There is growing concern regarding the probable impact of climate change on Pakistan’s scarce water resources. Escalating temperatures, melting glaciers, flood outbreak, excessive saline water intrusion in coastal areas, increasing hazard of glaciers outburst and heavy rainfall during monsoon season are some of the visible effects of climate change in the country’s hydrologic resources in the coming decades.
Following climate change effects, there are two interrelated issues that need to be highlighted. First, due to the increasing scale of saline or brackish water, there is increased contamination of ground water with excess sodium level and hence unavailability of soft or sweet water for domestic and agriculture consumption. The second issue relates to the degradation of mangrove forests, which can overcome the first issue, and significantly compounds the problem for the coastal areas of Pakistan.
In the coastal areas of Sindh and Balochistan, especially along the coastal belt of Gwadar and Karachi, ground water is often brackish or saline due to its proximity to the sea. This is likely to create problems for the rapidly growing population in these areas hence making them vulnerable to the unavailability of fresh water. Degradation of the ecosystem and of natural resources such as mangroves forests is adding fuel to such disasters.
Mangroves are used as fuel wood by the coastal communities. According to estimates, each year in Pakistan an equivalent of 650 acres of dense mangrove forests is used as fuel in the coastal areas. About 680 tons of mangrove leaves are collected by the people of local villages each year to feed cattle. The same estimates indicate that approximately 16,000 camels visit the forests for grazing every year. Another damaging factor is urbanisation and building societies around coastal areas, causing rapid deforestation of mangroves.
At one point, (less than three decades ago) mangroves covered 243,000 hectares (ha) of the Sindh (Karachi) coastal area, which has been reduced to 98,014 hectares indicating about three percent loss each year. A satellite study suggested that, despite plantation drives in 2009, 2013 and 2015, there was only a slight level of improvement (only 1.6 percent in eight years).
Scientists consider mangroves a natural agent of converting saline water into fresh water. In the coastal areas of Pakistan most of the underground water is contaminated with sodium or salt. There are no water treatment facilities available for the coastal communities. A few initiatives have recently been started to use sea water for domestic use. Certain conventional methods like reverse osmosis membrane technology are used for desalination of sea water to meet the water demand in several countries like Oman, Saudi Arabia, UAE, Spain, China, India and Japan. Pakistan has also taken this initiative to meet the growing demand for fresh water in the coastal areas (rural and urban) of Pakistan.
However, this technology has certain drawbacks such as high energy consumption, short durability, treatment of membrane fouling and high maintenance cost. In case of Pakistan, the plant may use solar energy to operate the desalination plants. However, the construction, establishment and operational costs of these plants will run in billions of rupees. On average, a typical large-scale solar desalination plant costs approximately $700 million to build; it can provide 1000 million litres per day with an additional running cost of $0.40 per 1000 litres per day. These estimates do not include land, labour, water pipelines, transport, maintenance and depreciation cost. Such projects are only feasible if the overall economy of a country is doing well. An efficient use of resources is the need of hour, when we keep Pakistan’s financial situation in mind. Nature itself is an efficient and effective way to overcome the problem of saline water.
Worldwide, mangroves are known for their treasured ecosystems and biodiversity. They have a natural ability to filter sodium from contaminated ground water. Mangrove trees excrete salt through their leaves, roots and branches, which enables them to survive within the saline marshlands, while other plants cannot survive in such conditions. For instance, research indicates that the root system of mangroves makes them so effective to filter out salt from saline water that any individual can directly drink fresh water from the root by cutting it. Mangrove species do not require salty water for survival; they have a significant advantage over other plants that do not bear salt. They may also absorb excess nitrates and phosphates, hence averting contamination of water in the area. These plants play a vital role in the conservation of sea life and filtration of the ground water system. In short, they are resilient to climate change and hence can help control other climate issues like reducing the damage caused by floods and controlling carbon emission by about 18 percent more than other plants.
The water filtering process of mangroves has been a hot topic among scientists. According to a recent research study, titled ‘Novel Water Filtration of Saline Water in Outermost layer of Mangrove Roots’, mangrove roots can ratify an innovative ability for long-lasting desalination of saline water with high salt rejection rate. That brings us to the biotechnology system by which it can convert sea water into fresh water for domestic and agriculture use. Conventional methods may solve water scarcity in less time – but at an immense cost. There is a serious need for sustainable, low-cost and natural ways of undertaking the process; and this is possible.
The economic aspect of mangroves is also essential and worth considering because about 80 percent of the fish caught in the coastal area get their food from the mangroves ecosystem. Pakistan’s fisheries account for a large percent of the foreign exchange reserves. Concerns regarding conservation of mangroves should be a priority of our country because future threats to water availability and ecosystem are an imminent challenge that needs to be dealt with through proper planning and implementation.
A recent plantation drive of mangroves by the Pakistan Navy – the Mangroves Plantation Campaign 2018 – targeting Sindh and Balochistan coastal areas with an estimated two million mangroves plantation, is one example of supporting the cause. Such incentives and awareness regarding the significance of mangroves among the local communities should be taken up by the government. The people must be made aware of this so as to safeguard the future existence of mangrove forests in Pakistan.
The writer works at the Ministry of Planning Development & Reforms (Planning Commission) Pakistan.
