- Although different natural factors are responsible for emission of Green House Gases (GHGs) such as Methane, Carbon-di-oxide t.c. in the atmosphere leading to global warming, but self-correcting mechanism of earth’s environment nullify these impacts.
- Major natural contributors of green house gases are living organisms such as humans and livestock and natural phenomenon such as volcanic eruptions and forest fires.
- However, these contributors are part of natural cycle and are adjusted in accordance with natural self-correcting mechanism.
- For Example: Although, volcanoes emit green house gases contributing in global warming, but they also emit Sulfate aerosols can cool the climate.
- Similarly, plants act as a sink for carbon-di-oxide which is emitted by humans and other animals.
- However the imbalance arises when large amount of green house gases is emitted than absorbed by the natural sinks.
Reports: Impact of human activities on increasing intensity global warming
- According to the Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report, after 1950, 100% of global warming is stated to be caused due to human activities.
- Since 1850, almost all the long-term warming has been caused by the human activities due to artificial production of gases such as Nitrous Oxide and ground level ozone formation.
- Fifth assessment report, the IPCC stated that it is “extremely likely that more than half of the observed increase in global average surface temperature” from 1951 to 2010 was caused by human activity.
- More than half of modern global warming was caused due to activities of humans.
- US Fourth National Climate Assessment report has also found that between 93% to 123% of observed 1951-2010 warming was due to human activities.
Human activities: Increasing intensity of global warming
- Fossil Fuels: Burning of fossil fuels such as coal, natural gas, petroleum productst.c
- Scientific experiments: Emission of GHGs (green house gases) in events of nuclear testing, rocket propulsions, industrial production e.t.c
- Livestock Rearing: A cattle ranching which includes rearing of large number of cattle on a single farm for commercial purposes is also a chief emitter of green house gas. Cattle emit methane produced naturally by their digestive system.
- Infrastructure Development: Infrastructure development has turned out to be major contributor of green house gases as cement and concrete used are major source of it.
- Large amount of GHGs are also produced due to recreational activities during festivals due to use of fire crackers.
Case Study: Urban Heat Island effect
- An urban heat island is a metropolitan area with a lot warmer climate than the rural areas surrounding it.
- Heat energy which is created by cars, buses, and trains in big cities leads to creation of urban heat islands.
- These Islands are characterized by high day time as well as night time temperature leading to rise in level of overall temperature.
Different reasons for UHI creation
- Infrastructure Development: When houses, shops, and industrial buildings are constructed it can create a UHI.
- Building materials which are very good insulators of heat hold it for a longer period of time making the areas around buildings warmer.
- Waste Heat: "Waste heat" is also one of the major contributors of Urban Heat Island. Household appliances, cars and factories burning off energy releasing waste energy into the atmosphere.
Initiatives taken to reduce UHI impact
- Green Roofs: Using green roofs or the roofs of buildings covered in plants helps to cool temperature of overall infrastructure of Urban Areas.
- Afforestation: Plants absorb carbon dioxide, a leading pollutant and can also reduce the heat of the surrounding areas.
- Using lighter-colored materials on buildings helps, too. Light colors reflect more sunlight and trap less heat.
- Domestic waste: Garbage dumps which are located outside cities in open air are also a major emitter of different green house gases.
- These dumps emit a large amount green house gases causing intense green house gas impact on environment.
- Chemicals: Paints, lubricants, chemicals used in industries e.t.c emit large amount of green house gases which have high greenhouse potential such as Nitrous oxide, Hydro fluorocarbons (HFCs), Per-Fluorocarbons (PFCs) Sulfur hexafluoride (SF6)t.c
- These green house gases exist in environment for a longer period of time causing cascading effects of green house effect on environment.
- Deforestation: Deforestation is also an indirect cause of global warming. Forests are major sink of carbon-di-oxide. Due to cutting of forests, concentration of greenhouse gases in atmosphere increases.
- Use of chemical fertilizers: Microbial action on nitrogenous fertilizers in soil, burning of biomass, fossil fuels and forests for agriculture causes formation of nitrous oxide which is a major greenhouse gas.
Negative impacts of global warming on earth’s environment
- Ocean Acidification: Ocean acidification is decrease in the pH of the Earth's oceans which is caused by the uptake of carbon dioxide from the atmosphere.
- Oceans are major sink of carbon-di-oxide which when absorb it carbonic acid is formed transforming oceanic water into acidic from basic nature.
- Rise in Sea Level: Melting of glaciers caused by global warming results in rise of sea level.
- Threat to third pole region: The region around the Pamir Knot is called third pole area. It has highest concentration of snow outside poles and is source of many perennial rivers of Asia.
- Global warming and melting of glaciers has led to melting of snow caps in this region causing threat to livelihood and life of millions of people.
- Threat to Marine biodiversity: Global warming has seriously disrupted marine ecosystems. The flooding of many coastal wetlands has resulted in the loss of breeding grounds of fish, shrimps and birds. This system has unique biodiversity as these are meeting point of two ecosystems.
- Contamination of Ground Water: Due to sea level rise the sea water intrudes in coastal ground water. It will make the people living in coastal areas with no drinking water left with them.
- Impact on agriculture: Even a 2°C rise in global temperature may impact crops advesely. Soil moisture content will decrease and evapo-transpiration will increase leading to adverse impact on production of different crops.
- Increase in temperature and humidity will increase pest growth and vectors.
- Impact on Human Health: An increase in average global temperature will increase the incidence of infectious diseases, such as malaria, schistosomiasis, sleeping sickness, dengue and yellow fever due to extension in the range of vectors such as mosquitoes, flies and snails that transmit infectious disease.
- Due to the global warming, one of the prime carriers of dengue and yellow fever the Aedes aegypti has extended its range in such diverse regions as Coasta Rica, Colombia, Kenya and India.
Other side of the coin: Positive Impacts of global warming
- Carbon-di-oxide fertilization: An elevated carbon dioxide levels has come up an agricultural blessing as it has accelerated the pace of photosynthesis leading to higher agricultural productivity in arctic regions and countries with cold climate.
- This increase in rate of photosynthesis due to enhanced carbon dioxide levels is called carbon dioxide fertilization.
- The phenomenon has significant impact on production of Wheat in countries like Russia.
- Arctic land Reclamation: Melting of ice and increasing in biological activity in permafrost has resulted in reclamation of land in arctic regions. It has resulted in bumper production of crops in some of the regions such as Russia. Russia has turned out to be a net exporter of wheat from a net importer in last decade.
- Afforestation: Forests are natural sinks of Green House Gases. Planting more and more trees will lead to decrease in concentration of GHGs thus control in global warming.
- Sustainable Agriculture: It includes marching towards organic farming and using less fertilizers and pesticide. Further, reducing animal ranching will lessen the emission of gases such as methane.
- Green-mobility: Opting for sustainable mobility options including electric vehicles, bicycles instead of motor bikes, using public transport e.t.c will help to lessen consumption of fossil fuel and emission of green house gases.
- Reuse and Recycle Strategy: It will decrease the production process which emits GHGs and will check global warming.
International Initiatives to combat global warming
- United Nations Framework Convention on Climate Change (UNFCCC) was the first initiative towards reducing green house emission. It organizes Conference of Parties (COP) to discuss global strategy to combat climate change.
- Koyoto protocol (1997) started the first commitment period to reduce the emission of six green house gases such as Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O) Hydrofluorocarbons (HFCs), Per-fluorocarbons (PFCs) and Sulphur hexafluoride (SF6) by 2020.
- Countries that had ratified the Kyoto Protocol were assigned maximum carbon emission levels for specific periods and were allowed to participate in carbon credit trading. It is legally binding with a provision of penalty on violation.
- Paris agreement was second milestone in this regard. Its aim is to strengthen the global response to the threat of climate change by keeping a global temperature rise this century below 2 degrees Celsius and above pre-industrial levels.
- After enforcement of the agreement, second commitment period of reducing GHGs will start from 2020.
India’s National Commitments regarding Greenhouse reduction
- India is determined to reduce green house gas emission by various methods such as promotion of electric vehicles, improvement of sustainable public transport infrastructure, regulation of emission standards for industry as well as mobility and production of non-fossil based clean and sustainable energy.
- India has already achieved clean electricity generation capacity of more than 134 GW by 2020 which is more than half of its revised target of 220 GW of clean energy production by 2022.
- It has also achieved milestone in delivering clean fuels such as LPG to every household checking air pollution by burning biomass.
Both IPCCC Fifth assessment report and US Fourth National Climate Assessment report have clearly stated that human are solely responsible for increasing of the green house concentration across the globe after 1950. Despite various types of checks put by different international climatic forum, there has not been any significant reduction in global green house gas concentration. India must push its efforts to maximum level in order achieve its INDC targets pertaining to achieving climate goals well as Sustainable development goals.