GS III Technology, Economic Development, Biodiversity, Environment, Security and Disaster Management

Antarctic Ice sheets are considered to be one of the Climate tipping points. In this context, assess the impact of global warming on Antarctica.

The Antarctic Ice Sheet, which has the biggest potential for sea-level rise, may be at or very close to a melting tipping point, according to a new study by the Norwegian research organisation NORCE Research, United Kingdom’s Northumbria University and Germany’s Potsdam University (PIK). In the phase beyond this point, the ice sheet cannot stop melting even if global warming is contained or reversed.

Climate Tipping Points:

• Climate Tipping Points or CTPs are markers of a larger climate system which when triggered beyond a threshold, perpetuates warming on its own.
• According to IPCC, tipping points are ‘critical thresholds in a system that, when exceeded, can lead to a significant change in the state of the system, often with an understanding that the change is irreversible.’
• At 1.5^o C, five tipping points become possible, including changes to vast northern forests and the loss of almost all mountain glaciers, the die-off of tropical coral reefs and changes to the west African monsoon.
• In total, the researchers found evidence for 16 tipping points, with the final six requiring global heating of at least 2^o C to be triggered.
• The tipping points would take effect on timescales varying from a few years to centuries.
• At more than 2^o C, the nine global tipping points identified are the collapse of Greenland, West Antarctic, and two parts of the east Antarctic ice sheets, the partial and total collapse of Atlantic Meridional Overturning Circulation (AMOC), Amazon dieback, permafrost collapse and winter sea ice loss in the Arctic.

The most pressing tipping points are:

1. Greenland Ice sheets

2. Atlantic Meridional Overturning Circulation

3. Amazon Rainforest

4. Permafrost

5. Antarctic Ice Sheets

6. Coral Reefs Die off

Global warming and Antarctica:

• If Antarctica loses even a small amount of its massive ice, it could cause serious problems for coastal areas and the global economy.
• As little as 25-degree Celsius rise in ocean temperatures or even zero warming over current levels, the West Antarctic Ice Sheet will have led to 4 metre sea-level rise by the time it reaches equilibrium ice sheet states.
• Equilibrium ice sheet state refers to the final extent of the ice sheet after it has gone through the entire process of melting under current climatic conditions, which could take several years considering the slow response time of ice sheets.
• In the phase beyond this point, the ice sheet cannot stop melting even if global warming is contained or reversed. In the scientific parlance, such behaviour is called ‘hysteresis’. This means the process (in this case melting) has entered an input-output loop and can keep occurring independently.
• Heating of oceans that surround Antarctica, rather than atmospheric warming, is responsible for pushing ice sheets into interglacial state.
• Once the tipping point is crossed, restoring the ice sheets to their current stable condition will be unfeasible. It would need several millennia of temperatures at or below pre-industrial conditions.

Way forward:

1. Religious implementation of the Paris Agreement and the subsequent Nationally Determined Contributions.
2. Promotion of international cooperation in climate change mitigation and adaptation.
3. Achieving net zero emissions before 2050 and 2070 by developed and developing countries respectively.

Source:

https://www.downtoearth.org.in/climate-change/antarctic-ice-sheet-may-have-reached-tipping-point-of-no-return-study

News:

Antarctic Ice Sheet may have reached tipping point of no return: Study