Since there are no currently active contests, we have switched Climate CoLab to read-only mode.
Learn more at
Skip navigation
Share via:


Build a rooftop garden harnessing both urban farming and recycling of usable water.



Gardens wouls be built on rooftops to reduce sunlight reflection from roof materials, and to reduce greenhouse gas levels. Roof materials such as concrete, metal, and some paints increase the amount of sunlight that is reflected into the atmosphere. Because of the photosynthesis process, carbon dioxide would be lowered by a rooftop garden. It also helps to conserve water, by using greywater. Greywater is used wastewater from showers, dishwashers, and other appliances that is safe for plants. Pipelines would be connected from sources of greywater to an irrigation system on the roof. This would help to make water use more efficient and less wasteful.

Category of the action


What actions do you propose?

People would need to construct the garden, pipes, and irrigation system. It could also be used for public work.

Who will take these actions?

Landowners, local governments and/or plumbers, technicians, and garden specialists.

Where will these actions be taken?

urban and suburban environments

What are other key benefits?

Apart from the environmental and water impacts, garden care can be used by local governments as public work to lower unemployment.

What are the proposal’s costs?

Cost of pipes, plants, and building services would vary.

Time line

It is mostly a short term project, but the scale of building can increase over the medium term.

Related proposals


Environmental Protection Agency

National Aeronautics and Space Administration

GRACE Communications Foundation