We already know the fastest, least expensive way to slow climate change: Use less energy. With a little effort, and not much money, most of us could reduce our energy diets by 25 percent or more—doing the Earth a favor while also helping our wallets.

    Not long ago, my wife, PJ, and I tried a new diet—not to lose a little weight but to answer an annoying question about climate change. Scientists have reported recently that the world is bending up even faster than predicted only a few years ago, and that the consequences could be severe if we don't keep reducing emissions(排放) of carbon dioxide (CO₂ ) and other greenhouse gases that are trapping heat in our atmosphere.

    We decided to try an experiment. For one month we recorded our personal emissions of CO₂. We wanted to see how much we could cut back, so we went on a strict diet. The average US household(家庭) produces about 150 pounds of CO₂  a day by doing common-place things like turning on air-conditioning or driving cars. That's more than twice the European average and almost five times the global average, mostly because Americans drive more and have bigger houses. But how much should we try to reduce?

    For an answer, I checked with Tim Flannery, author of The Weather Makers: How Man is Changing the Climate and What it Means for Life on Earth. In his book, he had challenged readers to make deep cuts in personal emissions to keep the world from reaching extremely important tipping points, such as the melting(融化) of the ice sheets in Greenland or West Antarctica. "To stay below that point, we need to reduce CO₂  emissions by 80 percent," he said.

    Good advice, I thought. I'd opened our bedroom windows to let in the wind. We'd gotten so used to keeping our air-conditioning going around the clock. I'd almost forgotten the windows even opened. We should not let this happen again. It's time for us to change our habits if necessary.

What's On?

Trouble in Mind

    Alice Childress won an Off-Broadway award in 1956 for this story of a black actress rehearsing a play with a white director who increasingly finds it impossible for the show to go on. Tanya Moodie and Joseph Marcell star in the play directed by Laurence Boswell.

8.30p.m. —10.30p.m, Theatre Royal. Box office: 01225 448844.

Lazarus

    Inspired by the sci-fi (science fiction) novel and movie, The Man Who Fell to Earth, this musical deals with a hero, Thomas Newton. Likely to be the autumn's hottest ticket, the score includes new songs composed by Bowie.

7.00p.m. — 9.00p.m., King's Cross theatre. Box office: 0844 871 7604.

The Gaul

    On the night of 8 February 1974, a fisherman FV Gaul disappeared off the coast of Norway. For people on board, waiting for news was great suffering. Theories began to come up, including the possibility that the boat had fallen victim to cold war. Even when he was discovered, many still felt there were questions that remained unanswered. Mark Babych directs Janet Plater's play.

8.00p.m. —11.00 p.m., Royal Shakespeare theatre. Box office: 01482 323638.

The Suppliant Women

    It is a new version of Aeschylus's 2,500-year-old play about a group of women seeking shelter who make the long journey to escape forced marriage. It was written by David Greig and directed by Ramin Gray. An ancient piece asks a contemporary question: when we are in trouble, who will open their doors and give us a harbor?

8.30p.m. —10.00p.m, Hampstead theatre. Box office: 0131 248 4848.

    Some of the world's most famous musicians recently gathered in Paris and New Orleans to celebrate the first annual International Jazz Day. UNESCO( United Nations Educational, Scientific and Cultural Organization) recently set April 30 as a day to raise awareness of jazz music, its significance, and its potential as a unifying(联合) voice across cultures.

    Despite the celebrations, though, in the U.S. the jazz audience continues to shrink and grow older, and the music has failed to connect with younger generations.

    It's Jason Moran's job to help change that. As the Kennedy Center's artistic adviser for jazz, Moran hopes to widen the audience for jazz, make the music more accessible, and preserve its history and culture.

    ＂Jazz seems like it's not really a part of the American appetite,＂ Moran tells National Public Radio's reporter Neal Conan. ＂What I'm hoping to accomplish is that my generation and younger start to reconsider and understand that jazz is not black and write anymore. It's actually color, and it's actually digital.＂

    Moran says one of the problems with jazz today is that the entertainment aspect of the music has been lost. ＂The music can't be presented today the way it was in 1908 or 1958. It has to continue to move, because the way the world works is not the same,＂ says Moran.

    Last year, Moran worked on a project that arranged Fats Waller's music for a dance party, ＂just to kind of put it back in the mind that Waller is dance music as much as it is concert music,＂ says Moran. ＂For me, it's the recontextualization. In music, where does the emotion(情感) lie? Are we, as humans, gaining any insight(感悟) on how talk about ourselves and how something as abstract as a Charlie Parker record gets us into a dialogue about our emotions and our thoughts? Sometimes we lose sight that the music has a wider context,＂ says Moran, ＂so I want to continue those dialogues. Those are the things I want to foster.＂

High-Wire Act

    Mickey Wilson had been on the mountain only a few seconds when he heard the scream. Wilson, 28 years old, had just gotten off the cable car (索道缆车) at the Arapahoe Basin Ski Area in Keystone, Colorado, along with his friends Billy Simmons and Hans Mueller. Their friend Richard had been on the cable car ahead of them, but when the men reached the top of the lift, he had disappeared. The men walked toward the source of the scream and found skiers stopped on the slope, pointing to the cable car. And then the friends screamed too.

    "Oh, Richard!" yelled Mueller.

    When Richard had tried to jump off the cable car, his backpack had been caught in the chair, which then dragged him back down the hill. In the process, the backpack belt twisted around his neck, making him breathless. Now Richard's body was swinging four feet above the snow. The cable car operator had quickly stopped it, and the friends kicked off their skis and ran toward the scene. They made a human pyramid to try to reach Richard, but the unconscious man was too far off the ground. With the clock ticking, Wilson ran to the ladder of a nearby lift tower. Scared skiers watched as he struggled the 25 feet. After he reached the top, Wilson's first challenge was to climb onto the two-inch steel cable that held the chairs. He handled the balance and height bravely, but he knew he could not walk on the cable. Therefore, he calmed down and sat over it and then used his hands to pull himself to Richard quickly. Wilson's greatest fear wasn't that he'd fall, but that he wouldn't reach Richard. "This was life or death," he said.

    When he reached Richard's chair, Wilson swung a leg over the cable and attempted to drop down onto it. But as he did that, his jacket caught on the movable footrest, which was in the up position. The footrest began to slide down, with Wilson attached. But before that could happen, he managed to free himself and reached Richard.

    Fortunately, the ski patrol (巡查) had gathered below and performed emergency treatment on Richard, who had been hanging for about five minutes, then skied him down to an ambulance.

    That night, Richard called from the hospital to express his thanks to Wilson, his other friends and the workers at the Arapahoe Basin Ski Area.

    When Kim Chil-doo was young, he says, he wanted to be a model. But he gave up that idea to make money. Now, at age 65, he appears in television advertisements and fashion magazines. With his gray beard and long hair, he is South Korea's first senior model.

    Kim is one of many older people in South Korea the country has the world's fastest growing ageing population. Almost half of the country's older people live in poverty. Some take low-paying jobs to support themselves after retiring. But Kim and some other seniors have shown how older South Koreans can find unusual job opportunities later in life.

    You Sung-lae is 59. When she was a child, she wanted to be an actress. But instead, she says, she got married and had children. Now she is training to appear on a catwalk to show clothes. She was wearing a bright blue jacket, orange high heeled shoes and designer sunglasses.

    You is also helping the fashion business by attracting older buyers. Older buyers have become big players. While many older people do not have much money, others have bought their homes and built savings. Now, those seniors are ready to spend some of their money on themselves.

    Some businesses are also trying to use older people's skills and experiences. For example, Cho Young-min started a company using Skype to connect older instructors in Korea with students around the world. The students are interested in learning Korean, and the instructors are interested in sharing their knowledge.

    Another man, Ji Byung-soo found success by performing a dance song on a televised singing contest. He is 77. Now he earns enough money to donate to a local support center. Last month, he danced nonstop at a youth festival in Seoul while young people called his name. "Life begins in your 70s," Ji said. "Let's be happy and have fun."