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
Carbon and water cycles
albedo, evapotranspiration, cloud formation and weathering
- External forcing mechanisms –
- Orbital variations
- Solar output
- 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
- Water vapour (H2O)
- Carbon dioxide (CO2)
- Nitrous oxide (N2O)
- Four major gases contributing to the greenhouse effect are
- Water vapour, 36-70%
- Carbon dioxide, 9-26%
- Methane, 4-9%
- 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
- Other sources include termites, ocean sediments, volcanoes, wildlife etc.
- Ozone depletion implies two phenomena –
- a steady decline of about 4% in the total volume of ozone in Earth’s stratosphere(the ozone layer) and
- 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 (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
- Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substance (ODS) are mainly responsible for man-made chemical ozone depletion
- 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
- 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
- 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.
- 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
- 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 –
- 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
- 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
- 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.
- 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
- 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
- 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 –
- anthropogenic emissions of greenhouse gases (GHGs)
- 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
- 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.
- Deforestation is defined as the removal of vegetation in a forest to the extent that it no longer supports its natural flora and fauna
- 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
- 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
- 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
- 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.
- 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
- 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.
- 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 –
- 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.
- National Mission for Enhanced Energy Efficiency
- National Mission on sustainable Habitat
- To promote energy efficiency as a core component of urban planning
- National Water Mission –
- 20% improvement in water use efficiency through pricing and other measures.
- National Mission for sustainable the Himalayan Ecosystem
- The plan aims to conserve biodiversity, forest cover, and other ecological values in the Himalayan region
- 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
- 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
- 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
- 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
- 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