Close to 5,700 lakes in the Northern Hemisphere may permanently lose ice cover this century, 179 of them in the next decade, at current greenhouse gas emissions, despite a possible polar vortex this year, researchers at York University have found. Those lakes include large bays in some of the deepest of the Great Lakes, such as Lake Superior and Lake Michigan, which could permanently become ice free by 2055 if nothing is done to curb greenhouse gas emissions or by 2085 with moderate changes. Many of these lakes that are predicted to stop freezing over are near large human populations and are an important source of drinking water. A loss of ice could affect the quantity and quality of the water. "We need ice on lakes to curtail and minimize evaporation rates in the winter," says lead researcher Sapna Sharma, an associate professor in the Faculty of Science. "Without ice cover, evaporation rates would increase, and water levels could decline. We would lose freshwater, which we need for drinking and everyday activities. Ice cover is extremely important both ecologically and socio-economically." The researchers, including Postdoctoral Fellows Kevin Blagrave and Alessandro Filazzola, looked at 51,000 lakes in the Northern Hemisphere to forecast whether those lakes would become ice-free using annual winter temperature projections from 2020 to 2098 with 12 climate change scenarios. A northern lake, Credit: York University Postdoctoral Fellow Alessandro Filazzola "With increased greenhouse gas emissions, we expect greater increases in winter air temperatures, which are expected to increase much more than summer temperatures in the Northern Hemisphere," says Filazzola. "It's this warming of a couple of degrees, as result of carbon emissions, that will cause the loss of lake ice into the future." The most at-risk lakes are those in southern and coastal regions of the Northern Hemisphere, some of which are amongst the largest lakes in the world. "It is quite dramatic for some of these lakes, that froze often, but within a few decades they stop freezing indefinitely," says Filazzola. "It's pretty shocking to imagine a lake that would normally freeze no longer doing so." The researchers found that when the air temperature was above -0.9 C, most lakes no longer froze. For shallow lakes, the air temperature could be zero or a bit above. Larger and deeper lakes need colder temperatures to freeze—some as cold as -4.8 C—than shallow lakes. A northern lake. Credit: York University Postdoctoral Fellow Alessandro Filazzola "Ice cover is also important for maintaining the quality of our freshwater," says Sharma. "In years where there isn't ice cover or when the ice melts earlier, there have been observations that water temperatures are warmer in the summer, there are increased rates of primary production, plant growth, as well as an increased presence of algal blooms, some of which may be toxic." To preserve lake ice cover, more aggressive measures to mitigate greenhouse gas emissions are needed now, says Sharma. "I was surprised at how quickly we may see this transition to permanent loss of ice cover in lakes that had previously frozen near consistently for centuries." https://phys.org/news/2021-01-northern-lakes-ice-permanently-impacting.html
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The flash flood that hit Kampung Korina in Sikuati, here, on Monday following more than 50 hours of continuous rain, was the worst in over 30 years for the village. Jamiah Yunus, 78, who has been living in the village for 40 years, said flash floods had occurred in the village before but it was only up to knee level and receded fast compared to this time when it reached over three metres within a short time. She said the water rose fast about 7 am on Monday and her family quickly saved various important items before evacuating to the relief centre. "I was shocked to see the water level rising fast because for a long time, this village has not experienced such a flash flood...usually, it would subside fast and we needn't move to a relief centre," she said when met at the relief centre in Sekolah Kebangsaan Sikuati. Up to noon Tuesday, 932 flood victims from 283 families were at the relief centre and the number was expected to increase later on as the rain continued. Meanwhile, another villager, Tamahri Delus, 53, said as Kampung Korina had not been frequently hit by flash floods since over 30 years ago, her house was not built on stilts but this time, the flood had destroyed many of her belongings including sofas and mattresses. "I remember the big flash flood that hit our village 30 years ago. However, in the following years, they were not serious and we did not have to evacuate as the floodwaters subsided fast," she added. Makin Duali, 46, who has been living Kampung Korina for 10 years now, said this was the first time that he saw the flooded village looking like a sea. Kudat Department of Irrigation and Drainage personnel, Liew Vun Yap, said up to noon Tuesday, the water level in Sungai Korina was at 2.3 metres, above the river's danger level of 1.6 metres. "We are monitoring the water level every hour and reporting it to our operations room. Although it is still raining, the water level seems to be receding compared to the level of 2.8 metres this (Tuesday) morning," he said. Source: Bernama https://www.sott.net/article/447180-50-hours-of-continuous-rain-hits-village-in-Malaysia-worst-flash-floods-in-over-30-years-over-3-meters-deep
81 views · Jan 13th

More from 777 times

204 views · Jan 13th
The flash flood that hit Kampung Korina in Sikuati, here, on Monday following more than 50 hours of continuous rain, was the worst in over 30 years for the village. Jamiah Yunus, 78, who has been living in the village for 40 years, said flash floods had occurred in the village before but it was only up to knee level and receded fast compared to this time when it reached over three metres within a short time. She said the water rose fast about 7 am on Monday and her family quickly saved various important items before evacuating to the relief centre. "I was shocked to see the water level rising fast because for a long time, this village has not experienced such a flash flood...usually, it would subside fast and we needn't move to a relief centre," she said when met at the relief centre in Sekolah Kebangsaan Sikuati. Up to noon Tuesday, 932 flood victims from 283 families were at the relief centre and the number was expected to increase later on as the rain continued. Meanwhile, another villager, Tamahri Delus, 53, said as Kampung Korina had not been frequently hit by flash floods since over 30 years ago, her house was not built on stilts but this time, the flood had destroyed many of her belongings including sofas and mattresses. "I remember the big flash flood that hit our village 30 years ago. However, in the following years, they were not serious and we did not have to evacuate as the floodwaters subsided fast," she added. Makin Duali, 46, who has been living Kampung Korina for 10 years now, said this was the first time that he saw the flooded village looking like a sea. Kudat Department of Irrigation and Drainage personnel, Liew Vun Yap, said up to noon Tuesday, the water level in Sungai Korina was at 2.3 metres, above the river's danger level of 1.6 metres. "We are monitoring the water level every hour and reporting it to our operations room. Although it is still raining, the water level seems to be receding compared to the level of 2.8 metres this (Tuesday) morning," he said. Source: Bernama https://www.sott.net/article/447180-50-hours-of-continuous-rain-hits-village-in-Malaysia-worst-flash-floods-in-over-30-years-over-3-meters-deep
81 views · Jan 13th