Article

Climate Change and Impact on Cryosphere

News

• The most ambitious Arctic research expedition called  Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) has recently been initiated. Frozen in the Arctic sea ice, scientists from 17 nations will conduct research at the epicentre of climate change on board the German research icebreaker RV Polarstern for an entire year.
• A major new report- Special Report on the Ocean and Cryosphere in a Changing Climate, predicts extreme sea level events that used to occur once every hundred years will occur at least once a year in many regions around the world by 2050.

Background

About MOSAiC MOSAiC will be the first year-round expedition into the central Arctic exploring the Arctic climate system. It will contribute to a quantum leap in our understanding of the coupled Arctic climate system and its representation in global climate models. The focus of MOSAiC lies on direct in-situ observations of the climate processes that couple the atmosphere, ocean, sea ice, biogeochemistry, and ecosystem. Many processes in the Arctic climate system are poorly represented in climate models because they are not sufficiently understood. As long as we do not understand these processes, Arctic climate projections will not be robust. The understanding of Arctic climate processes is limited by a dramatic lack of observations in the central Arctic, especially in winter and spring. During these seasons sea ice is so thick that even the best research icebreakers cannot penetrate into the Arctic and researchers have always been locked out. The dramatic changes in the Arctic climate system and the fast retreat of Arctic sea ice strongly affect global climate. The inability of modern climate models to reproduce Arctic climate change is one of the most pressing problems in understanding and predicting global climate change. All these issues will be addressed by the project.

• Historical records suggest that Arctic sea ice began to decline around 1900, with a more accelerated ice loss since the 1950s. Since 1979, satellite records have confirmed an overall decline in summer sea ice coverage of around 13% per decade.
• Although fears that Arctic sea ice would reach a ‘tipping point’ and rapidly disappear currently seem to be unfounded, the mainstream view of scientists is that we will see ice-free summers in the Arctic ocean within the next few decades.
• The Greenland ice sheet has been found to be losing ice mass over the last twenty years, and this ice loss is becoming faster.
• Antarctic ice consists of a land mass topped by an ice sheet and surrounded by sea ice. Antarctic sea ice extent is increasing at around 1% per decade, thought to be caused by shifting weather patterns reacting to changes in ozone, high in the atmosphere.
• The 2007 IPCC report concluded that the Antarctic ice sheet was most likely losing ice overall – with the Antarctic Peninsula (in the west of the continent) warming and the eastern continental interior cooling slightly.
• Due to higher pace of climate change the pace of melting of cryosphere has also increased which is posing immense danger on various aspects of human life.

What is Cryosphere?

• The areas of snow or ice, which are subject to temperatures below 32°F for at least part of the year, compose the cryosphere. The term “cryosphere” comes from the Greek word, “krios,” which means cold.
• Ice and snow on land are one part of the cryosphere. This includes the largest parts of the cryosphere, the continental ice sheets found in Greenland and Antarctica, as well as ice caps, glaciers, and areas of snow and permafrost. When continental ice flows out from land and to the sea surface, we get shelf ice.
• The other part of the cryosphere is ice that is found in water. This includes frozen parts of the ocean, such as waters surrounding Antarctica and the Arctic. It also includes frozen rivers and lakes, which mainly occur in polar areas.

Why is Cryosphere significant?

• The cryosphere stores nearly 80% of all fresh water. About 77% of Earth’s freshwater is frozen, 91% of which is contained in the Antarctic ice sheet, 8% in the Greenland ice sheet, and the remaining 1% is contained in glaciers.
• Acting like a highly reflective blanket, the cryosphere protects Earth from getting too warm. Snow and ice have a high “albedo,” which means that they reflect a significant amount of solar radiation back into space. Snow and ice can reflect between 80-90% of incident solar energy, while vegetation and soils reflect as little as 20-30%. Sunlight that is reflected back into space does not get absorbed by the Earth as heat. A high albedo, then, is an important cooling factor in the global climate system.
• It acts as an insulating layer over land and ocean surfaces, holding in heat and moisture that would otherwise escape into the atmosphere. This insulation, then, also acts to cool the global climate. Heat transfer between the ocean and atmosphere is several magnitudes greater over the open ocean than when sea ice is present; the thickness of the sea ice is also important in this regard, with thick ice insulating 1-2 times greater than thin ice. Warm water from the tropics circulates to the poles and would otherwise significantly escape as heat into the polar atmosphere if it were not for the insulation that sea ice provides.
• As cold seawater can hold more salt than warmer seawater, polar seawater is dense and sinks to the bottom of the ocean, spreading out across the globe and acting as a pump which drives oceanic circulation that transfers energy between the equator and the poles. Polar temperatures could decrease significantly at the poles without the action of this oceanic “conveyor belt,” stimulating a period of increased glaciation, or an ice age. Increasing amounts of freshwater ice introduced into the ocean from adjoining land sources act to decrease the salinity of the polar oceans, which can slow down or even inhibit this conveyor belt.
• The cryosphere provides vital information about past, present, and future climate. Ice cores drilled from ice sheets and glaciers provide annual records of temperature, precipitation, atmospheric composition, volcanic activity, and wind patterns going back more than 800,000 years.

Impacts of Melting Ice

Research has found that the environmental changes at both poles cannot result from natural climate change alone and is directly attributable to man-made climate change. Various other effects of climate change on the cryosphere (apart from the impact on roles played by cryosphere as mentioned above) include-

• Sea Level Rise: The cryosphere is an important part of our water cycle. Ice locks water out of the cycle for long periods of time – with large-scale melting, a vast amount of water can be released back into the water cycle in a relatively short amount of time. Unsurprisingly, water from the current cryosphere melt is contributing to global sea level rise.
• Impact on the river flow: Many millions of people around the globe dependent on rivers fed by mountain glaciers. In the short-term summer river flow is likely to increase – but further into the future river flow is likely to decrease as the ice feeding rivers disappears.
• Carbon & methane release: Permafrost contains large amounts of carbon, stored as frozen methane or organic material unable to decay in its frozen state. It is estimated that if permafrost melt continues, around 190 gigatonnes of carbon could be released into the atmosphere by 2200, further warming the planet.
• A more immediate potential threat from melting permafrost is the methane released from seafloor permafrost in the Arctic Ocean could enhance ocean acidification in that region over the next century.

Conclusion

• Given the acute impact of climate change and its consequent harm to the cryosphere on the overall balance of the planet, it is high time that the international community comes together and figure out ways to slow down the process, build resilience and finally to take steps to cease all those human activities that cause climate change.
• Internationally the International Cryosphere Climate Initiative (ICCI) was launched in 2009. is a network of senior policy experts and researchers working with governments and organizations to create, shape and implement initiatives designed to preserve as much of the Earth’s cryosphere as possible.
• ICCI programs target the unique climate dynamics at work in the cryosphere, while at the same time lending increased urgency to global climate efforts aimed at CO2 and other greenhouse gases by communicating the unexpected rapidity and global implications of cryosphere warming.
• The IPCC report, also, underlines how measures including immediate, ambitious, and coordinated actions to curb greenhouse gas emissions could still limit climate change and its related impacts.
• According to the report if we reduce emissions sharply, consequences for people and their livelihoods will still be challenging, but they will be potentially more manageable for those who are most vulnerable.
• The report reveals the benefits of ambitious and effective adaptation for sustainable development. Conversely, there may be escalating costs and risks associated with delayed action.
• The report cites other vital measures to address climate change, including education and climate literacy, monitoring and forecasting, financing, sharing of data, addressing social vulnerability and equity issues, and intensifying cooperation and coordination among governing authorities.