Climate study is very important as all life forms survive in this world due to favorable climatic conditions and any change in climate will affect all biological lives around the world by altering forests, crop yields and water supplies. Climate change is the average measure of variation in meteorological variables in a particular region over long period of time (usually 30 years). These variables include temperature, humidity, atmospheric pressure, wind, precipitation, solar radiation, etc.
Agriculture is the main source of feeding for whole world and Pakistan and agricultural crop production has always been dependent on climate and its variables in particular region. The key effects of climate change include changing patterns of crop production, changing patterns of rainfall, changing agricultural zones, increasing average temperatures, changing length of the seasons, floods and droughts. Pakistan has more diverse ecosystem, a varying climate ranging from sub-zero temperatures in the north to above 50°C in the south and it has a large farming sector with a high level of dependence on irrigation.
By 2050 it could lose 50% of its wheat productivity. Recent ranking by International organization Maplecroft of UK has placed Pakistan at 28th amongst those that will be most severely affected. World Bank, climate change experts warned Pakistan of five major risks related to climate change. Those include rise in sea level, glacial retreats, floods, higher average temperature and higher frequency of droughts. Agricultural crops will face different vulnerabilities due to climate change which may include, less crop yield due to heat stress on crops by increased temperatures, crops will face water shortages due to increased evapotranspiration and low rainfall in dry areas, ecosystem will show uncertain rainfall patterns, frequency of extreme climate events like floods, droughts and cyclones will be increased. Therefore, climate change is a reality and a foremost challenge for researchers, academia, planners and policymakers alike. Pakistan ranks 135th in carbon dioxide emissions), methane (hydrocarbon gas), nitrous oxide (produced by soil cultivation practices, fertilizers), chlorofluorocarbons (CFCs), (synthetic compounds of entirely of industrial origin).
Impact of climate change on agricultural crop productivity:
The growing season length of wheat and rice in Pakistan will be reduced as a result of climate change with negative effects on yield. Reduction will be greatest in the semi-arid areas and rice seemed to be more sensitive to climate changes than wheat.
i-Soil erosion: It has been reported by GOP that about 3-5 mha of productive land has lost due to wind erosion in Punjab, Sindh and Baluchistan.
iii- Salinity: It has been reported that 6.14 mha area of Pakistan is affected due to salinity and sodicity, of which 3.9 is in Punjab, 0.6mha in Sindh and 0.2 mha is in Baluchistan.
2-Short Life cycle or Growth period: Rise in temperature forces crop to mature earlier, thus, crops will be unable to realize full production potential.
3-Low crop yield: Climate change will reduce growing season length, leading to heavy loss in yield because crop will be unable to reach its full production-potential. That due to rise in temperature greater than 2.5°C, wheat and rice production in rained areas have reduced by 25%.
4-Water availability: Rivers derive more than 80% of water from glaciers melting at Himalayas due to rise in temperature. According to IPCC reports, Himalayas glaciers melting will increase flooding within next 2-3 decades as seen presently in case of Pakistan facing frequency of flooding.
5- High evapotranspiration rate:
6- Extreme Climatic Events: Increased incidence of extreme climate events like floods, hailstorms, cyclones, droughts, heavy precipitation, and dust storms will increase in future reported by IPCC. These unpredictable climate events will destroy standing food crops in field, will spoil food grains quality by damaging food grains stored in godowns due to roof leakage, and stored peats developing diseases.
Climate change effects in different Areas of Pakistan
Pakistan has different crop productive areas that will be affected by climate change in different ways. All irrigated, rain-fed, mountainous, coastal and deltaic areas of Pakistan are vulnerable to climate extreme events.
1-Irrigated areas: About 80% of the nation’s food and fiber needs are fulfilled through irrigated agriculture in the plains which is the main source of food production.
2-Arid regions: Aridity Index of Pakistan Agricultural Research Council (PARC) reorted that out of total cultivated area of Pakistan of 22.51 million ha (mha), 2.5 mha (10%) are semi-arid, 10.7 mha are arid (48%) and 7.3 mha (32%) are hyper-arid. Province-wise, the dry areas constitute 23% of the cultivated area of Punjab, 54% of Sindh, and 60% of both KPK (Khyber Pakhtun Khawa) and Baluchistan. High temperatures could affect agricultural productivity negatively in these areas by altering growing periods of the crops, shifting of cropping seasons and patterns, increasing crop stresses (thermal and moisture), changing irrigation water requirements and enhancing the risk of pests and diseases.
3-Mountainous areas: Country has low forest cover (4.5 %) with a high rate of deforestation at the rate of 0.2 – 0.4 % per annum. climate change will have long-term far reaching impacts by threatening biodiversity.
In 1949-50, the agriculture sector was contributing 53 percent in the country’s GDP, which dropped to 31 percent during 1980-81, and during 2012-13 it has dropped drastically to only 21.4 percent. Therefore, in order to guarantee food security, Pakistan must adapt strategies for yield reductions from floods, droughts and rising temperatures, while at the same time addressing its contributions to global climate change.
Climate change problem can be managed and involves many dimensions of science, economics, society, politics and moral and ethical questions. It can be responded and managed through two approaches: adaptation and mitigation.
1-Adaptation: Majority of the farmers in Pakistan have land area of 20 hectares (ha) or less, corresponding to 79% of the farmed area. These farmers have lower capacities and resources to adapt to climate change. So, various strategies should be followed to boost economical level of farmers at small scale.
2-Mitigation: Mitigation mainly concerns to avoid dangerous human interference with the climate system, and stabilize greenhouse gas levels in a timeframe sufficient to allow ecosystems to adapt naturally to climate change. It can be achieved through reducing sources (burning of fossil fuels, heat or transport) of these gases or by enhancing sinks (oceans, forests and soil) of these gases.
Dr. Muqarrab Ali1, Muhammad Nazim1, Dr. Omer Farooq2 and Qurat-ul-Ain Sadiq3
1 Department of Agronomy, Muhammad Nawaz Sharif, University of Agriculture Multan, Pakistan
2Department of Agronomy, Bahauddin Zakariya University of Multan, Punjab, Pakistan
3Department of Soil and Enivironmental Sciences, Muhammad Nawaz Shareef,University of Agriculture Multan, Pakistan