【推荐1】A new study says that more than half the world’s ocean area is “becoming greener”, and the trend is connected to human-caused global warming.

It’s not clear what is driving the greening. In some places, it could indicate changes in the amount of plankton or other organic material floating in the water. Plankton are a cornerstone of the ocean food chain, and these kinds of shifts could have ripple effects throughout the entire marine ecosystem.

The study, published on Wednesday in the journal Nature, examines 20 years of satellite data measuring light reflected at the surface of the water all across the globe, subtle changes that aren’t necessarily visible to the naked eye. The research finds that 56 percent of the world’s oceans are shifting in color — and on the whole, they’re growing greener. The trend is especially strong in the lower latitudes, including the subtropics and tropics.

The researchers then used a computer model to find out whether climate change was playing a part. They conducted one set of simulations representing the oceans under a strong climate change scenario, and then compared them with a second set of simulations imagining a world in which climate change didn’t exist. The model suggests that rising global temperatures are to blame.

The exact reasons still require some scientific digging. While climate change seems to be the culprit, the study also indicates that rising ocean temperatures in and of themselves aren’t driving the greening.

There are plenty of other ways global warming is affecting the world’s oceans, by changing the structure and flow of certain currents, for instance. These kinds of changes can affect the growth of phytoplankton and other factors that might be contributing to the greening.

The findings weren’t a surprise to the researchers. They’re consistent with the way researchers expect the global oceans to change as the world keeps on warming.

“I’ve been running simulations that have been telling me for years that these changes in ocean color are going to happen,” study co-author Stephanie Dutkiewicz, a senior research scientist at the Massachusetts Institute of Technology, said in a statement. “To actually see it happening for real is no unexpected, but frightening.”

【推荐2】Shocking declines in bird populations are taking place around the world. Loss of natural habitats is cited as the key threat to bird biodiversity. Climate change is identified as a possible driver of bird population declines.

“We are now witnessing the first signs of a new wave of extinctions of continentally distributed bird species,” says lead author Alexander Lees, senior lecturer at Manchester Metropolitan University in the United Kingdom. “Bird diversity peaks globally in the tropics and it is there that we also find the highest number of threatened species.”

The study says about 48% of existing bird species worldwide are known or suspected to be undergoing population declines. Populations are stable for 39% of species. Only 6% are showing increasing population trends, and the status of 7% is still unknown. The study authors reviewed changes in bird biodiversity using data from the International Union for Conservation of Nature’s   “Red List” to reveal population changes among the world’s 11,000 bird species, The findings mirror the results of a 2019 study which determined that nearly 3 billion breeding birds have been lost during the past 50 years across the United States and Canada.

Despite their findings, study authors say there is hope for bird conservation efforts, but transformative change is needed. “The fate of bird populations is strongly dependent on stopping the loss of habitats,” says Lees. “That is often driven by demand for resources. We need to better consider how commodity (货物) flows can contribute to biodiversity loss and try to reduce the human footprint on the natural world.”

“Fortunately, the global network of bird conservation organizations taking part in this study have the tools to prevent further loss of bird species and abundance,” adds Rosenberg. “From land protection to policies supporting sustainable resource-use, it all depends on the will of governments to live side by side with nature on our shared planet.”