Relevance: GS-3: Achievements of Indians in science & technology; indigenization of technology and developing new technology; Conservation, environmental pollution and degradation, environmental impact assessment; Disaster and disaster management

Key Phrases : Climate Change, Weather Pattern, Fragile Himalayas, India’s Observational Network, Cloud Bursts

Context:

• India is being visited by more extreme weather, with the recent years being the warmest and driest in history that contains the very rare example of consecutive droughts, cases of brief bursts of torrential rain in various parts of the country.
• This brings into discussion the importance of weather prediction and issues faced by weather agencies.

Background

• Climate change has hampered the ability of the forecasting agencies to accurately predict severe events.
• Weather bureaus across the world are focusing on augmenting the observational network density and the weather prediction model ling to improve predictability.

What is climate change?

• Climate change refers to long-term shifts in temperatures and weather patterns.
• These shifts may be natural, but since the 1800s, human activities have been the main driver of climate change, primarily due to the burning of fossil fuels like coal, oil, and gas, which produces heat-trapping gasses.
• It threatens people with food and water scarcity, increased flooding, extreme heat, more disease, and economic loss. Human migration and conflict can be a result.
• WHO calls climate change the greatest threat to global health in the 21st century.

Impact of Climate Change on Indian Monsoon

• Even though the monsoon rainfall in India has not shown any significant trend, the number of heavy rainfall events has increased and that of light rainfall events has decreased due to climate change.
• Digital data of the monsoon rainfall since 1901 shows that parts of north, east and northeast India show a decrease in rainfall, while some areas in the west, such as west Rajasthan, show an increase in precipitation.
• The submission of the government in Parliament says that Uttar Pradesh, Bihar, West Bengal, Meghalaya and Nagaland have shown significant decreasing trends in the southwest monsoon rainfall during the recent 30-year period.
• The annual rainfall over these five states, along with Arunachal Pradesh and Himachal Pradesh, has also shown significant decreasing trends.
• Thus, there is no significant trend in the country as a whole. The monsoon is random and it shows large-scale variations. That means if it is not raining, it is not raining. If it is raining, it is raining heavily.
• The rainfall is more intense when there is a low-pressure system. This is one of the most important trends found in the tropical belt, including India.

Spike in surface air temperature

• Climate change has increased the surface air temperature, which in turn has increased the evaporation rate. Since warmer air holds more moisture, it leads to intense rainfall.
• Climate change has increased the instability in the atmosphere, leading to an increase in convective activity such as thunderstorms, lightning and heavy rainfall.
• This increase in heavy rainfall events and decrease in light precipitation are due to climate change
• The severity of cyclones in the Arabian Sea is also increasing. This increase in the frequency of extreme weather events is posing a challenge to forecasters.

Fragile Himalayas

• With climate change, the fragility of the Himalayas is increasing. The frequency of mini-cloud bursts i.e. more than 5 cm rainfall in an hour, is increasing in the Himalayas which can cause damage.

India’s Observational Network

• Augmentation of radars, automatic weather stations and rain gauges and satellites have been used to improve predictability.
• The number of radars will increase from 34 at present to 67 by 2025.
• IMD’s forecast accuracy has improved by about 30 to 40 per cent for severe weather events like cyclones, heavy rains, thunderstorms, heat waves, cold waves and fog in the last five years.
• This has been made possible due to an improvement in the observational network, modeling and computing systems of the IMD and the Ministry of Earth Sciences (MoES).
• Sister organizations such as the IITM and the NCMRWF carry out atmospheric modeling and the INCOIS carries out ocean state modeling and supports the IMD's forecasting improvement.

India’s upgradation plans

• The MoES plans to upgrade its high-performance computing system from a capacity of 10 petaflops currently to 30 petaflops in the next two years. It will help assimilate more data into the model that can then be run at higher resolutions.
• At present, the IMD/MoES weather modeling system (global forecasting system) has a resolution of 12 km against the target of 6 km. Similarly, the resolution of the regional modeling system will be improved from 3 km to 1 km.
• The lower the range of a weather model, the higher its resolution and the greater the precision.
• IMD is providing forecasts up to the district and block levels currently. Going ahead, it will provide forecasts up to clusters at the panchayat level and specific locations within cities.

Way Forward

• The number of deaths due to cyclones, heat waves etc. has reduced over the years because of an improvement in the early warning lead time and preparedness, planning, prevention and mitigation approaches.
• There has been a tremendous improvement in service delivery - weather information for health, power, agriculture, air quality, hydrology, airports and marine sectors - in the last three years.
• Despite these technological advancements, studies have proved that the ability to predict heavy rainfall is hampered due to climate change.
• Thus, more study needs to be conducted to enhance capabilities of these institutions. It needs cooperation and coordination at global level as the threat of climate change and its impact are common for all of us.

Source: The Hindu BL

Mains Question:

Q. Despite technological advancements in India, studies have proved that the ability of IMD to predict heavy rainfall is hampered due to climate change. Elucidate. [150 Words].