【推荐1】Can cities and nature exist together? The answer is yes.

Visitors to Mexico’s second city, Monterrey, will not fail to be impressed by its mountains. But it is now set to be famous for another reason, its large, man- made environmental features.

Monterrey plans to build 18 green corridors (走廊) of trees to fight climate change. Taken together, these projects plan to create over 940,000 square meters of parks, and over 73 km of city streets, taking part in the “extreme tree planting”.

The city is set to start its plan for green corridors with the “Park Lake” project in the city’s northern area. This will create 80,000 square meters of green public space. In general, this first project aims to offer environmental services such as the water supply to deal with the problem of not having enough water, as well as combatting the extreme heat in the area, and to improve access to green spaces and recreational (娱乐的) areas for locals. The project is not about government actions; it is about creating community together with the people. It is realizing a good connection between companies, between people and government.

What is planned for the first stage of the project? Locals can expect increased recreational features like exercise areas and spaces for picnics, outdoor games, and quality play areas for children.

Designing Buildings reports that green corridors also connect the animals that have been separated by human development such as roads and houses, leading to an increase in the population of animals and preventing animals and plants from becoming too weak.

These green corridors are used for many different purposes, offering an impressive list of social and environmental benefits to humans, and wild animals and plants. These include greater city and environmental qualities such as recreational areas, community gardening, and the cooling space under the trees. They encourage sports activities, social communication, happiness in nature, and non-polluting vehicles such as bicycles. They also help to prevent heat islands from forming, and protect people from air pollution.

【推荐2】Not all waste has to go to waste. Most of the world’s 2.22 billion tons of annual trash ends up in landfills or open dumps. Veena Sahajwalla, a materials scientist and engineer at the University of New South Wales in Sydney, Australia, has created a solution to our massive trash problem: waste microfactories. These little trash processors— some as small as 500 square feet — house a series of machines that recycle waste and transform it into new materials with thermal technology. The new all-in-one approach could leave our current recycling processes in the dust.

Sahajwalla launched the world’s first waste microfactory targeting electronic waste, or e-waste, in 2018 in Sydney. A second one began recycling plastics in 2019. Now, her lab group is working with university and industry partners to commercialize their patented Microfactory technology. “The small scale of the machines will make it easier for them to one day operate on renewable energy, unlike most large manufacturing plants. The approach will also allow cities to recycle waste into new products on location, avoiding the long, often international, high-emission journeys between recycling processors and manufacturing plants. With a microfactory, gone are the days of needing separate facilities to collect and store materials, extract elements and produce new products,” says Sahajwalla.

Traditionally, recycling plants break down materials for reuse in similar products — like melting down plastic to make more plastic things. Sahajwalla’s invention evolves this idea by taking materials from an old product and creating something different. “The kids don’t look like the parents,” she says. For example, the microfactories can break down old smartphones and computer monitors and extract silica (from the glass) and carbon (from the plastic casing), and then combine them into silicon carbide nanowires. This generates a common ceramic material with many industrial uses. Sahajwalla refers to this process as “the fourth R” adding “re-form” to the common phrase “reduce, reuse, recycle”.

In 2019, just 17.4 percent of e-waste was recycled, so the ability to re-form offers a crucial new development in the challenge of recycling complex electronic devices. “We can do so much more with materials,” says Sahajwalla. “Traditional recycling has not worked for every recycling challenge.” She and her team are already working to install the next waste microfactory in the Australian town of Cootamundra by early 2021, with the goal of expanding around the country over the next few years.

【推荐3】In recent years, the popular idea of reducing carbon footprints by eating locally to cut down food miles has come under close examination. However, a recent study published in Nature Food indicates that global food miles might account for as much as 20 percent of food-related emissions, a significantly higher percentage than previous estimations. This statement begs the question: Are food miles more significant than we initially believed?

Food miles represent the distance food travels from production to consumption, with previous studies suggesting that the emissions from these miles are tiny compared to the emissions produced during the food growing process. For instance, producing one kilogram of beef generates almost 99 kg of CO₂, while apples only produce 0.4 kg per kilogram. If the goal is to minimize dietary carbon footprints, it would be more beneficial to choose foods with lower overall carbon footprints, even if they have to travel a distance. Therefore, reducing meat and dairy intake could prove to be a more effective strategy.

The recent study doesn’t contradict (相矛盾) this conclusion. The reason why the reported proportion is higher is that the calculation includes all transport involved, including the transportation of fertilizers, farm equipment, and pesticides (杀虫剂). Hannah Ritchie, a researcher at the University of Oxford, suggests that a term other than “food miles” would be more appropriate to avoid any confusion. If the study had followed the standard definition of food miles, the per-centage would drop to 9 percent, which corresponds more closely with the 4 to 6 percent found in prior research.

Moreover, the study theorizes that even if all food was produced in the countries where it is consumed, the reduction in emissions would only be 1.7 percent overall. This is due to the fact that a larger proportion of food would be transported by road rather than by sea, with trucks producing higher emissions per ton of cargo than ships.

“So, overall, the bottom line is still that what you eat has a much bigger impact on emissions than the distance that food has to travel to reach you,” said Ritchie.