Climate Change and Global Warming

  • Climate change refers to change in variation of weather around longer-term average conditions
  • Climate change is caused by factors such as
  • biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions
  • Human activities responsible for climate change is often referred to as “global warming”
  • Factors that can shape climate are called climate forcing or “forcing mechanisms”
  • Types –
  • Internal forcing mechanisms –natural processes within the climate system itself
  • External forcing mechanisms

Natural (e.g. changes in solar output)

Anthropogenic (e.g. increased emissions of greenhouse gases)

  • Forcing mechanisms
  • Internal forcing mechanisms
  • Ocean variability
  • Life

Carbon and water cycles

albedo, evapotranspiration, cloud formation and weathering


  • External forcing mechanisms –
  • Orbital variations
  • Solar output
  • Volcanism
  • Plate tectonics
  • Human influences

Global Warming –

  • Global warming is the term for observed century-scale rise in the average temperature of the Earth’s climate system and its related effects
  • Most of global warming is caused by increasing concentration of greenhouse gases and other human activities
  • It leads to changes in global climate patterns
  • Impacts –
  • Rise in sea level
  • Expansion of deserts in the subtropics
  • Decreasing crop yields
  • Extreme weather events including heat waves, droughts, heavy rainfall, and heavy snowfall
  • Change in rainfall patterns
  • Melting of glaciers and ice caps
  • Ocean acidification
  • species extinctions due to shifting temperature regimes
  • Increased spread of diseases

Greenhouse Effect –

  • The greenhouse effect is the process by which a planetary surface is warmed by radiation from its atmosphere to a temperature above normal
  • Earth’s natural greenhouse effect is critical to supporting life.
  • Human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming
  • Green houses Gases –
  • A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range.
  • In the solar system, the atmosphere of Venus, Mars and Titan also contain gases that cause a greenhouse effect
  • Most abundant greenhouse gases in Earth’s atmosphere in order are
  1. Water vapour (H2O)
  2. Carbon dioxide (CO2)
  3. Methane(CH4)
  4. Nitrous oxide (N2O)
  5. Ozone(O3)
  6. Chlorofluorocarbons(CFC)
  • Four major gases contributing to the greenhouse effect are
  1. Water vapour, 36-70%
  2. Carbon dioxide, 9-26%
  3. Methane, 4-9%
  4. Ozone, 3-7%
  • Water vapour
  • Water vapour is the biggest overall contributor to the greenhouse effect
  • amount of water vapour in the air at any time is strongly related to the amount of other greenhouse gases in the atmosphere
  • Carbon dioxide(CO2)
  • CO2 is produced by fossil fuel burning and other activities such as cement production and tropical deforestation
  • Carbon dioxide is of greatest concern because it exerts a larger overall warming influence than all of those other gases combined
  • increasing global temperature also cause concentrations of carbon dioxide
  • Methane (CH4) – Sources
  • Wetlands including paddy fields
  • Leakage from natural gas systems
  • Raising of livestock
  • Landfills
  • Other sources include termites, ocean sediments, volcanoes, wildlife etc.

Ozone Depletion

Basics –

  • Ozone depletion implies two phenomena –
  1. a steady decline of about 4% in the total volume of ozone in Earth’s stratosphere(the ozone layer) and
  2. Ozone hole : a much larger springtime decrease in stratospheric ozone around Earth’s polar regions

In addition to these, there are also springtime polar tropospheric ozone depletion events.

  • Ozone

Ozone (O3) is an allotrope of oxygen consisting of three atoms of oxygen

  • Ozone cycle –
  • Ozone is formed in the stratosphere when oxygen molecules photodissociate after intaking an ultraviolet photon
  • Ozone molecules absorb UV light and splits into a molecule of O2 and an oxygen atom
  • The oxygen atom then joins up with an oxygen molecule to regenerate ozone
  • Destruction of O3 –
  • Ozone is destroyed by a number of free radical catalysts such as hydroxyl radical (OH), nitric oxide radical (NO), chlorine atom(Cl) and bromine atom
  • The Cl and Br atoms destroy the ozone molecules through a variety of catalytic cycles
  • On a per atom basis, bromine is even more efficient than chlorine at destroying ozone

CFCs –

  • Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substance (ODS) are mainly responsible for man-made chemical ozone depletion
  • Sources
  • They were used in air conditioning and cooling units, as aerosol spray propellants
  • They also occur as by-products of some chemical processes
  • CFC molecules can stay in the upper atmosphere for about a century, destroying up to one hundred thousand ozone molecules

Observations –

  • The most pronounced decrease in ozone has been in the lower stratosphere.
  • Ozone hole is measured by reduction in the total column ozone above a point on the Earth’s surface, which is expressed in Dobson units
  • Antarctic –
  • Reductions of up to 70% in the ozone column observed in the austral spring over Antarctica and first reported in 1985
  • Since the 1990s, Antarctic total column ozone in September and October continued to be 40-50% lower than pre-ozone-hole values
  • Chlorine catalyzed ozone depletion is drastically enhanced in the presence of polar stratospheric clouds (PSCs) during winter
  • Occurrence of ozone hole above Antarctica is not because there are more CFCs concentrated but because the low temperature help form polar stratospheric
  • Arctic –
  • In the Arctic, the amount lost is more variable year-to-year than in the Antarctic
  • The greatest Arctic declines, up to 30%, are in the winter and spring, when the stratosphere is coldest
  • Mid-latitudes –
  • In middle latitudes, it is more accurate to speak of ozone depletion rather than holes.
  • In the northern mid-latitudes ozone declined to about 6%-8% below pre-1980 values
  • In the Southern Hemisphere’s mid-latitudes, total ozone remained at 6% below pre-1980 values
  • Tropics
  • In the tropics, there are no significant decline
  • Halogen-containing compounds do not have sufficient time to break down and release chlorine and bromine atoms at tropical latitudes
  • Polar stratospheric clouds (PSCs)
  • They play an important role in enhancing ozone depletion
  • PSCs form more readily in the extreme cold of the Arctic and Antarctic stratosphere
  • This is why ozone holes first formed, and are deeper, over Antarctica.

Consequences –

  • Increased UV
  • Health problems –
  • Basal and squamous cell carcinomas
  • most common forms of skin cancer in humans linked to UVB exposure
  • Malignant melanoma
  • skin cancer
  • Cortical cataracts
  • Increased production of vitamin D
  • Increased tropospheric ozone –
  • Ground-level ozone is toxic due to its strong oxidant properties.
  • The risks are particularly high for young children, the elderly, and those with asthma or other respiratory difficulties.
  • ozone at ground level is produced mainly by the action of UV radiation on combustion gases from vehicle exhausts
  • Effects on crops –
  • Plant growth can be directly affected by UVB radiation
  • Cyanobacteria are sensitive to UV radiation
  • Global warming

Facts –

  • Single chlorine atom is able to react with 100,000 ozone molecules before it is removed from the catalytic cycle.
  • The source of the warmth of the stratosphere is the absorption of UV radiation by ozone, hence reduced ozone leads to cooling
  • In 1994, UNGA designated September 16 as “World Ozone Day” to commemorate the Montreal Protocol signed in 1987.

Vienna Convention –

About –

  • The Vienna Convention for the Protection of the Ozone layer.
  • It is often called a framework convention, because it served as a framework for efforts to protect the globe’s ozone layer

Adoption –

  • The Vienna Convention was adopted in 1985 and entered into force on 22 Sep 1988.
  • In 2009, the Vienna Convention became the first Convention of any kind to achieve universal ratification.
  • It has been ratified by 197 states
  • India is a Party to the Vienna convention since 19 June 1991

Objectives –

  • To promote cooperation, research and information exchange on the effects of human activities on the ozone layer.
  • To adopt legislative or administrative measures against activities likely to have adverse effects on the ozone layer.

Implementation –

  • It acts as a framework for the international efforts to protect the ozone layer.
  • It does not include legally blindly reduction goals for the use of CFCs, the main chemical agents causing ozone depletion.
  • The parties to the Vienna Convention meet once every three years to take decisions designed to administer the Convention

Montreal Protocol –

  • About –
  • Montreal Protocol on Substances that Deplete the Ozone Layer
  • A Protocol to the Vienna Convention for the Protection of the Ozone Layer
  • Montreal Protocol is an international treaty to protect the ozone layer by phasing out the production of ozone depletion substances
  • Adoption –
  • It was agreed on 16 September 1987, and entered into force on 1 January 1989
  • It has been ratified by 197 parties making them the first universally ratified treaties in United Nations history
  • India became a Party the Montreal Protocol on 17 September 1992
  • It has undergone eight revision since 1989

Facts –

  • As a result of the international agreement, the ozone hole in Antarctica is slowly recovering
  • Climate projections indicate that the ozone layer will return to 1980 level between 2050 and 2070

Climate Change and Agriculture

About –

  • Climate change and agriculture are interrelated processes, both of which take place on a global scale.
  • The impact of climate change on agriculture could result in problems with food security and may threaten the livelihood activities

Agriculture contributes to climate change by –

  1. anthropogenic emissions of greenhouse gases (GHGs)
  2. by the conversion of non-agricultural land into agricultural land

Important Impacts –

  • A shift in climate and agricultural zones towards the poles
  • Changes in production patterns due to higher temperatures
  • A boost in agricultural productivity due to increased carbon dioxide in the atmosphere
  • Changes in temperature influences pest and disease incidence on crops, livestock and poultry
  • Changing precipitation patterns
  • Extreme events ( eg. high rainfall/floods/heat wave/ cold wave/ cycle/ hail/frost) cause enormous losses of standing crops, live stock and fisheries
  • Influences milk production in animals and spawning in fish
  • Increased vulnerability of the landless and the poor
  • Changes in the nutritional quality of some foods
  • Negative impact on rice, wheat and horticulture
  • Neutral or positive on some crops like soybean, groundnut, coconut, potato in some zones

Facts –

  • 25% of carbon dioxide emissions, are produced by agricultural sources through
  • Most of the methane in the atmosphere comes from domestic ruminants, forest fires, wetland rice cultivated and waste products
  • Conventional tillage and fertilizer use account for 70% of the nitrous oxides
  • Intensive agricultural methods are reported to have determined effects on the environment.


Basics –

  • Deforestation is defined as the removal of vegetation in a forest to the extent that it no longer supports its natural flora and fauna

Causes –

  • Unsustainable agriculture
  • Large tracts of forests are cleared for expansion of agriculture
  • The forest soil after clearing are unable to support farming for long periods due to exhaustion of nutrients
  • Once the soils become unfit for cultivation, the area suffers from soil erosion and degradation
  • Shifting cultivation
  • Also known as slash and burn farming
  • Practiced in the states of Assam, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Andaman and Nicobar Island
  • Fuel wood, Over grazing
  • Floods, Forest fires
  • Developmental projects, Mining projects, Urbanization

Effects of Deforestation –

  • Soil erosion
  • The washing away of soil by the flow of water is called soil erosion
  • The loss of top soil in India, is 18.5% of the global soil loss
  • deforestation has acceleration the erosion along the slopes of the lower Himalayas and Aravali hills causing frequent landslides
  • Flash floods –
  • A sudden local flood of great volume and short duration caused by heavy downpour
  • Climate change
  • chronic droughts
  • global warming
  • due to increase in percentage of carbon dioxide in the atmosphere
  • Reduced precipitation
  • Loss of biodiversity
  • In arid and semiarid regions, the restoration of the ecosystem is difficult.
  • many species become extinct or reduce in numbers due to desertification


Definition –

  • The gradual transformation f habitable land into desert by climate change or by destructive use of the land.
  • Desertification and loss of biological potential will restrict the transformation of dry lands into productive ecosystem
  • Unsustainable resources management practices drive desertification, and accentuate the poverty of people affected by desertification
  • Causes
  • Overgrazing, over-exploitation, deforestation, inappropriate irrigation, population pressure, urbanisation, poverty, inequitable sharing of resources.

Desertification status of India –

  • About 228 mha (69%) of India’s total geographical area (about 328 mha) is under dry lands (arid, semi-arid and dry sub-humid)
  • 32 percent of India’s total land area is affected by land degradation (of which desertification is a major component)
  • 18 million hectares, or 24.8 percent of the country’s geographic area is undergoing desertification
  • Rajasthan accounts for the most desertification land (23 Mha) followed by Gujarat, Maharashtra and Jammu and Kashmir (13 Mha each) and Orissa and Andhra Pradesh (5 Mha) each

Control measures –

  • India as a signatory to United Nations Convention to Combat Desertification (UNCCD)
  • National Action Programme for combating desertification since 2001 to prevent desertification.
  • Arid Zone Research
  • National Mission for Green India
  • Integrated Wasteland Development Programme
  • National Watershed Development Programme
  • Development Project for Rainfed Areas
  • Soil Conservation in the catchment of River Valley projects
  • National Afforestation Programme
  • Mahatma Gandhi National Rural Employment Guarantee Scheme

United Nations Convention to Combat Desertification

About –

  • UNCCD is a Convention to combat desertification and mitigate the effects of drought through action programs
  • It is the first and only internationally legally blinding framework set up to address the problem of desertification
  • It incorporates long-term strategies supported by international cooperation and partnership arrangements.

Formation –

  • The convention was a direct result of Rio Conference’s Agenda 21.
  • The convention was adopted in Paris, France on 17 June 1994 and entered into force in December 1996.
  • Secretariat –
  • The permanent secretariat of the UNCCD was established during the first conference of the parties (COP1) held in Rome in 1997
  • It has been located in Bonn, Germany since January 1999, and moved from its first Bonn address in Haus carstanjen to the new UN Campus in July 2006

Organization –

  • It has 196 parties
  • The UNCCD has been ratified by 195 states plus the European Union
  • All member states of the UN are parties to convention
  • The conference of the Parties (COP) oversees the implementation of the Convention
  • The UN Convention to Combat Desertification has established a committee on science and technology (CST)
  • The CST collects, analvses and reviews relevant data. It also promotes cooperation in the field of combating desertification
  • National Action Programmes (NAP)
  • National Action Programmes (NAP) are one of the key instruments in the implementation of the convention
  • They are strengthened Action Programmes on Sub-regional (SRAP) and Regional (RAP) level.
  • National Action Programmes are developed in the framework of a participative approach involving the local communities.

Facts –

  • The year 2006 was declared “International Year of Deserts and Desertification”
  • In 2013, Canada became the first country to announce its intention to withdraw from the convention.

National Action Plan on Climate Change (NAPCC)

  • About NAPCC outlines the existing and future policies and programs to address climate change mitigation and adaptation
  • The plan “indentifies measures that promote our development objectives while also yielding co-benefits for addressing climate change effectively
  • The plan identifies eight core “ national missions” running through 2017

8 Missions –

  1. National Solar Mission –
  • The NAPCC aims to promote the development and use of solar energy for power generation and other uses
  • The ultimate objective is to make solar energy competitive with fossil-based energy options.
  1. National Mission for Enhanced Energy Efficiency
  2. National Mission on sustainable Habitat
  • To promote energy efficiency as a core component of urban planning
  1. National Water Mission –
  • 20% improvement in water use efficiency through pricing and other measures.
  1. National Mission for sustainable the Himalayan Ecosystem
  • The plan aims to conserve biodiversity, forest cover, and other ecological values in the Himalayan region
  1. National Mission for a “Green India”
  • Afforestation of a million hectares f degraded forest lands
  • expanding forest cover from 23% to 33% of India’s territory
  1. National Mission for sustainable Agriculture
  • The plan aims to support climate adaption in agriculture through the
  • development of climate-resilient crops
  • expansion of weather insurance mechanisms
  • agricultural practices
  1. National Mission on strategies knowledge for climate change
  • To gain a better understanding of climate science, impacts and challenges
  • New climate science research fund, improved climate modelling, and increased international collaboration.

Climate Investment Funds

About –

  • The climate Investment Funds (CIFs) were designed by developed and developing countries.
  • They are implemented with the multilateral development banks (MDBs) to bridge the financing and learning gap between now and the next international climate change agreement.
  • The CIFs aim to enable countries to continue on their development path and achieve the Millennium Development Goals.
  • The World Bank is the Trustee of the CIFs –
  • The funds were approved by the World Bank Board of Directors in July 2008 and on September 26, 2008 received pledges of US$6.5 billion

Funds –

  • Clean Technology Fund –
  • promotes scaled-up financing for demonstration, deployment and transfer of low carbon technologies with a significant potential for long-term greenhouse gas emissions savings
  • Investments are planned for renewable energy and highly efficient technologies
  • To reduce carbon intensity, for the transport sector
  • To address both efficiency and to promote modal shits
  • and for energy efficiency in buildings, industry and agriculture

Strategies Climate Fund –

  • comprise targeted programs with dedicated funding to provide financing to pilot new approaches with potential for scaling up
  • It will help more vulnerable countries adapt their development programs to confront of climate change and deforestation
  • The Pilot program for climate resilience (PPCR) is the first program under the Strategic climate fund