Three decades ago, from mid June to mid August was rainy season. Based on this, farmers cultivated Ropa Aman and other crops at the coastal area. Now the situation has almost changed. Recent published a report of World Bank based on climate change showed that heat will increase and rain will decrease at the rainy season in Bangladesh. Heavy rain fall will happen in a very short time. Draught will be seen several times and it will increase in south- west area of the country. These kinds of draught might be seen regularly. The number of thunder will increase. Therefore, rain dependent crops production will decrease. Water flow is higher at the storm and flood than before. As a result, main crops Boro and Aman production will be hampered. These signs have already been seen in Potuakhali, Barguna, Bhola, Firozpur, Barishal, Zalakathi and southern coastal area.
A few years ago, slightly rain fall happened at Magh-Falgun in this region. The cold was so severe but rain was not seen for seasonal crops. This year rain fall did not happen in the Bangla months, Baisakh- Joistha, that is, April- May- June. Even at the full monsoon, in the months, July- August, sufficient rain fall did not occur.
Unnatural incident is found analysing the data of Bangladesh Water Development Board of Patuakhali and Barguna. Cyclone Mahasen attacked Patua khali coastal area on 16 May this year. As a result, 330 mm rainfall occurred within 24 hours in Barguna. In Patuakhali, the amount of rain was almost 400mm. After that, rain was not seen for many days. Rather, draught and heat were severe in southern coastal area. Salinity increased in the water of rivers. As a result, farmers could not cultivate Ropa Aman.
Monsoon rain has decreased, as found in last few years’ information. In 2007, from July to September, the amount of rainfall was 1,836mm in Patakhali and Borguna. At the same time in 2008, the amount of rainfall increased to 1,921mm. In 2009, it dropped off at 1280mm. It further declined in 2010 and the amount was 912mm. In 2011, the amount of rainfall increased at 1,712mm but again, it decreased in 2012 comparing with the previous year at 1066.
Prodip Kumar Chatterjee, an officer of Kalapara weather office of Patuakhali informed that, in each month of rainy season, the average amount of rainfall is 515mm, which is low from last three or four decades. The variation in rainfall is seen across the entire Bangladesh although the tides of the rivers of southern coastal area are seen natural. According to the data of meter gaze branch of water development board of Barguna and Patuakhali, the highest tide of rivers in Barguna and Patuakhali were 3.45 metres. In 2005, it increased to 3.51 metres. All of a sudden, the height of the tide decreased in 2006 and it reached the height of 2.96 meters. In 2007, during the cyclone SIDR, the height of the tide reached 4.22 metres. In 2009, tidal bore were raised into 3.65 meters by the cyclone AILA. This year on May 16, the tidal bore rose to 3.36 meters in cyclone Mahasen.
It has been evident that every year sea level rises due to global warming. A joint research of Bangladesh and Germany has given a report that last 300 years, the average rate of the rise of sea level is about 0.8 metre melting ice. As a result, the lands of the coastal area went under the water of 1.2-5.2 meters every year. In future, sea level may rise 7mm melting ice. As a result, coastal area may go under water from 3.3 to 8.9 millimetres. What would be more upsetting is that the warmth would rise and rain would become imbalanced.
In this regard, AKM Mostofa Zaman, Dean, faculty of Disaster Management, Patuakhali University of Science and Technical said that an aspect of climate change is the change of the rain during the monsoon. The amount of rainfall has declined in an alarming level and the warmth is rising. As a result, many natural calamities like cyclone, flood, and tidal bore have become evident regularly. It has further accelerated long lasting submerged water, inability of the production of crops and saltiness. Thus, it is highly necessary to take long-term initiatives to confront the curse of untoward climate change. Otherwise, the life in the coastal area will lose its normalcy that will put the lives of people living there into the tide of peril.