Climate change in India has been having tremendous effects on India. India was ranked fourth among the list of countries most affected by climate change in 2015. Rising temperature on the Tibetan Plateau are resulting in the retreat of the Himalayan glaciers, which is a threat to the flow of the Ganges, Brahmaputra, Yamuna, and other major rivers. Frequency of heat waves is also increasing in India due to climate change.
Extreme Weather Conditions in India
The increase in frequency and intensity of extreme weather conditions is considered as an impact of the changing climate patterns all over the Indian region as well as the world. In July 2021, there were heavy rains in Maharashtra, which claimed almost 200 lives. Ever since the major disaster in Uttarakhand in 2013, India has witnessed extreme weather conditions almost every year. There have been floods in Jammu and Kashmir, Kerala, Tamil Nadu, Karnataka, Maharashtra, and several other parts of the country due to excessive rainfall.
When the south-west monsoon began retreating from the subcontinent in October 2021, Kerala and Uttarakhand received heavy rainfall. Besides, there have been variations in the pattern and intensity of rainfall in other parts of the country as well. In 2018, Kerala witnessed a severe spell of rainfall, which caused havoc and claimed many lives. The unprecedented set of extreme weather events has badly impacted the western coast of India. Since 2018, cyclones have come very close to the west coast and Kerala has experienced widespread floods.
In case of Kerala, the two rain-bearing active ‘low pressure systems’ in the Arabian Sea, and in the Bay of Bengal contributed to heavy rains in September 2021. Moreover, there were western disturbances, i.e., periodic influxes of the moisture-laden clouds from the Mediterranean, which caused rain in northern India. The warmth in the Bay of Bengal usually causes heavy rainfall to several parts of North-Eastern India.
Warming in the Indian Ocean is at the fastest rate. Some regions like the western Indian Ocean, including the Arabian Sea, have been registering long-term average above 1.2 degrees Celsius which is causing an increase in storms and extreme rain events in the Indian Ocean rim countries. Like the Bay of Bengal the Arabian Sea, too, has been warmer due to rise in temperature and has been leading to significant cyclonic activity. The Arctic Ocean too is getting warmer and has been drawing colder air from the poles with greater intensity. This has been adding increased moisture, leading to more intense western disturbance activity over North India.
Between 1950 and 2017, 285 flooding events were reported in India, which affected about 850 million people, leaving 19 million homeless and killing about 71,000 people. During the last decade, the damage due to floods has been about US $3 billion per year. According to a recent study from the Ministry of Earth Sciences, the floods, cyclones, heat and cold waves, and lightning have taken about 1.4 lakh lives during the past five decades.
Multiple extreme weather events have also overlapped and increased the impact of cyclones. Due to global warming, there is more moisture in the air that cyclones would absorb and pour over land. The back-to-back cyclones in 2020 and 2021 generated storm surges with high tides, pushing seawater into land. Accompanied by heavy rains, the storms flooded the coastal regions.
Impact of Temperature on Natural Environment
Temperatures in India have risen by 0.7 degree Celsius between 1901 and 2018.
A study in 2018 projected droughts to increase in north and north-western India in the near future. Around the end of the century, most parts of India might face more severe droughts. Similarly, severe landslides and floods have been projected to become increasingly common in states such as Assam, etc.
Impact of Rising Sea-level on Ecosystem
There are concerns in Meghalaya and other North-Eastern states that rising sea levels would submerge much of Bangladesh and lead to a refugee crisis for North-Eastern states. Bangladesh and parts of India that border Bangladesh might lose vast tracts of coastal land if severe climate changes take place. Low-lying islands in the Sunderbans have been submerged due to ongoing rise in sea level, leading to thousands of people having been displaced.
Rising temperatures have also led to ecological disasters, such as a coral bleaching event in 1998, which killed more than 70 per cent of corals in the reef ecosystems off Lakshadweep and the Andamans.
Recurring Pattern due to Climate Change
According to the World Meteorological Organization (WMO), global average temperatures would breach the 1.5-degree Celsius rise as an annual average in the next five years. To prevent long-term global average temperatures from rising well below 2 degrees Celsius, the world nations agreed to curb emissions, under the Paris Agreement as keeping the temperatures at 1.5 degrees Celsius would substantially reduce further increase in risks and impacts of climate change. However, India has not been able to curb emissions thus far.
Though the global climate system would not collapse in a flurry of extreme weather events even if we cross 1.5-degree Celsius, warming has its marks that could be seen in any single day of global weather since the 2000s. In fact, the 1.5-degree Celsius threshold accounts only for the changes in global surface temperatures. Ocean which are around 4 km deep absorb more than 93 per cent of the additional heat from global warming.
According to the India Meteorological Department (IMD), the number and intensity of the cyclones have increased in the Arabian Sea since the 1980s, a threat to the densely populated western coast of India. Cyclone Tauktae, in May 2021, indicates the third consecutive year when cyclone came very close in the Arabian Sea and impacted Kerala, Karnataka, Goa, Maharashtra, and Gujarat, islands and territories of Lakshadweep, etc., on the west coast.
Accuracy of Weather Prediction
In the last few years, there has been tremendous improvement in prediction of cyclones and heat waves, due to which thousands of lives have been saved. Though the IMD could forecast the overlapping impacts of the cyclones, there is not enough data to understand the compounding extreme events. Also, effective forecast of events such as cloudburst, or urban flooding, still remains a challenge.
The accuracy of monsoon forecasts, especially of extreme rainfall events, has increased from about 60 per cent 10 years ago, to over 80 per cent, now. While cyclone forecasting has improved, leading to lives being saved, the rapid intensification of cyclones, a change of 55 km/hr wind speed in less than 24 hours, has become a challenge for both forecasters and disaster management authorities. Cyclone Tauktae was immediately followed by Cyclone Yaas on the east coast, flooding the Odisha and Bengal coastline for days.
The latitude and longitude of India are 20′ North and 77′ East, respectively. Hence, India falls in the tropical region. India is bordered by the Bay of Bengal, Arabian Sea, and the Indian Ocean and has a coastline of more than 7,000 km. Cyclones, the monsoon, and thunderstorms are characteristic of tropical weather systems. Tropical weather is linked with convective forces of the atmosphere. The intense heating of the Earth’s surface has been playing a dominant role in the genesis, evolution, characteristics, propagation, and movement of the weather in India. In tropical zone, the weather is a little less predictable.
The IMD is now able to predict the potential zone of occurrence of thunderstorms, five days in advance. It is not easy to predict thunderstorms because they are localised in about a 1–10 km area, and are expected to last barely for half an hour to three hours. The IMD is able to predict the specific location of thunderstorm at least three hours in advance. Prediction and accuracy by the IMD is among the best in the world.
India is one of the very few countries that have been providing lightning forecasts. The IMD has been able to identify the potential hotspots about two weeks in advance. Lightning warnings are issued every three hours on the day of occurrence from over 1,000 stations across the country. The IMD has also developed an application (app) called ‘Damini’, which has been providing location-specific information about the occurrence of lightning during the past 5, 10, and 15 minutes, and a lightning forecast for the next 45 minutes.
Furthermore, the IMD also provides heat wave predictions with great accuracy. Due to heat waves, a large number of deaths have been reported till few years ago. However, now with the accurate forecasting, and the effective communication and dissemination of information, deaths due to heat waves have been reduced considerably.
The IMD is also working on cold waves predictions.
IMD is on its path to improve impact-based forecasts by incorporating hazards, vulnerability, and risk analysis for four significant severe weather events: tropical cyclones, heavy rainfall, thunderstorms, and heat waves. By improving observation and communication systems, the IMD, is preparing to provide updated weather information available to everyone through mobile apps, etc.
Visible Trends in Extreme Weather
The temperature rise has been more in the northern, central, and eastern parts, and less over peninsular India. Not only is the surface is getting hotter, due to the rise in temperature due to the impact of extreme weather, but also, the troposphere has been increasing its water-holding capacity. When the atmosphere has the capacity to hold more moisture, it would have the capacity to cause more rainfall. This phenomenon has increased the probability of occurrence of heavy rainfall. This trend is more evident in Maharashtra, Gujarat, Odisha, and West Bengal.
There has been a decrease in the number of light and moderate rainfall days, while the number of extreme rainfall events have increased. This trend could be seen in the central belt of India. Kerala, Jharakhand, and adjoining areas have witnessed a decrease in rainfall activity but there has been an increase in the same for West Bengal, western Uttar Pradesh, and parts of Karnataka.
In the central and northern parts of India, there have been heat waves. However, cold wave conditions may decrease due to rise in temperature. Lightning and thunderstorms events are increasing.
Conclusion Besides rise in temperature, there are certain other factors responsible for the fluctuations in climate. For instance, Kerala and Uttarakhand have large tracts of hilly terrain that are prone to landslips and are unsuitable for human habitation. However, construction is taking place at rapid pace. Several ecologists and environmentalists have warned of the consequences of unplanned development.
Therefore, it is advisable that observed coastal data, along with future climate projections, should be used to prepare an in-depth coastal risk assessment for all the Indian Ocean rim countries, as they are vulnerable to climate change and are at high-risk from extreme weather events. So, India’s hunger for relevant weather-related information is expected to grow steadily in order to plan long-term development pathways.
© Spectrum Books Pvt Ltd.