【推荐2】California researchers have found that oxygen levels and water temperatures play a key role in the health of deep-sea fish populations.

Scientists studied fish on the floor of the Gulf（海湾） of California. "This is an example of some of the video that we are analyzing for this research," said Natalya Gallo, a post-doctoral researcher at the Scripps Institution of Oceanography. She pointed to a video taken along the seafloor on the Gulf of California near the Mexican coast. The film came from a remotely controlled submarine.

Researchers use the underwater tool to calculate the influence of a warming ocean on fish. “The really big question that we're trying to answer is how sensitive deep-sea communities（群落），and in general ocean communities are going to be to these changes,” Gallo said.

Gallo and the other researchers on the team studied the northern gulf, which is closer to normal ocean conditions and the southern gulf, which has one of the planet's most extreme low oxygen ocean zones.

The findings will help scientists understand changes in other places. As the ocean gets hotter, the warmer water is not capable of holding the same amount of oxygen. "We know that oxygen is declining in the ocean globally," said Lisa Levin, a Scripps Institution of Oceanography, biological oceanographer. "And that the really low oxygen zones, oxygen minimum zones are expanding as the ocean warms."

Scientists already expect certain outcomes from climate-related changes. "The body size of animals will get lower as the ocean warms and the oxygen declines and overall, the oceans will become less productive," Levin said. The research findings are published in the current edition of the Journal Marine Ecology Progress Series.

【推荐3】Climate change will bring and has already brought a wide variety of threatening destruction to human existence. Some of these are well-known and already operative, like the wildfires racing along California’s freeways or the permanent droughts that have been upsetting Mediterranean farmers. But are these all terrible disasters we can come up with that are brought about by climate change?

Absolutely not. None of the challenges posed by our warming climate has appeared larger in the popular imagination than sea-level rise, as global populations and wealth are heavily concentrated in low-lying coastal cities. The best available models suggest that 37 million people currently live in places that will be below high tide by 2050-in an optimistic low-carbon-emissions scenario (设想).

Or rather, that’s what such models suggested before this week. On Tuesday, a new study revealed that those alarming statistics were wildly inaccurate. The actual impacts of sea-level rise are going to be much, much worse.

Previous estimates of the impact that rising tides would have on coastal cities relied on essentially a three-dimensional map of Earth obtained from satellite readings. But those readings were fundamentally unreliable because they often measured the planet’s upper surfaces — such as treetops and tall buildings — rather than its ground level. These mistakes led scientists to overestimate the elevation (海拔) of many regions of Earth.

In a new study published by the journal Nature Communications, scientists from Princeton, University detail this methodological problem, then use artificial intelligence to determine the previous literature’s error rate. Their research yields some amazing updates to our conventional understanding of what the next century has in store for our coastlines.

In its optimistic scenario, the Princeton study projects that lands currently occupied by 150 million people will lie below high tide in 2050. But as warming destroys many of the world’s agricultural regions, climate change could accelerate migration from rural areas to coastal cities.

The new study does include one piece of slightly encouraging news. While previous models suggested that 28 million humans currently live in places that already lie below high tide, the actual number is closer to 110 million — which means seawalls and other barriers have proven sufficient to keep many cities dry even as sea levels have risen around them. Still, the scale of barrier construction necessary to save low-lying cities from collapse is now, apparently, far greater than previously understood when the task already looked terribly expensive, particularly for developing countries.

If the Princeton researchers’ projections are correct, avoiding mass death and suffering in the coming decades will require not only rapidly reducing carbon emissions and strengthening construction of seawalls but also furthering mass migrations away from low-lying cities and islands and toward higher ground.

【推荐1】Do you often listen to music at loud volume? Over one billion young people are at risk of hearing loss because of listening to loud noise for long periods of time. Listening to music or watching a TV show at loud volume is harmful to your hearing.

The United Nations has standards for safe listening. It is not safe to listen to sounds that are louder than 85 dB(分贝) for eight hours or 100 dB for 15 minutes. The sound of a busy road is about 85 dB and the sound of a rock concert can be about 100 dB.

Loud noise is harmful to the inner ears. Most of us are born with about 16,000 hair cell (听毛细胞) in our inner ears. These cells notice sounds. However, listening to loud noise for a long time can make these cells work too hard and cause some of them to die. This is what causes hearing loss.

Some people might think that their music isn’t all that loud. But this can depend on where you are. For example, if you are in a noisy place like the subway, you might turn up your music too loud without realising it. Later, when you listen to it at the same volume in a quiet place, you might feel uncomfortable.

The “safe level” for most sound is below 80 dB for up to 40 hours a week. A level of 80 dB is roughly equal to the noise of a subway.

【推荐3】Washing windows on a skyscraper is a dirty job. Hanging off the side of a building can also be dangerous, notes Oliver Nicholls, 19. So this 12th-grader invented a robot to handle the job.

Some recent incidents inspired his project. In one, a couple of high-rise window washers were standing on a platform that fell down. No one died, but the pair was seriously injured. Oliver also witnessed someone fall and break his leg while cleaning a glass awning (雨篷) over the entrance to a building.

The new robot is about the size of a medium-sized picnic cooler and weighs 12 to15 kilograms. It's designed to hang off the side of a building from ropes, just as current window－washing platforms do. A hose（软管）carries water to the robot. A cable (电缆) delivers it electric power. The computer controls the robot up-and-down movements by adjusting the ropes from which the robot hangs. When the robot needs to move from one window to another, a set of propellers（螺旋桨） starts to work. They push the robot a short distance away from the building, while the ropes slide along a railing（栏杆）to carry the robot over to the next window. Then, as a different set of propellers holds the robot tight against the window, the cleaning cycle repeats. Oliver tested his robot by cleaning sample windows he'd built in his backyard. The robot’s propellers can hold the robot against a building even in winds as high as 45 kilometers per hour, the teen reports. He performed those tests using his family’s leaf blower.

Besides limiting the chance of injury, this window-washing robot could save building owners a bit of money. If commercialized, Oliver estimates it would cost about ＄11,000. That's about the same cost as hiring a crew to clean a 7-story building. So Oliver suspects his robot might be able to pay for itself after cleaning just one such building.