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A Nepali sherpa reached the summit of Mount Everest for a record 28th time on Tuesday, an official said, completing his second ascent in just a week, as the toll in this year's climbing season reached 11, reports Reuters.
Kami Rita Sherpa, 53, reached the 8,849-metre (29,032-feet) summit by the traditional southeast ridge route, said Nepali tourism official Bigyan Koirala, following his 27th climb last week.
Pioneered by the first summiteers, New Zealander Sir Edmund Hillary and Sherpa Tenzing Norgay in 1953, the route remains the most popular path to the world’s tallest peak.
"Whether these animals were furry or not remains an open question," Kammerer said.
The mass extinction, occurring over a span of a million years or so, set the stage for the rise of the dinosaurs in the subsequent Triassic Period. Massive volcanism unleashed lava flows across large portions of Eurasia and pumped carbon dioxide into the atmosphere for thousands of years. This caused a spike in worldwide temperatures, depletion of oxygen in the seas and atmosphere, ocean acidification and global desertification.
Top predators were especially vulnerable to extinction because they required the most food and space.
"They tend to take a relatively long time to mature and have few offspring. When ecosystems are disrupted and prey supplies are reduced or available habitat is limited, top predators are disproportionately affected," Kammerer said.
The researchers see parallels between the Permian crisis and today's human-induced climate change.
"The hardship these species faced was as a direct result of a global-warming climate crisis, so they really had no choice but to adapt to it or go extinct. This is clear by evidence of their brief perseverance in spite of these conditions, but eventually they disappeared one by one," said paleontologist and study co-author Pia Viglietti of the Field Museum in Chicago.
"Unlike our Permian predecessors," Viglietti added, "we actually have the ability to do something to prevent this kind of ecosystem crisis from happening again."