Green and Cool Roofs Provide Relief for Hot Cities, but Should be Sited Carefully

A housing project in Brooklyn is taking nine apartment buildings and retrofitting them to be more sustainable and cut carbon emissions. Casa Pasiva is a $20 million project that aims to reduce heating and cooling costs because of updated machinery and thick exteriors that will improve air quality. Funding for these types of initiatives is not always certain, but a collaboration between a developer and a nonprofit, with some city financing, made this first-of-a-kind green building renovation in New York possible.

CityTree doesn't resemble the typical tree, but it provides the environmental benefit of 275: this structure, designed for urban landscaping by "Green City Solutions," filters air, cools the surrounding environment and removes CO2 and harmful air pollutants. As climate change worsens our air quality, these structures have proven to monitor and combat the air pollutants in cities all over the world.

To reduce greenhouse gas emissions that contribute to climate change and air pollution, Habitat for Humanity Salt Lake Valley is building airtight homes that will also reduce energy costs and be affordable for people experiencing economic hardship. The home are largely being built by volunteers, so the process has been slow and there have been mistakes in building the homes. However, the homes are estimated to reduce carbon dioxide emissions by 4.9 tons a year.

The United Kingdom has started cracking down on high-emission vehicle drivers by creating restricted zones that fine drivers of cars that emit a designated amount of pollution into the air; the carbon emissions in this type of zone in London has decreased by more than a third in six months. Now, the U.K. is taking their sustainability initiative a step further by labeling low-emission cars with green license plates that allow them to be easily recognized - and rewarded.

An economic shift to renewable energy could take decades, but thanks to rapidly evolving disruptive technologies, dropping prices of solar and wind power sources, and increasing market demand for green business, the new age of renewable energy could encompass the world economy much more quickly.

Organizations in Egypt and Bangladesh are greening their cities by turning rooftops into urban gardens that can grow food, reduce air pollution, and decrease air temperatures. Green Savers in Dhaka has installed more than 5,000 rooftop gardens in the city and Urban Greens in Cairo partners with sponsors to install hydroponic rooftop gardens for families experiencing economic hardship. It’s been a challenge to convince people that the cost to maintain these spaces is worthwhile, but through community outreach efforts, these organizations have seen an increase in interest in installing rooftop gardens.

Paris Habitat, the city’s main social housing agency, used hempcrete — a concrete-like mixture of hemp, lime, and water — as insulation in one of its apartment complexes. This material helps maintain temperature and reduces a building’s energy use and greenhouse gas emissions. The cost of using hempcrete can be expensive but making the material is more environmentally friendly, and has shown that it can be implemented for affordable housing and not just for those who already have the means to pay for it.

Scientists at Oxford University have come up with a process that could turn carbon dioxide into jet fuel. The greenhouse gas, which is a major contributor to climate change, is constantly emitted by the aviation industry and this method would allow for that gas to be recycled into a liquid fuel for flights. Scaling the experiment has its challenges, but the process could result in net-zero emissions from airplanes.

In Paris, about 7,500 buildings are heated using geothermal energy, a cost-saving and carbon neutral energy source. Water is drawn from deep below ground at a central location and heated by the earth, and then sent via underground pipes to individual buildings. The Bagneux and Chatillon district has scaled up the system, providing heat to over 40,000 people. Districts created joint ventures to reduce construction costs and residents do not notice the energy source shift because when the temperature drops to a point where geothermal energy is not viable, gas boilers automatically keeps the heat flowing.

With rising temperatures occurring all over the world, cities are implementing plans to combat heat waves and protect its residents. The city of Ahmedabad in India has been a model for heat resiliency after it created its first heat action plan that centered around “community-focused social measures.” Because of the plan, a 2015 heat wave resulted in fewer than 20 fatalities compared with thousands of deaths in previous years. Other cities like New York City are also participating in heat resiliency efforts aimed at protecting all of its residents.