Hassan Belal Zaidi
Published Date: Feb 12, 2016
Sound byte: ‘Expect more extreme weather this year’
Snow on the Margalla Hills is not the only freak weather event that has occurred in Pakistan recently. Scientists are now saying that a massive El Nino – developing off the coast of South America – is radically altering weather patterns around the world.
To understand what this phenomenon is and what impact it could have on the climate of Pakistan, Dawn spoke to Dr Fahad Saeed, who heads the Climate Change and Environment Research Unit at the Sustainable Development Policy Institute in Islamabad.
Q: How exactly would an El Nino impact the climate of a country like Pakistan, which is on the other side of the globe?
A: An El Nino is said to impact the weather over a vast part of the globe. Normally, trade winds over the central and eastern Pacific Ocean cause warm water to move from east to west, towards the western Pacific and Indian oceans. However, during an El Nino, the effect is reversed and the trade winds fail to bring warm westwards. When that happens, the western Pacific gets colder than average and the eastern Pacific gets warmer than average.
Colder than average water in the western Pacific and Indian oceans will suppress convection, affecting the formation of the monsoons which bring rain to the subcontinent. The failure of the monsoon generally results in drought-like conditions in India and Pakistan.
In addition, the Western Depression, which brings rainclouds to the northern areas of Pakistan from the Mediterranean, are largely controlled by the sub-tropical jet stream – wind currents that meander the globe around 10km from the surface. If that is blocked, it can shift weather patterns catastrophically.
For example, the 2010 floods occurred due to the blocking of this sub-tropical jet stream. But the same phenomenon manifested itself as a deadly heat wave over Russia, resulting in thousands of deaths in Moscow.
Q: What can be the real-life impacts of this phenomenon in Pakistan?
A: There have been several studies showing links between El Nino and the sub-tropical jet stream. Based on an analysis of global meteorological data, a recent study has also suggested that El Nino may cause excessive precipitation in the Middle East, as well as the northern and north-western parts of Pakistan, in the winter months.
Recent cold and wet conditions in the northern parts of the country may be attributed to the El Nino, but it can also manifest itself in the form of drought-like conditions in the summer months.
The earth’s weather system is so complex that although 2014 was expected to be a dry year because of a prevalent mild El Nino, one intense precipitation event in September of that year in Kashmir caused flooding in India and Pakistan. I think Pakistani authorities should expect similarly extreme climatic events this year as well, especially in the summers.
Q: How can Pakistan better prepare itself to cope with the freak weather conditions that El Ninos may cause?
A: The role of the Pakistan Meteorological Department in forecasting such extreme weather events well in advance, is essential. Moreover coordination between the Met Office and disaster management authorities at the national, provincial and district-level is key.
To cope with the possibility of drought-like conditions, authorities should have a contingency plan to combat negative impacts, especially for rain-fed crops. Moreover, we recently witnessed a severe heat wave event in Karachi, which resulted in many casualties.
So from floods, to longer-than-usual dry spells and more heat waves, a variety of weather conditions are expected in the country due to the presence of the enormous El Nino we’re currently seeing.Source: http://www.dawn.com/news/1238998/sound-byte-expect-more-extreme-weather-this-year