General Studies (Paper - 3) : Model Question & Answers

Question: What is the difference between adaptation and mitigation to climate change? Discuss some of the adaptation and mitigation measures that can be taken in the present scenario of climate change.

Climate Change and Water Resources

• Climate change is not only a major global environmental problem but also an issue of great worry to a country like India.

Causes of climate changes

• Green house effect: Green House Gases have an important role in controlling the temperature of the Earth and keeping it sufficiently warm for life to survive. But excess of these gases is having harmful consequences.

Impact on water resources

• The impact of climate change was found to be more prominent on seasonal rather than annual water availability.

• Flow in the peninsular river mainly depends on the monsoon rainfall and ground water recharge.

• The runoff of Himalayan Rivers is expected to be highly vulnerable to climate change because warmer climate will increase the melting of snow and ice.

• Melting of glaciers and reduction in solid precipitation in mountain regions would have a direct impact on water resources affecting the drinking water, irrigation, hydropower generation and other uses of water.

• Glacial melt is expected to increase under changed climate conditions, which would lead to increased summer flows in some river systems for a few decades.

• Changes in amount of pattern and intensity of rainfall would affect stream flow and the demand for water. High flood level can cause substantial damage to key economic sectors.

Assessment Method

• General circulation models or global climate models that represent physical and chemical processes in the atmosphere, cryosphere, land surface and ocean are the most advanced tools to simulate the response of the global climate system to rising concentration of GHGs.

• Any climate change impact assessment on water resources study requires the down-scaling of the precipitation and other variables such as temperature, relative humidity, solar radiation, wind direction and wind speed from the global scale to the regional scale.

Adaptation and Mitigation

• Adaption to climate change refers to adjustment in natural or human systems in response to actual or expected climatic stimuli or their effect which moderates harm or exploits beneficial opportunities.

• It can be of different types: Anticipatory or proactive adaption takes place before impacts of climate changes are observed.

• Mitigation is as an anthropogenic intervention to reduce the sources or enhance the sinks of green house gases.

• While mitigation tackles the causes, adaptation tackles its effect.

• The more mitigation the less will be the impacts to which the society will have to adjust and less risk for which people will have to be prepared.

• Agriculture and forestry have significant potential for GHG mitigation. Economic diversification for countries that depend on limited and climate-sensitive economic activities such as the export of climate-sensitive crops is an important adaption strategy.

Land-use change and management

• Many practices advocated to conserve soil carbon reduced- tillage, more vegetative cover, greater use of perennial crops-also control erosion and help to improve water quality.

• These practices may also have other potential adverse effects like enhanced contamination of ground water with nutrients or pesticides through leaching under reduced tillage.

Afforestation or reforestation

• As plants are the carbon sinks, through afforestation in a region they will help mitigate the climate change.

• It may also help to regulate the hydrological cycle.

• It uses more water than crops or natural short vegetation.

• The lands that are subjected to afforestation or reforestation may be related to increased interception loss, especially where canopy is wet for a large proportion of the year or in drier regions to the development of massive root systems which allow water extraction ad use during prolonged dry seasons.

• It has many good hydrological effects. After afforestation in wet areas, the amount of direct runoff initially decreases rapidly, then gradually become constant and base flows increases slowly as age of trees increases.

• This suggests that reforestation and afforestation help to reduce small floods and enhance water conservation.

Actions needed

• Improve hydro-meteorological network for better monitoring.

• Update basin wise water availability in the current situation.

• Determining extent of current climatic/hydro-metrological variability and future projections in variability due to climate change including the impact on rainfall frequency and intensity.

• Generate reliable downscaling of GCM projections to regional and basin level.

• Assess impact of Climate change on

  • Surface water availability and their interaction

  • Land use/land cover and their coupled impact on water resources.

  • Rainfall intensity-duration-frequency relationship in urban areas

  • Magnitude –frequency of drought

  • Sediment loads and management implication

• Review hydrological planning design and operating standards in view of changed scenario.

• To cope up with enhanced scarcity and variability in water sector, develop adequate infrastructure.

• Develop databases and tool boxes and practice integrated water resources management.