Dobson Unit

      • Dobson Unit: a unit for measuring ozone concentration.
      • One Dobson Unit: number of ozone molecules required to create a layer of 0.01 mm thick pure ozone at 00C and 1-atmosphere pressure.
      • The ozone layer’s average thickness is 300 Dobson Units, or 3 mm thick.


Arctic Ozone Hole

    • News: A hole in the ozone layer above the Arctic got closed recently.
    • A Polar Vortex split due to rising temperature allowed ozone-rich air into the Arctic led to the healing of the ozone hole.

    Why did the Arctic ozone hole form this year?

    • The polar vortex during winter was “incredibly strong and persistent” this year.
    • Hence, frigid Arctic air stayed mostly locked in the Arctic, instead of wobbling around and spilling extremely cold air into places like the U.S.
    • This cold air (-80°C) allowed the formation of Polar Stratospheric Clouds.
    • These create a conducive environment for CFCs to react with sunlight. It makes chlorine, which destroys ozone.


Note: Polar vortex

  • It is a large area of low pressure and cold air surrounding both the poles.
  • It always exists near the poles. However, it weakens in summer and strengthens in winter.
  • The term “vortex” refers to the counter-clockwise flow of air that helps keep colder air near the Poles.

Note:  Why Arctic Ozone hole is rare compared to Antarctic Ozone Hole?

      • Arctic ozone hole is observed about once per decade.
      • The Antarctic ozone hole is recorded annually over the last 35 years.
      • Reason: moreland in the Southern Hemisphere.
      • Ozone layer absorbs UV light. Ozone depletion cools the stratospheric air, hence strengthens the polar vortex winds, and affects the Rossby waves.


Antarctica's first documented heat waveReasons

  • Negative Southern Annular Mode (SAM): due to strong warming of the stratosphere over Antarctica in 2019.
    • It significantly reduced the size of the ozone hole.
    • This led to ingress of warm air from the lower latitude.
  • The Indian Ocean Dipole was in a strong “positive” state due to a late retreat of the Indian monsoon.
    • i.e. water in the western Indian Ocean was warmer than normal.

Worldwide impacts: the global ocean conveyor belt

    • a constant system of deep-ocean circulation
    • it balances oceanic heat around the planet
    • melting ice sheet adds to global sea level rise.


Arctic Heat Wave

    • Recently, Arctic Circle recorded over 380C temperatures in Verkhoyansk, Siberia.
    • Likely an all-time high.


Indian Ocean Dipole (IOD) or Indian Niño

  • The positive IOD refers to the warmer western basin of the Indian Ocean as compared to the Eastern basin.

Antarctic oscillation or Southern Annular Mode (SAM)

  • It refers to the north-south movement of the strong westerly winds.
  • Positive phase: the westerly wind belt that drives the Antarctic Circumpolar Current intensifies and contracts towards Antarctica.
  • Negative phase: this belt moving towards the Equator.
  • These winds cause oceanic upwelling of warm circumpolar deep water along the Antarctic continental shelf.
  • Recent positive trends in the SAM are attributed to increasing greenhouse gas levels and stratospheric ozone depletion.

Mire, peatland or quagmire

    • A mire, peatland, or quagmire is a wetland, dominated by living peat-forming plants.
    • These are a heterogeneous mixture of plant material (mosses, humus, etc.) that had accumulated in a water-saturated area.
    • Incomplete decomposition of organic matter, due to water-logging and subsequent anoxia (absence of oxygen).
    • Covers 3% global land area.
    • Largest natural terrestrial carbon store.
    • Occurrence: Found in permafrost regions (near poles, at high altitudes), in coastal areas, beneath tropical rainforest, and in boreal forests.
    • Peatlands serve as natural firebreaks between sections of the forest.
    • Damaged peatlands are a major source of GHG emissions, almost 6% of global anthropogenic CO2 emissions.


Petersberg Climate Dialogue

    • It is an informal annual meeting: attended by high-level ministers and representatives of various countries regarding international climate actions.
    • It was launched in 2010 by Germany after failed climate negotiations of the 2009 Copenhagen Summit.
    • Co-chair: It is the country presiding over the next conference of UNFCCC.

    News: Its 11th session was held via video conferences due to COVID-19.

    • India participated.
    • Co-chaired by Germany and the UK. UK is the incoming Presidency of 26th COP to UNFCCC.


    • Scheduled to be held in Glasgow, Scotland in 2020
    • Postponed to 2021 due to COVID-19.
    • Aim: to have been the first “global stocktake” outlined in Paris Agreement.
    • ‘Global stocktake’ is the proposed review of the impact of countries’ climate change actions.


European Climate Law

  • Unveiled by European Union (EU)
  • EU’s 2050 net-zero emissions target is to be legally binding.
  • A new 2030 EU target for GHG emission reductions proposed.
  • The law is a follow-up of the European Green Deal last year. The deal was to make the EU the first climate-neutral bloc by 2050.

International Development Association (IDA)

    • IDA is part of the World Bank.
    • It helps the world’s poorest countries.
    • Loans (credits) and grants to boost economic growth, reduce inequalities, etc.
    • Debt relief: through the Heavily Indebted Poor Countries (HIPC) Initiative and the Multilateral Debt Relief Initiative (MDRI).

Program for Asia Resilience to Climate Change (PARCC- 2018)

    • A trust fund to strengthen disaster and climate resilience in South Asia.
      • Afghanistan, Bangladesh, Bhutan, India, Maldives, Myanmar, Nepal, Pakistan, and Sri Lanka.
    • Administered by the World Bank.
    • Supported by the UK’s Department for International Development.

Agricultural emissions in India

  • Recently center launched Green-Ag Project to reduce agricultural emissions.
  • In India agriculture and livestock accounts for 18% of gross national emissions.
  • It is the third-highest sector after energy and industry.

Enteric fermentation

    • It is a digestive process by which carbohydrates are broken down by microorganisms into simple molecules for absorption into the bloodstream of an animal.
    • Because of human agricultural reliance in many parts of the world on animals which digest by enteric fermentation, it is one of the factors in increased methane emissions.
    • Microbes in the digestive tract, or rumen, decompose and ferment food, produce methane as a by- product.

Global Methane Initiative (GMI)

    • It is a voluntary, international public-private initiative.
    • Aim: to reduce methane emissions and advance methane recovery and use as a clean energy source.
    • Focuses five sectors of anthropogenic methane emissions: agriculture, coal mining, municipal solid waste, municipal wastewater, and oil and gas systems.
    • Methane is the second-largest contributor to atmospheric concentrations of GHGs.
    • It creates an international platform to build capacity, develop methane abatement strategies, engage in technology transfer, remove political and economic barriers, etc.
    • India is a member.


Clearing methane using hydroxyl radicals

    • Hydroxyl radical (OH) is the main oxidant of CH4.
    • It is responsible for about 90% of methane removal in the atmosphere.
    • OH is known as the cleanser of the atmosphere: These are a form of the sink because they scrub the atmosphere clean of pollutant molecules and break them down.


Cooling Emissions and Policy Synthesis Report

  • Released by UNEP and International Energy Agency (IEA).
  • It is based on assessment of climate benefits of efficient and climate friendly cooling.
  • It lays out actions which candeliver efficient and climate friendly cooling for all.

Key findings

  • Phase-out of ozone-depleting substances, such as CFCs, under the Montreal Protocol, led to the introduction of replacement compounds, like HCFCs and later HFCs.
  • While HFCs do not deplete stratospheric ozone, many of these replacements are powerful GHGs.
  • Increasing demand for cooling is contributing to emissions of HFCs, CO2, and black carbon.
  • Direct and indirect emissions from ACs and refrigeration can rise 90% above 2017 levels by the year 2050, without policy interventions.

Atmospheric aerosols

  • These are tiny solid/liquid/mixed particles suspended in the air.
  • Aerosol Radiative Forcing (ARF): It is the net change in energy balance of earth system due to some forced perturbation by anthropogenic aerosols.
  • Effect of aerosols on climate is quantified in terms of ARF
  • News: ARF over trans-Himalayas is larger than the global averages.
    • Research by Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital.

Effect of aerosols on climate

  • Atmospheric cooling and heating
  • Surface snow: Absorbing aerosols lowers surface albedo.
  • Aerosol particles act as cloud condensation nuclei (CCN).
  • First indirect effect of aerosol: (cloud-albedo effect): reflecting back solar radiation leads to cooling of Earth’s surface.
  • Semi direct effect of aerosol: Cloud formation: Absorbing aerosols cause an increase in lower level static stability inhibiting convection leading to a decrease in cloud cover.
  • Monsoon: aerosols alter the land-sea temperature contrast as well as the tropospheric temperature structure.

Loss of Ice Cover in Arctic

Largest decline in last 41 years due to global warming.

Milne ice shelf, Canada lost more than 40% ice in last 2 days.

Note: Ice shelves are permanent floating sheets of ice that connect to a landmass. However, they can also form wherever ice flows from land into cold ocean waters.


Ministry of Earth Sciences (MoES) launches two initiatives

Knowledge Resource Centre Network (KRCNet)

  • An integrated information system for single-point fulltime access to Knowledge products like books, reports, journals, etc.
  • Under the Digital India initiative.
  • The traditional libraries of MoES will be upgraded into KRC.

Mobile App "Mausam” for India

  • Meteorological Department
  • To communicate weather information and forecasts without technical jargon.

5 services: Current Weather, Nowcast (localized hourly warnings), City Forecast, Warnings, and Radar products.


Accelerating CCUS Technologies (ACT)

  • CCUS: means Carbon Capture, Utilisation & Storage
  • ACT is an international initiative to establish CCUS as a tool to combat global warming.
  • It will facilitate the emergence of CCUS via transnational funding.
  • 16 members including India.
  • It will be in action from 2016- 2021.

Gender, Climate & Security Report

  • Sustaining Inclusive Peace on the Frontlines of Climate Change Report
  • Published by the UNEP, UN Women, UNDP, and UN-DPPA

Note: UN Department of Political and Peacebuilding Affairs (DPPA)

  • Established in 2019
  • Due to the reform of the UN peace and security infrastructure. It brought together the former Department of Political Affairs (DPA) and the UN Peacebuilding Support Office.
  • It plays a central role in UN efforts to prevent deadly conflict.
  • It provides support to the UN’s peace initiatives, and in UN political missions.

Enhancing Nationally Determined Contributions (NDCs) for Food Systems Report

  • published by WWF, UNEP, EAT (a global, non-profit startup), and Climate Focus (international think tank).
  • It guides policymakers to increase ambition in NDCs, which they resubmit under Paris Agreement.
  • In Paris Agreement, countries will participate in Global Stocktake every five years to assess collective progress to achieve long-term goals.

Key findings:

  • Food systems account for 35% of all GHG emissions.
  • Approx. 90% of NDCs fail to take food systems approaches to reduce it.