Melting glaciers: consequences
Le réchauffement climatique engendre des conséquences majeures tels que la réduction de la superficie des glaciers, la fonte de la calotte glaciaire, le recul de la banquise et la disparition des icebergs.
The fast melting of a glacier caused by global warming, can lead to waters redirection and river drought. This phenomenon has been observed in the Yukon Territory in Canada based on a study made in August 2016 and published in Nature Geosciences, by the geographer Daniel Shugar. He went to the river Slims and then discovered that it was totally dried up. In May 2016, the Kaskawulsh glacier melted in only 4 days; which modified waters runoff. Before the melting, the glacier supplies the Kluane Lake then the Yukon River before flowing into the Bering Sea. From now on, they supply the Kaskawulsh River then the Alsek River which flows into the Pacific Ocean, at 1300 km from its original destination.
- During the 20st century, a substantial increase of the sea level has been detected. Since 1993 the entry of satellite monitoring has indicated a raise of 3 cm from 1993 to 2003. Both phenomenons are responsible for the rise of this level:
- Sea water expansion due to warming of ocean water
- Melting land ice. It is considered that oceans rise has been around six centimeters for 20 years.
- Ice melting is a disaster for populations and animals (polar bears, seals, caribous, penguins…) victims of their habitat destruction.
- Ice melting contributes to global warming: white ice areas reflect the sunlight whereas the melt area of oceans absorbs them, which increases heat.
Polar bears population should drop by nearly 30% by 2050. According to a study, the International Union for Nature conservation (UICN), the ice sea loss phenomenon is increasing faster than expected, yet the ice sea allows bears to access their prey. The extension of ice-free periods could hence increase fasting periods for the species, which could cause a decline in fertility and famines. The number of slimmed and starved polar bears keeps increasing as witnessed by the German photographer Kerstin Langenberger, specifically famous for having published the photo of a bear with just skin and bones, wandering around on a drifting ice block on August 22nd in 2015. Polar bears living in the American Arctic area appear among threatened species by the Endangered Species Act.
- Ice melting is a threat to native people, who are forced to migrate to survive.
- Ice melting leads to a raise of seas level, which can thus bring about flooding, specifically coastal areas threatening the survival of many villages.
- We observe a decline of drinking water resource: Drinking Water Rivers are supplied by glaciers which are melting or disappearing, which leads to a major reduction of water resource, already facing a scarcity situation in many countries.
Ice floe reduction on the continent leads to a reduction of krill quantity (type of shrimp), which has a direct impact on the whole food chain, which depends on it.