super typhoon winds throughout Hong Kong, and even a devastating earthquake in Oaxaca, Mexico. It’s clear resiliency in urban life is a growing concern. Therefore, it’s fitting that the theme for World CIties’ Day is Building Sustainable and Resilient Cities.

Thankfully D.C. is taking a proactive approach. Back in 2016 the District Department of Energy and the Environment (DOEE) drafted the Climate Ready D.C. Plan –  the District’s strategy for making our city more resilient to future climate change while helping to ensure that it continues to grow greener, healthier, and more livable. Thanks to the tireless effort of our advocacy team and volunteers, the city adapted an easy management tool, and one of the smartest investments for resilient cities – trees!


D.C.’s trees are an incredible tool for dealing with the effects of climate change. They work really hard to absorb excess stormwater and to cool surrounding air. Tree leaves catch rain at the canopy level too — that reduces the sheer volume of stormwater that can overwhelm our sewer system during heavy storms. We recommended everything from planting trees in raingardens, to strategically planting trees near buildings to keep them cooler, and planting trees near riverbanks to keep soil stable during floods. Ultimately all of these strategies were incorporated into the final Climate Ready DC Plan!

So this World Cities Day, what are you doing to ensure our city is resilient? If you can’t think of anything, join us for a tree planting, advocacy event, or inventory to increase tree canopy and D.C.’s climate resilience.

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