Dr. Mujahid Ali and Dr. M. Irfan Ashraf (Horticulture, UAF)
Stephen Hawking described that within a century, we need to inhabit Mars as well as other planets. If scientists do not consider we may not tolerate climate change, disease and other fatal versions of destiny which we are certainly imposing (BBC News, 2017).
Global warming is an alarming situation for agriculture. Its aggravating conditions are imposing serious threat to heat sensitive crops. Quitting of the United States from Paris agreements is so serious issue. Along with all global nations Pakistan is also threatening with this situation. Battisti and Naylor, 2009 did make a graph which explains having more chances or probability of affecting by global warming with red areas including Pakistan. Due to global warming water scarcity is also creating trouble in Pakistan. Similar findings were also explained by Food and Agriculture (1998) along with Hong Kong (2012) reports which explained that Panjab province of Pakistan is going dry and hot gradually. In Punjab, some areas in summer become too hot having temperature maximum about 51°C. Pakistan is in a geographic location where the average temperature is predicted to rise faster than elsewhere, increasing 7.2 degrees Fahrenheit (4 degrees Celsius) by the year 2100, according to a 2012 World Wildlife Fund report.
All provinces are of Pakistan are affecting a lot. Pakistan as the agriculture sector is mostly located in Punjab so it will cause economic loss. Global warming has again changed the growing and sowing seasons of various crops. For example, for wheat, the sowing season was different than 20 years ago in Punjab. Summer is not only becoming sever but also its duration is longer than before. Smog is creating another problem for human, animals, and plants in Pakistan. To control the open field environment is impossible. Due to lack of resouces and poor conditions of our farmers Pakistan has almost 100 percent open areas for agriculture. So, agriculture in Pakistan is to the victim in the world.
Global warming is linked to climate change which is due to several factors. Anthropogenic activities i.e. greenhouse gases. Methane, water vapors, and carbon dioxide etc. act as greenhouse gases. Greenhouse gases mean those gases which can absorb heat from the environment and becomes the cause of global warming. High temperature causes damaging effects on all stages of the plants. Some crops lose their economic value during heat stress at early stages. While some crops drop its flowers and fruits so causes great loss. The high temperature is especially damaging summer vegetables as we can’t see any vegetable in June-July in Punjab.
In developing countries like Pakistan, to face such situations agro-forestry is valuable as when farmer grow trees on the side of the fields it not only as shelters belts but also becomes the source of partial shade for growing crops. The other strategy is the foliar spray of various chemicals like plant growth regulators PGRs, osmoprotectants, plant growth enhancers with its optimal doses can maintain turgor of the plant. Anti-transpirants chemicals should be identified as to control transpiration is the main factor to cope with high temperature to balance turgor of the plants.
Another approach is a layer of organic mulch (wheat straw, rice straw, sugarcane bagasse, cotton straw or sticks etc.) in the field will save from damage acting as insulation to the soil and help the plants retain moisture. It will cope with the effect of the strong sunlight by soaking it up before the heat gets to the ground below. During summer heat evaporate water immediately from the soil surface. To a limited extent, the progressive grower can install sprinklers for irrigation which can cause cooling the microclimate.
Keeping in view above mentioned facts it is the screening of all crops is much importance based on their heat tolerant ability. Heat tolerance is a vital tool for research purpose so that farmers can get a high yield in a globally changing scenario. It has been found that some varieties of the same species can tolerate high temperature significantly. So, the government should take the step to understand the issue of global warming for sustainable agriculture in the country.