Micro-plastics have occupied almost every part of the planet today, including the most distant reaches.

The Arctic is far from clean, though it s rarely stepped in by visitors. Melanie Bergmann, a marine ecologist (海洋生态学家) and her colleagues had been studying plastics on the Arctic seafloor since 2002. In deep sea, they found about 6,0000 particles (微粒) in every 2.2 pounds of mud. In sea ice, there were as much as 12,000 pieces per 34 ounces of melted ice.

Scientists measured micro-plastics in snow from this distant location and found a lot, which could only have caught rides on the wind. The study raises concerns about the pollution that micro-plastics brought to the air, bringing a health risk to people and animals that breathe them in. But they are less worried about the threat that breathed-in pollutants have to wildlife than about polluted snow going into water.

The science on the health effects of micro-plastics is still going on.“For human health, we now now very little," says micro-plastics researcher Chelsea Rochman, “There is a lot of concern. For wildlife, we know that micro-plastics may go into every level of the food chain." Laboratory studies find some physical and chemical effects from micro-plastics, but the findings vary by the plastic type, shape experiments will be carried out soon with use of equipment if financial support approves."

Even worse is the threat from airborne micro-plastics in the area---too small to be noticed and may actually enter cells. Research on that also has been done and it could be a bigger problem, according to Rochman.

China’s war on garbage is as digital as the country itself. Think QR codes attached to trash bags that allow the government to trace exactly where its trash comes from.

On July 1, Shanghai began a compulsory garbage sorting program. Households and companies must classify their wastes into four categories and dump them in appointed places at certain times. The strict program became a headache for some residents. Not even the most environmentally conscious person can get all the answers right. Like, which bin does the newspaper you just used to pick up dog poop (粪便)belong to?

Gratefully, China’s tech startups are here to help. For instance, China’s biggest internet companies responded with new search features that help people identify what wastes are “wet”, “dry”, “toxic”, or “recyclable”. Simply pull up a mini app on WeChat, Baidu or Alipay and enter the keyword. The tech firms will give you the answer and why.

Alipay, Alibaba’s electronics payment company, claims its garbage sorting mini app added one million users under just three days. The mini app has so far indexed (编索引) more than 4,000 types of rubbish. Its database is still growing, and soon it will save people from typing by using image recognition to classify trash when they snap a photo of it. If people are too busy or lazy to hit the collection schedule, well, startups are offering trash service at the doorstep. A third-party developer helped Alipay build a recycling mini app and is now collecting garbage from 8,000 apartment complexes across 11 cities. To date, two million people have sold recyclable materials through its platform.

Besides helping households out, companies are also building software to make property managers, life easier. Some residential complexes in Shanghai began using QR codes to trace the origin of garbage. This way, regulators in the region know exactly which family has produced the trash and fine violators.

The number of birds in North America has declined by almost 3 billion since 1970, according to a study published in Science. The researchers estimated changes in the populations of 529 species using long-term bird-monitoring databases. Those data showed that the number of individual birds across all of those species had decreased by 29 percent, from around 10 billion in 1970 to just over 7 billion in 2017.

“The data they used provide probably the best long-term, large information on species abundances for any group of animals or plants anywhere in the world,” Natalie Wright, a bird biologist tells The Atlantic. “There’s always uncertainty, but if they are wrong, they are likely underestimating the size of population declines.”

The team also examined 10 years’ worth of data from a network of 143 weather radars, which pick up bird migrations, and found a reduction in migratory biomass of about 14 percent since 2007. “Two completely different and independent monitoring techniques thus signal major population loss across the continent,” the authors wrote in their paper.

The results are particularly concerning because many of the species showing declines are not considered rare or in danger, but are almost everywhere and potentially act as important contributors to food webs and ecosystem function. More than 90 percent of the loss in abundance in the survey data was due to declines in 12 families, including sparrows and blackbirds. Some other species, including many ducks, instead showed increases in abundance—possibly as a result of focused conservation efforts in recent years.

The findings should be a wake-up call. Many of the birds studied spend time in multiple countries within and beyond North America. What our birds need now is a historic, global effort that unites people and organizations with one common goal: bringing our birds back.