Day 45 – Q 2.What will happen if one day all the ice caps melt away? Analyse. What are the most potent threats to ice caps? Discuss.
2. What will happen if one day all the ice caps melt away? Analyse. What are the most potent threats to ice caps? Discuss.
अगर एक दिन सारे आइस कैप पिघल जाएं तो क्या होगा? विश्लेषण करें। आइस कैप के लिए सबसे प्रबल खतरे क्या हैं? चर्चा करें।
The cryosphere is the part of the Earth system comprised of frozen water: ice sheets and glaciers, snow, permafrost and sea ice. As the climate warms, the inevitable response of the cryosphere is enhanced melting.
Effects of melting of ice caps:
- Loss of ice means more heat is absorbed: Albedo is a measure of how well a surface reflects sunlight. Snow-covered sea ice has a high albedo and reflects 85% of sunlight. But the open water revealed as ice melts is darker and absorbs more – reflecting just 7%. The less sunlight the Earth’s surface reflects the more heat the planet absorbs.
- Thawing permafrost amplifies warming: Rising Arctic temperatures are thawing once-frozen ground in the Arctic – known as “permafrost”. Scientists are concerned that CO2 and methane released from the carbon-rich permafrost could cause additional warming by adding to greenhouse gases already in the atmosphere.
- Melting Greenland ice sheet raises sea levels: As land ice melts, it adds freshwater to the oceans causing sea levels to rise, and surface melt from Greenland is increasing, as the image below shows. Satellite data suggest over the last 20 years, the Greenland ice sheet has lost 140bn tonnes of ice per year.
- Decreases the salinity: Polar ice caps are made of fresh water, so adding more fresh water without adding more salt makes the ocean water less saline. This can cause problems for organisms that are well adapted to the very salty ocean waters.
- Melting sea ice can influence winter weather: As temperatures rise faster in the Arctic than at lower latitudes, this changes large-scale temperature and pressure gradients – which may have consequences for extreme weather in the northern hemisphere.
- Ocean circulations could change: Impact of Arctic and Greenland ice melt could be that the freshwater runoff into the ocean disrupts part of a major circulation system known as the Atlantic Meridional Overturning Circulation (AMOC). The AMOC carries warm surface water northward from the tropics, giving Western Europe its mild climate.
- Changes to Wildlife: In the Arctic, as sea ice melts, wildlife like walrus are losing their home and polar bears are spending more time on land, causing higher rates of conflict between people and bears.
- Indigenous Peoples: Tribals in the Northern Hemisphere are experiencing reduced hunting seasons because of increased early spring ice melts. Because they mostly live in the coastal regions near the arctic, they depend on sea ice as a means for transportation and hunting. As the ice melts, their means to support themselves decrease.
- Transportation decreases: Declining coverage of sea ice and snow, which will affect marine and ground transportation across the Arctic.
Threats to ice caps:
- Anthropogenic causes: The industrial revolution, carbon dioxide and other greenhouse gas emissions have raised temperatures, even higher in the poles, and as a result, glaciers are rapidly melting, calving off into the sea and retreating on land.
- Fishing: Fishing for krill could be particularly significant as these are at the bottom of many Antarctic food chains.
- Tourism: With the accompanying pollutants that accompany ships and aircraft, the possibility of oil spills and the effects of lots of people and infrastructure on wildlife and the wider environment.
- Pollution: CFC’s and other ozone depletion materials are responsible for the ozone hole that has appeared over Antarctica for over 30 years, chemicals produced thousands of miles away are found in Antarctic ice and in the bodies of wildlife.
- Methane: Melting permafrost releases methane: a greenhouse gas more potent than carbon dioxide in terms of warming potential.
- Oil spills and gas extraction: An extractive oil and gas industry poses new danger to already vulnerable animal populations.
Melting sea ice is also likely to have global consequences by unlocking new shipping routes and exposing more fossil fuel reserves. But it is clear that although Arctic and Antartic sea ice only covers a small fraction of the Earth’s surface, there may well be serious climate-related impacts