The COVID-19 pandemic (流行病) reduced global greenhouse gas emissions by 7 percent this year, released by the Global Carbon Project on Friday.

“The amount fell by 2.4 billion metric tons    1    the current level of 34 billion metric tons of carbon dioxide (CO2)”, said the study    2    (publish) in the journal Earth Systems Science Data. “The drop occurs    3    (chief) because people are staying home and traveling    4    (little) by car and plane, and emissions    5    (expect) to jump back up after the pandemic ends”, the research team said. The data show that ground transportation makes up about one-fifth of emissions of carbon dioxide. Though the record    6    (drop), the world on average put 1,075 metric tons of CO2 into    7    air every second. The scientists of the study said that long-term emissions trends would be heavily influenced by how    8    (country) power their pandemic recovery plans.

UN Secretary-General Antonio Guterres on Tuesday appealed for ambitious climate action,    9    (say) 2021 must be the year    10    the world leaps forward into a net-zero emissions future.

2 . Light pollution is a significant but overlooked driver of the rapid decline of insect populations, according to the most comprehensive review of the scientific evidence to date.

Artificial light at night can affect every aspect of insects' lives, the researchers said. "We strongly believe artificial light at night — in combination with habitat loss, chemical pollution.invasive (入侵的) species, and climate change — is driving insect declines, " the scientists concluded after assessing more than 150 studies.

Insect population collapses have been reported around the world, and the first global scientific review published in February, said widespread declines threatened to cause a "catastrophic collapse of nature's ecosystems".

There are thought to be millions of insect species, most still unknown to science, and about half are active at night. Those active in the day may also be disturbed by light at night when they are at rest.

The most familiar impact of light pollution is moths (飞蛾) flapping around a bulb, mistaking it for the moon. Some insects use the polarisation of light to find the water they need to breed, as light waves line up after reflecting from a smooth surface. But artificial light can scupper (使泡汤) this. Insects are important prey (猎物) for many species, but light pollution can tip the balance in favour of the predator if it traps insects around lights. Such increases in predation risk were likely to cause the rapid extinction of affected species, the researchers said.

The researchers said most human-caused threats to insects have analogues in nature, such as climate change and invasive species. But light pollution is particularly hard for insects to deal with.

However, unlike other drivers of decline, light pollution is relatively easy to prevent. Simply turning off lights that are not needed is the most obvious action, he said, while making lights motion-activated also cuts light pollution. Shading lights so only the area needed is lit up is important. It is the same with avoiding blue-white lights, which interfere with daily rhythms. LED lights also offer hope as they can be easily tuned to avoid harmful colours and flicker rates.