How a Colombian City Cooled Dramatically in Just Three Years

A collaboration between tree-planting organizations in Washington D.C. helps Catholic church properties to plant and care for trees. The free trees are an effort to combat urban heat and benefit the local environment.

The Texas Trees Foundation is bringing thousands of trees to Dallas communities experiencing the worst of the urban heat island effect to help keep them cool. The organization supplies the trees and teaches residents how to care for them.

In Phoenix, Arizona, a citywide tree-planting initiative is slowly increasing canopy cover to reduce the urban heat island effect in neighborhoods that need it the most. Residents pick between several varieties of desert-adapted trees, which are planted on their property by professional arborists, and take care of them with a provided kit.

Organizations in cities across the United States, including Philadelphia and Tucson, are simultaneously combatting urban heat and hunger by planting fruit trees and edible plants that provide shade and food that community members can harvest.

The Office of Heat Response and Mitigation works to address the urban heat effect caused by intense summer temperatures. The Office has worked on several practices like coating streets and surfaces in light-colored, water-based asphalt treatments that reflect sunlight and absorb less heat than standard pavement. So far, 100 miles of residential roads have been covered in the treatment and roads with the treatment have an average surface temperature that is 10.5 to 12 degrees Fahrenheit lower than traditional asphalt.

In Paris, building-based agriculture, like rooftop gardens, allows for the production of nutritious food close to where they will be eaten. The practice helps eliminate carbon emissions, improve food security, and improve climate resilience.

The city of Amsterdam funded a blue-green roofs program to reduce both flooding and the urban heat island effect. The water collection system stores and releases rainwater, the variety of indigenous plants increase biodiversity, and the connected digital network allows them all to be controlled remotely.

Bulk-purchase "group-buy" programs for heat pumps have achieved 15-30% cost savings for participants, and on Gabriola Island, over 1,000 units have been installed, making carbon-free heating and cooling more accessible.

In Spain, Higueruela transformed wind farm revenues into municipal investments—funding schools, transportation, senior care, and local jobs—which stabilized the town's declining population and created a sustainable economic model that now provides 40% of its annual budget. A key success factor includes allowing the community to negotiate and reject projects that don't serve local interests.

The creation of forest gardens—the modern term for an ancient agroforestry model that mixes shrubs, herbs, vines, fruit and nut trees, and perennial vegetables—are helping supply communities in sub-Saharan Africa with food, medicine, and animal feed. The U.S.-based NGO TREES claims to have created 38,000 active forest gardens in five countries, each comprising about 4,000 trees. This has restored 99,743 acres of degraded land, having reached 56,273 farmers and their families across 174 community projects.