The temporary weather conditions can continue for shorter period of time, but when these weather fluctuations persist for longer time period (about 30 or more years), we call them climate change.
Our daily weather has many variations in itself. Many times, these variations feel familiar but weather conditions never repeat exactly. We also observe that changing in seasons and kinds of changing weathers are linked with each other.
These seasonal weather changes can observe at any given location. Because these weather changes are due to rotation of earth around sun. We can expect them, plan them and have preparations for them in advance. Due to change in seasonal cycle farmers plan the sowing and harvesting of crops according to weather.
In comparison with short term seasonal weather changes, long term weather conditions are modest. It is because their effects can persist decades or throughout human life span. Moreover, these variations can prove critical and destructive if we do not have expectations or preparations for them.
These temporary weather conditions can continue for shorter period of time, but when these weather fluctuations persist for longer time period (about 30 or more years), then we call this phenomenon climate change.
From the last few decades, it is globally acknowledged that Earth’s climate is changing. From the era of industrial revolution to the present years, the average temperature of Earth’s air surface increases about 0.8◦C.
According to the studies conducted by Intergovernmental Panel on Climate Change (IPCC) in 2014, from the past few decades the hottest decade was 2000s and the warmest year in that decade was 2014.
According to 2009 findings, agriculture sector directly contribute to 14% of GHG emission globally, in correspondence with CO2, and indirectly make additional contributions of 17% of emission by other factors like change in land use and alteration for crop management.
Amounts of greenhouse gases (GHGs) i.e. carbon dioxide (CO2), methane (CH4), nitrogen oxides (NOx), and sulphur oxides (SOx) are touching the extraordinary levels from the past 800,000 years. Increase in the amounts of these GHGs can cause warming of globe, which influence the overall world climate, thus we call it climate change.
The environmental scientists categorize the causes of climatic changes in to two categories; natural and anthropogenic.
From the evidences collected from last 150 years, it is estimated that main portion of global warming (0.1◦C decade‾1) came from anthropogenic or man-made activities like fossil fuels burning and land use changes etc.
Climate change has a huge impact on agriculture sector by altering the amounts of rainfall, temperature, CO2 fertilization, climatic variations and runoff of surface water. According to various studies, there are sufficient evidences of climate change which are negatively impacting the sector of agriculture and framers of less developing and under developing countries.
Climate change effect on cereal crops in Pakistan
Several studies reveal that, most important and major cereal crops like wheat, rice and maize are very sensitive to rise in temperature even in minute amounts and negatively affected by these temperature changes.
In Sindh Pakistan, during the years 2014-15 wheat yield was about 3,747 kg hectare-1 which was almost 32.26 % higher than average national yield. Although Pakistan is producing more wheat yield every year but due to unusual climatic conditions like pre-monsoon rainfalls, floods, low or no rainfall at the time of crop need, wheat production is still very low as compare to the production in developed countries.
Pakistan is among least wheat producer country throughout the world with 23 mounds Acre-1 as compare to Netherland where this amount is 91 mounds Acre-1.
After wheat second most important cereal crop of Pakistan is rice. Every year Pakistan exports almost 2 million tons of rice which is 10% of total world’s trade. Among other cereal crops rice are more likely to influence by climatic variations especially from water shortage.
According to estimates by Government of Pakistan, during 2011-12 canal irrigation water availability was less than 10% and water use was almost 128 billion m3. Ground water is also reducing with an average of 0.3 m year-1, and with passing years this amount is reducing due to excessive exploitation and misuse (approximately 7 m) of ground water.
The higher cost of pumping out of groundwater and labor shortage during growing season are major factors for yield decline. Due to these factors in 2011 production of rice was 6160 million tons. Whereas, in 2012 this was 5536 million tons, significantly less due to intense weather fluctuations.
After wheat and rice most important and highly temperature sensitive food crop in Pakistan is maize. It produces in two seasons: winter and spring.
Production and cultivation of maize is highly dependent on water availability and temperature variation at any stage of growth. Drought stress and temperature fluctuations at any growth stage can lead to reduction or loss of grain yield.
During 2011-12 maize production reduce to lowest levels of 3707 thousand tons, approximately 13.7 % of decline rate.
Climate change and food security
In the scenario of climate change, first and most damaging things are food crops. Climate change pose major threat to the food crops security at local, regional and global levels. Climatic conditions changes can disturb food availability, limit food access and badly affect the food crop quality.
Productivity of agricultural food crops are directly link with enhancing temperatures, changing rainfall patterns, intensive weather events, and water shortage. Increasing severe and extreme weathers phenomenon can also disturb the food availability that results in higher price of food products.
This situation intensifies with continuously extreme weather conditions and prediction of longer period to persist in future also. High temperature weathers can also lead to contamination and spoilage of food.
Loss of agricultural products due to climate change has become a severe issue. Several studies exhibit that suitable management practices and latest adaptations, can mitigate climate change effects on crops.
In both natural and human-made systems, adaptations can implement in response to real or estimated climatic activities. These mitigative measures lowers the risk of harm and improve the chances to get benefits.
In response to climate change many small-scale farmers in developing and less-developed countries are starting management of their agricultural practices. They are managing their practices on basis of experiences and knowledge of agricultural technology, in response to climatic changes.
In case of food security, it is essential to investigate the benefits of adaptive measures for betterment of agricultural productivity.