Science_blog: crop

Saturday, 18 March 2023

Adaptations and mitigation: Questions and answers part 6

Q: Please describe relationships between climate extreme and climate change, status of climate change in your country.

Relationships between climate extreme and climate change:

1) A warmer atmosphere can hold more water, fueling more intense rain and snow events. But at the other end of the spectrum, the warming climate can amplify conditions conducive to drought—like heatwaves, evapotranspiration and reduced soil moisture. The combination of these two extremes in one location can increase disasters like flooding and landslides.

2) A growing body of evidence shows strong connections between climate change and extreme events, and impacts once thought of as a distant future threat are already occurring and widespread.

3)The Character and severity of impacts from climate extremes depend not only on the extremes themselves but also on exposure and vulnerability.

4) Changing climate leads to changes in the frequency, intensity, spatial extent, duration,and timing of extreme weather and climate events, and can result in unprecedented extreme weather and climate events.

Status of climate change in India:

a) Extreme Heat: In India, an increase in the linear trend of about 0.4 0C in the surface air temperature has been observed in the past century. A warming trend is visible along the west coast, central India, interior peninsula and the North-Eastern India,but some cooling trends are also visible in the North-West India and parts of south India.

b) Changing Rainfall Patterns: A trend of about 10 to 12% (of the normal) increase in monsoon rains were reported along the west coast, northern Andhra Pradesh and north-western India during the last century. A decreasing trend of about 6 to 8% is observed over the last 100 years over eastern Madhya Pradesh, North-Eastern India and some parts of Gujarat and Kerala (NAPCC,2008).

c) Droughts: Droughts have major consequences. In 1987 and 2002-2003, droughts affected more than half of India’s crop area and led to a huge fall in crop production.

d) Groundwater: it is difficult to predict future ground water levels, falling water tables can be expected to reduce further on account of increasing demand for water from a growing population and agricultural production.

e) Glacier Melt: The available data on snowfall in Himalayan ranges show a recession in some parts of the Himalayan ranges. The river systems of the Brahmaputra, the Ganges and the Indus draws water directly from melting of the Himalayas.

f) Sea level rise: Due to sea level rise, the fresh water sources near the coastal areas will suffer from salt intrusion. Kolkata and Mumbai, both densely populated cities, are particularly vulnerable to the impacts of sea-level rise, tropical cyclones, and river flooding.

g) Agriculture and food security: Food production in India is sensitive to climate change like variations in temperature and monsoon rainfall. Rise in temperature has a direct impact on the Rabi crop and every 1 degree celcius rise will reduce wheat production by 4 to 5 Million Tons. Every small change in temperature and rainfall has significant effect on the quality and quantity of fruits, vegetables, tea, coffee, basmati rice and aromatic and medicinal plants. It is predicted that a loss of 10 to 40% in production may occur by 2100 due to climate change (NAPCC).

h) Water Security: Urbanization, population growth, economic development, and increasing demand for water from agriculture and industry are likely to aggravate the situation further.

i) Energy Security: Climate-related impacts on water resources can undermine the two dominant forms of power generation in India - hydropower and thermal power generation - both of which depend on adequate water supplies to function effectively.

j) Health: Effluent emissions to water bodies and salination of rivers through sea level rise may increase the incidence of water borne diseases. Deaths due to heat wave are reported from several parts of the country from time to time, particularly during the summer. It is observed that changes in climatic patterns may alter the distribution of vector species (Malaria, Kala-azar, Filaria, Chikungunia, Encephalitis ) and increase its spread in new areas. An increase in temperature and relative humidity may enlarge the transmission windows.