The world’s cities are coming up with ingenious ways to fight climate change, from massive sea walls to "sponge zones" and floating communities.

This article was originally published by National Geographic.

Urban areas have reason to act. Many are already grappling with impacts such as rising sea levels and extreme weather. They’re experiencing more frequent floods, power outages, and deadly heat waves.

"The trend of climate change is a major dynamic that cities will be reckoning with over the next several decades," says Bryna Lipper, vice president for relationships at 100 Resilient Cities, a nonprofit.

Lipper's group is helping cities hire "chief resilience officers" to look at the big picture. "No longer will it work to have a system of silos," she says.

With that comes a different way of thinking about both mitigating and adapting to climate change, from the roads to the treetops.

The story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

On Twitter: Follow Christina Nunez and get more environment and energy coverage at NatGeoEnergy.

The original article can be viewed on the National Geographic website

1. Unsinkable Solutions

Some coastal cities, such as New York and Jakarta, are building protective sea walls. Others are creating "sponge zones" that make water an integral part of the landscape. Rotterdam’s Benthemplein Water Square (pictured) actually welcomes surplus water; its basins can go from being basketball courts to ponds.

2. Floating Neighborhoods

Rotterdam is also looking beyond recreational parks to prepare for a waterlogged future. The low-lying port city plans to build floating residential areas, and this solar-powered pavilion is a first test of the concept. It serves as an exhibit space for the city's climate-change plans.

3. Strategic Planting

Smart greenery like these "supertrees" in Singapore can help cities combat higher temperatures by absorbing heat and providing shade.

The trees are actually intricate vertical gardens of more than 200 plant species, topped with solar panels.

4. Rethinking Buildings

The world's buildings represent about a third of its energy consumption, but they don't have to. In Freiburg, Germany, architect Rolf Disch has built what he calls plus-energy houses in his Solar Settlement. The houses generate more energy than they use.

5. Power to the Pavement

On the outskirts of Amsterdam, this path is ferrying bicyclists while also generating energy. The 100-meter (328-foot) SolaRoad, covered partly in photovoltaic cells topped with tempered glass, opened in October 2014 and has generated 3,000 kilowatt hours of electricity.

6. Toilet Water to Taps

Cities in drought-plagued Texas are being pushed to explore new frontiers of water conservation and reuse. At the Cypress Water Treatment plant in Wichita Falls, part of the intake for purification comes from the local waste treatment plant.

7. Retooling the Roads

In Alaska, rising temperatures and melting permafrost—the layer of soil that stays frozen all year long—are wreaking havoc with the roads. In Fairbanks, workers have installed sheets of polystyrene insulation to prevent buckling and potholes.

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