The Sahara is the world’s largest and most magic desert, but knowledge about it is surprisingly limited. Even estimates of when it formed vary widely, from more than five million years ago to mere thousands. Now, however, geographers studying wind-carried Saharan dust on the Canary Islands have come closer to settling this: it is, they report, close to five million years old.

One reason for the uncertainty over the Sahara’s age is that researchers use different methods to estimate it. These include studying desert dust found in sediment (沉积物) under the Atlantic Ocean, analyzing sandstone and modeling the ancient climate. To help settle the uncertainty, Daniel, geographer of the U.S. Geological Survey, and his workmates looked at sediment on Spain’s Canary Islands. They found evidence of Saharan dust. The dust appeared in ancient soil layers (层), whose age they assessed on the basis of fossils (化石) found in the same layers — and that age agreed with the earlier ocean’s sediment studies. The researchers reported their findings in November in Palaeogeography.

“The conclusion of the study is very good,” says Zhongshi Zhang, a climate modeler at the University of Bergen in Norway, who was not involved in the work. “Because the dust found on the islands is distinct from the ocean’s record,” Zhang adds, “it helps to build the case for a five-million-year age.”

The Sahara is the biggest source of wind-carried dust in the world — and that dust’s journey does not end in the Canary Islands, which lie just off the western coast of Africa. It continues onto places such as the Amazon rain forest in South America, Daniel notes. Amazon soils are poor in nutrients, and he says the new results help to show how rich dust from Africa could have been supporting the South American region’s incredible biodiversity for millions of years — adding to the Amazon’s own origin story.

The top-selling album (唱片) Songs of the Humpback Whale was released in 1970. This collection of nature recordings changed the way many people thought about whales and eventually helped save thousands of whales’ lives.

The album might never have been made if it hadn’t been for a sound engineer named Frank Watlington. In the 1960s, Watlington was making underwater recordings when he noticed some strange, deep sounds, which he realized were coming from whales.

Watlington played the recordings for a pair of biologists named Roger and Katy Payne. When they listened, they were instantly hooked on the beauty of the whales’ voices.

Katy Payne studied music as well as biology, and she was amazed by how the whales communicate like an opera singer. She also noticed another interesting detail: they had recognizable patterns. In biology terms, an animal call with a repeating pattern is called a song. The songs of whales are so complex that some scientists have even compared them to composers and poets.

The Paynes thought that other people needed to hear the beauty of the whales’ songs, so Roger organized the recordings into an album. At the time when the album came out, whales were often hunted and traded for money and some whale species were dying out. Most people had never thought of whales as creatures that could communicate through songs. But after hearing the album, many people began to think differently.

The album led people to start the Save the Whales movement. Musicians began using whale songs in their music, and whales were included in movies and television shows. In 1982, the deep-sea whaling was banned. Before the ban, more than 50,000 whales per year were killed. After it, the number went down below 2,000.

It might seem incredible that just one album could help save the lives of so many whales. But this one-of-a-kind album revealed secrets long hidden beneath the waves and allowed these amazing creatures to finally share their songs with the human world.

As the family of 16 Asian elephants started moving north, no one knew where they were heading, or why. Elephants sometimes go beyond their nature reserves, but they always return.

Not this time.

Over the course of 16 months, they crop-attacked and road-tripped 300 miles north to Kunming. They were causing a great deal of economic loss, and there was the ever-present risk of an elephant attacking a curious onlooker.

The simple answer would be to tranquilize the giant mammals and transport them back to the reserve. But that would be risky for this group, especially the three young elephants. Instead, officials launched an emergency task force to keep everyone, elephants and humans alike, safe. Tons of pineapples and bananas were used to attract them away from towns. Electric walls and road barriers drove them toward safer routes. These measures involved tens of thousands of people at a cost equal to hundreds of thousands of dollars.

In a year torn by climate change, struggle, and COVID-19, some might be doubtful about this practice. They might say the same about searching for an undiscovered species of frog on never before climbed mountains, or building new museums, or protecting the Great Wall.

But reserving our natural and human heritage is about encouraging good in the world. We need wildlife and ancient heritage, just as we need health and peace. They’re the background against which our lives take place, and they help us make sense of our own stories. They provide the context for our existence. They’re our past, present, and future. It’s not a zero-sum game, anyway. We can protect elephants and develop vaccines at the same time. The year 2021 is proof of that.

Although it’s still not clear why the elephants left in the first place, one theory is that as their numbers in Yunnan Province have increased, the animals have needed to expand their space. That could be considered good news for this endangered species. But the story of the elephants’ long walk proves something else too: that the world we created and the world nature created are certainly connected, for better or for worse.