GS Paper: GS3-18.Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment.

Why in the News?

A new calculation suggests that climate models might be overestimating how long plants keep carbon before releasing it as per the recent study published in Science by an international research team.

Study from the Relics of the Cold War:

• The nuclear bomb tests conducted during the Cold War inadvertently provided scientists with valuable data for climate research.
  • The tests released significant amounts of radiocarbon into the atmosphere, allowing researchers to study its movement and absorption by vegetation.
• The presence of radiocarbon in the atmosphere serves as a marker for understanding carbon dynamics.
  • The study analyzed the radiocarbon levels before and after the 1963 Limited Test Ban Treaty, which halted atmospheric nuclear testing, providing insights into how carbon is cycled between the atmosphere and vegetation.
• The study highlights that many climate models have not incorporated radiocarbon data, which could lead to inaccuracies in predicting carbon cycling and its impact on climate change.
  • Only one model, the Community Earth System Model 2, has accounted for radiocarbon, but it predicted lower absorption levels than the study found.

How the Whole System is Cycling Faster?

• Accelerated Carbon Exchange: The researchers concluded that the entire carbon cycle is operating faster than previously understood.
  • This means that while plants absorb more CO2, they also release it back into the atmosphere more quickly, leading to a more dynamic and less stable carbon storage system.
• Implications for Climate Mitigation: The findings suggest that strategies relying on plant carbon sequestration to offset fossil fuel emissions may need to be reevaluated.
  • If plants are releasing carbon sooner than expected, the potential for mitigating climate change through natural carbon sinks could be less effective than previously thought.

Way forward: 

• Incorporate Radiocarbon Data: Integrate radiocarbon data into existing and future climate models to more accurately predict carbon cycling and the role of vegetation in carbon sequestration. This will lead to more reliable forecasts of climate change impacts and inform better policy decisions.
• Develop Dynamic Carbon Cycle Models: Improve models to account for the faster carbon cycling observed, ensuring they reflect the actual pace at which carbon is absorbed and released by plants. This will help in refining strategies for climate mitigation.

Why in the News?

New research has documented previously unseen shapes at the base of a West Antarctic ice shelf.  

Base of a West Antarctic Ice Shelf

• Basal Melt Dynamics: The base of West Antarctic ice shelves, including the Dotson Ice Shelf, experiences basal melt driven by warm ocean water. This process leads to thinning and hollows out cavities beneath the ice, reducing structural support for the grounded ice above.
• Autonomous Underwater Vehicle (AUV) Research: Recent research utilized an AUV equipped with multibeam sonar to explore the topography of the basal melt cavity beneath the Dotson Ice Shelf, revealing previously unquantified melt mechanisms and unique formations at the ice shelf’s base.
  • Warm salty water, which is transported through ocean currents, significantly contributes to the melting of ice shelves. This bottom-up melting is critical to understanding the dynamics of ice loss and its implications for global sea level rise.
  • The AUV discovered tear-shaped indents and other unique shapes at the base of the ice shelf, indicating diverse melting patterns influenced by the flow of warm water.

Reasons behind ocean warming

• Greenhouse Gas Emissions: Since the Industrial Revolution, human activities such as burning fossil fuels have significantly increased greenhouse gas (GHG) concentrations in the atmosphere, including carbon dioxide, methane, and nitrous oxide. These gases trap heat, leading to global warming.
• Heat Absorption: The oceans have absorbed more than 93% of the excess heat from greenhouse gas emissions since the 1970s. This resulted in an average increase in ocean temperature of about 1°F (0.6°C) over the past century.
• Impact of El Niño: The El Niño weather pattern, characterized by the abnormal warming of surface waters in the equatorial Pacific Ocean, contributes to both ocean warming and rising global surface temperatures.

International Efforts and Agreements

• The United Nations Framework Convention on Climate Change (UNFCCC) was signed by 166 countries in 1992, acknowledging humanity’s role in climate change.
• The Paris Agreement, adopted in 2015, sets the international community the goal of limiting global warming to “well below” 2°C in this century.
• The Green Climate Fund, established in 2010, aims to help developing countries adopt initiatives to combat climate change and deforestation

Way forward: 

• Enhanced Global Commitments: Nations need to reinforce their commitments under international agreements like the Paris Agreement. This includes setting more ambitious targets for reducing greenhouse gas emissions and adhering to these goals through stringent policies and regulations.
• Funding and Technology Transfer: Developed countries should increase financial contributions to climate funds such as the Green Climate Fund to support mitigation and adaptation efforts in developing countries.

Mains Question for practice: 

Q Bring out the relationship between the shrinking Himalayan glaciers and the symptoms of climate change in the Indian sub-continent. (2014)