Download - Evidences of climate change and drought
BY MEDIDA SUNIL KUMAR
Evidences of Climate Change and Drought
What is mean by climate?
What is mean by climate change?
What is mean by climatic variability?
Past Climate of Earth
1. Earliest Atmosphere:
Primarily H2, water vapor, CH4 and NH4 like Jupiter and Saturn.
2. Second Atmosphere:
Consisting largely of N2 plus CO2 and inert gases, was produced by volcanism
Early Sun put out 30% lower solar radiance associated one cold glacial phase about 2.4
billion years ago
Late Archaean eon O2 containing atmosphere began to develop, apparently produced by
photosynthesizing cyanobacteria
3. Third Atmosphere:
Movement of plate tectonics and volcanism released CO2
Free oxygen did not exist in the atmosphere until about 2.4 billion years ago
The amount of oxygen in the atmosphere has fluctuated over the last 600 million years,
significantly higher than today's 21%.
Evolution of Earth’s Atmosphere
Causes of Climate Change
Natural Causes
Volcanoes
Solar Output
Earth's Orbit around the Sun
Anthropogenic Causes
Fossil Fuels
Industrial Revolution
Change in Land use
Solar activity vs temperature
Greenhouse GasPre-1750
Tropospheric Concentration
Recent Tropospheric
Concentration
Change in Tropospheric
Concentration
Carbon dioxide (CO2) 280 ppm 400 ppm 40%
Methane (CH4) 700 ppb 1874 ppb 168%
Nitrous oxide (N2O) 270 ppb 324 ppb 20%
Chlorofluorocarbons (CFCs)
0 21-529 ppb NA
Ozone (O3) 25 ppb 34 ppb 36%
We Have Also Altered the Atmosphere
Evidence of Changing Climate Evaporation & rainfall are increasing
Coastal glaciers are retreating
Mountain glaciers are disappearing
Permafrost is thawing
Sea ice is shrinking
Greenland is melting
Sea level is rising
Species are moving
Evaporation & Precipitation are increasing
NCDC, 2000
Effect is not uniform; most places getting wetter, some getting drier.
Muir Glacier, Alaska, 1941-2004
NSIDC/WDC for Glaciology, Boulder, compiler. 2002, updated 2006. Online glacier photograph database. Boulder, CO: National Snow and Ice Data Center.
August 1941 August 2004
Coastal Glaciers Retreating
Glacier Retreating
1875 2004
Courtesy Lonnie Thompson
Mountain glaciers are disappearing
Permafrost melts when T ≥ 0°C ACIA 2004
Permafrost is ThawingAverage annual ground temperature, Fairbanks, AK
°C
NASA photograph
North Polar ice cap is sea ice -- it’s floating and so does not change sea level when it melts.
But the reduced reflectivity when the ice is replaced by water amplifies the warming effect of greenhouse gases.
Arctic Summer Ice is Shrinking
1979 2003
Greenland is melting
ACIA, 2004
Summer surface melting on Greenland, 1979-2002
Greenland melting (continued)
2005 broke the 2002 record
Sea Level
Data source: Coastal tide gauge records. Credit: CSIRO. 2012. Data source: Satellite sea level observations. Credit: CLS/Cnes/Legos. 2012
Sea-level from satellites: 4 cm rise in last 10 years
Rise in global ocean heat content 1955-2005
Some ups and downs, but clear overall increaseLevitus et al., 2005, GRL
Extreme weather events
Image Credit: http://www.grida.no/graphic.aspx?f=series/et-common/trends_L.gif
Global surface temperature 1855-2010
Observed surface temperature trend
Trends significant at the 5% level indicated with a ‘+’. Grey: insufficient data
Vulnerability of India to Climate Change
WHAT WILL HAPPEN IN THE CASE SEA LEVEL RISE ??
DROUGHT
Drought is one of the most widespread complex and complicated
disasters.
Extended period of deficient rainfall relative to normal's
68% of the country’s geographical area is prone to drought in varying
degrees
Chronically drought prone areas: – @ 33% (RF: <750 mm)
Drought prone area: – @ 35% (750-1125 mm)
Drought onset: Total rainfall deficiency is > 10 percent of normal's
Severe drought: Total rainfall deficiency is > 25 percent of normal‘s
Period No Region affected by famines/droughts
5th century BC 1 Kashmir , Ayodhya (eastern UP), Rajasthan, Gujarat,Maharashtra & Punjab
1st century BC 1 Kashmir9th century AD 1 Kashmir10th century AD 2 Kashmir , Punjab, large parts of northern India11th century AD 2 Delhi, Bihar , Bengal, Orissa, Rajasthan & Kashmir13th century AD 4 Orissa, Bihar , Assam, Bengal, Rajasthan, Maharashtra & Gujarat14th century AD 5 Delhi, Rajasthan, Maharashtra, Mysore, Karnataka & Gujarat 15th century AD 5 Rajasthan, Maharashtra, Orissa, Assam & most parts of India,
especially the areas along the rivers Ganga & Yamuna16th century AD 6 Most of the then Bombay presidency, Punjab, Maharashtra, Delhi,
Rajasthan, Kutch & central India17th century AD 6 Gujarat, Maharashtra, Rajasthan & Bengal18th century AD 24 Bombay presidency , Gujarat, Maharashtra & Madras19th century AD 38 Rajasthan, Gujarat, Orissa, Maharashtra, Andhra Pradesh,
Kashmir , Himachal Pradesh & Bihar 20th century AD 60 Rajasthan, Gujarat, Orissa, Andhra Pradesh, Kashmir, Himachal
Pradesh, Bihar , Maharashtra, Jammu &KashmirSource ‘Drought of Relief’, Down to Earth, May 2001
Chronology of drought and famine in India
Typical Effects of drought Failure or loss of crops.
Loss of dairy and fishery production.
Reduced energy production.
Increased unemployment
Soil erosion.
Acute shortage of drinking water.
Health hazards and loss of life.
Widespread poverty.
Prices of all commodity shoot up.
Strategies adopted before drought at household level
• Crop diversification on/ crop variety diversification
• Livelihood diversification
• Staggering of seedling periods
• Early migration
• Keeping land fallow
• Limited re-sowing
Early warning and response mechanisms
Close monitoring of drought
Augmentation of water supply and conservation
Proper and scientific expansion of irrigation facilities
Land use
Inter-basin transfer of river waters
Promoting Water-shed programmes
Main mitigation strategies