Global warming threatens to hold back human progress, and make unachievable all UN targets to reduce poverty, according to some of the world's leading international and development groups.

    In a report published today, Oxfam, Greenpeace and other groups say rich governments must immediately address climate change to avoid even “unbearable levels” of worldwide poverty.

     “Food production, water supplies, public health and people's livelihoods are already being damaged and weakened,” the report says. “There is no approach possible. The world must meet its commitments to achieve poverty reduction and also deal with climate change, which are closely linked.”

    The report, which draws on UN predictions of the effects of climate change in poor countries over the next 50 years, says poor countries will experience more flooding, declining food production, more disease and the extinction of entire eco-systems on which many of the world's poorest people depend.

     “Climate change needs to be addressed now. The poor will bear the great consequence of it. The frontline experience of many of us working in international development indicates that communities are having to fight more extreme weather conditions.”

    Climate change will cause great damage to agriculture and water supplies and will increase diseases. “By 2025 the number of the world's population living in countries of significant water stress will almost double, to 6 billion people. Tropical (热带的) and sub-tropical areas will be hardest hit — those countries already suffering from food shortage”.

    Poor countries mostly do not need hi-tech solutions, but would most benefit from education, research and being shown how to farm better. The report says unchecked global warming, more than wars or political upheaval (政变), will displace millions of people and unsettle many countries.

Around the World by Wheelchair

    Rick Hansen was always an active kid and loved to fish. When returning in a truck one day from a fishing trip, he had an accident and suffered injuries to his spine (脊柱)，This 15-year-old young man awoke to find that he had lost the use of his legs. However, he didn't give up. Many months later he began to compete in wheelchair sports. At the age of 27, he decided to wheel around the world to raise awareness and money for spinal cord research. His tour took him through 34 countries around the world between 1985 and1987. In this Man of Motion World Tour, he wheeled 24,901.55 miles, which is equal to the distance around the earth.

    Bad weather and difficult, rocky roads often provided challenges for Rick, but he continued to push himself to complete the trip. He was determined to succeed. Even mountains did not stop Rick Hansen. He wheeled himself up the Rocky Mountains and several other major mountains in the world. He even wheeled himself along the Great Wall of China!

    “Never Give Up On Your Dream” was his motto and he hasn't given up yet. He completed his world tour raising $24 million. He continues to work to increase knowledge of spinal cord injury. He is a true Canadian hero who shows what determination can achieve.

    Mexico sites on an island plateau (高原) surrounded by volcanic peaks, which makes air quality a constant concern for people who live there.

    In April, the country took a decisive step toward improving air quality by enacting a temporary ban on private and Federal vehicles in the city. The rule forbids people from driving in the city one day each week and one Saturday each month. Electric vehicles, government service vehicles, public transport options and school buses are not included in the ban.

    Mexico City isn't the first urban center to be involved in car-free living. But the ban is more than an awareness-raiser. It was enacted with the direct aim of solving air pollution. In March, the city sank into a deep brown haze of smog when the pollution levels passed the 200 mark. The city ordered some 1.1m of the area's 4.7m cars off the streets and also offered free bus and subway rides.

    Mexico City's temporary vehicle ban raises questions about the best ways to improve urban air quality. India, whose citizens breathe some of the world's dirtiest air, has tried a variety of solutions. Earlier this year, the Indian government started a 4% sales tax on new-car purchases.

    Beijing also has experience with cleaning the air. The city introduced alternate-day rules in advance of the 2008 Olympic Games, which produced good results. And then there is the London congestion (拥挤) charge, introduced in 2003. The charge has had a measurable effect on air quality.

For now, Mexico City — named by the United Nations as the most polluted city on the planet in 1992 — can look forward to the start of the region's rainy season, when daily showers will help lo clean the air.

    Charlie studied in a famous college for four years. He studied hard and did well in all his subjects. He hoped to become a good teacher. This year he left the college and began to work in a middle school. He likes his students and is strict with them. He does his best to make his classes lively and interesting.

    One day he carefully explained a chemical reaction to the students of Grade 2 in the chemistry lab.

    “Be careful, everyone,” he said loudly. “Before I make the experiment, there're twenty five atoms of carbon (碳原子), but after I finish it, there're twenty four atoms of carbon left!”

He stopped to watch the classroom and hoped his students would go on explaining it. But the young men looked at each other and nobody answered him. He had to ask,

    “What happens? What makes the atom lost?”

    The classroom was very quiet and none of the students looked at their teacher.

    “Who can tell us where it has gone?”

    Suddenly a soft voice came from the back row, “We did not see anybody leave the lab!”

    The Asian country announced yesterday that China was putting tariffs or taxes on about $3 billion worth of imports from the U.S. The tariffs are on 128 American-made products, ranging from pork and fruit to steel pipes. This will make it more expensive for America businesses to sell those products in China. And China says this was done as a response to the tariffs that the U.S. recently put on imports of Chinese steel and aluminum.

    Meanwhile, U.S. President Donald Trump says more tariffs, new ones worth as much a $50 billion are being planned by the U.S. on additional goods from China. So, one big question is, will all this cause a trade war, when countries take turns putting tariffs on each other 's goods, causing prices to rise?

    We don't know yet. The U.S. and China ship hundreds of billions of dollars of goods back and forth every year. So, the tariffs we've seen so far are a tiny part of that. And America's treasury secretary says the U.S. and China are talking behind the scenes about how to prevent a possible trade war.

    But a number of experts are concerned this could turn into one and so are some stock investors. The Chinese tariffs were a major factor in a drop of the U.S. stock market yesterday when the Dow Jones Industrial Average fell 459 points. But just like it's hard to tell if a trade war is on the horizon, it's also hard to tell what kind of effects one could have decades down the road.

    Humans and many other mammals have unusually efficient internal temperature regulating systems that automatically maintain stable core body temperatures（核心体温）in cold winters and warm summers. In addition, people have developed cultural patterns and technologies that help them adjust to extremes of temperature and humidity（湿度）.

In very cold climates, there is a constant danger of developing hypothermia（低体温）, which is a life threatening drop in core body temperature to below normal levels. The normal temperature for humans is about 37.0℃. However, differences in persons and even the time of day can cause it to be as much as 6℃ higher or lower in healthy individuals. It is also normal for core body temperature to be lower in elderly people. Hypothermia begins to occur when the core body temperature drops to 34.4℃. Below 29.4℃, the body cools more rapidly because its natural temperature regulating system usually fails. The rapid decline in core body temperature is likely to result in death. However, there have been rare cases in which people have been saved after their temperatures had dropped to 13.9-15.6℃. This happened in 1999 to a Swedish woman who was trapped under an ice sheet in freezing water for 80 minutes. She was found unconscious, not breathing, and her heart had stopped beating, yet she was eventually saved despite the fact that her temperature had dropped to 13.7℃.

In extremely hot climates or as a result of uncontrollable infections, core body temperatures can rise to equally dangerous levels. This is hyperthermia. Life threatening hyperthermia typically starts in humans when their temperatures rise to 40.6-41.7℃. Only a few days at this extraordinarily high temperature level is likely to result in the worsening of internal organs and death.