Why does it rain in winter?

bdnews24.com

Rain on a foggy winter morning. Sounds great, right? But it isn't as good as it feels because the cause of this unusual phenomenon in Bangladesh is climate change.

Climate refers to the average weather patterns of a particular area over 30-40 years. Bangladesh has a tropical climate. As it is a coastal nation and has a monsoon season, neither winter nor summer is as severe as in the other countries. Usually, summer in Bangladesh is hot and rainy, whereas winter is dry. However, recent winters have seen rain showers in Dhaka and other parts of the country.

Ideally, the season should be windy and dry, but the Bangladesh Meteorological Department noticed a tropical depression developing across the Bay of Bengal recently. Depressions in the sea almost always cause rainfall in winter. During winter, a centre of high pressure sets in northeastern India, which is close to where Bangladesh lies.

When a fast-moving area of cold air moves into a region of warmer air, it forces its way under the warm air, which is pushed upwards. As it rises, air pressure falls. This rising air can lead to a low-pressure system or depression.

When a depression forms and passes over the Bay of Bengal, it causes rainfall. Later the depression may rise, and the result could be a cyclone that strikes the coast or could die out under the sea. Cyclones can cause massive damage in Bangladesh's coastal regions. But why do these depressions occur in such an odd season?

This happens due to climate change, which occurs because of human activity. As a result of this activity, temperatures are increasing all over the world. This activity means we have to endure the effects of greenhouse gasses too.

Any climate change in Bangladesh is part of climate change worldwide. It is generally claimed that the Earth's temperature has increased since the beginning of the 20th century. This phenomenon, called global warming, is attributed to the increase in atmospheric carbon dioxide (CO2) due to the burning of fossil fuels. This temperature rise is melting the icebergs in frigid areas and causing the melted water to trickle down to the oceans.

According to some analysts, the effects of increased temperature will have both destructive and beneficial consequences, which will be catastrophic to some areas but helpful to others. Global warming will cause the polar ice caps and Himalayan ice caps to melt at a slow pace. Consequently, it is estimated that the sea level will rise by 2-3 metres by 2050. In that case, all low-lying coastal plains and delta areas, including significant parts of Bangladesh, will be submerged worldwide, reducing fertile agricultural land and, thus food production. This will increase food shortages, hunger, poverty, and human misery on a global scale.

If this prediction comes true, a significant portion of the southern half of Bangladesh will be submerged by the Bay of Bengal. However, there is another side to the argument. Climate change on a global scale does not occur overnight; in fact, it occurs over a time scale of thousands of years.

I strongly feel as though we need to stop this kind of change to save the world. We need to reduce emissions of greenhouse gases and fight the causes of global warming to stop this. Burning fossil fuels should be banned more than is absolutely necessary, and we must learn to depend on solar and other forms of green energy.

Reporter's age: 14 District: Dhaka