Some breathtaking blue lakes may not be so blue in the future, thanks to climate change. In the first global record of lake color, researchers estimate that roughly one-third of Earth’s lakes are blue. But, if average summer air temperatures should rise by a few degrees, some of those pure waters could turn green or brown, the team reports in the Geophysical Research Letters.
Lake color depends in part on what’s in the water, but factors such as water depth and surrounding land use also matter. Compared with blue lakes, green or brown lakes are caused by more algae (水藻), sediment and organic matter, says Xiao Yang, a hydrologist at Southern Methodist University. If some lakes do become less blue, people will probably lose some of the resources they have valued.
Yang and his colleagues used satellite photos from 2013 to 2020 to analyze the color of more than 85, 000 lakes that are detectable around the world. The scientists found that lakes in cooler regions, with average summer temperatures below 19℃, tend to have a blue color compared to lakes with warmer water. This warmer environment encourages more algae growth, and thus its tint is changed, giving it a green-brown look, according to Yang. But what is worth mentioning is that the average summer temperatures may increase another 3℃—an amount that scientists think is possible by the end of the century.
Lake color can suggest the stability of a lake’s ecosystem, with shifting shades indicating changing conditions for the creatures living in the water. One benefit of the new study is that it gives scientists a baseline for assessing how climate change is affecting Earth’s freshwater resources. Continued monitoring of lakes could help scientists detect future changes.
1. What contributes to blue lakes?| A．Lower temperature. | B．More sediment. |
| C．Organic matter. | D．More algae. |
| A．Size. | B．Color. | C．Shape. | D．Surface. |
| A．It is stable in any condition. | B．It affects the water properties. |
| C．It shifts with climate changes. | D．It decides creatures in the water. |
| A．Water tends to stay pure above 22℃. |
| B．Satellites can analyze water temperature. |
| C．Warmer water will contain more resources. |
| D．Green-brown lakes will be more 70 years later. |
相似题推荐
【推荐1】China has seen important achievements in improving the environment and green development over the past 70 years, especially in fighting against desertification (沙漠化).
Desertification was a serious problem in the 1990s. It caused deadly sandstorms, and did great harm to the local (当地的) people. As President Xi Jinping has said, clear waters and green mountains are the most valuable things. The government and people have been making every effort to fight against desertification. In the process (过程), Chinese people’s efforts and determination to create “green” areas have played a crucial role, without which nothing may be achieved.
A lot of campaigns (活动) have been carried out by the central government to improve the environment. For example, in 1998, China started the Natural Forest Protection Program. Thanks to the program, forests in China increased greatly from 12 percent in the 1980s to nearly 23 percent last year.
Another example of the campaign is the Elion Resources Group, which has been recognized by the UN for its contribution that has slowed desertification.
In Kubuqi, a desert in the North China, Elion has successfully greened 600,000 hectares (公顷) of land. Surprisingly, it also has helped lift more than 102,000 people out of poverty through the development of solar energy and tourism, as well as planting herbs (草药) for traditional Chinese medicine.
In addition, the group’s technologies have also been used in many other important programs, including Yangtze River Ecological Park and Qilian Mountain National Park.
“We will develop new ways to improve our ability to control the sand with the help of modern technologies, such as drones (无人机), AI, big data and the internet of things,” said Ao Baoping, president of Elion Green Land Technology.
1. What does the underlined word “crucial” in the second paragraph mean?| A．Active. | B．Direct. | C．Key. | D．Practical. |
| A．More areas in China are covered with forest. |
| B．A similar new campaigns will be carried out. |
| C．The result of the program is far from satisfactory. |
| D．The central government has carried out a lot of campaigns to develop the economy. |
| A．Its main aim was to lift local people out of poverty. |
| B．It made Kubuqi become a center for tourism. |
| C．It has got help from other ecological programs. |
| D．It will use modern technologies to fight desertification. |
| A．In a text book. | B．In a newspaper. |
| C．In a science novel. | D．In an advertisement. |
【推荐2】Europeans got more of their electricity from renewable sources than fossil fuels for the first time last year, according to an annual report from Ember and Agora Energiewende.
The report, which has been tracking European Union’s power sector since 2015, found that renewables delivered 38% of electricity last year, compared to 37% delivered by fossil fuels.
The shift comes as other sources, such as wind and solar power, have risen in the European Union. Both sources have nearly doubled since 2015, and as of last year accounted for one-fifth of electricity generation in EU countries, the report found. It’s also the reason why coal power declined 20% last year, making up only 13% of electricity generated in Europe.
“Rapid growth in wind and solar has forced coal into decline, but this is just the beginning,” said Dave Jones, senior electricity analyst for Ember and lead author on the report, in a statement. “Europe is relying on wind and solar to ensure not only coal is phased out by 2030, but also to phase out gas generation, replace closing nuclear power plants, and to meet rising electricity demand from electric cars and heat pumps.”
Last year’s COVID-19 lockdown measures resulted in less demand for electricity across the globe. European demand decreased by 4% in 2020, according to the report, which said COVID trends had no effect on the growth of renewable energy sources. Since 2015, Europe’s electricity emissions recorded a historic decline, becoming 29% cleaner, the report noted.
The milestone follows commitments from EU leaders last month to cut greenhouse gas emissions by 55% from 1990 levels by 2030. In the United States, their counterparts (同身份的人) successfully developed renewable energy to overtake coal consumption in recent years. Last May, renewable energy sources were consumed more than coal for the first time since 1885.
“Post-pandemic economic recovery must not slow down climate action,” said Patrick Graichen, director of Agora Energiewende, in a statement. “We therefore need strong climate policies — such as in the Green Deal — to ensure steady progress.”
1. What happened in EU countries according to the first three paragraphs?| A．The use of renewables declined by 38% last year. |
| B．20% of electricity was generated by renewables last year. |
| C．Fossil fuels were no longer used to generate electricity. |
| D．Coal power made up just 13% of electricity generation last year. |
| A．Cutting greenhouse gas emissions forced coal into decline. |
| B．Coal consumption is phased out due to rapid growth in wind and solar. |
| C．More nuclear power plants should be built to meet electricity demand. |
| D．Fossil fuels will eventually be abandoned in European countries. |
| A．The demand for renewables decreased across the globe. |
| B．Electricity consumption dropped to a historic record. |
| C．The growth in wind and solar power was hardly influenced. |
| D．The economy was making steady progress. |
| A．To compare renewable sources with fossil fuels. |
| B．To report on electricity generation in Europe. |
| C．To emphasize recovery in post-pandemic era. |
| D．To advocate strong climate policies in Europe. |
【推荐3】We've got to do a better job of stopping global warming, a new report says.
The report, released Wednesday by the United Nations, says the world isn't doing nearly enough to control fossil fuel production to the level that's needed to stop "catastrophic" levels of global warming, pointing fingers at both developed countries and developing countries.
However, developing countries currently cannot sustain (维持) themselves, let alone grow, without relying heavily on fossil fuels. To them, fossil fuels are still the cheapest, most reliable energy resources available. India, for example, is home to one-third of the world's 1. 2 billion citizens living in poverty. That's 400 million people in one country without sufficient food or shelter. India hopes to shift to renewable energy as its economy grows, but the investment needed to meet its renewable energy goals “is over ten times the country's annual spending on agriculture and infrastructure (基础设施).” Unless something changes, developing countries like India cannot fight climate change.
Yet the weather changes and consequences of global warming, like tons of droughts and poverty are already impacting economic growth in many countries. Is there a solution?
According to a World Bank report, “poor and middle-income countries account for just over half of total carbon emissions.” And this percentage will only rise as developing countries grow. In Sub-Sabaran Africa, the number of people living in poverty increased by 98% in the thirty years, while carbon dioxide on average decreased by 17%. Given the current energy situation, if sub-Saharan Africans are to escape extreme poverty, they will have to increase their carbon use unless developed countries step in to offer clean alternatives and financial aid.
After all, global warming is, by definition, a global crisis. Reducing this threat will require global cooperation and global solutions.
1. What does the writer want to convey in paragraph three?| A．India has difficulty in feeding itself. |
| B．India has the largest number of poverty. |
| C．India cannot afford to develop clean energy. |
| D．India relies heavier on fossil fuels than USA |
| A．They'll be rid of extreme poverty. | B．They'll stop developing economy. |
| C．They'll care much for carbon emissions. | D．They'll pursue economic growth at heavy cost. |
| A．Poverty is the root of global warming. |
| B．Huge gap does exist between countries. |
| C．Developing countries cannot afford global warming. |
| D．Global warming demands global effort and solutions. |
| A．Conflicts between countries. | B．Ways of global cooperation. |
| C．Potential crises on the earth. | D．The importance of clean alternatives. |
【推荐1】Veronica Vorobet learned about caring in her home country of Romania by nursing her grandparents. In 2013, after their deaths, she moved to England to find a job using the freedom provided by EU (European Union)membership.
Vorobet, 36, is one of a quarter of a million care workers who are not UK citizens, a rising percentage of whom have come from the EU in recent years.They have become an essential part of a low-paid workforce that is constantly understaffed(人手不足的），with about 120,000 unoccupied positions.
Yesterday, she expressed disappointment with the announcement that there would be no special treatment for carers coming into the UK after Brexit -British exit from the EU.
“I want to see people treated the way I want to be treated and to make a difference in people's lives, making a feeling of home for everyone,” she told the Guardian. “The foreign workers are important in this. They are able to work under a lot of stress and long hours. In my country we are very close to our elderly people and that is what we show here. We try to be close to them and respect their wishes."
She said her approach was to treat residents as if they were her own grandparents and provide similar levels of “support and love.” When she arrived in the UK, Vorobet started as a junior care worker on minimum wage in a home for older people in Petersfield, Hampshire. Seven years on and having studied for an NVQ in health and social care, she is a deputy(副的) care manager at St Anthony's residential care home in Watford, part of RMD Care. There she works alongside other Romanian people, and care workers from Indian, Sri Lanka and Kenya.
Her most recent trial has been keeping coronavirus(冠状病毒）out of the home, so far successfully. She said that given the difficulty of taking on care workers, European workers have helped create stability in the workforce. Staff turnover rates in adult social care currently stand at about 30% a year.
“The government should do their research and find out who does these jobs and understand the risk of taking this decision. The risk is that there won't be enough staff to look after the people in need," she said.
1. Why does the author mention “with about 120,000 unoccupied positions" in Paragraph 2?| A．To predict the future workforce in the UK. |
| B．To highlight the current situation of the UK. |
| C．To show the importance of foreign carers in the UK. |
| D．To reveal foreign carers' determination to stay in the UK. |
| A．They are hardworking and considerate. |
| B．They are unwilling to work with a low pay. |
| C．They work at the risk of being physically abused. |
| D．They have to leave their countries to seek a fortune. |
| A．European workers must be fired soon |
| B．foreign carers will be treated with a low pay |
| C．foreign carers in the UK will be given no particular treatment |
| D．the British government bans European workers from finding jobs in England |
| A．To introduce Vorobet, a woman from UK. |
| B．To present the current situation of the EU carers. |
| C．To reveal the problems of the UK after Brexit. |
| D．To predict the future workforce in the UK. |
【推荐2】Ants keep traffic flowing by changing their behavior to meet changing conditions, according to new research.
For their experiment, researchers from the University of Toulouse and the University of Arizona focused on Argentine ants, which are only 2-3 millimeters long and frequently move from colony (栖息地) to colony depending on how far food is. Tapping into the ants' talent for fast commutes (通勤), the researchers constructed bridges between their colonies. The bridges varied in width from a fifth to three-quarters of an inch.
Then the researchers sat back and monitored the traffic. To their surprise, even when those narrower bridges were nearly overloaded, there were no 20-ant pile-ups. And traffic remained steady regardless of how crowed the bridges were because ants could adjust to the flow of road conditions.
"When crowding on the path increased, ants assessed it locally and adjusted their speed accordingly to avoid any interruption of traffic flow," the researchers said. "Moreover, ants avoided entering a crowded path and made sure the bridge was never overloaded."
The lesson for humans? The traffic problem mostly lies in our loss of the quality that the ants have. You've probably noticed it on your own commute to work. Driving is fun when there're few cars on the road-a lane-change (车道变换)here, a little acceleration there. Then traffic slows down. But some impatient drivers still constantly move between lanes.
"Traffic jams are common in human society where some people are focusing on their own personal objectives," the researchers said. "In contrast, ants share a common goal: the survival of the colony, thus they're expected to act cooperatively to get food."
The research also suggests that the ever-widening of highways may never free us from traffic jams. As long as we drive along with our own agendas, no matter how many other people are on the road, we'll always end up in a traffic jam. Indeed, less space may be a good thing. It leaves less room for personal choices and forces us to take a page from the driving handbook of ants.
1. What did the researchers do to the ants in the experiment?| A．They fed them with much delicious food. |
| B．They trained them to avoid heavy traffic. |
| C．They built bridges linking their colonies. |
| D．They improved their colonies constantly. |
| A．They worked together to remove the road blocks. |
| B．They sped up to get out of the traffic jam quickly. . |
| C．They made their way carefully in the given direction. |
| D．They adjusted themselves for the flow of the traffic. |
| A．Poor road const ruction. | B．People's inability to adjust. |
| C．People's selfish driving. | D．Too many vehicles on roads. |
| A．What ants help us do for driving safety. |
| B．What ants can teach us about traffic jams. |
| C．Why ants drive much better than humans. |
| D．Why ants are best at handling traffic jams. |
【推荐3】Scientists have solved the mystery of why the overwhelming majority of mammoth fossils(化石) are male.
Much like wild elephants today, young male Ice Age mammoths probably travelled around alone and more often got themselves into risky situations where they were swept into rivers, or fell through ice or into mud, lakes or sinkholes that preserved their bones for thousands of years, scientists say.
Females, on the other hand, travelled in groups led by an older matriarch who knew the landscape and directed her group away from danger.
“Without the benefit of living in a herd led by an experienced female, male mammoths had a much higher risk of dying in natural traps such as mud holes, rock cracks and lakes,” said co-author Love Dalen of the Swedish Museum of Natural History in a report published on Thursday in the journal Current Biology.
The study used genetic data to determine the sex of 98 woolly mammoth fossils in Siberia. Researchers found that 69% of the samples were male, a heavily unbalanced sex ratio, assuming that the sexes were fairly even at birth.
“We were very surprised because there was no reason to expect a sex bias in the fossil record,” said first author Patricia Pecnerova, also of the Swedish Museum of Natural History.
Therefore, researchers believe that something about the way they lived influenced the way they died.
Most bones, tusks, and teeth from mammoths and other Ice Age animals haven’t survived,” explained Dalen.
“It is highly likely that the remains that are found in Siberia these days have been preserved because they have been buried, and thus protected from weathering.”
These giant, tusked plant eaters disappeared about 4,000 years ago. While there is no scientific agreement about the causes of their disappearance from the planet, most believe that climate change, excessive hunting by humans and the spread of other animals into mammoth feeding grounds were influential factors.
1. The underlined word “matriarch” in paragraph 3 means ________.| A．figure head | B．female leader |
| C．experienced animal | D．mature mammoth |
| A．The increasing competition for food. |
| B．The cooling of the earth’s temperature. |
| C．The disappearance of male mammoths. |
| D．The risky behaviour of younger mammoths. |
| A．A newspaper article. | B．An academic essay. |
| C．A historical description. | D．A science fiction story. |
