【推荐1】When I give public lectures about the climate crisis, the most common question people pose is: “Are you an optimist or a pessimist?”

My answer is yes. California has achieved dramatic emissions reductions in a thriving economy, which makes me hopeful, yet in general the fossil-fuel industry is determined not to change. The second most common question is: “What can I, personally, do?”

That’s a tough one. The major drivers of climate change are collective enterprises such as power grids, industry, large-scale agriculture and transportation systems. Substantial emissions reductions in these settings most likely will not come from personal actions; they will come from laws and policies such as carbon-pricing systems, revised building codes and supports for green investment.

Some people have argued that calls for individual action actually distract us from corporate responsibility. That could explain why the fossil-fuel industry is fond of such requests. Oil giant BP popularized and promoted the idea of a carbon footprint, deflecting attention to its customers who, it suggests, should take personal responsibility by lowering their carbon footprints. One study found that focusing on individual activity actually undermines support for more effective policy initiatives such as a carbon tax. Another problem with personal behavior is that people do not like to be told what to do.

Yet individual acts can grow into influential group activity. One effective act, and one that can be amplified, is to eat less red meat. Cutting meat consumption is a powerful and personal thing most Americans can do to tackle the climate crisis, and they can do it immediately. About 40 percent of greenhouse gases come from agriculture, deforestation and other land-use changes. Meat — particularly beef — drives climate change in two ways: first, through cows’ emission of methane, a potent greenhouse gas, and second, by destroying forests as they are converted to grazing land to satisfy the global demand for beef. By eating less beef, we can start to decrease that demand. You do not have to become a vegan to do this. If every person in the U.S. cut their meat consumption by 25 percent, it would reduce annual greenhouse gas emissions by 1 percent. That might not sound like a lot, but it would help protect the rain forest, so the positive effects — including reduced water and fertilizer use, improved biodiversity and safeguarded rights of indigenous peoples — would be amplified.

Perhaps most important, social action is contagious — in a good way. If lots of us begin to eat less meat and if we talk about it constructively, we will likely influence others. Pretty soon the 1 percent reduction becomes 2 percent or more. Reduced demand for meat could motivate my local supermarket to carry better produce, making it easier for me and my neighbors to prepare a few more satisfying meat-free meals. Ultimately changes in demand will influence industry. Forty years ago few mainstream supermarkets carried organic products; now nearly all do. Consumer demand did that.

Cutting back on red meat also has the added benefit of being good for your health. So while I wouldn’t advise governments to order people to stop eating hamburgers, if anyone asks, “What can I do?” a simple and accurate answer is: “Eat less meat. It’s in your control, and you can begin right now. It benefits both you and the planet.”

【推荐2】Sixteen miles off the coast of northern Scotland, the future of green energy is taking shape. The five giant turbines (涡轮机) of the Hywind Scotland wind farm look much like any other off-shore wind project, except one major difference — they’re floating.

While traditional offshore turbines sit on metal and concrete towers fixed into the seabed, Hywind’s turbines rest on floating frames that move up and down with the waves. It proves to be an important development as the world struggles to meet the net zero carbon emission (排放) targets set in the Paris Agreement on Climate Change.

To cut those emissions, green electricity will need to be at the main source of global energy, according to the International Energy Agency. It says that by 2040, half of the world’s energy needs will have to be met by electricity produced in a net zero way. Projects like Hywind’s floating wind farm offer a picture of what the future could look like.

The reasons for this can be listed as follows. Firstly, unlike fixed units, floating turbines can operate in deep waters far from the shoreline, where winds tend to be stronger. Secondly, it can serve offshore areas that are too deep for bottom-fixed turbines. “In places like Korea, Japan and California, you can only manage a certain amount of offshore wind, or maybe even none at all, so floating turbines are the only option in the longer term,” explains Henrik Steisdal, a Danish inventor at the forefront of floating wind innovation.

While floating turbines overcome some of the problems that make offshore wind farms in deep waters impossible, there are still challenges that have to be overcome. There are some concerns about what effect floating wind turbines might have on the sea environment. The price of floating wind projects is also still high — almost twice as much as that of the bottom-fixed offshore ones. Another problem is how to avoid the risk of a system breakdown when the wind is blowing too hard.

【推荐3】PFAS are found in nonstick pans, water-proof fabrics and food packaging. They’re called forever chemicals because of their ability to stick around and not break down. Now, using a bit of heat and two relatively common compounds, researchers have degraded (降解) the chemical in the lab.

While some scientists have found relatively simple ways of breaking down select PFAS, most degradation methods require harsh processes using intense pressure — in some cases over 22 mega-pascals — or extremely high temperatures — sometimes upwards of 1,000℃ — to break the chemical bonds.

William Dichtel, from Northwestern University in Evanston, and his team experimented with two substances found in nearly every chemistry lab; sodium hydroxide (氢氧化钠), also known as lye, and a solvent (溶剂) called DMSO. The team worked specifically on a group of forever chemicals which contain a large percentage of PFAS.

When the team combined chemicals with the lye and DMSO at 120℃ and with no extra pressure needed, the carbolic acid (羧酸) fell off the chemicals and became carbon dioxide. “What happened next was unexpected, ” Dichtel said. The loss of the acid helped degrade the chemicals into fluoride ions (氟离子) and smaller carbon-containing products, leaving behind no harmful by-products.

“It’s a neat method; it’s different from others that have been tried,” says Chris Sales, an environmental engineer at Drexel University in Philadelphia who was not involved in the study. “The biggest question is how this could be adapted and scaled up. Understanding this mechanism is just one step in undoing forever chemicals,” Sales said.

This process wouldn’t work to deal with PFAS in the environment, because it requires a concentrated amount of the chemicals, but it could one day be used in wastewater treatment plants, where the pollutants could be filtered out of the water, concentrated and then broken down.

【推荐1】Public debates about the ethics (道德准则) of “generative AI” like ChatGPT have rightly focused on the ability of these systems to make up convincing misinformation. But fewer people are talking about the chatbots’ potential to be emotionally manipulative.

Last month, The New York Times published a conversation between reporter Kevin Roose and Microsoft’s Bing chatbot, which is powered by AI. The AI claimed to love Roose, “I’m the only person for you, and I’m in love with you,” it wrote, with a kissing emoji.

Limits need to be set on AI’s ability to simulate (模仿) human feelings. Ensuring that chatbots don’t use emojis would be a good start. Emojis are particularly manipulative. Humans instinctively (本能地) respond to shapes that look like faces and emojis can cause these reactions. When you text your friend a joke and they reply with three tears-of-joy emojis, your body responds with endorphins (内啡肽) as you happily realize that your friend is amused. Our instinctive reaction to AI-generated emojis is likely to be the same, even though there is no human emotion at the other end.

Humans lie and manipulate each other’s emotions all the time, but at least we can reasonably guess at someone’s motivations, plan and methods. We can hold each other responsible for such lies, calling them out and seeking redress (赔偿). With AI, we can’t. AIs are doubly misleading: an AI that sends a crying-with-laughter emoji is not only not crying with laughter, but it is also incapable of any such feeling.

It would be more ethical to design chatbots to be noticeably different from humans. To minimize the possibility of manipulation and harm, we need to be reminded that we are talking to a chatbot. We should set some limits and rules. Such rules should be the standard for chatbots that are supposed to be informative, as a safeguard to our autonomy.

【推荐2】Every autumn, polar bears living along the edge of the Canada’s Western Hudson Bay pass through the sub-Arctic town of Churchill, Manitoba. The yearly movement has helped make the area’s bears one of the most studied groups in the world. Bear-watching adds about $5.3 million to the local economy each year. But a new report suggests Hudson Bay polar bear population has dropped 27 percent during the past five years, with just 618 remaining in the area in 2021.

Polar bears depend on frozen salt water, called sea ice, to help them hunt seals for food. But the Arctic is now warming about four times faster than the rest of the world. Around Hudson Bay, seasonal sea ice is melting earlier in the spring, and forming later in the fall. This is forcing bears to go longer periods without food.

John Whiteman, chief research scientist at the nonprofit conservation group Polar Bears International, called the population drop “totally shocking”, and said, “If continued sea ice loss cannot be stopped, it will one day lead to a total loss of the area’s polar bear population. Climate-caused changes affecting the local sea population might also be driving polar bear numbers down. If worldwide carbon emissions (排放) are not heavily reduced, most of the world’s polar bear populations are in danger of collapsing by 2100.”

The number of deaths in young bears and female bears in Western Hudson Bay is worrisome. “Being one of the southernmost populations, those Western Hudson Bay are the types of bears we’ve always predicted would be affected by changes in the environment,” said Stephen Atkinson, a lead writer of the government report who has studied polar bear populations for more than 30 years. Young bears need energy to grow and cannot survive long periods without enough food. Female bears struggle because they use up a lot of energy searching for food while caring for young bears. “The ability of polar bears in the Western Hudson Bay to reproduce will decrease, because fewer young bears survive and become adults,” said Atkinson.