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Wildlife populations have fallen by more than two-thirds in less than 50 years, according to a major report (PDF) by the conservation group WWF. The report says this “catastrophic decline” shows no sign of slowing. And it warns that nature is being destroyed by humans at a rate never seen before. The report looked at thousands of different wildlife species monitored by conservation scientists in habitats across the world. They recorded an average 68% fall in more than 20,000 populations of mammals, birds, amphibians, reptiles and fish since 1970.

Measuring the variety of all life on Earth is complex, with a number of different measures. Taken together, they provide evidence that biodiversity is being destroyed at a rate unprecedented in human history. This particular report uses an index of whether populations of wildlife are going up or down. It does not tell us the number of species lost, or extinctions. The largest declines are in tropical areas. The drop of 94% for Latin America and the Caribbean is the largest anywhere in the world, driven by a cocktail of threats to reptiles, amphibians and birds. Research published in the journal Nature suggests that to turn the tide we must transform the way we produce and consume food, including reducing food waste and eating food with a lower environmental impact.

At 94 years old and with over 60 years of wildlife documentary-making under his belt, Sir David Attenborough is well-placed to share his thoughts about the future of our planet. And on Sunday, in the new BBC documentary Extinction: The Facts, the legendary presenter had a warning for all humans about the creatures we share the Earth with. “Over the course of my life, I’ve encountered some of the world’s most remarkable species of animals,” Attenborough says at the start of the hour-long film. “Only now do I realize just how lucky I’ve been. Many of these wonders seem set to disappear forever. We’re facing a crisis, and one that has consequences for us all. It threatens our ability to feed ourselves, to control our climate — it even puts us at greater risk of pandemic diseases such as COVID-19.”

With the help of a number of academics and experts, Attenborough goes on to explain that extinction is now happening much faster than it used to — with 570 plant species and 700 animal species disappearing since the year 1500. “Studies suggest that extinction is now happening a hundred times faster than the natural evolutionary rate,” Attenborough says. “And it’s accelerating.” A follow-up to Attenborough’s 2019 explainer documentary, Climate Change: The Facts, Extinction: The Facts delves into some of the main causes of extinction and disastrous biodiversity loss today, including habitat destruction (either caused by land use or human-induced climate change or both), unsustainable agricultural and fishing practices, and poaching. The documentary examines a number of species across the world that are at risk, from the two remaining northern white rhinos in Kenya’s Ol Pejeta Conservancy to the 25 percent of assessed plant species currently at risk of disappearing forever.
Although the documentary is a heavy and often bleak watch, it does end with a message of hope. “One thing we do know, is that if nature is given the chance, it can bounce back,” concludes Attenb

One of the big challenges of making 100 percent renewable energy [sic] a reality is long-term storage,” says Julian Hunt, an engineering scientist at the International Institute for Applied Systems Analysis in Austria. Hunt and his collaborators have devised a novel system to complement lithium-ion battery use for energy storage over the long run: Mountain Gravity Energy Storage, or MGES for short. Similar to hydroelectric power, MGES involves storing material at elevation to produce gravitational energy. The energy is recovered when the stored material falls and turns turbines to generate electricity. The group describes its system in a paper published November 6 in Energy.

“Instead of building a dam, we propose building a big sand or gravel reservoir,” explains Hunt. The key to MGES lies in finding two mountaintop sites that have a suitable difference in elevation — 1,000 meters is ideal. “The greater the height difference, the cheaper the technology,” he says. The sites will look similar, with each comprised of a mine-like station to store the sand or gravel, and a filling station directly below it. Valves release the material into waiting vessels, which are then transported via cranes and motor-run cables to the upper site. There, the sand or gravel is stored — for weeks, months, or even years — until it’s ready to be used. When the material is moved back down the mountain, that stored gravitational energy is released and converted into electrical energy.

Not only is the system more environmentally friendly [sic] than pumped-storage hydropower and dams, but it’s more flexible to meet varying energy demands.

“Hunt estimates that the annual cost of storing energy via this system will vary between $50 to $100 per megawatt hour (MWh),” the report adds. “And he says that the energy expended to transport materials to the upper sits will be offset by the amount of gravitational energy the system produces.”