Social Implications of Climate Change for
Coastal Areas of Pakistan
Paper Presented at
Euro-Asian Research and Training in
Climate Change Management
2007
Dr. Mirza Arshad Ali Beg
Former Director General PCSIR
136-C Rafahe Aam Housing Society, Malir Halt, Karachi-75210
e-mail:
Introduction
Social implications consequent upon the catalytic role of extremes in climate changes can be traced back to ancient civilizations and the downfall of dynasties: the Tang dynasty in China and Maya of South America is attributed to them(Catherine Brahic, Collapse of civilisations linked to monsoon changes 04 January 2007, NewScientist.com news service). Gerald Haug of the GeoForschungsZentrum in Germany and colleagues, while studying geological records of monsoons over the past 16,000 years(Gerald Haug, GeoForschungsZentrum) have found a startling correlation between climate extremes and the fall of these civilizations. The records show that around the time that these civilizations went into decline, they experienced stronger than average winds in the winter and weaker summer monsoon rains. These weak rains would have reduced crop yields. The Maya civilisation and Tang dynasty were contemporary and there is a striking similarity between the Chinese and Latin American climate data. These include a general shift towards a drier climate around AD 750 and three very dry periods between then and AD 910, the last of which coincides with both the Maya and the Tang collapse.
Despite correlations of the above kind, climate has been considered as one of the many unpredictable and complicated elements of the environment upon which human societies depend for their survival. It is because of its sensitivity and complexity that it is difficult to determine the factors governing the climatic fluctuations and the degree to which they affect the society. There is for example considerable controversy concerning the Bengal Famine of 1942, and the Sahelian famine of the late 1960s and early 1970s. There are evidences that both events were the direct result of climatic variation, but there are equally strong evidences to support that the underdeveloped economic infrastructure of the countries affected, external interference in affairs of those countries, or inflexible techniques of animal and crop husbandry, were the root cause.
Climatic variations whether local or global have the most serious social implications on the environment of coastal areas, mainly because their unpredictable nature is further complicated by their interfacing with all major components of the environment viz. land, sea, water, air and sunshine or electromagnetic radiation. They are therefore exposed to all major hazards emanating from the land, sea, air and space. They are particularly vulnerable to storm impacts, flooding, wind damage and erosion. Of recent they have become more vulnerable due to man made interventions that are seemingly cause for change in natural cycles and erratic variation in climate.
Climate changes on seacoast are both unpredictable and erratic. Accordingly coastal communities who opt to live on the seacoast develop their own system to protect themselves from marine-related hazards and to keep themselves in preparedness for disasters. This is why Netherlands has had to go for construction of dykes along the coast. This mitigation measure was considered essential to minimize the losses that were being inflicted on the living environment along the coast. Coastal populations are impacted by a variety of natural hazards, including erosion, saltwater intrusion, subsidence, and floods due to both storm surges and swollen rivers, besides tsunamis.
The severity of the impacts of these natural hazards can be modified by:
- Local factors, for example, the exposition of the coast to the sea, the presence or absence of natural protection (sand barrier, coral reefs, dunes, vegetation), among others, and
- Man made interventions.
Man made modifications have, however, made extensive amendments in the local factors by either removing the protection systems or altering them to suit to specific requirement irrespective of the damages done to the ecosystem. Such modifications have altered several ecosystems and increased the vulnerability of coastal communities, infrastructure and ecosystems to cope with the onslaught of the impending disaster. Their vulnerability seems at the threshold since the frequency of disaster events is on an increase and floods, storms and destructive waves are taking larger share of economic, social and environmental losses.
The increase in frequency of marine-related hazards is being taken as an indicator of climatic change leading to alteration in heat balance, melting of glaciers, sea level rise, progressive inundation of low-lying coastal areas and enhanced erosion of unprotected erodible coastlines. Losses resulting from exposure to hazards, and to development along coastal margins and the impacts that result during hazards and generate hazardous conditions that affect coastal ecosystems, are expected to increase due to impoverished environment, poverty, promotion of development projects with little regard for adverse environmental impact, and the effects of global climate change.
Climate Change
Definition
Weather is the combination of natural phenomena as temperature, precipitation, light intensity and duration, wind direction and velocity and relative humidity. In any given location these weather factors assume a certain pattern changing from day to day, week to week, month to month and season to season and the same pattern repeats from year to year. The pattern of change is the climate of the location.
The United Nations Framework Convention on Climate Change (UNFCCC), in order to make a distinction between Climate Change attributable to human activities altering the atmospheric composition, and Climate variability attributable to natural causes, defines climate change in its Article 1, as: a change of climate, which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods. Predicting and managing the likely impact of Climate Change on the ecosystem of the earth is a real challenge, but considering the recurrence of environmental catastrophes with increasing frequency, it is timely to analyse these problems as well as their social implications.
Working Group II of the IPCC suggests that policy makers need to contemplate immediate actions. First, because anticipated Climate Changes should not be wait for to happen before taking actions, since by that time it might be too late to amend, and second, because appropriate management responses consist in a no-regret-policy since efforts to reduce the vulnerability and increase the resilience of sites to existing non-climatic pressures and threats would also reduce their vulnerability to Climate Change related stresses. It has, however, been accepted by the IPCC that the impact of Climate Change is projected to have different effects within and between countries. The challenge of addressing Climate Change raises an important issue of equity.
The Intergovernmental Panel on Climate Change (IPCC) has, in its Third Assessment Report stated “The Earth’s climate system has demonstrably changed on both global and regional scales since the pre-industrial era, with some of these changes attributable to human activities”. To limit the amplitude of Climate Change, mitigation (reducing the emission and enhancing the sinks of greenhouse gases) is needed, and “adaptation is a necessary strategy at all scales to complement Climate Change mitigation efforts”.
Situation Analysis
The impact of Climate Change having different consequences within and between countries has indeed been noticed in the context of diversity in the ecosystems of Pakistan (Mirza Arshad Ali Beg, Comments on Pakistan National Communication on Implementation of UNFCCC, May 2001). The situation current in 2001 indicated that Pakistan is faced with extremes of climate variations resulting from natural as well as man made modifications. The aftermath of Cyclone 02A, which landed on the low lying coastal area of Badin in May 1999 and the floods in the same area in 2003, were a preview of the impending disaster due to climate change.
Climates dominated by monsoons experience the most pronounced seasonal wind shifts. In South Asia, the rainy season, typically beginning in June, is preceded by nearly two months of scorching temperatures, cooled only with the commencement of the summer rains brought by the southwesterlies. January is the peak of the dry season, which is marked by cool, dry northeasterly flow over most of the region.
The monsoon climates are especially vulnerable to disruptions in global weather, which have, in any given year led to drought, flooding, or both. The over 150 years of data and assessment of driving forces behind the southwest monsoon circulation has resulted in a better understanding of weather extremes experienced throughout the tropics, and their subsequent impact on ecological balance governing aquatic ecology. These data conclusively indicate that no other region outside the monsoon belt is as much vulnerable to the extremes of wetness and dryness as the tropical monsoon belt.
Changes in Ecological Balance & Water Resource Depletion
Man made interventions have caused water scarcity in the region that includes Pakistan. The scarcity is likely to continue for the next few decades, mainly because of inadequate management of the precious resource. This has created a mismatch between availability from surface run off and extensive water use. Withdrawal from all sources viz. rivers, lakes, and reservoirs, and mining of underground aquifers at an unprecedented rate had increased not only in Pakistan but also in Asia, in general, by almost 300% between 1950 and 1995, and may have increased further if the availability was not a constraint.
A mismatch between availability of water and its extensive use that has increased by almost 250% during the last 50 years in Pakistan, has resulted in withdrawal from all sources viz. rivers, canals, wells, tubewells, karezes and springs(Economic Survey 1999-2000, Government of Pakistan, Finance Division, Economic Advisor’s Wing, Islamabad). This type of modification in the ecosystem has increased aridity in the region and has instigated losses of habitat, vegetative cover, biomass and biodiversity(The Pakistan National Conservation Strategy, Environment & Urban Affairs Division, GoP, and IUCN). Construction of large dams, diversion of river flow into an intricate irrigation system and over harvesting of groundwater resources constitutes the greatest intervention of ecosystem of the region, and a large interference in the water cycle by increasing the losses due to evaporation and seepages and the consequent increased availability of water vapour, a greenhouse gas in the air.
The process of augmented withdrawal during the decade after 1995 proceeded to the extent that Pakistan is relegated to water stressed country from the status of water surplus country. It is estimated that almost 10% of the agricultural food production is now dependent on mined groundwater. Water tables that were falling at a rate of a metre a year have been going down at a much rapid rate. In the Quetta valley, for example it has fallen by 30 metre during the last 20 years. A similar situation is being faced in China, India, Mexico and Yemen, the other countries falling in the same belt.
Loss of storage in the aquifers and their mining already indicates that availability of water in Pakistan has decreased and is less likely to be reversed since recharging of the aquifer takes several hundred years, if left to the natural process of surface water infiltration. Fluctuations in water table are vulnerable to weather changes e.g. changes in temperature, humidity and rainfall, besides soil permeability. These changes affect the rate of evaporation and evapotranspiration and also the sub-soil flow. Aridity causes increased evaporation, which in certain cases is in excess of 3 cusecs per squaremile in certain worse areas. Evaporation from soil surface is related to the depth of groundwater. It is very high, ranging up to 50% of thesurface water evaporation for a groundwater depth of 2 to 3 ft; 33 to 55% for a depth of 5 ft and 20% for a depth of 10 ft.
Social Implication of Excessive Extraction of Water
In 1951, when population stood at 34 million, per capita availability of water was 5300 cubic meter, which has now decreased to 1105 cubic meter, just touching water scarcity level of 1000 cubic meter. With a present growth in population and the low rainfall, the threshold limit of water scarcity i.e. 1000 m3 of water per capita per year may be reached as early as the year 2010. The estimates show that the current water shortage of 9 million acre feet would aggravate to 25 MAF if all planned dams under Vision 2025 are not constructed by 2016(Economic Survey of Pakistan 2005-06).
Increasing the water use by over 300% is the greatest man made intervention of ecosystem aimed at achieving a fast rate of economic growth. Ecosystem of concerned regions of the earth has been modified by different practices for use of surface and ground water for irrigation and for domestic use. Construction of large dams with a height of over 15 metre at a rate of 300 every year has caused the largest intervention in the water cycle by having over 40,000 dams constructed all over the world. An adverse effect noticed from the operation of large dams led to the construction of small dams and hundreds of thousands of ponds. Dams and ponds increased the losses due to evaporation and seepages and the consequent increased availability of water vapour in the air. They have caused depletion of groundwater resources and reduction in the flow of freshwater into the estuarine areas besides losing the advantages that were naturally available from the ecosystem e.g. firewood, livestock, poultry, fish, cow dung, biomass, mangrove forest cover and biodiversity.
Construction of embankments to protect land from flooding constitutes another set of interventions that has caused an irreversible damage to the ecosystem of the riverine, estuarine and coastal areas in Pakistan. The embankments have removed the floodplains and the aquifer is not being recharged with the same frequency and intensity as in the past and thus the ecology has changed abruptly, adversely and irreversibly. They have, besides depriving the delta area of its traditional rice crop in the kharif season and oilseeds and millet in the rabi season, induced salinization of groundwater by seawater intrusion through intensive harvesting of groundwater.
Reduced availability of water due to this man made intervention has led to the rice grown in the coastal belt just off the coastal area near Keti Bunder and Shah Bunder, being almost abandoned, while rendering the mangrove forests under stress.
The annual rainfall as well as seepage due to floods, which were the constituents of the ecological processes that balance the inflow and outflow of water, have been disturbed by extensive withdrawal and diversion into canals which leaves only about 24.6 billion cubic metre (bcm) for Lower Sindh. The groundwater resources are not being replenished to help in building up the reservoirs of the areas adjacent to rivers and in filling up their sub-soil, or the deep zones of groundwater.
The recharge in the delta area is restricted to area within the embankment system, whose construction was aimed at providing protection against flooding. This constitutes another set of interventions that has caused an irreversible damage to the ecosystem of the riverine and delta areas. The embankments have removed the floodplains and the aquifer there is not being recharged with the same frequency and intensity as in the 1950s. The ecology of floodplains and delta area changed after the mid-1960s, and its adverse and irreversible impacts have, besides depriving the delta area of its traditional rice crop, induced seawater intrusion through intensive harvesting of groundwater(Mirza Arshad Ali Beg, Ecological Imbalances in the coastal areas of Pakistan and Karachi harbour, Pakistan Journal of Marine Sciences, 4(2), 159-74, 1995), (H.T. Sorley (1964) The Gazetteer of West Pakistan: The Former Province of Sind, Government of West Pakistan, Lahore, pp-11,).
Water Budget Management
Components of Water Budget: Pakistan receives its 180bcm or 145 MAF of surface flow from (i) Snow and glacier melt and (ii) Monsoon system, as the main constituents of its water budget. Themelting of perennial snow cover and glaciers in the Lesser Himalayas, which are the south oriented outer ranges of the Himalayas in the northern part of Indus Basin, starts when the sun moves northward after March each year and is a major source of the river flow. The Kailasrange holds the key to the supply of watertotwo mainriver systems viz. the Indus that drains its water to the west and southwest, and the Brahamaputra, which flows east and then via Assam to the Bay of Bengal. It is interesting that both the rivers rise from Lake Mansarowar.
Glaciers
The melt-water of glaciers of Pakistan is the principal source of supply to the rivers, which feed the irrigation system. Siachin alone is estimated to contain 100 million acre feet (100 MAF) of water, which is little less than the total annual irrigation diversion in the Indus Plain. The glacial and snowmelt in the upper Indus catchment area are the source of 80% flow during the summer. There is only minor variation in the timing and volume of annual flow of snowmelt. 95 bcm or 84% of the total mean flow measured for the Indus at Kalabagh takes place between April and September, which is the kharif season.