3 . In ancient Egypt, the rich soils along the Nile River supported roughly 3 million people. Now there are 30 times that number of people living in Egypt, with the Egyptian population soaring from 45 million in the 1980s to over 100 million now.

Just 4% of Egypt’s land is suitable for agriculture, and that number is reducing quickly due to the urban and suburban development. “It’s not an overstatement to say that this is a crisis,” said Nasem Badreldin, an expert at the University of Manitoba. “Satellite data shows that Egypt is losing about 2% of its farmland per decade due to urbanization, and the process is speeding. If this continues, Egypt will face serious food security problems.” According to one analysis, the amount of farmland near Alexandria dropped by 11% between 1987 and 2019, while urban areas increased by 11%. In recent years, the Egyptian government has promised to end unlicensed building on farmland, which remains a difficult task to fulfill.

Urbanization isn’t the only factor to reduce Egypt’s farmland. Sea level rise of 1.6 millimeters per year has contributed to the salinization (盐碱化) of farmland in Egypt. About 15% of Egypt’s richest farmland has already been damaged by sea level rise and saltwater intrusion (侵入). One response to the loss of farmland has included efforts to green parts of the desert. For instance, Farouk El-Baz, Boston University scientist, has planned to build highways, railways, water pipelines, and power lines to promote the establishment of new farmland in deserts west of the delta.

While that project hasn’t been finished, much of desert has turned into farmland in recent decades. The satellite photos show new farmland along the Cairo Highway. A mixture of center-pivot irrigation (灌溉) and drip irrigation makes farming in this area possible. “It is certainly possible to establish new farmland from the desert by tapping groundwater resources, though it’s a little expensive process,” said Badreldin.

5 . Deserts could be the best places on Earth for harvesting solar power. They are spacious, relatively flat, and never short of sunlight. So researchers imagine it might be possible to transform the world’s largest desert, the Sahara, into a large solar farm, capable of meeting four times the world’s current energy demand.

While the black surfaces of solar panels absorb most of the sunlight that reaches them, only around 15% of that incoming energy gets turned into electricity. The rest is returned to the environment as heat, affecting the climate. If these effects were only local, they might not matter in a thinly populated desert. But the area of the installations in the Sahara would be vast, covering thousands of square miles. Heat released from an area this size will be redistributed by the flow of air in the atmosphere, having regional and even global effects on the climate.

A 2018 study used a climate model to assess the effects of building massive solar farms in the Sahara. The model revealed that when the size of the solar farm reaches 20% of the total area of the Sahara, the heat released by the darker solar panels creates a big temperature difference between the land and the surrounding oceans that ultimately lowers surface air pressure and causes wet air to rise and condense (凝结) into raindrops. With more rainfall, plants grow and the desert reflects less of the sun’s energy since vegetation absorbs light better than sand and soil. With more plants present, more water is evaporated (蒸发), creating a better environment that causes vegetation to spread.

So, a large solar farm could generate enough energy and at the same time turn one of the most abominable environments on Earth into a habitable place. Sounds perfect, right? Not quite. In a recent study, we used an advanced Earth system model to closely examine how Saharan solar farms interact with the climate. It showed there could be unintended effects in remote parts of the land and ocean.

We are only beginning to understand the potential consequences of establishing massive solar farms in deserts. Solutions like this may help society reduce the use of fossil energy, but Earth system studies like ours underscore the importance of considering the numerous coupled responses of the atmosphere, oceans, and land surface when examining their benefits and risks.

An Interview about Plastic Pollution

8 . One of the biggest topics of the last decade, sustainability has become the beacon (灯塔) of hope to protect the planet. From supermarkets taking action on plastic packaging to the zero waste movement that can be practised from your kitchen, changes made by individuals and organizations across the globe has had an impact on the way we think, shop and live.

So what does that mean for the world of technology? You’d be forgiven for thinking that the words “sustainable” and “tech” don’t usually go hand in hand.E-waste is, after all, one of the planet’s biggest contributing waste streams. Not only that, but the materials that go into tech products are also part of the problem.

But with a challenge comes an opportunity, and there’s already some brilliant progress happening — great news for those of us wanting to be more sustainable with our tech. Firstly, renewed is having its moment. While consumers would previously turn their noses up at the idea of a second-hand device, there’s been a huge surge in demand for renewed tech. The second major step in tackling the problem of e-waste is a change in attitudes from owning a product to subscribing for one. A subscription for a smartphone might sound like a foreign concept, but it’s already gaining momentum. At the forefront of this movement is London-based tech startup Raylo, a pending B Corp which offers a subscription service for the latest iPhone. As customers aren’t paying to own the phone at the end of their contract, the monthly price is significantly lower than average.

Studies show that extending a phone’s lifespan from one to four years can decrease its environmental impact by about 40%.So the next time it comes to refreshing your device — whether a smartphone, laptop, tablet or something else-consider the more environmentally-friendly options that are at your fingertips.

10 . Imagine a world without insects. It might sound good at first without creepy-crawly bugs and annoying flies in your apartment. However, the consequences would be disastrous.

The number of insects has dropped by more than half in the past decades, according to British biologist Dave Goulson, author of Silent Earth: Averting the Insect Apocalypse. As insects make up most of the known species on this planet, this data is not good news, The Guardian reported on July 25.

Insects are indeed on the path to extinction, according to the first global scientific review of insect population decline, which was published in the journal Biological Conservation in January 2019. The researchers say intensive agriculture has been the main cause of the decline. Pesticides, in particular, destroy insect habitats. Urbanization and climate change are also significant factors.

“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” the researchers wrote in the review. “The repercussions (影响) this will have for the planet’s ecosystems are catastrophic to say the least.”

What would happen to Earth without insects? It’s almost impossible to predict, but the consequences would be far-reaching. We need insects to pollinate (授粉) crops, recycle plant and animal material, keep the soil healthy and much more. Without insects, many animals would have nothing to eat, and the predators of those animals would go hungry as well. The ecosystem would be thrown off balance.

“If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind,” said Francisco Sanchez-Bayo at the University of Sydney, Australia, one of the authors of the review.

The first step to halting this process is “to engender a society that values the natural world, both for what it does for us and for its own sake”, Goulson suggests. “The obvious place to start is with our children, encouraging environmental awareness from an early age.”