Environment & Ecology: Climate Change

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Environment & Ecology
Published
12-Feb-2020

Climate Change

The United Nations Framework Convention on Climate Change (UNFCCC) defines ‘climate change’ as a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods.
The major characteristics of climate change include rise in average global temperature, ice cap melting, changes in precipitation, and increase in ocean temperature leading to sea level rise. Climate change leads to Global Warming.

Factors Affecting Climate Change

There are many factors which either magnify or reduce the effects of the earth’s climate.
Factors such as greenhouse gases increase the temperature of earth, while some aerosols and volcanic eruption reduce the temperature of the earth.
For example, large volcanic eruptions can eject enough ash into the atmosphere to reduce the temperature for a year or more until the sulphur particles settle on the ground. These sulphur particles reflect sunlight from the earth.
Estimation of the effect of each gas on climate change depends on the following three factors:
Concentration of gas in the atmosphere: Concentration of gas in the atmosphere is described in terms of parts per million (ppm). For example, at present, there are nearly 420 parts of carbon per million. Before Industrial revolution, concentration of carbon was only 270 ppm. If carbon concentration increases beyond 450 ppm, then it is believed that Earth would face catastrophic impacts.
Life span of gas in the atmosphere: Life span in the atmosphere varies with the nature of the gas. Life span of CO2 ranges from 50-200 years; methane has a life span of 12 years; nitrous oxide has a life span of 120 years and fluorinated gas has a life span of even more than 1000 years.
Global warming potential of a gas: The same quantity of methane has 21 times, nitrous oxide has 310 times and fluorinated gases have 140 to 23,900 time’s global warming potential as that of carbon dioxide.

GLOBAL WARMING

Global warming is an average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns.
Global warming can occur from a variety of causes, both natural and human induced.
In common usage, “global warming” often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities.

Impacts of Global Warming

Rise in Sea level
Changes in rainfall patterns
Increased likelihood of extreme events such as heat wave, flooding, hurricanes, etc
Melting of the ice caps
Melting of glaciers
Widespread vanishing of animal populations due to habitat loss
Spread of disease (like malaria, etc)
Bleaching of Coral Reefs
Loss of Plankton due to warming of seas

Gases that contribute to the greenhouse effect include:

Gases that trap heat in the atmosphere are called greenhouse gases.

Carbon dioxide (CO2): Carbon dioxide enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and other biological materials, 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, combustion of fossil fuels and solid waste, as well as during treatment of wastewater.
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").

How long do they stay in the atmosphere?

Each of these gases can remain in the atmosphere for different amounts of time, ranging from a few years to thousands of years.
All of these gases remain in the atmosphere long enough to become well mixed, meaning that the amount that is measured in the atmosphere is roughly the same all over the world, regardless of the source of the emissions.

Non Green House Gases and Aerosols

Black Carbon

It is a component of fine particulate matter of the size2.5 μm. It consists of pure carbon, which originates from the incomplete combustion of fossil fuels, coal, biofuel, biomass, wood, rubber etc. It is emitted in the form of soot.
SOOT is an air borne mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It originates from pyrolysis.

Brown Carbon

Brown carbon is brown smoke released by the combustion of organic matter. It coexists with black carbon when released in the atmosphere.

Sources of brown carbon are:

Breakdown products from biomass burning
Tar materials from smouldering freres
Coal combustion
Combustion of fossil fuels and automobile exhaust
Mixture of organic compounds emitted from soil
Formed in the atmosphere from reactions of biogenic organic gases, given off naturally by trees and other organisms, that condenses to form aerosol particles.

Blue Carbon

It is the carbon captured by the world’s oceans and coastal ecosystems.
This carbon is captured by living organisms in oceans is stored in the form of aquatic biomass.
Blue carbon ecosystem act as the major sink for capturing atmospheric carbon and reducing warming effects.

Green Carbon

It is the carbon captured into terrestrial plant biomass in photosynthesis and stored in the plants and soil of natural ecosystems and is a vital part of the global carbon cycle.

Radioactive Forcing and Global Warming

Net radiation: It is defined as the difference between the solar radiation absorbed by the Earth-atmosphere system and the long
wave radiation emitted by the Earth-atmosphere system to space. Net radiation influences the Earth’s climate because it determines the energy available for heating the atmosphere, ocean and land. Hence net radiation influences the seasonal variation of rainfall and the strength of the global circulation patterns.
Radioactive Forcing: The change in net radiation caused by changes in concentration of greenhouse gas or aerosol concentrations is called as radioactive forcing or climate forcing. It is quantified at tropopause or the zone between troposphere and the stratosphere. The unit of radioactive forcing is watts per square meter of the Earth’s surface. It is observed in two different trends
- Positive radioactive forcing: It means that the amount of incoming solar energy is more than the amount of radiations going out. It warms the earth- atmosphere system
- Negative radioactive forcing: It means that the amount of outgoing energy is more than the amount of incoming energy. It cools earth- atmosphere system

Global Warming Potential (GWP)

Global warming potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide.
A GWP is calculated over a specific time interval, commonly 20, 100, or 500 years. GWP is expressed as a factor of carbon dioxide (whose GWP is standardized to 1).
The GWP depends on the following factors:
- The absorption of infrared radiation by a given species
- The spectral location of its absorbing wavelengths
- The atmospheric lifetime of the species
Thus, a high GWP correlates with a large infrared absorption and a long atmospheric lifetime. The dependence of GWP on the wavelength of absorption is more complicated. Even if a gas absorbs radiation efficiently at a certain wavelength, this may not affect its GWP much if the atmosphere already absorbs most radiation at that wavelength. A gas has the most effect if it absorbs in a “window” of wavelengths where the atmosphere is fairly transparent.

Causes of Climate Change

The amount of solar energy, its absorption, distribution, radiation and redistribution in the atmosphere or overall the energy budget of the earth are the major factors which effect the climate and can cause a definite change.
The change in climate can be seen as a long -term process or the short-term process. Amongst the causes responsible for climate change the natural factors attribute to the long-term climate change while the anthropogenic (manmade) factors attribute to the short-term change in the climate. The factors responsible for climate change are broadly grouped into following categories
- Extra-terrestrial sources
- Terrestrial sources
- Anthropogenic sources

Extra-Terrestrial Sources of Climate Change

Interstellar Nebulae: The path of earth around the galaxy is elliptical and its passage in every 270 to 400 million years is near to centre of the galaxy. In every 300 million years, earth passes through the dust lane arm of the galaxy. The arm has accumulation of interstellar matter or the Nebulae. This nebula of galaxy interpose between sun and earth, because of which there is reduction in solar radiation reaching the earth surface which might bring in a climate change.
Solar irradiance: There is a regular fluctuation in the amount of energy irradiated from the outer surface of the sun or the photosphere, this alteration brings changes in the temperatures and precipitation.
Sunspot Cycles: Sunspots are temporary spots on the photosphere of the sun which are caused by increased magnetic flux. During sunspot, surface temperature of the sun decreases but the events of solar flares and coronal mass ejection increases. Sunspots are seen in every 11 years’ cycle. Increase in sunspot activity increases the events of warming and vice versa.
Extra-terrestrial bodies collision: Collision of extra-terrestrial bodies like meteorites, comets etc. near the earth’s axis of revolution produces a cloud of dust between the sun and earth. It reduces the net solar radiation on earth. It is also likable that the extra-terrestrial events would have caused the Big Freeze on earth some 12,000 years ago.

Terrestrial Sources of Climate Change

Atmospheric dust: Atmospheric particulates reduce the amount of solar energy reaching the earth surface. Majority of the atmospheric particulates remain in the troposphere or lower stratosphere. Atmospheric particulates are caused due to following:
- Dust particulates
- Salt particles
- Pollens
- Smoke and soot
- Volcanic dust and Ashes
Solar Albedo: It is the measure of effectiveness in reflecting radiant solar energy. Surface albedo is the ratio of radiation reflected to radiation incident. Albedo is dimensionless and is measured in a scale of 0 to 1. Black bodies or black hole has albedo scale of 0 and white bodies have albedo in the scale of 1. The average albedo at the top of atmosphere is 30 - 35%. Surface albedo varies from location to location.
Factors which affect the surface albedo in any area are:
- Geographical and surface characteristics
- Composition of the atmosphere
- Position of the sun
- Angle and wavelength of incident solar rays
Continental drift and Pole wandering: The drifting of continents explained by plate tectonics causes change in relative position of continents, ocean basins and the poles. The clustering of continents around the pole causes glaciation of major land masses while scattering away of continents from the poles causes deglaciation of any area.
Oceanic Variation: Ocean currents can alter climate, as they transfer vast amount of heat in climate system. They affect the water vapor content of atmosphere significantly.

Anthropogenic Sources of Climate Change

The main human activities that contribute to an enhancement of the natural greenhouse effect are:

Combustion of fossil fuels, which releases greenhouse gases.
Clearing of forests for agriculture, which releases carbon dioxide through increased biomass decay.
Deforestation, soil tillage and land degradation, which release carbon from the land system and reduce its capacity to absorb and store carbon

Impacts of the Climate Change:

Impact on Biodiversity

Climate change is expected to have a significant influence on terrestrial biodiversity at all system levels – ecosystem, species and genetic diversity.
The changing climate will stimulate species-level changes in range and abundance, life cycle and behaviour, and, over time, genetic evolutionary responses.
These changes will in turn be linked with changes in natural disturbance patterns and changes in ecosystem structure and function.

Impact on Agriculture

According to World Meteorological Organization, climate change can adversely impact global environment, agricultural productivity and the quality of human life.
More importantly in developing countries, it will be difficult for farmers to carry on farming in the increased temperatures.
While in temperate latitudes a rise in temperature would help countries increase food productivity, it will have adverse effects in India and countries in the tropics.
The monsoon accounting for 75% of India’s rainfall significantly impacts country’s agriculture and livelihood of tens of millions of small farmers.
Climate change is likely to intensify the variability of monsoon dynamics, leading to a rise in extreme seasonal aberrations, such as increased precipitation and devastating floods in some parts of the country as well as reduced rainfall and prolonged droughts in other areas.

Impact on fisheries and Aquaculture

Climate change, more particularly harsher weather conditions, will have impact on the quality, productivity, output and viability of fish and aquaculture enterprises, thereby affecting fishing community.
The small-scale fishers may be faced with greater uncertainty as availability, access, stability and use of aquatic food and supplies would diminish and work opportunities would dwindle. Aquaculture development opportunities will increase in particular in tropical and sub-tropical regions.
The climate change in warmer regions offers new opportunities as production in warmer regions will increase because of better growth rates, a longer growing season and the availability of new fish farming areas where it was once too cold.

Impact on Demography

Rising sea levels owing to climate change would force communities in low-lying coastal areas and river deltas to move to higher ground level.
Similarly, increase in frequency of droughts due to climate change would force farmers and pastoralists, who rely on rainfall to raise their crops and livestock, to migrate to areas in search of land and water.
This migration/displacement of people would result in direct conflict and competition between migrants and established communities for access to land and water.
It may be difficult for displaced communities to maintain their farming or pastoral traditions.

Impact on Glacier

Glaciers the world over are thinning and shrinking as the planet warms, and glaciers in the Himalayas are receding faster than anywhere else.
If the earth keeps warming at the current rate, Himalayan glaciers are likely to disappear altogether in 25 years.
In the absence of glaciers, rivers in the Indo-Gangetic plain will become much more seasonal, threatening the rabi crop as well as domestic and industrial water supplies in the non-monsoon months.
In addition, more precipitation will fall as rain rather than snow and the greater water run-offs will increase flooding.

Impact on Weather

Increasing global temperatures will lead to higher maximum temperatures, more heat waves, and fewer cold days over most land areas.
More severe drought in some areas, combined with other factors, has contributed to larger and more frequent wildfires.

Impact on Human Health

Changes in the greenhouse gas concentrations and other drivers alter the global climate and bring about myriad human health consequences.
Environmental consequences of climate change, such as extreme heat waves, rising sea-levels, changes in precipitation resulting in flooding and droughts, intense hurricanes, and degraded air quality have impact directly and indirectly on the physical, social, and psychological health of humans.

Impact on Water Resources

Climate change will have an impact on the predictability and variability in the availability of water and also increase in frequencies of droughts and floods.
Worst sufferers would be farmers of the rainfed agriculture, which covers 60% of all cultivated land in the country.
The risk of crop failures will increase in semi-arid zones with prolonged dry seasons forcing people to migrate, when stability of food production cannot be assured.
Irrigated areas in large river basins and deltas can also be at risk because of a combination of factors, such as reduced runoff, salinity, increasing floods, sea level rise, urban and industrial pollution.

Lead to Sea Level Rise

The Bay of Bengal points to the sea rising 3.14 mm a year in the mangrove swamps of ‘the Sunderbans delta’ against a global average of 2 mm, threatening the low-lying area which is home to about 4 million people.
A trend of sea level rise of 1 cm. per decade has been recorded along the Indian coast. The major delta area of the Ganga, Brahmaputra and Indus rivers, which have large populations reliant on riverine resources, will be affected by changes in water regimes, salt water intrusions and land loss.
The rise in sea temperature also causes coral bleaching, which negatively affects fishes, sponges, giant clams, and other sea creatures.
The El Nino event of 1998 resulted massive mortality of corals in the Lakshadweep and Andaman and Nicobar islands.

Threat to Cities

The Indian cities will face the impact of climate change in various forms. Indian urban infrastructure is less advanced and over-stressed in most cities.
The floods and heavy rains caused by climate change will devastate the urban dwellings and make havoc to the lakhs of poor lives.
Nowadays rural population is migrating towards cities increasing the demands of power, housing and drinking water and transportation.
The water scarcity due to glacial melting and irregular rainfalls will reduce the availability of clean drinking water.

Steps taken by Government for mitigation:

India’s Energy Conservation Act ( Energy Conservation Act), 2001; The 2010 amendment to the S ENERGY CONSERVATION ACT created PAT scheme as a market-based trading scheme enable industries to meet the mandatory energy efficiency standards that had begun to be developed under the original Energy Conservation Act.
PAT scheme is now India’s main effort-defining policy. It is overseen by the BEE and was introduced by the National Mission on Enhanced Energy Efficiency (NMEEE).
Use of Renewable Energy-The Electricity Act 2003 together with the National Electricity Policy 2005 (NEP) and the Tariff Policy (TP) mandate promotion of electricity generation from renewable sources. The Electricity Act and these policies envisage regulatory interventions for promotion of renewable energy sources.
Climate Friendly Transport Sector-Transport India has taken substantial initiatives to make the transport sector less emission intensive. One of the major initiatives has been upgradation of vehicular emission norms such as Bharat Stage II, Bharat Stage III and Bharat Stage IV. The commercial manufacture of battery-operated vehicles has begun in India with a view to promoting low/ no carbon emitting vehicles.
Conservation of Agriculture, Forest and Water Resources- National Mission for Sustainable Agriculture. There are also programmes for crop improvement and drought proofing. India has launched an ambitious Green India Mission to increase the quality and quantity of forest cover in 10 million ha of land. Also an incentive-based additional special grant of US$ 1.2 billion had been announced by the central government to all states for sustainable forestry management.
Forestry Sector- The National Forest Policy (1988), Participatory Forest Management/Joint Forest Management Programme, National Afforestation Programme, National Forestry Action Programme and National Watershed Development Project for Rainfed Areas.
Coastal Area- Coastal Ocean Monitoring and Prediction Systems (COMAPS), Land Ocean Interactions in the Coastal Zone (LOICZ), Integrated Coastal and Marine Area Management (ICMAM), and Society of Integrated Coastal Management (SICOM).
Enhancing Adaptive Capacity- the National Bank for Agriculture and Rural Development (NABARD) is India’s National Implementing Entity (NIE) for the Adaptation Fund created under the UNFCCC. At present, NABARD is the only NIE in the Asia Pacific Region.

Earth at risk of becoming irreversible hothouse: Study

Our planet is at the risk of entering an irreversible ‘hothouse’ condition - where the global temperatures will rise by four to five degrees and sea levels may surge by up to 60 metres higher than today - even if targets under the Paris climate deal are met.

Findings & Concerns

According to the researchers, keeping global warming to within 1.5-2 degrees Celsius may be more difficult than previously assessed.
Human emissions of greenhouse gas are not the sole determinant of temperature on Earth.
Human-induced global warming of two degrees Celsius may trigger other Earth system processes, often called “feedbacks,” that can drive further warming - even if we stop emitting greenhouse gases.
Avoiding this scenario requires a redirection of human actions from exploitation to stewardship of the Earth system
The study consider ten natural feedback processes, some of which are “tipping elements” that lead to abrupt change if a critical threshold is crossed.
Maximizing the chances of avoiding a “Hothouse Earth” requires not only reduction of carbon dioxide and other greenhouse gas emissions but also enhancement and creation of new biological carbon stores through improved forest, agricultural and soil management, and technologies that remove carbon dioxide from the atmosphere and store it underground.

Bharat Stage IV (BS-IV) cars

About

This is according to the mass emission standards for flex-fuel M15 or M100 and MD 95 vehicles notified last year.

The use of blended fuel M-15 in BS-IV cars can result in lowering of greenhouse gas emissions by about 5 to 10 %, thereby improving air quality.

M-15 fuel

It is a blend of 15 % methanol and 85 % Gasoline.
It is a clean burning drop in fuel which can replace both petrol & diesel in transportation & LPG, Wood, Kerosene in cooking fuel.
It can also replace diesel in Railways, Marine Sector, Power Generation and this could be the ideal complement to Hybrid and Electric Mobility.
Methanol Economy is the 'Bridge' to the dream of a complete "Hydrogen based fuel systems".
M-15 in petrol and diesel will reduce pollution by 33% and 80 % respectively.
It burns efficiently in all internal combustion engines, produces no particulate matter, no soot, almost nil SOX and NOX emissions (Near Zero Pollution).

Bharat stage emission standards

These emission standards were set by the central government to keep a check on the pollutant levels emitted by vehicles that use combustion engines.
The norms were introduced in 2000. With appropriate fuel and technology, they limit the release of air pollutants such as nitrogen oxides, carbon monoxide, hydrocarbons, particulate matter (PM) and sulphur oxides from vehicles
These norms are based on European emission norms which, for example, are referred to in a similar manner like ‘Euro 4’ and ‘Euro 6’. These norms are followed largely by all automakers across the globe and act as a good reference point as to how much does a vehicle pollute.
To bring them into force, the Central Pollution Control Board sets timelines and standards which have to be followed by automakers.
The higher the number gets, the stricter the Bharat Stage emission norms get which eventually means it becomes trickier (and costlier) for automakers to meet them.
Bharat Stage VI (BS-VI) norms are two stages ahead of the present BS IV norms in regulating emissions. BS-VI norm would come into force from April 1, 2020 in India.

Difference between BS-VI and BS-IV

The major difference is the presence of sulphur in the fuel. While the BS-IV fuels contain 50 parts per million (ppm) sulphur, the BS-VI grade fuel only has 10 ppm sulphur content.

‘Impressive’ tortoise sighted in Arunachal Pradesh

Context

A team of herpetologists from the Forest Department and two NGOs, Help Earth and Turtle Survival Alliance (TSA), found a pair of the rare species,Impressed Tortoise (ManouriaImpressa) in Arunachal Pradesh.

About

More on news

This is the first-ever recorded sighting (not discovery) in India of this tortoise which is on a red list of threatened species, taking the count to five and the non-marine chelonian count to 29. Chelonian is an order of reptile that includes turtles, terrapins and tortoises.
The species has a golden brown shell and skin.

There are only two species of tortoises under the Manouria genus. Northeast India was known to be the home of only the Asian Forest Tortoise (Manouriaemys) until the discovery of the Impressed Tortoise.
The male Impressed Tortoise is smaller than the female which is 30 cm in length, so it is medium sized. This Manouria species is one-third the size of the Asian Forest Tortoise.
Turtle Survival Alliance, an organisation working towards tortoise conservation, described it as a 'critically endangered' tortoise species which was elusive, vulnerable, and most importantly, never been sighted in India.
It inhabits hilly regions, moist primarily forest hill tracts of the Indo-Burma hot spot (Cambodia, China, Laos, Malaysia, Myanmar, Thailand and Vietnam). Its habitat is difficult to access and that makes its protection tough.
The last reported range extension of the species was from Gwa, Myanmar. The records of IUCN (International Union for Conservation of Nature) show it to be fungivorous (fungi-eating). It is also considered difficult specie for captive breeding. The clutch size (number of eggs laid at a time) is 10-21 eggs and not much is known of its nesting behaviour.
The impressed tortoise measures one foot, and has a ‘brilliant’ spine, which is bent upwards and beautifully serrated. It’s a magnificent looking creature — impressive in colour and shape. That is why it’s called the impressed tortoise in the first place.

Implications of the finding

It hailed it as a landmark moment in turtle conservation. The implications of the finding is big since always in our country, in conservation action plan, lesser animals are sidelined, always the focus is on elephants, tigers or rhinos and may be this discovery will create an impact, very little may be but a perception change might come and more researchers will join in turtle conservation.
With this discovery, India becomes the third most turtle-rich country in the world. There are 24 turtles (aquatic) species found in the country.