Some weeks ago I read an article Urban greening can save species, cool warming cities, and make us happy. On an over-hot day in London it seems appropriate to give you the tl;dr version (edited quotes):

The current climate and ecological crisis demands a radical redesign of how we live and organise society. These urgent changes, although complex, are far from impossible.

Some are simple, beautiful, and beneficial to all. By greening our cities with street trees, urban parks, and community and rooftop gardens, we can keep ourselves cool amid rising temperatures, reverse the steady erosion of the rich tapestry of life on Earth, and foster happiness and social connection in the process.

Greenery in urban spaces helps improve city microclimates. While hotter cities compel urbanites to increase air conditioning in order to stay cool, on a sunny day, a single healthy tree can have the cooling power of more than ten air-conditioning units.

Plants also help keep harmful pollutants such as microscopic particulate matter at bay. While some vehicles are needed in city centres, mass greening can help negate their pollution and keep cities cool.

Evidence shows numerous social, psychological, and health benefits of human exposure to green spaces, including: stress and anxiety reduction, improved cognitive functioning, lowered risks of depression, and overall greater mental and physical well-being; involvement in community gardening can increase social cohesion and social bonds.

Human socio-economic activities, especially those of the world’s rich, have destroyed natural habitats, consumed vast tracts of forest, polluted waterways, and disrupted the seasonal rhythms on which life depends. But (re-)establishing wild meadows and native plant and tree communities provides essential pollinators with new spaces to thrive, while creating spaces to reintroduce keystone species.

Mass greening and rewilding of our cities is already happening in many urban spaces around the world. The Mayor of Paris has ambitious plans to “green” 100 hectares of the city by 2020 and London’s Mayor hopes to make London the world’s first “National Park City” through mass tree planting and park restoration.

Urban greening alone will not be enough to meet the daunting challenges ahead; we also need to fundamentally transform our growth-oriented economies and massively reduce global inequality.