Ocean salinity refers to the total amount of salt dissolved in seawater. It is calculated as the amount of grams of salt per kilogram of seawater and also denoted as parts per thousand (ppt). The normal range of ocean salinity ranges between 33-37 grams per liter (33‰-370‰).

Factors determining ocean salinity:

• Evaporation: The rate of evaporation and salinity are positively related. Higher the evaporation rate, higher the salinity. With high temperatures and low humidity, more evaporation takes place and salt concentration increases thus increasing total salinity.
• Precipitation: It is inversely proportional to salinity i.e., higher precipitation results in lower salinity and vice versa.
• The influx of river water: Rivers bring in fresh water to the ocean and reduce the salt concentration of the sea by diluting it in the influx region.
• Atmospheric pressure and wind direction: Anticyclonic conditions generally raise the salinity of oceanic surface water when it has stable air and a higher temperature as it leads to less rainfall and high evaporation. Similarly wind and currents provide assistance in the redistribution of oceanic salinity.
• Global warming: It may affect factors such as temperature, ice melting, and other factors that directly and indirectly impact the salinity of seawater.

The spatial distribution of salinity includes both vertical and horizontal distribution.

• Vertical distribution: As depicted in the figure, salinity varies with depth depending on the latitude and there is a distinct zone called the halocline, where salinity changes sharply. For e.g., salinity increases with increasing depth in high latitudes i.e. there is positive relationship between the amount of salinity and depth because of denser water below.
• Horizontal distribution: The basic principle of salinity distribution is that it decreases from the equator to the poles. However, the highest salinity is not found on the equator due to high rainfall, but in the tropical regions (20 – 40 degrees North) owing to high temperatures and humidity and less precipitation. Salinity decreases towards polar zones due to the influx of melting ice water.

• Regional distribution of salinity: The salinity for normal open ocean ranges between 33 ppt and 37 ppt. In the land-locked Red Sea, it is as high as 41 ppt, while in the estuaries and the Arctic, the salinity fluctuates from 0-35 ppt, seasonally. In hot and dry regions, where evaporation is high, the salinity sometimes reaches 70 ppt. For instance, the Mediterranean Sea records higher salinity due to high evaporation.

Similarly, salinity variation in the Pacific Ocean is mainly due to its shape and larger areal extent. It decreases from 35 ppt-31 ppt on the western parts of the northern hemisphere because of the influx of melted water from the Arctic region. In the same way, after 15°-20° south, it decreases to 33 ppt. The average salinity of the Indian Ocean is 35 ppt. The low salinity trend is observed in the Bay of Bengal due to a large influx of river water. On the contrary, the Arabian Sea shows higher salinity due to high evaporation and low influx of fresh water.

As per UNICEF, India is among the world’s most disaster-prone countries with both its States and Union Territories exposed to recurrent natural hazards. Thus, the role of local bodies like Panchayati Raj Institutions (PRIs) becomes imperative in disaster management as they being nearer to the people and more familiar with the local requirements, are in a better position to undertake relief tasks. Further, with both, they can help effectively in spreading awareness and ensure people’s participation in fighting the crisis.

Challenges faced by PRIs in tackling disasters

• Lack of clarity regarding roles and responsibilities of PRIs in disaster management. For instance, even with respect to the National Disaster Management Act 2005, the powers and responsibilities of panchayats are inadequately defined and left to be determined by respective State governments.
• The low level of devolution of powers and functions by the States leads to a lack of a system, resources, and capacity to act independently by PRIs, especially in the field of disaster management.
• The Panchayats are not given enough funds and are often bypassed by State-controlled line departments.
• Lack of training of elected representatives and official functionaries regarding mechanisms and strategies of Disaster Management.

Considering the important role that local communities can play in reducing vulnerabilities and early recovery, the Ministry of Panchayati Raj has prepared the Disaster Management Plan so that all Panchayati Raj Institutions along with communities can be prepared for any disaster. It can address the above challenges faced by PRIs in the following way:

• Institutional arrangement: It calls for constituting a village committee on Disaster Management in each village and a working group on disaster management in each Panchayat for planning, implementation and monitoring of the plan.
• Mainstreaming of Community-Based DMP of Villages and Panchayats: Every Indian village would have a Village Disaster Management Plan. These plans would be the basis for preparation. of respective Gram Panchayat Development Plan (GPDP) and subsequently the formulation of Block Development Plan (BDP) and District Development Plan (DDP).
• Hazard Risk, Vulnerability, and Capacity Analysis: It involves vulnerability mapping, and zoning for natural disasters such as cyclones, floods, drought, earthquakes, tsunamis, etc. for respective Panchayats.
• Socially Inclusive Disaster Risk Reduction in Rural Areas: The plan calls for incorporating socially inclusive disaster risk needs of Vulnerable Groups like Sexual Minorities, Scheduled Castes and Scheduled Tribes, Children, and Specially Abled Persons in each Panchayat.
• Capacity Building Framework: The plan envisages competence-based training for two members of every village committee on disaster management, members of the working group on disaster management for each Panchayat, etc.
• Coordination, Convergence, and Collective Action: The plan advocates functional coordination with multiple agencies, convergence with structure and system of disaster management.

• • Implementation of the plan will be in convergence mode with the ongoing scheme of Rashtriya Gram Swaraj Abhiyan (RGSA), schemes of Central Government and State Governments and Disaster Management Authorities (DMAs), and Grants on the basis of the recommendation of the Fifteenth Finance Commission.

The Disaster Management Plan of the Ministry of Panchayati Raj aims to build disaster resilience at the grassroots level among the Panchayats and establish a framework to align the disaster management measures in rural areas to that of the National Disaster Management Authority.