Kim Cobb, a professor at the Georgia Institute of Technology in Atlanta, is one of a small but growing minority of academics     1     are cutting back on their air travel because of climate change. Travelling to conferences, lectures, workshops, and the like frequently by plane       2    （view） as important for scientists to get together and exchange information. But Cobb and others     3     （be） now questioning that idea pushing conferences to provide more chances to participate remotely, and     4    （change） their personal behavior to do their part in dealing with the climate change crisis. On a website called No Fly Climate Sci, for example,     5    （rough） 200 academics - many of them climate scientists     6     （promise） to fly as little as possible since the effort started two years ago.

Cobb, for her part, started to ask conference organizers who invited her to speak     7     she could do so remotely; about three-quarters of     8     time, they agreed. When the answer, was no, she, declined the     9     （invite）. That approach brought Cobb's air travel last year down by 75%, and she plans     10    （continue） the practice. "It has been fairly rewarding. ", she says, "a really positive change."

I've always loved the ocean. In the    1     (seven) grade,I started volunteering at the Monterey Bay Aquarium in California. I was upset to learn that many sea animals eat plastic garbage,     2     (think)it is food.

I decided to do something     3     (educate) people about this problem. I held presentations at schools to teach kids about plastic waste. I wanted to reach businesses too. I decided that if I learned of a company    4     used a lot of plastic, I'd send it an email urging it to cut back.

One day, I saw a commercial for a health-care company. People in the ad were using plastic straws （吸管）.   I found the contact information of the company    5     emailed its president. I told him how     6     (harm) plastic could be to the environment and asked him to consider using more eco-friendly options. I was so    7     (excite) when he wrote back to me.He said he would make sure that the company cut its use of plastic straws in half.

I kept going. Whenever I heard of businesses using plastic, I'd send an email. One of the biggest companies I wrote to     8     (be) Alaska Airlines Paris. A company     9     (represent) wrote back and told me the airline was switching over     10     plastic to paper cups on all of its 1,200 daily flights.

7 . I have worked as a keeper at the National Zoo, Paris for 11 years. Spot and Stripe are the first tiger cubs that have ever been born here. Globally, a third of Sumatran cubs in zoos don't make it to adulthood, so I decided to give them round-the-clock care at home.

I've got two children—the younger one, Kynan, was extremely happy about the tigers arriving - but all of us really looked forward to being part of their lives and watching them grow. I wasn't worried about bringing them into my home with my wife and kids. These were cubs. They weighed about 2.5 kg and were so small that there was absolutely no risk.

As they grew more mobile, we let them move freely around the house during the day, but when we were asleep we had to contain them in a large room, otherwise they'd get up to mischief. We'd come down in the morning to find they'd turned the room upside down, and left it looking like a zoo.

Things quickly got very intense due to the huge amount of energy required to look after them. There were some tough times and I just felt extremely tired. I was grateful that my family was there to help. We had to have a bit of a production line going, making up “tiger milk”, washing baby bottles, and cleaning the floors.

When Spot and Stripe were four months old, they were learning how to open doors and jump fences, and we knew it really was time for them to go. It was hard for us to finally part with them. For the first few days, Kynan was always a bit disappointed that the cubs weren't there.

I'm not sad about it. I'm hands-on with them every day at the zoo, and I do look back very fondly on the time that we had them.

8 . Early fifth-century philosopher St．Augustine famously wrote that he knew what time was unless someone asked him．Albert Einstein added another wrinkle when he theorized that time varies depending on where you measure it．Today's state-of-the-art atomic（原子的） clocks have proven Einstein right．Even advanced physics can't decisively tell us what time is, because the answer depends on the question you're asking．

Forget about time as an absolute．What if，instead of considering time in terms of astronomy,we related time to ecology？What if we allowed environmental conditions to set the tempo（节奏） of human life？We're increasingly aware of the fact that we can't control Earth systems with engineering alone，and realizing that we need to moderate（调节）our actions if we hope to live in balance．What if our definition of time reflected that？

Recently，I conceptualized a new approach to timekeeping that's connected to circumstances on our planet，conditions that might change as a result of global warming．We're now building a clock at the Anchorage Museum that reflects the total flow of several major Alaskan rivers，which are sensitive to local and global environmental changes．We've programmed it to match an atomic clock if the waterways continue to flow at their present rate．If the rivers run faster in the future on average，the clock will get ahead of standard time．If they run slower，you'll see the opposite effect．

The clock registers both short-term irregularities and long-term trends in river dynamics．It's a sort of observatory that reveals how the rivers are behaving from their own temporal frame（时间框架），and allows us to witness those changes on our smartwatches or phones．Anyone who opts to go on Alaska Mean River Time will live in harmony with the planet．Anyone who considers river time in relation to atomic time will encounter a major imbalance and may be motivated to counteract it by consuming less fuel or supporting greener policies．

Even if this method of timekeeping is novel in its particulars，early agricultural societies also connected time to natural phenomena．In pre-Classical Greece，for instance，people“corrected”official calendars by shifting dates forward or backward to reflect the change of season．Temporal connection to the environment was vital to their survival．Likewise，river time and other timekeeping systems we're developing may encourage environmental awareness．

When St．Augustine admitted his inability to define time， he highlighted one of time 's most noticeable qualities：Time becomes meaningful only in a defined context．Any timekeeping system is valid，and each is as praiseworthy as its purpose．

9 . Hundreds of scientists, writers and academics sounded a warning to humanity in an open letter published last December: Policymakers and the rest of us must engage openly with the risk of global collapse. Researchers in many areas have projected the widespread collapse as “a credible scenario(情景) this century”.

A survey of scientists found that extreme weather events, food insecurity, and freshwater shortages might create global collapse. Of course, if you are a non-human species, collapse is well underway.

The call for public engagement with the unthinkable is especially germane in this moment of still-uncontrolled pandemic and economic crises in the world's most technologically advanced nations. Not very long ago, it was also unthinkable that a virus would shut down nations and that safety nets would be proven so disastrously lacking in flexibility.

The international scholars’ warning letter doesn't say exactly what collapse will look like or when it might happen. Collapseology, the study of collapse, is more concerned with identifying trends and with them the dangers of everyday civilization. Among the signatories(签署者) of the warning was Bob Johnson, the originator of the “ecological footprint” concept, which measures the total amount of environmental input needed to maintain a given lifestyle. With the current footprint of humanity, “it seems that global collapse is certain to happen in some form, possibly within a decade, certainly within this century,” Johnson said in an email.

“Only if we discuss the consequences of our biophysical limits,” the December warning letter says, “can we have the hope to reduce their speed, severity and harm”. And yet messengers of the coming disturbance are likely to be ignored. We all want to hope things will turn out fine. As a poet wrote,

Man is a victim of dope(麻醉品)

In the incurable form of hope.

The hundreds of scholars who signed the letter are intent(执着) on quieting hope that ignores preparedness. “Let's look directly into the issue of collapse,” they say, “and deal with the terrible possibilities of what we see there to make the best of a troubling future.”

There     1    (be) a dramatic rise in the number of extreme weather events over the past 20 years,    2    (cause) largely by rising global temperatures,according to a new report from the United Nations. From 2000 to 2019, there were 7,348 major natural disasters around the world,    3    (result) in USD 2,970 billion in economic loss．Much of this increase can be due to climate change. The findings show a critical need     4     (invest) in disaster prevention.