IN September 2012, the federal climate change ministry developed the National Climate Change Policy. The goal of the policy was to mainstream climate change in various sectors. However, the policy has mostly remained dormant.
In November 2013, the federal climate change division produced a framework document for the implementation of climate change policy. The document proposed actions across a range of sectors, which were mainly directed towards conservation. For example, the document proposed installation of water meters to check the indiscriminate use of drinking water supplies. A Climate Change Commission has been recently formed for the implementation of the climate change policy, and the framework document.
The Fifth Assessment Report of the UN Intergovernmental Panel on Climate Change (IPCC) concludes that the warming of the climate system is definite, and extreme weather events associated with climate change pose particular challenges to human settlements.
Climate change predictions for South Asia include increased temperatures, rainfall and flooding, droughts and increased intensity of extreme weather events. Extreme weather events (heatwaves and floods) have already occurred in Sindh. An extreme heatwave occurred in Karachi, Hyderabad and Sukkur in June this year, killing 1,200 people in Karachi and 200 in other cities of Sindh. Another heatwave occurred in Karachi and other parts of Sindh for four days in September.
Cities in Sindh are changing due to the impact of climate change. Urban infrastructure and quality of life are facing significant threats. Karachi’s water supply is dependent on the Indus River, which is far away from the city. Increased temperatures are expected to decrease the per capita availability of water. Hyderabad and Sukkur also depend on the Indus for their water supply. Water shortages have already occurred in these cities.
Higher temperatures will decrease the dissolved oxygen levels in the river. The bacterial respiration rates will rise with increasing temperature, enhancing the biochemical oxygen demand of the river. Taste and odour problems are also associated with high temperatures. High temperatures mobilise heavy metals from the bottom sediments. Use of chlorine in water treatment plants will also increase because chlorine decays relatively quickly in warm water. Simply stated, increased temperatures will degrade the water quality of the Indus.
Heavy rainfall worsens stream water quality by increasing organic load, turbidity, microbial population and inflow of agrochemicals. Arsenic and fluorides are likely to be mobilised in case of heavy rainfall. Salinity intrusion is expected in wells located in coastal areas in extreme weather events, disrupting water quality.
Water treatment plants treating raw water containing high organic load run the risk of the formation of trihalomethanes, when humic substances react with chlorine. Flooding of water treatment plants occurs during increased rainfall. The entire urban water supply system will be impacted due to climate change in Sindh’s cities.
There are various scenarios for sea-level rise, ranging from just over half a metre rise predicted by IPCC, to two metres by independent US researchers by 2100. A two-metre sea-level rise in Karachi would submerge many parts of the city. Karachi is also vulnerable to cyclones and storm surges, which can disrupt the city’s municipal services.
Frequent rainfall will deteriorate the road surface and steel bridges. High temperatures will affect the aging bitumen of the road surface, causing cracks. Built-up areas in Karachi, Hyderabad and Sukkur, during heatwaves, will magnify the impact of heat due to the ‘heat island effect’, especially in the absence of green infrastructure in the cities. Green infrastructure is defined as a strategically planned network of natural and semi-natural areas.
Urban sanitation facilities are highly sensitive to flooding and storm surges. As they work on gravitational pull, they are often situated at the lowest point. They can, therefore, be easily inundated by rising water levels.
In case of solid waste management operations in Karachi, Hyderabad and Sukkur, increased precipitation will cause inundation of the landfill road network, instability of landfill slopes, and increased leachate from landfills. The state of awareness about climate change in Sindh is practically zero. For example, at a recent public hearing on the Karachi Mass Transit Plan 2030, and opinions expressed in print media, hardly anyone raised the point of impact of climate change on the six bus rapid transit corridors under the mass transit plan.
Robust adaptation plans are required for cities in Sindh, based on vulnerability assessment. Moreover, a proper institutional set-up within the Sindh government is required which can take well-coordinated actions on adaptation plans.
The writer has studied environmental engineering from the Asian Institute of Technology, Bangkok.
Published in Dawn, October 7th , 2015