Environmental Science for WBCS Mains Part-I PDF
“Climate Change and Global warming“
The phrase ‘climate change’ represents a change in the long-term weather patterns.
The Intergovernmental Panel on Climate Change (IPCC)
- The Intergovernmental Panel on Climate Change (IPCC) is the international body for assessing the science related to climate change.
- The IPCC was set up in 1988 by the World Meteorological Organization (WMO) and United Nations Environment Programme (UNEP) to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation. Headquarters at Geneva, Switzerland.
The World Meteorological Organization (WMO)
- Established by the ratification of the WMO Convention on 23 March 1950, WMO became the specialised agency of the United Nations for meteorology (weather and climate), operational hydrology and related geophysical sciences a year later. Headquartered in Geneva.
India’s effort to counter Climate Change
- India is now the world’s sixth largest economy largest greenhouse gas (GHG) emitter, accounting for about 5% of global emissions.
National Action Plan on Climate Change (NAPCC)
- The Action Plan was released on 30th June 2008.
- The NAPCC describes eight missions that deal with climate change adaptation and mitigation:
1. National Solar Mission: Aims to promote the use of solar energy in India by making it competitive with fossil fuels. It will promote activities to encourage research and development to improve efficiency and affordability of solar power and energy storage systems.
2. National Mission for Enhanced Energy Efficiency: Aims to improve energy efficiency of domestic, commercial and industrial sectors in India by creating an enabling policy regime and encouraging innovative business models for improving energy efficiency.
3. National Mission for Sustainable Habitat: Aims at encouraging sustainable urban planning in India with the help of policy, infrastructural and research interventions in sectors such as buildings, waste management, water resources and transportation.
4. National Water Mission: Aims to ensure sustainable water supply by conserving water, minimizing waste and ensuring equitable distribution of water resources throughout India.
5. National Mission for Strategic Knowledge on Climate Change: Aims to create a comprehensive knowledge system that informs and supports climate change action in India with the help of research and communication-based actions.
6. National Mission for Sustainable Agriculture: Aims at improving sustainability, productivity, remuneration and climate resilience of agriculture in India. These goals will be achieved by capacity building, research, infrastructural and institutional interventions in the Indian agricultural sector.
7. National Mission for Green India: Aims to protect, enhance and restore forests and respond to climate change with appropriate adaptation and mitigation activities. It plans to increase green cover and focuses on multiple ecosystem services—especially biodiversity, water, biomass, mangroves, wetlands and critical habitats, with carbon sequestration as a co-benefit.
8. National Mission for Sustaining the Himalayan Ecosystem: Aims to enhance understanding of climate change impacts and adaptations required in the Himalayas. The information obtained from this mission will feed into policy formulation for suitable management practices for the Himalayan ecosystem.
The Indian Network on Climate Change Assessment (INCCA)
- The Indian Network on Climate Change Assessment (INCCA) is a proposed network of scientists in India to be set up to publish peer-reviewed findings on climate change in India.
- It was announced on 7 October 2009
- Global warming, also referred to as climate change, is the observed century-scale rise in the average temperature of the Earth’s climate system and its related effects.
- In 2013, the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report concluded, “It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.” The largest human influence has been the emission of greenhouse gases.
- Climate model projections summarized in the report indicated that during the 21st century, the global surface temperature is likely to rise a further 0.3 to 1.7 °C (0.5 to 3.1 °F) in the lowest emissions scenario, and 2.6 to 4.8 °C (4.7 to 8.6 °F) in the highest emissions scenario.
Global Warming – Impacts
- Rise in Sea level
- Changes in rainfall patterns.
- Increased likelihood of extreme events such as heat wave, flooding, , hurricane etc.
- Melting of the ice caps’
- Melting of glaciers.
- Widespread vanishing of animal populations due to habitat loss
- Spread of diseases(like malaria etc)
- Global dimming is defined as the decrease in the amounts of solar radiation reaching the surface of the Earth.
- The by-product of fossil fuels are tiny particles or pollutants which absorb solar energy and reflect back sunlight into the space.
- This phenomenon was first recognized in the year 1950.
- Scientists believe that since 1950, the sun’s energy reaching Earth has dropped by 9% in Antarctica, 10% in the USA, 16% in parts of Europe and 30% in Russia – putting the overall average drop to be at an enormous 22%. This causes high risk to our environment.
- The critical issue of Global Dimming was first raised through a documentary called Horizon by BBC on 15 January 2005.
- Greenhouse gas is a gas in an atmosphere that absorbs and emits radiant energy within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.
- The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.
- Without greenhouse gases, the average temperature of Earth’s surface would be about −18 °C (0 °F), rather than the present average of 15 °C (59 °F).
- In the Solar System, the atmospheres of Venus, Mars and Titan also contain gases that cause a greenhouse effect.
In order, the most abundant greenhouse gases in Earth’s atmosphere are:
- Water vapor (H2O)
- Carbon dioxide (CO2)
- Methane (CH4)
- Nitrous oxide (N2O)
- Ozone (O3)
- Chlorofluorocarbons (CFCs)
- Hydrofluorocarbons (incl. HCFCs and HFCs)
- Carbon dioxide (CO2): Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions (e.g., manufacture of cement). Carbon dioxide is removed from the atmosphere (or “sequestered”) when it is absorbed by plants as part of the biological carbon cycle.
- Methane (CH4): Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
- Nitrous oxide (N2O): Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
- Fluorinated gases: Hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride are synthetic, powerful greenhouse gases that are emitted from a variety of industrial processes. Fluorinated gases are sometimes used as substitutes for stratospheric ozone-depleting substances (e.g., chlorofluorocarbons, hydrochlorofluorocarbons, and halons). These gases are typically emitted in smaller quantities, but because they are potent greenhouse gases, they are sometimes referred to as High Global Warming Potential gases (“High GWP gases”).
Black Carbon (BC)
- Black Carbon (BC) commonly known as soot, has recently emerged as a major contributor to global climate change, possibly second only to CO2 as the main driver of change.
- BC particles strongly absorb sunlight and give soot its black color.
- BC is produced both naturally and by human activities as a result of the incomplete combustion of fossil fuels, biofuels, and biomass. Primary sources include emissions from diesel engines, cook stoves, wood burning and forest fires
- Approximately 20% of black carbon is emitted from burning biofuels, 40% from fossil fuels, and 40% from open biomass burning
- Black carbon emissions are highest in and around major source regions. This results in regional hotspots of atmospheric solar heating due to black carbon.
Hotspot areas include:
- The Indo-Gangetic plains of India
- Eastern China
- Most of Southeast Asia and Indonesia
- Black carbon warms the Earth by absorbing heat in the atmosphere and by reducing albedo, (the ability to reflect sunlight) when deposited on snow and ice.
- Regionally, BC disrupts cloudiness and monsoon rainfall and accelerates melting of mountain glaciers such as the Hindu Kush-Himalayan glaciers.
- Brown carbon is a ubiquitous and unidentified component of organic aerosol which has recently come into the forefront of atmospheric research.
- Light-absorbing organic matter (other than soot) in atmospheric aerosols of various origins, e.g., soil humics, humic-like substances (HULIS), tarrymaterials from corobustion, bioaerosols, etc.
- Biomass burning (possibly domestic wood burning) is shown to be a major source of brown Carbon Smoke from agricultural fires may be an additional source.
- “Brown Carbon;’ is generally referred for greenhouse gases and “Black Carbon” for particles resulting from impure combustion, such as soot and dust.