【推荐2】Not long ago, my wife and I tried a new diet—not to lose weight but to answer a question about climate change. Scientists have reported that the world is heating up even faster than they predicted just a few years ago. The consequences, they say, could be severe if we don’t keep reducing emissions of carbon dioxide (CO₂) and other greenhouse gases that are trapping heat in our atmosphere. But what can we do about it as individuals? And will our efforts really make any difference?

We decided to try an experiment: For one month we would track our personal emissions of CO₂ to see how much we could cut back. The average U.S. household produces about 80 kilos of CO₂, a day by doing commonplace things like turning on air conditioning or driving cars. This is more than twice the European average and almost five times the global average. But how much should we try to reduce?

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 challenged readers to make deep cuts in personal emissions to keep the world from reaching critical tipping points, such as the melting of the ice sheets in Greenland or West Antarctica. “To stay below that limitation, we need to reduce CO₂ emissions by 80 percent,” Tim Flannery said. “That sounds like a lot,” my wife said. “Can we really do that?”

It seemed unlikely to me, too. How close could we come to a lifestyle the planet could handle? Finally, we agreed to aim for 80 percent less than the U.S. average: a daily diet of about 13 kilograms of CO₂. Our first challenge was to find ways to convert our daily activities into kilos of CO₂ so that we could change our habits if necessary.

To get a rough idea of our current carbon footprint, I put numbers from recent bills into several calculators on websites. The results that came out were not very flattering. The Environmental Protection Agency (EPA) website figured our annual CO₂ emissions at 24,618 kilos, 30 percent higher than the average U.S. family with two people. Clearly, we had further to go than I thought.

【推荐3】Puppies can be taught. So can human children, though not for the first couple of years. Now, in the hope of fighting climate change, Dr Jan Langbein, of the Fredrich-Loweffler-Institut in Germany, and his colleagues hope they can train cows to use the toilet, too.

Cow pee（尿）contains a nitrogen-rich substance that, when broken down by enzymes（酶）, is transformed into ammonia（氨）. Bacteria in the soil, in turn, transform that ammonia into nitrous oxide, a greenhouse gas. Collecting and treating cow pee before the ammonia can be produced might, therefore, seem like a good idea. But it has proved difficult in the past without limiting the cows to small areas, which is bad for their welfare.

As Dr Langbein describes in Current Biology, this confusing problem could be solved if cows could be persuaded to voluntarily relieve themselves in a toilet. He has developed a three-stage process to help cows master toilet training. The first job was to establish the toilet. Calves（小牛）were limited to a toilet and rewarded with treats after peeing in it. Next, they were given the freedom to wander around a path outside the toilet. Peeing in the toilet were rewarded; those in the path were gently punished with a spray of water. Finally, the path was extended, to allow the animals to practice self-control over a greater distance.

Of the 16 calves involved in the training process, 11 were considered successfully toilet-trained by the end of it. Their overall performance, say the researchers, was almost comparable to that of human children. The animals managed to pee in the toilet around 77% of the time.

The next step, says Dr Langbein, is to see if cattle on a working farm can be similarly trained. Whether farmers will be keen is another question. Building toilets and training animals costs time and money, after all. But when it comes to climate change, every little helps.

【推荐3】For more than 60 years bringing the cost of food down had been one of the greatest challenge of the 21 century. That cost, however, is not in immediate cash, for most food is now far cheaper in relative terms than in 1960.

The cost is in the unintended damage of the very methods of food production that have made the food cheaper: in the pollution of water, the weakness of soil, the destruction of wildlife, the harm to animal welfare and the threat to human health caused by modern industrial agriculture.

First mechanisation, then mass use of chemical fertilisers and pesticides, and now genetic engineering — modern industrial farming has seemed unstoppable, as the yields of produce have soared. But it comes with extensive loss of wildlife and habitat, soil degradation and fertilizer run-off.

Put it together and it’s like a battleground, but consumers rarely make the connection at the dinner table. The problems are called “externalities” by economists because they’re not part of the main transaction, like growing and selling wheat. These costs aren’t directly paid by the producers or consumers.

But the costs to society can amount to shocking sums. According to a research by Professor Jules Pretty at the University of Essex, repairing the damage caused by intensive farming in one particular year costs £2, 343m in the UK alone, almost as much as the total UK and EU spend on British farming in that year.

Can the true cost of food be brought down? In some countries, moving away from industrial agriculture to address hunger is difficult. However, in developed countries, it’s more possible. Governments should support sustainable farming that benefits the environment, economy, health, and animal welfare. Instead of immediately switching to organic farming, Professor Pretty suggests adopting a “Greener Food Standard” which would push the market towards more sustainable environmental practices than the current norm, while not requiring the full commitment to organic production. This standard would guide farmers on better practices in farming, promoting a shift towards a more sustainable agricultural system for both producers and consumers.

【推荐1】A new artificial intelligence (AI) tool called ChatGPT has excited the Internet community with its superhuman abilities to solve math problems, produce college articles and write research papers. Some educators are warning that such Al systems will change the world of learning, teaching, and research, for better or worse.

Ethan Mollick, a professor at the University of Pennsylvania’s Wharton School of Business, sees its benefits as a learning partner. He has used it as his own teacher’s assistant, for help with preparing a lecture and grading instructions for MBA students. “You can ask it to find a mistake in your writing and correct it and tell you why you got it wrong,” he said. “It’s really amazing.”

But the superhuman assistant has its limitations (局限). ChatGPT was created by humans, after all. OpenAI has trained the tool using a large dataset of real human conversations. It sometimes lies to you, with confidence. There have been situations in which ChatGPT won’t tell you when it doesn’t have the answer.

That’s what Teresa Kubacka, a data scientist based in Zurich, Switzerland, found when she experimented with the language model. “I asked it about something that I thought that I know doesn’t exist (存在) so that I can judge whether it actually also has the idea of what exists and what doesn’t exist.” she said. ChatGPT produced an answer so specific sounding, backed with citations (引文), that Kubacka had to find out whether the made-up thing was actually real. “This is where it becomes kind of dangerous,” she said.

ChatGPT doesn’t produce good science, says Oren Etzioni, the founding CEO of the Allen Institute for AI. But he sees ChatGPT’s appearance as a good thing. He sees this as a moment for review. “ChatGPT is just a few days old, I like to say,” said Etzioni. “It’s giving us a chance to understand what he can and cannot do and to begin the conversation of ‘What are we going to do about it?’”

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【推荐2】Charity is simple in theory: A heart warms, a hand reaches out. In practice, though, charity can become a troubled mix of motives (动机) and consequences. Giving can be driven by guilt (负罪感), duty, praise, or perhaps the hope that giving will somehow make up for past cruelty (残酷) or ignorance. Too little charity is far less than valuable. Too much can cause dependence, which makes the receiver continuously ask for more.

Giving from the heart is good. But critics (批评家) have long worried about misdirected charity that does more harm than good. In his 2012 book, Harmful Charity: How Churches and Charities Hurt Those They Help (And How to Solve the Problem), Robert Lupton, an experienced social worker of 40 years of community work in inner-city Atlanta, argues that charity must not do for the poor what they can do for themselves.

Due to emergencies such as natural disasters, the afterward financial aid is greatly welcome. Mr. Lupton advocates (提倡) it should focus on the development of self-supporting. The task can be carried out via, for instance, offering microloans (小微贷款), hiring local builders and suppliers, and trying to found self-supported, locally owned and operated factories. What seldom works, he argues, are untargeted handouts from far-off providers and the sudden arrival of inexperienced volunteer-tourists hoping to earn personal reputation by digging wells or mending roofs that locals are perfectly able to take care of themselves.

Getting charity right isn’t easy. But from money raising to the rising in volunteering among Millennials (千禧一代), from the increasing worldwide willingness to give to the efforts by charity organizations to become more effective and fruitful, there is strong evidence that human beings’ ability of taking care of others is growing along with their ability to help without harming.

Charity can be as simple as holding the door for a stranger and as complex as a global campaign to get rid of malaria (疟疾). Charity works best when it returns the weak to strength, and helps a small town shaken by an earthquake get back on its feet. A successful charity is one that eventually is no longer needed.