More than 50 percent of the largest lakes in the world are losing water, storing less water than they did three decades ago, according to a new assessment published today in Science. The key causes are not surprising: The warming climate and unsustainable human consumption.

Lead author Fangfang Yao, a climate fellow at University of Virginia, and his team created a technique to measure changes in water levels of nearly 2,000 of the world’s biggest lakes and reservoirs (水库), which represent 95 percent of the total lake water storage on Earth.

They used 250,000 lake-area pictures taken by satellites between 1992 and 2020 to survey the area of 1,972 of Earth’s biggest lakes. They collected water levels from nine satellite altimeters (测高计) and used long-term water levels to reduce any uncertainty. For lakes without a long-term level record, they used recent water measurements made by newer instruments on satellites. Combining recent level measurements with longer-term area measurements allowed scientists to reconstruct the volume of lakes dating back decades.

The result was staggering: 53 percent of lakes globally experienced a decline in water storage. The authors compare this loss with the size of 17 Lake Meads, the largest reservoir in the United States.

To explain the trends in natural lakes, the team used recent advancements in water use and climate modeling. “Climate change and human water consumption were mainly responsible for the global net decline in natural lake volume and water losses in about 100 large lakes,” Yao said. “And many of the human and climate change footprints on lake water losses were previously unknown, such as the dryness of Lake Good-e-Zareh in Afghanistan.”

And their research offers an understanding into possible solutions. Yao said, “If human consumption is a large cause of lake water storage decline, then we can adapt and explore new policies to reduce large-scale (大范围) declines.” This happened in one of the lakes the team studied, Lake Sevan in Armenia. Lake Sevan has seen an increase in water storage, in the last 20 years, which the authors linked to the enforcement (实施) of conservation laws on water withdrawal since the early 2000s.

For some people, walking or running outdoors is a great way to work out. However, seeing trash (垃圾) all over the ground is not so pleasant. Well, some people are doing something about it. They are plogging!

“Plogging” began in Sweden. The name combines the Swedish word “plocka,” which means to pick up, and the word Jogging, which means to run slowly. A Swedish man named Erik, started the movement in 2016. On the World Environment Day website, Erik says that he would ride his bike to work every day. Concerned about the amount of trash and litter he saw each day on his way to work, he took matters into his own hands.

In Sweden, many people who exercise outdoors have been doing plogging for years. Take Jeff Horowitz for example. He is a personal trainer in Washington, D.C. He often picks up trash while running outside. “I didn’t know it was a thing really. This is just my personal ethics(道德标准). where 1 go for a run and if I happen to see a piece of garbage lying around and it’s within reach - it is a kind of a little test for me to see if I can grab it and throw it in a near trash can without stopping. And it helps clean up the neighborhood,” he announced.

Today, plogging is an official activity, one that is becoming increasingly popular. Cities around the world now hold plogging events. “I would just hope people would think twice before dropping a garbage on the ground. And, it’s easy to put your garbage in the trash cans. I just think people should think about it a little bit more. I do hope one day there will not be a need for plogging.” said an interviewee.

New methods have allowed researchers and scientists to find a way to reduce heat from buildings by about 30%. This new “green” solution is quite literally green as it involves fitting a living wall, according to a new research.

To see what effects renewing a living wall on an existing building using fabric and pockets to stick soil and plants onto the walls would have on the environment, the scientists decided to test it out on a building at a university in the UK, which was originally built in the 1970’s. As a control, part of the building was not fitted with the living wall. Both of the parts of the building were west-facing and the test was conducted over 5 weeks. What was found was that the part with the living wall lost 31.4% less heat as compared to the side without it. It also had a more stable temperature as the day progressed, so it took less energy to heat.

In the UK, approximately 57% buildings were built before 1964. They have caused 17% of greenhouse emission (排放), about 60% of which comes from space heating. If people could reduce heat loss from older buildings by 30%, a huge part of that could be removed, while regulations have changed more recently to improve the thermal performance of new constructions, it is the existing buildings that require the most energy to heat and are a significant contributor to carbon emissions. It is, therefore, essential that people begin to improve the thermal performance of these existing buildings if the UK is to reach its target of net zero carbon emission by 2050, and help to reduce the possibility of fuel poverty (贫困) from rising energy prices.

The new research suggests living walls can also provide significant energy savings to help reduce the carbon footprint of existing buildings. Perfecting these living wall systems, however, is now needed to help increase the environmental benefits and reduce some of the sustainability costs.