Climatic changes on hydrological cycles in Pakistan

Climate is the statistics of weather over long periods of time. It is different from weather in the sense that it is measured through variations in a given region over long periods of time.

Climatic changes on hydrological cycles in PakistanMost of these climate changes are because of very small changes Earth’s orbit that change the amount of solar energy our planet receives. But the recent climatic changes including global warming are extremely likely to be the result of human activities.

Since the industrial revolution of 20th Century, human activities like expanding industries, increasing traffic on road without thinking of any check on their effects on our climate, led our earth’s climate to present situation.

Global Warming is the general increase in average temperature of earth which effects the eco systems for long period of time resulting in the climatic changes that can be harmful for all living fauna & flora on this earth.’

With higher levels of carbon dioxide and continuous emissions of other greenhouse gases (nitrous oxide N2O, Methane CH4 and Water Vapors H2O) increased earth’s surface temperature by about 1.62 degrees Fahrenheit (0.9 degrees Celsius). Most of this increased in the last 35 years with 2016 the warmest year on record.

Water has a  tremendous ability of absorbing heat So, Oceans absorbed much of this increase in temperature resulting in an increase of 0.4 degrees Fahrenheit since 1969. At the pace of current CO2 emissions, scientists expect an increase of between 1.5° and 5.3°C (34.7° to 41.5°F) in average temperature by 2100.

Hydrologic cycle or Hydrological cycle, describes the continuous movement of water on, above and below the surface of the Earth.

The water moves continuously from one place to another, rivers leads it to seas and oceans from there it goes to atmosphere through the processes of evaporation, precipitation, condensation, infiltration, surface runoff and subsurface flow. In doing so, the water travels from many forms: solid (ice) and vapor.

As climate change results in the increase in global temperature, it intensifies the water cycle. It means more water evaporates to the atmosphere. Warmer Air can hold more amount of water which results in more intense rainstorms resulting in floods around the rivers.

At the same time, some areas face extreme dry conditions and even drought. Because temperature rises also results in soils getting dry out. Thus when rain comes much of the runs off the hard ground into river and streams and the soils remain dry.

Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century and is accelerating slightly every year.

Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent. This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.

Beside its environmental and societal consequences, the impact of climate change on the hydrologic cycle is frequently accompanied by important economic damages. The estimate of these damages over the last decades is alarming.

The key vulnerability of Pakistan Water Resources to Climate Change is increased variability in river flows due to change in frequency and intensity of extreme Climate events, the glacier retreat, increased Glacier Lake Outburst Floods (GLOFs),

River floods and droughts, depletion of water storage capacity, due to siltation/sedimentation, flash flooding, water-logging and salinity, degradation of environment causing impacts on water quality, shrinking wetlands and increasing demands for water in all the sectors.

Floods are one of the major natural calamities in Pakistan. These are mainly caused by heavy concentrated rainfall over the upper catchments of the main rivers. Pakistan has a unique flood related problem in the sense that the greater part of the flood generating upper catchments of the rivers.

This situation calls for obtaining the river flow data for some specific sites from India. This is provided by an agreement between Pakistan and India through their respective Commissioners for Indus Water which is renewed annually

Pakistan, being the downstream user of the rivers and also embroiled in political conflicts with the upper riparian state India, has to be particularly careful about flood management.

The canal irrigation system in Pakistan was developed more than one hundred years ago. Currently, this irrigation system is recognized as world’s largest integrated irrigation system, called as Indus River System which receives more than 65 % of the fresh water from the world’s largest glaciers reserves in the Karakorum-Hindukush-Himalaya (KHH) ranges.

In Pakistan, the shortage of irrigation water is due to climate change effect coupled with mismanagement, therefore has become burning issue for Pakistan’s agriculture, for increasing population and economy of the country. Similarly, those most impoverished farmers who grow crops for subsistence are unable to cope with this water shortage.

Here are some suggestions to compete advancing water crisis in Pakistan:

  1. First of all The Government of Pakistan should acknowledge water crisis as a major problem. If it’s not even acknowledged at national level, then there is no way we can cope with this challenge.
  2. There was a positive sign in last April when former Prime Minister Shahid Khaqan Abbasi announced Pakistan’s First National Water Policy concentrated on efforts to compete with the water crisis.
  3. The Governing Structure of Pakistan’s Water Sector comprised on multiple authorities with duplicate responsibilities. This structure needs to be streamlined. For this reason the recent efforts to make water policy failed because different institutions look at water issues differently from their own vintage point.
  4. Reforestation is another important step to compete with hazardous effects of climate changes just in line with the efforts of Prime Minister Imran Khan.
  5. Judicious use of water is needs to be encouraged among general public for carrying out daily tasks.
  6. Local and Provincial Governments should stop the unchecked flow of chemical and industrial waste in rivers to reduce the pollution of fresh water reservoirs.
  7. Annual water loses of Pakistan are about 48maf.So,efficient Irrigation systems like Drip and Sprinkler Irrigation systems are need to be promoted to reduce massive water use by Agricultural Sector.
  8. Farmers usually pay very low prices for water so they give it little value. So, the government should consider raising prices to improve the infrastructure of water distribution systems.
  9. New reservoirs should be built and emphasis should be on the small dams rather than indulging in large and complicated projects like Kalabagh Dam which became a Controversial issue.
  10. Coordination between the institutions should be enhanced for the making and implementation of different water projects. For instance, there is hardly any connection between two critical institution, ministries of agricultural and water.

Authors: Dr  Harron  Zaman, Muhammad Atif Shabir, Muhammad Bilal Farooq, Anas Afzal, Asif Iqbal ,Nadeem Akbar

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