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Does the current heat wave indicate that climate change is accelerating?

Published : Friday, 3 May, 2024 at 12:00 AM  Count : 381
MOHAMMAD ELIAS
Two-thirds of the worlds land is in the Northern Hemisphere.  And land heats up faster than water bodies.  Northern Hemisphere summer is therefore the hottest time of the year overall for Earth.  However, in the Northern Hemisphere summer temperatures usually peak a little later.  But, for the temperature extremes to start so early this year, at such a high rate and to persist for such a long time - is truly unprecedented.

The increasing greenhouse gases in the earths atmosphere are responsible for this, reminds a climate scientist.  An increase in greenhouse gases means that more heat is trapped near the surface than the ocean can absorb, because these gases absorb much more of the heat from the sun.

Carbon dioxide is the most persistent of the greenhouse gases.  It also emits huge amounts from volcanoes.  Last May, the summit of Mauna Lua volcano on the island of Hawaii detected emissions of 424 parts per million - the highest scientists believe in three million years.

 In addition, emissions of long-lived greenhouse gases such as methane and nitrous oxide are occurring at such high levels - perhaps never before seen in the history of human civilization.  Human activities are also turning the earth into a more terrible greenhouse day by day.  But before humans made these changes to the climate, the average global temperature rose by 1.2 degrees Celsius.

James Hansen, a climate scientist at Columbia University, said the kind of hot summer that used to occur every 100 years - between the 1950s and 1980s - began to occur on average every five years.  Suffocating summers are likely to occur all over the world.

 Overall, is the increase in greenhouse gases in the atmosphere, heat emissions from the Pacific Ocean, and inter annual temperature variability responsible for this years deadly summer heat?  Or is there something else behind it?

 Dr.  Hansen, however, thinks so.  According to him, global warming has changed dramatically since 2010.  Record high temperatures in cold water oceans like the North Atlantic have been a summer surprise this year.

According to scientists, such events contributed to the warming of the climate even at the end of the ice ages.  That is, as the amount of methane rises, so does global warming and the number of wetlands increases.  And from there more methane is released.  This cycle continues like this.

Global factors include the destruction of the worlds lungs, the Amazon forest, and the increase in carbon emissions and fuel burning due to commercial reasons in developed countries.  Although Bangladesh is not much responsible for this, its impact is falling on Bangladesh.  India, Bangladesh, Nepal, Bhutan, Afghanistan and China once had numerous rivers flowing in this zone.  But day by day these rivers have been killed by implementing various projects.  

As a result, many rivers have disappeared along with the reduction in length and width of the rivers.  Some of the places where the river receded have been filled with sand and some have been built up.  As a result, a lot of heat is spreading from there.  On the other hand, due to the presence of sand, a desert condition is created and due to this, the temperature of the surrounding area increases.  It is the first regional cause of temperature rise.  The second regional factor is the melting of Himalayan ice.  The temperature is then reflected back into the atmosphere by the Himalayan ice.  But now due to the melting of the ice, solid rock is visible.  As a result, the temperature stored in the stone is spreading to the surrounding area through the air and causing a type of heat burn.  Megacities or cities are growing in these regions, and traffic and population are increasing accordingly.  

For example, neighbouring country Indias population has surpassed that of China.  More than one-fifth of the worlds total population lives in this region.  The temperature is rising even while giving this huge population their civic benefits.

The largest contributor to temperature rise is local factors, which are locally increasing temperatures.  Among these local factors, the main reason for the increase in temperature is the decrease in greening of Dhaka city.  Bangladesh once had more than 25 percent green cover, but now its amount is very negligible.  Plants provide oxygen by absorbing carbon dioxide and heat from the environment. As a result, oxygen spreads in the air and keeps the surrounding area cool.  But now, in the name of beautification of the city, the big trees dividing the road are being cut down.  As a result, the oxygen and water vapour in the atmosphere decreases, increasing the temperature and due to the same reason, the rainfall also decreases.

A study shows that by 2050, heat waves will seriously affect the lives and livelihoods of more than 3.5 billion people worldwide, and more than half of them will live in cities.  Extreme heat waves are more dangerous for cities and the risk to cities continues to increase every year.  

Recently, a report titled Hot Cities, Chilled Economies: Impacts of Extreme Heat on Global Cities by the US-based Adrienne Arsht-Rockefeller Foundation Resilience Centre says that Dhaka is losing 6 billion dollars every year due to high temperatures and by the year 2050  8 thousand 4 billion dollars may exceed.  The labour productivity of the people of Dhaka is affected more by the high temperature than in any other city.  This loss may rise to 10 percent by 2050 if no action is taken to reduce the temperature.  The number of hot days is estimated to double by 2050.  It is feared that this will have an adverse effect on the vulnerable population, especially women, children and the elderly.

Survival of novel viruses and pathogens is increasing due to heat wave in Dhaka city.  It is increasing dengue, chikungunya, respiratory illness and other infectious diseases.  High temperature causes dehydration, allergy, heat cramps, heat stroke.

The writer is a Deputy Director( Finance and Budget), Retirement Benefit Board , Ministry Of Education



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