Climate change: stress on agriculture
By F. H. Mughal
The agriculture will face many challenges over the coming decades. Degrading soils and water resources will place enormous strains on food security for a growing population.
These conditions may be worsened by climate change. The impact on crop yields and productivity will vary considerably. Added heat stress, shifting monsoons, and dried soils may reduce yields.
Some crops may be damaged by higher temperatures, particularly if combined with water shortages. Certain weeds may expand their range into higher-latitude habitats. There is also some evidence that the expansion of insects and plant diseases towards poles will add to the risk of crop losses.
The croplands, pastures and forests that occupy 60 per cent of the earth’s surface are progressively being exposed to threats from increased climatic variability and, in the longer run, to climate change. Abnormal changes in air temperature and rainfall and resulting increases in frequency and intensity of drought and flood events have long-term implications for agriculture. Chronic food problems already exist. Climate change presents yet another significant challenge to be met. While overall food production may not be threatened, those least able to cope will likely bear additional adverse impacts.
Thermal expansion of seawater and an influx of freshwater from melting glaciers will raise sea levels. In Karachi, coastal zones are already vulnerable, as aspects of climate change were not considered during planning stage. Coastal areas have been changed in recent years, and thus, have been made even more vulnerable to higher sea levels. Salt-water intrusion will reduce the quality and quantity of freshwater supplies. Higher sea levels could also cause extreme events such as high tides, storm surges, and seismic sea waves (tsunami).
Climate change will lead to more precipitation and to more evaporation. Precipitation will probably increase in some areas and decline in others. Changing precipitation patterns will affect the extent to which water can be captured.
Downpours will, in general, become more intense. This would increase runoff and floods while reducing the ability of water to infiltrate the soil.
Since, in Pakistan, glacier melting will be one of the major climate change-related problems, the resiliency increase programme for poor vulnerable communities should focus on, and address issues like, raising awareness of climate change and its likely local impacts on communities; developing coping strategies; capturing local knowledge on climate variability; strengthening local livelihoods by ensuring its adaptability to climate change through more diversified income sources and changed agriculture practices; building local capacity to develop community-based plans for climate change preparedness; and empowering poor vulnerable communities to ensure that their needs are incorporated in provincial and national development plans.
The rising sea level will be a Karachi-specific problem. The city government, in addition to the adaptability plans, should also concentrate on mitigation aspects, by reducing emissions from motor vehicles, which contribute to climate change (carbon dioxide, nitrous oxide, methane).
Since, contributory factors for climate change and for air pollution are the same, efforts should build upon capacity to cost-effectively manage greenhouse gas and air pollutant emissions concurrently. This is often referred to as “co-control.” Air quality principles can be used by EPA (Environmental Protection Agency) to understand co-control opportunities in and synergies between climate change, energy and air quality management policies.
GHG emissions are often emitted concurrently with other air pollutants that have direct health impacts. The fact that fossil fuel combustion leads to emissions of both carbon dioxide and criteria air pollutants creates a logical connection between policies that manage GHG emissions and policies that manage air quality. Since air quality directly affects public health, it is not difficult to demonstrate the public health benefits of certain GHG reduction measures and policies.
In Pakistan, programmes and policies that address energy and climate change are often managed separately from air pollution control policies. This will make it difficult for the government to adopt an integrated or multi-pollutant approach to managing emissions.
As an example, the lead agency for implementing the energy intensity goal is Wapda and the lead agency for implementing emission control policy is (in case of Sindh), the EPA, Sindh. While the government looks at these as two unrelated policies, Pakistan’s heavy reliance on fossil energy creates powerful linkages and potential synergies between energy intensity and air emissions. Both policies clearly have implications for GHG emissions.