Climate change and atmosphere

Climate change and atmosphere

Atmosphere: The thick layer of air around the earth is called atmosphere.

Importance of atmosphere

  1. It provides us oxygen for respiration.
  2. It protects us from meteor and meteorites.
  3. It protects us from UV rays and cosmic rays from space.
  4. It maintains the temperature on earth.

Layers of atmosphere.

The atmosphere is divided into 5 layers on the basis of altitude, temperature, gases etc

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermosphere
  5. Exosphere
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Fig: Layers of atmosphere

Troposphere:

  1. It is the lowermost layer of atmosphere extended up to 16 km above earth’s surface.
  2. It contains above 96% of total air of atmosphere.
  3. Temperature goes on decreasing with increase in altitude at the rate of 6.5 C per km. Hence, it is called variable layer of atmosphere.
  4. All the meteorological/weather activities occur in this layer.
  5. This layer of atmosphere is mainly affected by human activities.

Stratosphere:

  1. This is the second layer of atmosphere which is extended up to 16-50 km above earth’s surface.
  2. It mainly contains ozone Layer (O3) gas. Hence, it is also called ozonosphere.
  3. Temperature goes an increasing with the increase of altitude.
  4. Jet planes fly in the lower most layer of stratosphere as visibility is very high.
  5. This layer absorbs about 99% of UV rays from sun and protects us from its harmful effect.

Mesopause:

  1. This is the third layer of atmosphere which is extended from 50-80km above earth’s surface.
  2. Temperature decreases with increase in altitude.
  3. This is the coldest layer of atmosphere.
  4. Very strong storm flows in this layer.
  5. Meteor burn in this layer.

Thermosphere:

  1. This is the fourth layer of atmosphere which is extended up to 80-720 km above earth’s surface.

Exosphere:

  1. This is the outer layer of atmosphere which is extended above 720 km above earth’s surface.

Ozone:

Composition of ozone gas:

O2 ———> O+O (UV-rays)

O2+O ———> O3 (UV-rays)

Decomposition of ozone gas:

O3 ———> O2+O (UV-rays)

O+O ———> O2 (UV-rays)

Importance of ozone layer

  1. It is the main cause of evolution of life.
  2. It protects us from harmful UV rays from sun.
  3. It protects aquatic and terrestrial ecosystem.
  4. It protect statues and monuments.

Depletion of ozone layer.

The decrement of ozone gas in the stratosphere due to various human activities is called depletion of ozone layer

Ozone depleting substances

  1. Chlorofluoro carbon
  2. Carbon tetra chloride
  3. Methyl chloroform
  4. Methyl Bromide
  5. Oxides of Nitrogen

Q. How does chlorofluorocarbon cause ozone layer depletion. Explain?

When chlorofluoro carbon release in the atmosphere t it reaches to atmosphere where it breaks due to the UV rays forming chlorine atom the chlorine atom thus formed reacts with ozone and forms oxygen. The process continues for about 100000 ozone molecules in this way chlorofluoro carbon causes ozone layer depletion.

CFCl3 ———> CFCl2+Cl (UV-rays)

Cl+O3 ———> ClO + O2

2ClO ———> 2Cl + O2

Q. Write the reaction due to which oxide of nitrogen causes ozone layer depletion.

NO+03 ———> NO2 + O2

2NO2+03 ———> N2O3+2O2

Effects of ozone layer depletion

  1. Effect on human health: UV rays reaching to earth surface causes skin problem, skin cancer, eye cataract, low immunity system in human health and animal etc.
  2. Effects on plants: UV ray cause low rate of photosynthesis process due to which growth rate of plants is affected.
  3. Effects on ecosystem: UV rays kills micro organisms, eggs and larva of aquatic animals etc due to which total ecosystem is affected.
  4. Rise in temperature: UV rays increase the temperature of earth atmosphere causing global warming.

a. Write the effect of ozone layer depletion on human health

  1. It causes skin disease and skin burn.
  2. It causes skin cancer.
  3. It causes  eye cataract.
  4. It causes low immune system.

Protection of ozone layer.

  1. Use and protection of chlorofluoro carbon should be banned.
  2. Use of chemical fertilizers should be minimized.
  3. Electric vehicles and industries should be used.
  4. Public awareness should be created.

Industrial gases: The gases produced by industries as by product are called industrial gases. Eg, CO2, carbon monoxide, sulphur dioxide etc.

Effects of industrial gases

  1. It causes eye-irritation, throat and nose irritation.
  2. It causes various respiratory and cardiovascular diseases.
  3. It causes acid rain.
  4. It causes industrial smog which decreases visibility of air.
  5. It causes global warming.

Acid rain: When industrial gases like CO2, CO SO2 are released in atmosphere, they react with rain water during rain and form acids. These acids fall with rain which is called acid rain.

SO2+H20 ———> H2SO3 (Sulphurous  acid)

2SO2+O2 ———> 2SO3

SO3+H20 ———> H2SO4 (Sulphuric  acid)

Climate change: The change in long term pattern of climate due to various causes is called climate change.

  1. National efforts on climate change
  2. National communication report
  3. Climate change policy – 2067
  4. Climate change adaptation strategic programme
  5. National Adaptation Programme
  6. Local Adaptation programme related to climate
  7. Other programmes

National efforts

a. National communication report: Nepal prepared and submitted a report on climate change  to conference of parties (COP) of UNO protocol. In this report, Nepal has mentioned the impacts of climate change, ways of adaptation and various policies and laws to combat climate change.

b. Climate change policy 2067: Nepal government formulated a policy to create public awareness about global warming and climate change for the reduction of adverse effects on human health, agriculture, forest etc

c. Climate Change adaptation Strategic Programme: The climate Investment Fund invited Nepal to participate in the global model programme related to adaption to climate change. It provides financial support to the poor countries. Nepal government then has conducted various programmes into 5 sectors which is called climate change adaptation strategic programme.

d. National Adaptation Programme: National Adaptation Programme was prepared in the year 2010 by the government of Nepal which conducts 250 programmes in different 9 sectors. It mainly evaluates the risk of climate change.

e. Local adaptation programme: It is designed to implement in local level which prepares and co-ordinates local and national level to minimize impact of climate change, especially to the endangered communities region and family.

f. Other programmes: Nepal government conducts other various programmes on climate change related to improved chimneys of brick factories, improved stove, use of bio-gas, free information system about natural disaster etc.

International efforts on climate change

  1. UN Framework Convention on climate change (UNECCC)
  2. UN Climate Change conference
  3. Agenda-21
  4. Inter governmental forum
  5. Kyoto protocol
  6. Methods to reduce greenhouse on the basis of Kyoto protocol
  7. Reduction of emission due to deforestation.

1. UN Framework Convention on climate change (UNECCC)

UNFCCC was held in the year 1992 in Rio de Janeiro, Brazil in which 154 countries with their national heads participated. This is also called Earth summit-1. It addresses various aspect like increasing environmental pollution sustainable development, climate change and methods of adaption on climate change.

2. UN climate change conference

UN has conducted about 20 conferences on climate change to inform the work and programmes in the member countries related to climate change. On the basis of this conferences, Nepal also brought climate change policy-2067.

3. Agenda-21

The action plan was formulated on the basis of slogan * Think globally acts locally” to conserve environment and ensure sustainable development. The project of Agenda 21 are centered on the challenges and ways to face the problem of 21st Century. This, agenda was decided on Earth Summit-I

4. Intergovernmental forum

It was established in 1988 AD. It prepares report to support UNFCCC. It consists of the scientific, technical, socio-economic information to understand risk of climate change and the mitigating measures.

5. Kyoto protocol:

It was adopted in December 1997 AD in Kyoto of Japan. Its main objective is to reduce climate change and production of greenhouse gases to control global warming. According to this the developed countries should reduce emissions of green house gases by 5.25% by 2012 AD and by 80%. until 2050.

Measures to reduce greenhouse gases (GHGs) according to Kyoto protect.

Kyoto protocol encourages developed and developing country to work under 3 market level mechanism to meet their GHG emission target. They are:

  1. International Emission trading
  2. Joint Implementation
  3. Clean development mechanism

Reduction of emission due to deforestation

Forests are the important natural resource for absorption of carbon. So, developed countries which produce large amount of GHGs should reduce the activities that destroy forest, instead the developed countries should help undeveloped countries providing necessary support.