Paper is one of our oldest, simplest and most important inventions. But it also presents a danger to the world in two significant ways. First, the making of paper requires the loss of millions of trees each year. Between 2001 and 2019, the world lost 386 million hectares of forest. Of the trees that were cut down, 42% went to paper production. And worldwide use of paper is expected to double in the next 40 years. Clearly, the planet cannot sustain such a high rate of forest loss.

The second great problem with paper is what happens once it is no longer useful. A huge quantity of wastepaper ends up in dumps and landfills (垃圾填埋场), where it can produce harmful gases. Paper in landfills leads to the release (释放) of methane, a gas that is a significant contributor in global warming.

One simple solution can greatly reduce both of these problems: paper recycling. Paper is mainly made from cellulose (纤维素), which makes up the cell walls of trees and many other plants. Because of its structure, cellulose can be used repeatedly in papermaking. So far, trees are the only source of cellulose that can fill the massive demand for paper products. Therefore, recycling paper is simply one of the best ways to save trees.

Thanks to advances in processing, recycled paper isn’t the dull-colored stuff many of us are familiar with any more. It now can offer the same print performance as non-recycled paper.

Effective recycling requires a consistent effort. The way to begin is with education and understanding. Once enough people realize the need for recycling, more effective recycling systems can be carried out. The massive loss of trees affects everybody on earth. Everyone should do their part to recycle paper and encourage government and industries to do the same.

Butterflies, a familiar sight around the world, are disappearing now.Over the past four decades, more than 450 butterfly species have been affected by threats from climate change. In the US alone, the monarch butterfly has seen a drop of 80%, from millions of them in the 1980s to only 29,000 in 2020; in 2017, scientists in Germany raised alarm bells after stressing that insects had decreased by more than 70% in 30 years.

As of now, there is no long-term data available to develop effective conservation strategies in those areas where the threat is particularly widespread. And long-term monitoring programs worldwide face a challenge—training locals as citizen biologists, which, although successful, requires significant and constant funding to cover wages.

In Ecuador, however, scientists have come up with a novel approach.In Yasuni National Park, they started a monitoring project where park rangers(护林员) were trained and then performed monitoring.The rangers were able to identify sampled butterflies with impressive accuracy-an 85% success rate-which is key to the success of these monitoring programs. The data gathered by the park rangers was so accurate that it did not significantly differ from data obtained by trained biologists in the area.

Other monitoring projects select individuals from the community to act as citizen biologists, so scientists may pull the plug on them when funding dries up. However, this study represents a long-term solution.Monitoring with an infrastructure (基础设施)already in place means that it can continue into the future regardless of funding.

"Our approach increases the possibility of constant monitoring in the long term by reducing costs such as lodging(住宿)and wages,"said lead author Maria Checa. "Furthermore, it also empowers(授权)local people, offers opportunities to public institutions to accomplish their environmental goals, and opens up possibilities for expansion into other highly threatened and important areas for biodiversity(生物多样性)conservation."

The populations of common animals are just as likely to rise or fall in number in a time of accelerating global warming as those of rare species, a study suggests.

Until recently, scientists were still accumulating data on how animal populations were shifting over time globally across the different regions of the planet.

Making use of the newly available data, a team of University of Edinburgh researchers studied nearly 10000 animal populations recorded in the Living Planet Database between 1970 and 2014 to provide a new perspective on animal population change. These include records of mammals, reptiles, sharks, fish, birds and amphibians.

The team found that 15 percent of all populations declined during the period, while 18 percent increased and 67 percent showed no significant change. Amphibians were the only group in which population sizes declined, while birds, mammals and reptiles experienced increases. The overall decline in amphibians makes them a priority for conservation efforts, researchers say, as their loss could have knock-on effects in food chains and wider ecosystems.

Gergana Daskalova, of the University of Edinburgh’s School of GeoSciences, who led the study, said, “We often assume that declines in animal numbers are prevalent everywhere. But we found that there are also many species which have increased over the last half of a century, such as those which do well in human-transformed landscapes or those which are the focus of conservation actions.”

Dr. Isla Myers-Smith, also of the School of GeoSciences, who co-authored the study, said, “Only as we bring together data from around the world, can we begin to really understand how global change is influencing the biodiversity of our planet.”