A overall misconception about climate alternate and global warming is the conclusion that these phenomena can completely be mirrored in the create of outrageous warmth waves at some stage in the summer months, with frosty climate seasons turning into consistently milder.
This led many in the country to be if truth be told caught off guard when, after the delayed arrival of frosty climate, a severe frigid wave swept all over the country in January this year. It changed into as soon as additionally accompanied by frosty winds and dense fog.
This, then all over again, changed into as soon as now no longer a one-off occurrence. It came about earlier than, and it’s completely seemingly to happen over and over in the kill.
Per the Bangladesh Meteorological Department’s (BMD) climate outlook for November 2024 to January 2025, the country might perchance perchance experience eight to 10 soft to practical frigid waves at some stage in the upcoming frosty climate. Of these, two to some might perchance perchance escalate into severe frigid waves, with temperatures dropping as low as 4 degrees Celsius in the northwestern, northeastern, and central areas.
BMD classifies a severe frigid wave as temperatures falling below 6 degrees Celsius in wide areas, frequently affecting day-to-day existence and posing smartly being dangers. Temperatures ranging from 6-8 degrees Celsius are defined as practical frigid waves, that would also trigger discomfort and affect agriculture. In the intervening time, these between 8-10 degrees Celsius are categorized as soft frigid waves, in overall resulting in frosty however manageable climate stipulations.
These fluctuations in temperature are current of the frosty climate season however might perchance perchance be extra pronounced this year attributable to altering climatic patterns. Subsequently, some argue that that is but any other example of climate alternate being overstated and the global environmental field is now no longer as dire as scientists suggest.
That might perchance perchance very smartly be removed from the truth.
Ironically, the out of the ordinary frigid spells seen at some stage in Bangladeshi winters are a manifestation of climate alternate. It’s miles a smartly timed reminder that global warming disrupts atmospheric and oceanic methods, contributing to these temperature extremes.
A most up-to-date stumble on printed in Nature Communications Earth and Surroundings, titled ‘Anomalous Arctic Warming Linked with Severe Iciness Weather in Northern Hemisphere Continents,’ chanced on that surprisingly warmth temperatures in the Arctic are linked to an increased probability of severe frosty climate climate all over Northern Hemisphere continents, which Bangladesh is a segment of.
The Arctic is warming faster than diversified parts of the arena, a phenomenon is named Arctic amplification. Right here is primarily attributable to the hasty melting of ice, which is going on at a price of about 13% per decade in the set.
Ice reflects extra sunlight than land or ocean, which might perchance perchance be darker and rob in additional warmth. Because the ice melts, it exposes darker surfaces delight in ocean water or land, which rob in additional sunlight and elevate warming. This creates a feedback loop, where melting ice ends in extra absorption of warmth and additional warming.
Arctic amplification additionally disrupts the jet toddle, a fleet-appealing air most up-to-date excessive in the atmosphere. Typically, the jet toddle helps to withhold the polar vortex — an set of frigid air that surrounds the Earth’s poles at some stage in frosty climate — contained.
On the opposite hand, because the jet toddle weakens and becomes extra wavy attributable to warming in the Arctic, the frigid air from the polar vortex can spill southward. This lets in less warm temperatures to achieve areas delight in South Asia, leading to less warm climate in these areas.
There are additionally some diversified components at play.
“The main reasons, moreover global warming, are twofold: the rise in outrageous events and native-level warming. Along with global warming, these components are contributing to a shift in the stable climate, which is seemingly inflicting each and each less warm and hotter stipulations all over the country,” said Dr Ashraf Dewan, partner professor at the College of Earth and Planetary Sciences at Curtin College.
He explained that global warming prompted by human actions is intensifying and making these outrageous events, corresponding to heavy rainfall, warmth waves, frigid spells, floods and droughts, extra recurrent. Rising sea temperatures, faster than previously anticipated, additional exacerbate these stipulations.
Bangladesh’s vulnerability is heightened attributable to its dense population and over-reliance on pure sources, making it particularly inclined to climate-connected disruptions.
Regional climate phenomena additionally play a pivotal function in the severity of Bangladeshi winters.
Dr Rashed Chowdhury, an applications scientist in water, climate, and society and an adjunct college member at Arizona Impart College, functions to La Niña as a key divulge. In the future of La Niña years, sea temperatures in the central and japanese Pacific Ocean drop considerably, disrupting global climate patterns. In South Asia, including Bangladesh, this frequently finally ends up in less warm-than-current winters.
He eminent that in accordance with most up-to-date projections, La Niña is anticipated to emerge from October to December 2024 and persist by January to March 2025.
“There might perchance be one more motive, I factor in, La Niña is especially foremost for this year’s less warm frosty climate — as at some stage in La Niña years, the jet toddle shifts southward and brings frigid air into the set, making the frosty climate in fact feel less warm in Bangladesh. So, the mixed affect of La Niña and the jet toddle might perchance perchance trigger the frosty climate to be less warm than fashioned in Bangladesh this year,” said Dr Chowdhury.
Per him, the next foremost motive is the Indian Ocean Dipole (IOD). If the IOD turns unfavorable, it would raise cooler air to the set, including Bangladesh.
The IOD will transition to a unfavorable segment almost as we hiss in November–January, which on the entire technique cooler waters in the western Indian Ocean and hotter waters in the east, potentially affecting climate patterns in the set, including Bangladesh.
“Lastly, one more wide divulge is frigid air appealing south from the Himalayas. Excessive-rigidity methods over northern India and Nepal push this frigid, dry air into Bangladesh, leading to a primary drop in temperatures, especially at some stage in the frosty climate months,” Dr Chowdhury concluded.
