By Iqra Nayab and Rahat Karim
Pakistan potentially faces a major climate change challenge. A concerted effort by the government and civil society at all levels is required to mitigate these threats. In the last 50 years, the annual mean temperature in Pakistan has increased by roughly 0.5°C. The number of heat wave days per year has increased nearly fivefold in the last 30 years. Annual precipitation has historically shown high variability but has slightly increased in the last 50 years. Sea level along the Karachi coast has risen approximately 10 centimeters in the last century.
By the end of this century, the annual mean temperature in Pakistan is expected to rise by 3°C to 5°C for a central global emissions scenario, while higher global emissions may yield a rise of 4°C to 6°C. Average annual rainfall is not expected to have a significant long-term trend, but is expected to exhibit large inter-annual variability. Sea level is expected to rise by a further 60 centimeters by the end of the century and will most likely affect the low-lying coastal areas south of Karachi toward Keti Bander and the Indus River delta.
These current climatic trends and future projections for Pakistan and reviews its impacts on different sectors such as agriculture, energy, water, transport and other urban infrastructure services, coastal areas, and health.
This shows that winter is shorter at both ends, hence, summer is now longer. A larger increase in nighttime temperatures than daytime temperatures is noticeable, indicating their adverse impacts on animal and agricultural productivity caused by heat stress, increased water requirements, and higher rates of respiration. In the last decade, a mixed trend in maximum temperatures has been observed during summer. However, the minimum temperature in summer in central parts of
Pakistan shows a pronounced warming trend, while in the extreme north and south, a slight cooling trend in some climatic zones. These climatic changes are highly affecting or agricultural sector that contributes 21% to the GDP. Crops grown in both irrigated areas and those under spate farming systems are highly sensitive to the amount of water available and temperature variability. It is estimated that with rise of temperature (+0.50C–20C), agricultural productivity will decrease by around 8%–10% by 2040.
The water sector is one of the most sensitive sectors to the impacts of climate change. Pakistan has the world’s largest contiguous Indus Basin Irrigation System that is largely dependent on precipitation, glaciers and snow melt, and ground water abstraction. The primary sources of water are rainfall during the monsoon season (50 million acre feet [MAF]), and river inflows (142 MAF) in the IRS. Ground water contributes around 48% of surface water available at the canal head of the irrigation system. Water is currently used in agriculture (92%), industries (3%), and domestic and infrastructure (5%). It is expected that in the future, sector water demand will increase due to socioeconomic development and the increase in population.
Forests are an important natural resource specifically in the context of rural livelihood. It provides timber, fuel wood, food, habitat for wildlife, and various important ecosystem services, such as mitigating carbon dioxide, and controlling or reducing cyclones and storms in coastal areas. Forest area in Pakistan is 4.19 Mha, representing 5% of the total land area. Coastal mangrove forests extend over 132,000 ha, representing about 3% of the forest area of Pakistan.
The Indus Delta alone supports 97% of the total mangrove forests and is home to over one million people, 135,000 of which depend on mangroves for their livelihood. It is predicted that most of the anticipated impacts of climate change, such as SLR, change in temperature and precipitation, and increasing frequency and intensity of extreme events, will affect the forest severely, threatening the biodiversity status, and soil quality.
The energy sector is the major contributor to climate change through its high GHG emissions and is also sensitive to its impacts. It is predicted that rising population, economic growth, and changing patterns of consumption including rising demand for air conditioning in the summer months will likely increase energy demand and consequently increase GHG emissions from the energy sector in Pakistan.