Green walls, designed so they are covered in vegetation, could help cut the amount of noise that enters buildings, a new study has found. In lab. tests, researchers found that a modular green wall system reduced sound levels by 15 decibels (dB). This leads them to believe that it is a promising sound reduction device that could improve quality-of-life for city residents.

Costs of installing, maintaining and disposing of some green wall systems may outweigh the value of some of their benefits for householders, a recent study suggests. While the researchers omitted some of the wider social benefits, they found that reductions in heating and air conditioning costs, longevity of green walls and increases in property values did not compensate for their costs. The researchers suggest that government incentives to lower set-up costs could significantly increase the walls' economic sustainability.

Desertification and land degradation affect the lives of around three billion people, according to UN estimates. Two ambitious projects aim at halting desertification and returning soil to productivity: the Great Green Wall project in northern Africa; and the Green Great Wall initiative in China.

We've heard of transformer apartments, but what about a transformer garden. These movable green walls create flexible outdoor spaces.