As the population of the planet increases, so does the number of homes, business, parking lots, schools, airports and roadways. All these structures use electricity and need to be lighted. Humans demand light. They want their homes more comfortable and they want their streets safe. The problem is that researchers are finding that all the light is having a negative effect on humans and wildlife as well.

    Less than 10 years ago I drove to a thinly populated section of my own, lay down in the middle of the road and watched an attractive meteor shower(流星雨). If I did that today, I wouldn't be able to see the meteor shower.

    Nowadays scientists are finding light pollution can be almost as bad as carbon dioxide （二氧化碳）pollution. One of the saddest parts of light pollution is that most of it is unnecessary and most of the outdoor light that we use is wasted. One only needs to look at a row of street lights to see how much of the lights shines upwards and lights the sky: a total waste of electricity.

    Additionally, the production of electricity creates pollution by releasing greenhouse gases. This affects the air we breathe and our quality of life.

    Scientists are also studying the effects of light pollution on wildlife. Thousands of birds die each year when they crash into highly lighted buildings, as they become puzzled by the light. It has been long known that tiny baby sea turtles become lost and follow the light on the shore instead of heading towards the sea.

    Fortunately, light pollution is one of the easiest sources of pollution that can be corrected without a negative effect. Following some guidelines and a little searching on Google can give you many ideas on how to reduce your contribution to light pollution.

    When I was a baby, I entertained you and made you laugh. Whenever I was “bad”, you'd shake your finger at me and ask, “How could you?”--but then you'd give up, and roll me over for a belly scratch and I believed that life could not be any more perfect.

    My housetraining was a long process, because you were terribly busy, but we worked on that together. We went for long walks, runs in the park and car rides. We stopped for ice cream. I took long naps in the sun waiting for you to come home at the end of the day.

    Gradually, you began spending more time at work and on your career, and more time searching for a human mate. Eventually, you fell in love. She, now your wife, is not a dog person, but I still welcomed her into our home. I was happy because you were happy. Then the human babies came along and I shared your excitement, I was fascinated by their pinkness, how they smelled, and I wanted to mother them too. Your wife was afraid I would bite them. But nevertheless, as they began to grow, I became their friend.

    Now, you have a new job in another city and you and they will be moving to an apartment that does not allow pets. You've made the right decision for your “family”, but there was a time when I was your only family.

    I was excited about the car ride until we arrived at the dog pound. It smelled of dogs and cats, of fear, of hopelessness. You filled out the paperwork and said, “I know you will find a good home for her.” They shrugged and gave you a pained look. The children were in tears as they waved me goodbye. And “How could you?” were the only three words that swept over my mind.

    Is it better to live with hope or without hope? At first, whenever anyone passed my pen (围栏), I rushed to the front, hoping it was you, that you had changed your mind and that this was all a bad dream.

    My beloved master, I will think of you and wait for you forever. I hope you receive more faithfulness from your family than you showed to me.

    I loved my aunt Suzy. She was such a kind old lady. I loved going to her house on holiday. She had been sick for the last few years and, though my job had taken me away across the town, I tried to visit her as much as possible. I helped with the shopping, the cooking and the cleaning and taking her pet cat Mazy to the vet.

    Sad as her passing away was, what happened to Mazy was even more worrying. Because aunt Suzy had no children, there wasn't anyone who seemed to care for her beloved cat friend. I would have taken her in a short time, but my apartment doesn't allow pets. First, we talked with her neighbors. Mr. Jenkins, who was alone and lived across the street, wasn't interested. Joe and Sally who lived next door had a small child with serious skin allergies(过敏症). My aunt's best friend Molly who had lived just down the road was unable to take care of herself as she had serious health problems.

    Second, we thought about our family members. My brother Bobby and his wife Jill were eliminated at once as they aren't cat people. My cousin in California was a bit interested, but we weren't sure about the trip as Mazy was nearly as old as my aunt (in cat years!). Finally, we came to the local humane society to see whether they would be able to help her find a new home. The problem was that most people and families only welcomed a smart little cat into their home, not a dull old one.

    In the end, we had to put Mazy to sleep. I had spoken with the vet and realized it was possible for the best. It was so hard to lose aunt Suzy and then have nowhere for Mazy to live. A few months went by and I had gone to my aunt's house to clear out some of her belongings. I happened to see her mailman. Jerry and we started to talk about my aunt when he asked about Mazy. I told him that we had to put Mazy to sleep because we couldn't find a home for her. Jerry got really quiet. “I promised Suzy that if anything ever happened to her, I'd take care of Mazy”, he said sadly. “Suzy always said she'd told her lawyer the arrangement.”

    Hearing this, my heart sank to my feet and I almost cried. The saddest part, I realized, was this all could have been avoided. I guess we were just so busy in those final months that we didn't think about it. We could have called my aunt's lawyer to take care of it in less than 10 minutes. I'll never forgive myself for not thinking of it sooner. And I'll never forgive myself for losing Mazy.

    Emoji might not be your first choice of communication in a disaster, but researchers feel they could make a difference during emergencies, where every second counts. Now, the Emoji-quake campaign is lobbying for an earthquake emoji to be added to the Unicode set — the standard group of icons available on digital devices worldwide. The campaign aims to find an earthquake-appropriate design to be submitted to Unicode.

    "Approximately up to one third of the world's population are exposed to earthquakes," explains University of Southampton seismologist (地震学家) Dr. Stephen Hicks, a founder of the campaign. "So we really want to be able to communicate to all of those regions, all of those different languages, and an emoji is an amazing way of doing that."

    Unlike many other weather and climate related events, where longer warning times or visible signs are available, earthquakes move incredibly quickly and are difficult  to measure while they are still occurring. Populations in areas like Japan and Mexico are dependent on earthquake early warning technology, which issues an alert on digital devices and broadcast media. "You may have seconds to get under a table or to protect yourself," explains Dr. Hicks. "That can be life saving in many cases. Naturally you don't want too much wording in the warning message."

    Pictographs (象形文字) and other visuals like emoji have a track record of being faster and easier to understand than written information. Dr. Sara McBride, a communications specialist, who is also part of the campaign, told BBC News, "Emoji can cross the boundaries of written languages, helping communicate valuable information to people who may struggle to read a certain language."

    The potential usefulness of emoji in emergencies could extend well beyond earthquakes. A team of designers also came up with emerji—an entire set of emoji dedicated to climate and environmental events.

    One of the biggest social issues in Japan is the increasingly low marriage rate among young people and the small birth rate, which led to an aging and eventually shrinking（萎缩） population. Most young Japanese women simply don't seem interested in having many children.

    Now what began in Japan is happening globally. As David Brooks wrote, birth rate is becoming smaller in much of the world, from Iran — 1.7 births rate per woman — to Russian, where low birth rates connected with high death rates mean the population is already shrinking. And this includes US, which has long had higher birth rates than most developed nations. Aging countries will face the burden of caring for large elderly populations without a larger resource of young workers.

    It's true that global aging is going to present some major challenges. Who will take care of the elderly? Will an older world be less active and slower to change and adapt? It's all true. Sometimes I worry about a coming generational war over resources, just as I worry about how I will take care of my own parents in their old age, just as I worry about who might take care of me.

    But here's the thing: an older world may have less pressure on the environment. As we all know, the environment is the real victim of overpopulation.

    So maybe a world that grows slower and grows older will put less pressure on the environment, and buy us a few more years to ensure our energy use, along with our birthrates, reaches a sustainable（可持续的）level. After all, we're supposed to get smarter as we got older. Hopefully that holds true for the planet as well.

    Does the amount of cash in a lost wallet influence how likely a person is to return it? Classical economic theories suggest that the greater the appeal, the less likely we are to be honest—but a new study turns the idea on its head, finding altruism(利他主义), and a powerful hate for viewing oneself as a "thief" outweigh the financial attraction.

    A team of researchers conducted a huge experiment concerning 355 cities in 40 countries. More than 17,000 identical wallets were dropped off at public places, each containing a grocery list, a key, and three business cards in the local language using made-up names and an email address. Some had no money while others contained the equivalent (等值) of $13.45.

    According to the research, people on average returned 40% of wallets with no money in them but 51%with money. It also shows extreme differences between countries. But although rates of people's honesty varied greatly from country to country, one thing remained remarkably constant: wallets with money, as opposed to no money, raised reporting rates.

    In the US, the UK and Poland, they repeated the experiment with even more money: $94.15, which increased reporting rates by an average of 11% compared to the smaller amount. They also found that having a key expanded reporting rates by 9.2%.

    The findings, which run counter to a fundamental principle of classical economics, suggest honesty, altruism and self-image can sometimes be more influential than economic self-interest.

    A purely economic approach to behavior suggests people would keep the wallets with the larger amounts of money due to the increased financial reward, but economics often doesn't account for a person's sense of honesty or self-image, according to behavioral scientists. Altruism also influenced the findings, the researchers say. Since the key is valuable to the owner but not the finder, this pointed toward an altruism concern in addition to the cost of negatively updating one's self image.