- Ozone gas in stratosphere prevents 99.5% entry of UV radiation (255nm) on earth.
- Chlorofluorocarbons / freons: non-reactive, non-flammable, non-toxic. Used in Refrigerators, spray cans, insulation foam and propellant.
- Once they’re released in atmosphere, they reach stratosphere=> react with UV=> release Chlorine free radicals => Ozone broken.
- 1980s: Scientists realized Chlorofluorocarbons (CFCs) reach had damaged Ozone layer above Antarctica. Result?
- Skin cancer, Cataract, Sunburns
- Phytoplanktons die=> fish population declines.
- Soil Moisutre content declines, plant proteins are mutated=> plant growth affected.
- Fibers and Wall paints fade faster.
- Late 80s: Montreal Protocol signed, to cut down use of
- chlorofluorocarbons (CFCs) / freons
- Halons in fire-extinguishers
- 2014: CFC has declined by 90%, Ozone layer showing signs of recovery- as per United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO).
- This will also prevented 2 million skin cancer cases per year.
- 2050: Ozone Layer will recover near mid-latitudes
- 2075: Ozone layer will recover near Antarctic.
- CFCs are replaced with HFCs (Hydroflurocarbons). Although HFCs don’t deplete Ozone layer but they’re greenhouse gases, hence contribute to global warming.
- Researchers found Carbon tetrachloride increased in atmosphere. This is a banned ozone-depleting carcinogenic solvent.
- Meaning, some companies in the third world countries are still using it illegally, as a cheaper alternative to HFCs.
|Assessment Report (AR)||Year|
|5th||Yet To Publish Entirely. (Only 2/3 Parts Published)|
IPCC 5th Assessment Report (AR5)
Three groups working to prepare this report
|group No.||working on||Published?|
|1||On physical science and climate change||September, 2013|
|2||Adaption measures [“Impact, Adaption and vulnerability”]||March 2014 (hence in news during April 2014)|
|3||Mitigation measures||yet to be published|
So now we come to the report that is making news=> Report on “Adaptation measures” under 5th assessment report. Since this is only a small part of the big report yet to come => so, don’t waste time doing lot of Ph.D majoori (labour) in this report.
Overall it says following:
- Soil moisture will decline globally => dry regions will become even more drier => global drought =>food shortage.
- Temperature has risen 0.2 cel since Industrial revolution.
- Climate change is inevitable challenge, but if we understand the challenge correctly then we can better tackle it.
- But, Science can help in adaptation and risk reduction. for example:
|Sea Level Rise||Build coastal barriers and plant mangroves|
|Agriculture||climate resilient seeds and agri-technology|
|Natural Disaster||Invest in technology for early detection of cyclones, flood and droughts=> training of personnel, take precautionary measures.|
Impact on India?
- The poor and developing countries of tropical regions are the most vulnerable of the climate change.
- Small island countries of Indian Ocean, like, Maldives, Mauritius and Shri Lanka, will migrate to India as climate refugee. (India has made such agreements with these countries)
- Indian coastal cities will face danger of submergence.
- Erratic Rainfall, melting of Himalayan glaciers, frequent flooding, draughts, storms and cyclones.
- Food insecurity for large population.
- New diseases and weather patterns.
- During summer, the Sahara desert undergoes low pressure depression => dust lifted upwards and flies towards Europe and America
- locally this is called “Simoom” or poison wind, because it causes heat strokes.
- In April 2014: a large mass of this dust storm fell over London, hence in news.
|Provides phosphate nutrients to Amazon soil.||Continuous and large scale dust storm decreases total soil fertility=forcing villagers to migrate to cities. This happened in USA during 40s, more than 2.5 million people migrated to California.|
|Provides nutrients to plankton in Mediterranean sea.|
|reduces the surface temperature sea and lowers the possibilities of hurricane|
|Harmattan wind carries this dust in Niger- brining soil nutrients K, Mg and Ca.|
|dust particles directly reflect sunlight backinto space, thus reducing amount of heat coming to Earth’s surface- this has both positive and negative impacts on long term climate.|