Skyscrapers of the future may rely heavily on your trash from today.

Scrap metal, algae, recycled cardboard and plastic bottles are all among a list of materials being considered by scientists and engineers around the world who are hoping to reduce the carbon footprint without slowing development, Popular Science reports. The goal, according to the U.S. Green Building Council, is for buildings to produce the same amount of energy they use by 2050.

Buildings currently generate pollution from two primary sources — steel and concrete. Both have large carbon footprints and use a lot of electricity, which burns carbon-intensive coal and natural gas.

To combat this, experts are looking to repurposed garbage as a potential solution. Items like insulation can be created using recycled cardboard and carpet can be made with old plastic bottles.

Engineers are also looking to wood as a better way to build. In addition to eliminating some steel and concrete materials, trees naturally soak up carbon and lock it away, preventing it from leaking back into the atmosphere.

A 20-story wood building could seize an estimated 3,000 tons of carbon per year, which is approximately the same as the output of 600 cars — making it a viable solution for sustainable design of the future.