Date : 03/11/2023

Relevance –GS Paper 1- Geography- Impact of climate change on monsoon

Keywords – ENSO, IOD, Blue Economy, Indian Ocean Region (IOR),SAAGAR

Context

• The Indian Ocean is the third-largest ocean, covering more than 70 million square kilometers, with the majority of its littorals belonging to developing countries. These nations are home to approximately one-third of the world's population, and they heavily rely on the ocean and its resources. The oceans and seas play a vital role in providing food security, eradicating poverty, and offering sustainable growth opportunities.
• The concept of the Blue Economy has gained global attention as it holds the potential to address food security, employment generation, economic sustainability, poverty alleviation, renewable energy sources, and climate change mitigation.

The Blue Economy:

• The Blue Economy, as defined by the World Bank, is the "sustainable use of ocean resources for economic growth, improved livelihoods, and jobs while preserving the health of ocean ecosystems." It represents a pathway to harness the economic potential of the world's oceans and seas.
• The Blue Economy is estimated to be worth over $1.5 trillion annually, with projections indicating that it could double to $3 trillion by 2030, according to the Organization for Economic Cooperation and Development (OECD). The OECD even considers oceans as the next great economic frontier.

Sustainable Development Goals (SDGs) and the Indian Ocean:

• The United Nations' Sustainable Development Goals (SDGs), adopted by all UN member states in 2015, highlight the importance of the oceans. SDG 14, "Life Below Water," is dedicated explicitly to the oceans, while other goals, such as SDG 7, "Affordable and Clean Energy," are inherently linked to the oceans.
• These goals emphasize the need for responsible and sustainable ocean management to achieve global development objectives.

Challenges to the Indian Ocean:

• The Indian Ocean is particularly vulnerable to the adverse effects of climate change. It is warming at a faster rate than other oceans, leading to sea-level rise and more frequent and intense extreme weather events.
• This warming is causing devastating floods and posing a threat to low-lying coastal regions.
• The situation in the Indian Ocean is further complicated by existing climate phenomena, such as the El-Nino Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).

ENSO and IOD:

• ENSO is a global-scale climate phenomenon driven by significant Sea Surface Temperature Anomalies (SSTAs) and ocean-atmosphere interactions in the Pacific Ocean. It can influence global temperatures and precipitation patterns, with warming and cooling phases known as El Nino and La Nina, respectively.



• The Indian Ocean Dipole (IOD) is a climate phenomenon in the Indian Ocean that results from differences in SSTs between its western and eastern regions. IOD is characterized by three phases: neutral, positive, and negative. Each phase has distinct impacts on regional weather patterns, leading to conditions such as droughts, floods, and altered circulation.

Impact of Climate Change on the Indian Ocean:

• The Indian Ocean is experiencing climate change at an accelerated pace, largely driven by increased greenhouse gas concentrations.
• This change is altering the ocean's mean state, favoring stronger SST variations. The warming and altered mean state could potentially reawaken the Indian Ocean El Nino, introducing El-Nino-like variability with cold and warm inter-annual events.

Indian Monsoon Patterns:

• The Southwest monsoon, spanning from June to September, is a highly intricate weather system. In simplified terms, it involves South-easterly winds originating from the Mascarene High in the southern hemisphere. As these winds cross the Equator, they are deflected by the Coriolis force, transforming into South-westerly winds.
• During their 4,500 km journey over the vast expanse of the Indian Ocean, these winds gather speed and moisture. Upon reaching India's Western Ghats, they unleash heavy rainfall. This monsoon progresses northward, taking about a month and a half to cover the entire country. The Heat Low, generated in Northwest India and neighboring areas due to intense pre-monsoon or summer heat, acts as the driving force, creating the necessary pressure difference.
• In India, the monsoon heralds the transition from hot, dry summer months to the rainy season. The usual onset date for monsoon over Kerala is June 1, but it can be early, delayed, or on time-based on various meteorological factors, including daily rainfall, wind patterns, and Outgoing Longwave Radiation (OLR).
• The monsoon's progress and withdrawal vary each year, leading to what is termed inter-annual variability. The non-interdependence of onset, advancement, and withdrawal makes the monsoon a fascinating and extensively studied weather phenomenon. Furthermore, various monsoon-related systems, such as monsoon lows, depressions, troughs, and circulations, add to the complexity, ensuring a sustained intrigue in the monsoon throughout its four-month duration.

Analysis of the Southwest Monsoon 2023:

• Monsoon Onset and Progression: The monsoon made its appearance on May 19, three days earlier than the usual date in the south Andaman Sea and Nicobar Islands but slowed down shortly after. Kerala experienced a delayed onset on June 8, with a one-week lag in the monsoon's arrival. However, it gained momentum and covered the entire country by July 2, six days ahead of the typical date.
• IMD Forecasts and Climatic Influences: The Indian Meteorological Department (IMD) initially forecasted monsoon rainfall at 96% of the Long Period Average (LPA) with a model error of ±5%. An updated forecast on May 26 adjusted this to 96% of LPA with a reduced model error of ±4%. The forecast also predicted the development of El Nino conditions, which historically suppress monsoon rainfall, but anticipated a positive Indian Ocean Dipole (IOD) to offset this effect.
• Interplay Between El Nino and IOD: The year 2023 saw an intriguing interplay between El Nino and the IOD. While El Nino tends to suppress rainfall, especially during the latter phase, the IOD acted in an offsetting manner, compensating for rainfall deficiencies. This dynamic influenced the monsoon's behavior
• Monthly Rainfall Patterns: June 2023 brought 91% of LPA rainfall for the entire country, while July witnessed heavy rainfall, totaling 113% of LPA. This not only made up for deficiencies but also resulted in excess rainfall by the end of the month. In contrast, August turned out to be the driest month in 122 years.
• Monsoon Conclusion: The monsoon season officially concluded on September 30, with September receiving 113% of LPA rainfall. The cumulative rainfall for the monsoon season in 2023 amounted to 82 cm, equivalent to 94.4% of the LPA, categorizing it as a normal monsoon. This marked the 13th consecutive year of normal monsoon rainfall.
• IMD's Forecast Accuracy: The IMD's forecasts regarding monsoon onset, El Nino, IOD, and overall rainfall in 2023 were notably accurate. With the exception of 2015, this marked the 17th time since 2005 that the IMD's forecast for the monsoon's onset over Kerala was proven correct.
• Monsoon Withdrawal: The withdrawal of the Southwest monsoon in 2023 commenced on September 25, with an 8-day delay compared to the typical schedule. Factors influencing monsoon withdrawal included the cessation of rainfall activity, anticyclone formation, and significant moisture reduction after September 1.

Cooperation for Climate Change Mitigation:

• Cooperation is essential among Indian Ocean Region (IOR) countries to address the challenges posed by climate change. India's SAGAR vision (Security And Growth for All in the Region) emphasizes cooperation in atmospheric, oceanic, seismic, and hydrological sciences. Joint scientific studies and collaborations align with the principles of SAGAR, fostering trust and easing geopolitical tensions in the region.
• Regional organizations like BIMSTEC (Bay of Bengal Initiative for Multi-Sectoral Technical and Economic Cooperation) and IORA (Indian Ocean Rim Association) provide platforms for cooperation in atmospheric and oceanic studies. These organizations comprise countries vulnerable to climate change impacts and have a shared interest in addressing these challenges.

The Blue Economy and Sustainable Development:

• The Blue Economy is not only an economic opportunity but also a means to reduce climate change risks.
• IORA's Blue Economy Declaration and the establishment of the Indian Ocean Blue Carbon Hub in Australia highlight the potential for sustainable development and climate change mitigation in the Indian Ocean Region. Cooperation in these initiatives can contribute to peace and stability in the region.

Conclusion:

The Indian Ocean is of paramount importance for the well-being of millions of people in the region. However, it faces significant challenges due to climate change. The concept of the Blue Economy offers a pathway to address these challenges by harnessing the ocean's economic potential. Regional cooperation through organizations like BIMSTEC and IORA is crucial for addressing climate change and promoting sustainable development. By working together, countries in the Indian Ocean Region can build a future that is economically prosperous and environmentally resilient.

Source- Down to Earth