Context:

Intergovernmental Panel on Climate Change (IPCC) recently published its sixth assessment report (AR6) titled “Climate Change 2021: The Physical Science Basis”.

Relevance:

GS-III: Environment and Ecology (Environmental Pollution and degradation, Conservation of Environment, Climate change and its impact, International Institutions and Agreements for combating climate change)

Dimensions of the Article:

  1. About the IPCC
  2. Highlights of the IPCC’s AR6: Climate Change 2021

About the IPCC

  • The Intergovernmental Panel on Climate Change (IPCC) is the international body for assessing the science related to climate change set up by the World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP) in 1988.
  • IPCC was created to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.
  • IPCC assessments provide a scientific basis for governments at all levels to develop climate related policies, and they underlie negotiations at the UN Climate Conference – the United Nations Framework Convention on Climate Change (UNFCCC).
  • IPCC does not carry out original research. It does not monitor climate or related phenomena itself. However, it conducts a systematic review of published literature and then produces a comprehensive assessment report.

IPCC Assessment Reports

  • The IPCC Assessment Reports are published once in about 7 years – and they are the most comprehensive scientific evaluations of the state of Earth’s climate. The 6th such assessment report was published in 2021.
  • Prior to the AR6 in 2021, five assessment reports have been produced with the first one being released in 1990. The fifth assessment report had come out in 2014 in the run up to the climate change conference in Paris.
  • The Assessment Reports are prepared by three working groups of scientists:
    • Working Group-I – Deals with the scientific basis for climate change.
    • Working Group-II – Looks at the likely impacts, vulnerabilities and adaptation issues.
    • Working Group-III – Deals with actions that can be taken to combat climate change.

Highlights of the IPCC’s AR6: Climate Change 2021

  • According to the authors of AR6 report, warming of Indian ocean will result into rise in sea levels causing more frequent and severe coastal flooding across low-level areas.
  • It will also result into intense and frequent heat waves and humid heat stress in the 21st century in South Asia.
  • Report highlights, even if the temperature is limited 1.5 degree Celsius from pre-industrial levels, extreme weather events will be witnessed.
  • Heatwaves, heavy rainfall events, and melting of glaciers is going to happen frequently, impacting countries like India.
  • Report warned developed countries to undertake immediate, deep emission cuts and decarbonisation.

Specific Points from the report:

  • The average surface temperature of the Earth will cross 1.5 °C over pre-industrial levels in the next 20 years (By 2040) and 2°C by the middle of the century without sharp reduction of emissions. This is the first time that the IPCC has said that the 1.5°C warming was inevitable even in the best case scenario.
  • Global surface temperature was 1.09°C higher in the decade between 2011-2020 than between 1850-1900. The last decade was hotter than any period of time in the past 1,25,000 years.
  • Carbon dioxide (CO2) Concentrations are the highest in at least two million years. Humans have emitted 2,400 billion tonnes of CO2 since the late 1800s. Most of this can be attributed to human activities, particularly the burning of fossil fuels.
  • Sea-level rise has tripled compared with 1901-1971. Coastal areas will see continued sea-level rise throughout the 21st century, resulting in coastal erosion and more frequent and severe flooding in low-lying areas. About 50% of the sea level rise is due to thermal expansion (when water heats up, it expands, thus warmer oceans simply occupy more space).
  • There will be an increase in hot extremes, extreme precipitation and drought for every additional 0.5 °C of warming. Additional warming will also weaken the Earth’s carbon sinks present in plants, soils, and the ocean.
  • The freezing level of mountains are likely to change and snowlines will retreat over the coming decades. Global Warming will have a serious impact on mountain ranges across the world, including the Himalayas. The level of temperature rise in the mountains and glacial melt is unprecedented in 2,000 years. The retreat of glaciers is now attributed to anthropogenic factors and human influence.

-Source: The Hindu

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