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.

    My husband hasn't stopped laughing about a funny thing that happened to me. It's funny now but it wasn't at the time.

    Last Friday, after doing all the family shopping in town, I wanted a rest before catching the train, so I bought a newspaper and some chocolate and went into the station coffee shop — that was a cheap self-service place with long tables to sit at. I put my heavy bag down on the floor, put the newspaper and chocolate on the table to keep a place, and went to get a cup of coffee.

    When I went back with the coffee, there was someone in the next seat. It was one of those wild-looking youngsters, with dark glasses and worn clothes, and hair colored bright red at the front. Not so unusual these days. What did surprise me was that he'd started to eat my chocolate!

    Naturally, I was annoyed. However, to avoid trouble — and really I was rather uneasy about him — I just looked down at the front page of the newspaper, tasted my coffee and took a bit of chocolate. The boy looked at me closely. Then he took a second piece of my chocolate. I could hardly believe it. Still I didn't dare to start an argument. When he took a third piece, I felt more angry than uneasy. I thought, "Well, I shall have the last piece." And I got it.

    The boy gave me a strange look, and then stood up. As he left he shouted out. "This woman's crazy!" Everyone stared. That was embarrassing enough, but it was worse when I finished my coffee and got ready to leave. My face went red — as red as his hair — when I realized I'd made a mistake. It wasn't my chocolate that he'd been taking. There was mine, unopened, just under my newspaper.

    Try this: For an entire day, forget about the clock. Eat when you're hungry and sleep when you're tired. What do you think will happen?

    You may be surprised to find that your day is much like most other days. You'll probably get hungry when you normally eat and tired when you normally sleep. Even though you don't know what time it is, your body does.

    These patterns of daily life are called circadian rhythms（生理节奏）, and they are more than just habits. Inside our bodies are several clocklike systems that follow a roughly 24-hour cycle. Throughout the day and night, our inner clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

    Everyone's rhythms are different, which is why you might like to stay up late while your sister always wants to go to bed early. But on the whole, everyone is programmed to fell tired at night and energetic during the day.

    Learning about our body clocks may help scientists understand why problems arise when we act out of step with our circadian rhythms. For example, traveling across time zones can make people wake up in the middle of the night. Regularly staying up late can make kids do worse in tests.

    "There is a growing sense that when we eat and when we sleep are important parts of how healthy we are," says Steven Shea, director of the Sleep Disorders Program at Brigham and Women's Hospital in Boston.

    One way to learn about how our body clocks tick is to mess them up and see what happens. That's what neurologist（神经病学家）Frank Scheer and his workmates did in a recent study.

    Staying up night after night, their studies suggest, could make kids extra hungry and more likely to gain weight. And regularly sleeping too little, Scheer says, may be one cause of the recent increase in childhood obesity.

Festivals in Wales this spring

    There's lots to see, do and experience in Wales this spring. And now it's time to embrace all things new and get ready to be entertained in the spring, come rain or shine.

    Wrexham, 10-12 May

    The annual festival showcases over 200 acts consisting of music, comedy, film and more. Since its opening event in 2011, Focus Wales has done a lot for emerging（新兴的）musicians across the country, and 2018 sees Welsh Music Prize winner The Gentle Good and Y Selar Best Band winners. Candelas, take the stage.

    Aberystwyth, 19-29 May

    Whether you prefer Hill Climbs or Sportives, the AberCycle Festival allows you to take all of it in from the saddle（鞍）of a bike, enjoying the world's most beautiful scenery. However, all work and no play makes us all dull boys and girls, so while you're in town be sure to pop in to one or two of the plenty of pubs in Aber（as the locals call it）for a nice, cold pint of Brains beer. You'll need it after all that cycling!

    Hay on Wye, 25-28 May

    The world's biggest music and philosophy festival returns in 2018 with its unique mix of tunes, talks and trapeze（吊杠）（yes, there are even circus performers!） Based in the magical surroundings of Hay on Wye, this four day festival takes place at the end of May and is perfect for everyone who likes a side of intellectualism（理智主义）with their traditional festival experience.

Lawrenny, 25-28 May

    In late May in the heart of the Pembrokeshire National Park, the Big Retreat Wales takes place. Essentially the festival is about wellness, but it's also so much more than that. Join in this May for four days of “fed good”, leaving your usual routine behind and diving into a delightful mix of workshops, activities, music and sustainable food produce.

    The Silk Road is a name given to the many trade routes that connected Europe and the Mediterranean（地中海）with the Asian world. The route is over 6,500 km long and got its name because the early Chinese traded silk along it. Although silk was the main trading item, there were many other goods that travelled along the Silk Road between Eastern Asia and Europe. In the course of time, medicine, perfumes, spices and livestock（家畜）found their way between continents.

    The Chinese learned to make silk thousands of years ago. For a long time they were the only ones who knew how to make this precious material. Only the emperor, his family and his highest advisers were allowed to wear clothes made of silk. For a long time the Chinese guarded this secret very carefully. The ancient Romans were the first Europeans who became aware of this wonderful material. Trading started, often with Indians as middlemen（中间人）who traded silk with the Chinese in exchange for gold and silver which they got from the Romans.

    Travelling along the route was dangerous. The hot desert, high mountains and sandstorms made traveling a rough business. Most of the goods along the Silk Road were carried by caravans（商队）. Traders sometimes brought goods from one destination on the silk Road to another, from where the goods would be transported by someone else. Over the centuries people settled along the ancient route and many cities emerged. Later on there were fewer hardships to overcome, but by no means was it easy.

    Religion, languages and diseases also spread along the Silk Road. Buddhism, which originated in India, spread to China along this route. European traders probably brought the plague from Asia to Europe along the ancient road.

    In the early Middle Ages, traffic along the route decreased because of the decline of the Roman Empire. Trading along the Silk Road became stronger again between the 13th and 14th centuries, when the Mongols controlled central Asia. During the Age of Exploration the Silk Road lost its importance because new sea routes to Asia were discovered.

    I'd done it before, and so I had no reason to believe that this time would be any different. I was sure that when I returned home from my mission trip. As always, I'd bring back nothing more some mud on my boots. A hole or two in my jeans and, of course, a lot of great memories.

    The summer before my high school graduation, I went to West Virginia with others as volunteers to repair the homes of those in need. Arriving at our destination, my group was assigned the task of rebuilding sections of a home that had been damaged by fire. No sooner had we parked on the home's dirt driveway than we saw an excited little girl, no more than six years old, standing in the doorway of the family's temporary home. Shoeless and wearing dirty clothes and the biggest smile I'd ever seen, she yelled, "Ma, Ma, they really came!" I didn't know it then, but her name was Dakota, and four more days would pass before she'd say another word near me.

    Behind Dakota was a woman in a wheelchair — her grandmother, we'd soon learn. I also discovered that my job that week would be to help change a fire-damaged dining room into a bedroom for this little girl. Grabbing our tools, we went to work. Over the following days, I noticed Dakota peeking at us every now and then as we worked. A few times, I tried talking with her, but she remained shy and distant, always flying around us like a tiny butterfly but keeping to herself.

    By our fifth and final day, however, this was about to change.

    Before I went to work on her home on that last morning, I spoke for a moment or two with the grandmother. I was especially pleased when she told me how much Dakota loved her new room — so much, in fact, that she'd begged to sleep in it the previous night, even though it wasn't quite ready. As we talked, I noticed something I hadn't seen before — Dakota was hiding behind her grandmother.

    Cautiously, she stepped into view, and I could see that just like her clothes, her face was still dirty. But no amount of soil could hide those bright blue eyes and big smile. She was simply adorable. I wanted so much to hug her, but respecting her shyness, I kept my distance.

    Slowly, she began walking toward me. It wasn't until she was just inches away that I noticed the folded piece of paper in her tiny hand. Silently, she reached up and handed it to me. Once unfolded, I looked at the drawing she'd made with her broken crayons on the back of an old coloring book cover. It was of two girls — one much taller than the other — and they were holding hands. She told me it was supposed to be me and her, and on the bottom of the paper were three little words that instantly broke my heart. Now almost in tears, I couldn't control myself anymore — I bent down and hugged her. She hugged me, too. And for the longest time, neither of us could let go.

    By early afternoon, we finished Dakota's bedroom, and so I gladly used the rare free time to get to know my newest friend. Sitting under a tree away from the others, we shared a few apples while she told me about her life. As I listened to her stories about the struggles she and her family went through daily, I began to realize how boring various aspects of my own life were.

    I left for home early the next morning. I was returning with muddy boots and holes in my Jeans. But because of Dakota, I brought back something else, too-a greater appreciation for all or the blessings of my life. I'll never forget that barefoot little butterfly with the big smile and dirty face. I pray that she'll never forget me either.