Jan 30, 2025 10:00 PM
Polar bear population decline the direct result of extended ‘energy deficit’ due to lack of food
https://www.eurekalert.org/news-releases/1072110
INTRO: U of T Scarborough researchers have directly linked population decline in polar bears living in Western Hudson Bay to shrinking sea ice caused by climate change. The researchers developed a model that finds population decline is the result of the bears not getting enough energy, and that’s due to a lack of food caused by shorter hunting seasons on dwindling sea ice.
“A loss of sea ice means bears spend less time hunting seals and more time fasting on land,” says Louise Archer, a U of T Scarborough postdoc and lead author of the study. “This negatively affects the bears’ energy balance, leading to reduced reproduction, cub survival and, ultimately, population decline.”
The “bio-energetic” model developed by the researchers tracks the amount of energy the bears are currently getting from hunting seals and the amount of energy they need in order to grow and reproduce. What’s unique about the model is that it follows the full lifecycle of individual polar bears — from cub to adulthood — and compares it to four decades of monitoring data from the Western Hudson Bay polar bear population between 1979 and 2021.
During this period, the polar bear population in this region has declined by nearly 50 per cent. The monitoring data shows the average size of polar bears is also in decline. The body mass of adult females has dropped by 39kg (86lbs) and one-year-old cubs by 26kg (47lbs) over a 37-year period... (MORE - details, no ads)
Climate change increases risk of successive natural hazards in the Himalayas
https://www.eurekalert.org/news-releases/1072149
INTRO: An international study has investigated the causes and impacts of the devastating flood disaster in the Himalayas in October 2023, which destroyed large areas along and surrounding the Teesta River in Sikkim, India. A research team from nine countries, including researchers from the University of Zurich (UZH), analyzed the complex drivers, causes and consequences of this flood cascade and reconstructed the exact time of its onset.
On 3 October 2023, approximately 14.7 million cubic meters of frozen moraine material collapsed into South Lhonak Lake, triggering a tsunami-like impact wave up to 20 meters high. The subsequent glacial lake outburst flood breached the moraine and released approximately 50 million cubic meters of water – enough to fill 20,000 Olympic-sized swimming pools.
The flood caused massive damage along the 385-kilometer-long valley, washing away some 270 million cubic meters of sediment and inundating infrastructure such as hydroelectric power plants on the Teesta River. At least 55 people were killed, and 70 others were reported missing.
“This event is a stark reminder of the vulnerability of high mountain regions to the effects of climate change,” says Christian Huggel, co-author of the study and head of the Environment and Climate research group at UZH. “The thawing of permafrost and the instability of rock, ice and moraine structures pose major risks.” (MORE - details, no ads)
https://www.eurekalert.org/news-releases/1072110
INTRO: U of T Scarborough researchers have directly linked population decline in polar bears living in Western Hudson Bay to shrinking sea ice caused by climate change. The researchers developed a model that finds population decline is the result of the bears not getting enough energy, and that’s due to a lack of food caused by shorter hunting seasons on dwindling sea ice.
“A loss of sea ice means bears spend less time hunting seals and more time fasting on land,” says Louise Archer, a U of T Scarborough postdoc and lead author of the study. “This negatively affects the bears’ energy balance, leading to reduced reproduction, cub survival and, ultimately, population decline.”
The “bio-energetic” model developed by the researchers tracks the amount of energy the bears are currently getting from hunting seals and the amount of energy they need in order to grow and reproduce. What’s unique about the model is that it follows the full lifecycle of individual polar bears — from cub to adulthood — and compares it to four decades of monitoring data from the Western Hudson Bay polar bear population between 1979 and 2021.
During this period, the polar bear population in this region has declined by nearly 50 per cent. The monitoring data shows the average size of polar bears is also in decline. The body mass of adult females has dropped by 39kg (86lbs) and one-year-old cubs by 26kg (47lbs) over a 37-year period... (MORE - details, no ads)
Climate change increases risk of successive natural hazards in the Himalayas
https://www.eurekalert.org/news-releases/1072149
INTRO: An international study has investigated the causes and impacts of the devastating flood disaster in the Himalayas in October 2023, which destroyed large areas along and surrounding the Teesta River in Sikkim, India. A research team from nine countries, including researchers from the University of Zurich (UZH), analyzed the complex drivers, causes and consequences of this flood cascade and reconstructed the exact time of its onset.
On 3 October 2023, approximately 14.7 million cubic meters of frozen moraine material collapsed into South Lhonak Lake, triggering a tsunami-like impact wave up to 20 meters high. The subsequent glacial lake outburst flood breached the moraine and released approximately 50 million cubic meters of water – enough to fill 20,000 Olympic-sized swimming pools.
The flood caused massive damage along the 385-kilometer-long valley, washing away some 270 million cubic meters of sediment and inundating infrastructure such as hydroelectric power plants on the Teesta River. At least 55 people were killed, and 70 others were reported missing.
“This event is a stark reminder of the vulnerability of high mountain regions to the effects of climate change,” says Christian Huggel, co-author of the study and head of the Environment and Climate research group at UZH. “The thawing of permafrost and the instability of rock, ice and moraine structures pose major risks.” (MORE - details, no ads)
