Thousands of emperor penguins in western Antarctica lost their chicks last year, largely due to gradually reducing sea ice, satellite data suggest.

While looking at satellite images in 2022, geographer Peter Fretwell noticed that ice in one area was melting (融化) especially early in the year. He and his colleagues wanted to measure the influence of this ice loss on emperor penguins in the Bellingshausen Sea off western Antarctica. So the researchers looked at satellite images of groups to determine the future of the breeding (繁殖) season. There were 62 emperor penguin groups throughout Antarctica. Of the five groups observed, four probably lost all their chicks, the team reports August 24.

Emperor penguins rely on stable (稳定的) sea ice throughout their breeding season. When an egg hatches (孵化), the newborn chick must fledge (羽化), losing its soft feathers to gain its waterproof coat. But in 2022, sea ice broke up before some groups were finished fledging. Without waterproof feathers, fledging birds were unable to survive, Fretwell says.

Some of those other groups have also experienced bad breeding seasons lately. On Antarctica’s Brunt Ice Shelf, the world’s second-largest emperor penguin group at the time had three years of breeding failure from 2016 to 2018 after storms broke up sea ice there, Fretwell and a colleague previously reported.

The new study, recording breeding failure across several groups at once, “is the first observation that agrees with the worst expectations of what could happen” as the Earth continues to warm, Schmidt says. “I’m worried—it’s not a good sign.” Recent estimates predict (预测) that the changing climate and melting sea ice could cut emperor penguin populations by more than half by 2100.

Although the future of emperor penguins is worrying, Fretwell still has hope. “If we can slow down global warming… we can turn around the future of the emperor penguin,” he says. “But that window of opportunity is getting smaller, so we really have to act now.”

Thanks to Earth, we have fresh air to breathe, clean water to drink and warm sunshine to enjoy. But it seems that we may have taken these things for granted and not realized that our planet is getting “sick”. 【小题1】 . More than 15,000 researchers around the world have written a letter to warn about environmental threats.

Among those environmental challenges, global warming sits at the top. Global average temperatures have risen by more than 0.5℃since 1992. 【小题2】 It means that heat waves would last around a third longer and rainstorms would be about a third more intense (猛烈的) if we take no action. The increase in sea levels would also be much higher. Countries like Singapore and Tokyo that are at low altitudes may be covered by the ocean in the future.

【小题3】 . It’s getting harder to get fresh water. Ocean pollution has become serious. Since 1992, the human population has grown by 2 billion, while the populations of all other animals have dropped by nearly 30 percent.

However, we have made some progress. That’s because we gradually stopped using chemicals that can break down ozone, a gas that protects Earth. 【小题5】 .

The Atlantic salmon (鲑鱼) of Scotland are hardy and determined animals. Each spring and summer, they return from the North Atlantic Ocean to lay eggs in Scotland’s shallow rivers,leaping up waterfalls and over barriers, pushing themselves upstream in enormous efforts. Some fail, and others succeed, but today they face yet another challenge.

During the mid-1980s, there were between eight and ten million salmon swimming around Scotland’s Atlantic coast; that number has now dropped sharply. There’s evidence of reducing the availability of the salmon’s prey (猎物) as climate change warms and acidifies oceans. New research suggests climate change is also bearing down on rivers, which is bad news for salmon.Adapted to life in cold water, salmon experience slow growth and population changes at high temperatures. Heat influences their health and reduces their resistance to disease.

“Now salmon are struggling to deal with the rising temperatures. There are recent records of 27°C in the upper reaches of the Dee catchment,” says Peter Cairns, director of an environmental charity. In 2018, Scotland recorded the lowest pole catch for salmon since records began. Evidence suggests that the degraded quality of river worsens the impact of our changing climate. “Atlantic salmon evolved using river systems in Scotland that were once way more forested and therefore shaded.” Yet Scotland is today one of the least wooded countries in Europe, with just 3 percent of its native woodland undamaged. Scientists have found that just 35percent of rivers in Scotland have enough tree cover for salmon survival.

A movement to get trees back on riverbanks is gathering pace. “Broad-leaf trees close tothe bank can reduce the light that enters the water,” explains fisheries scientist Anthony Hawkins. A new initiative called Riverwoods — led by the Scottish Wildlife Trust and supported by Scottish Water and several other government and regulatory bodies — aims to create a network of woodlands along Scotland’s riverbanks, and has already received a number of large funds.“Money is not the pressing business. River health is complex, but tree planting is one of the most basic things we can get started with right away,”says Cairns.