Bangladesh, Environmental, International, Life as it is, Political, Technical

We are hurtling towards a disastrous climate change (Part I)

The human race is staring at the disastrous climate change of their own making. The climate change clock is ticking remorselessly; it has gone past the 11th hour and, although not exactly on the 59th minute, but not too far from it. We pride ourselves to be civilised human beings, we claim unprecedented scientific and technical achievements; but we have failed to realise the damage we have inflicted and still are inflicting on our planet and our actions are anything but civilised. A large section of the human population under the guidance and influence of ‘civilised political leaders’ in many Western and Eastern countries is in complete denial of the climatic damage!

In order to appreciate how close are we to the tipping point of the irreversible climate change, we need to look at the factors that initiate climate change. The term ‘climate change’ embodies the totality of processes like global warming, sea levels rise, loss of polar ice caps, floods, fires, droughts and so forth. These processes do not take place for no reasons; there are deep rooted reasons for these effects.

The causes for these effects are multifarious. Causes range from emission of greenhouse gases from uncontrolled industrial activities, excessive exploitation of Earth’s resources, deforestation, rise in human population, demands for improved standards of living, increased air travel etc. All these factors contribute to climate change due to enhanced greenhouse gas emission. And the quantity that is primarily used to characterise climate change is the increase in global temperature.

The root cause of the increase in temperature is the increase in greenhouse gas concentration in Earth’s atmosphere. A sort of runaway situation has developed here. Increase in greenhouse gas leads to higher global temperature and higher global temperature leads to higher greenhouse gas. Unless decisive action is taken by human beings to arrest this situation, the human race is at peril. 

The legitimate question that arises here is that how can one assert this rise in global temperature leading to climate change is mainly due to human activities, when both natural processes and human activities do contribute to global temperature? That is a genuine question.  

The planet Earth had undergone over the millennia large climate swings. Scientists had looked into these variations in Earth’s climate over the past 650,000 years and found that there had been as many as seven ice ages during this period and in between ice ages there had been some warmer periods with increase in global temperatures. Modern human beings (Homo sapiens) had not yet evolved 650,000 years ago and so global temperatures could all be assigned to natural causes. There was no trend of temperature variation over this period.

When nearly 250,000 years ago, modern human beings emerged from the savannas in Africa, man started interacting with nature. But those primitive men had no way of exploiting the Earth; they were passive, subservient onlookers of nature.

Climatologists looked at the inter-glacial periods i.e. between two cold glacial spells and established a baseline temperature. After the baseline temperature was established, then any excess global temperature found over a period when human activity was known to have taken place can be assigned to human activities. This is an established scientific technique and it is applied to many scientific disciplines to separate out human activities from natural activities.

The planet Earth is blanketed by a layer of gases in the outer atmosphere. This atmosphere containing a variety of gases lets in solar radiation to come through, but blocks out or shields harmful ionising radiation from the outer skies. A small fraction of solar energy is reflected back from Earth’s surface to outer skies. Normally if the atmosphere is unpolluted, this reflected energy in the form of infrared radiation will escape to outer space. On the other hand, if there are pollutants such as carbon dioxide, methane etc, this radiation is held back and reflected towards Earth again. Thus, gradually excess energy is accumulated in the planet and its temperature goes up.

The types of gases that refuses to let infrared escape from Earth had been found to be carbon dioxide (CO2), methane gas (CH4), nitrous oxide (N2O), chlorofluorocarbon (CFC) and a few more. Atmospheric concentrations of carbon dioxide in ppm (parts per million) and methane gas in ppm over the period 1500 to the present time had been estimated by scientists and presented in the graphs below. The period 1720 to 1800 is the industrial revolution period when human activities kicked in large scale. Before this industrialisation period, humans were living in harmony with nature. It can be seen from both of these graphs that the industrial revolution was the spurt in increase in concentration which continued in accelerated fashion right up to the present day.

Greenhouse gas concentration from 1500 to 2000 AD

Along with these two graphs, one should consider the rise in global temperature which is shown below. The similarity in the overall shape and pattern of these graphs is striking and one can draw conclusion that are correlated. It shows beyond doubt that the rise in temperature above the 1850 to 1900 (industrialisation period) baseline is due to increased concentration of global warming pollutants – CO2 and CH4. There are other significant pollutants such as chlorofluorocarbon (CFC), but it is not shown here.

The CO2 concentration in pre-industrialised period was between 200 to 270 ppm and Earth had a thermally stable period. But now this concentration has risen to about 350 ppm leading to about 1ºC rise in temperature. But, if the present trend continues, by the end of the coming decade the temperature may well go up more than 1.5ºC and that would bring in very harsh conditions for all forms of life on Earth.

Global average temperature and industrial baseline.

From 1970s the scientists had been saying that human beings are damaging Earth’s atmosphere and its natural conditions and care should be taken to limit it or even reverse it. But political leaders of various persuasions, particularly Americans and vested interests dealing with fossil fuels, kept denying any global warming or any climate change etc. When confronted with increased severity and more frequent incidences of droughts, bush fires, floods, storms, tropical cyclones, cold spells etc, these climate deniers started saying that these are natural phenomena; nothing to do with human activities. Their denial is either based on ignorance or moral depravity.

Few countries holding such views are destroying the good work of large number of countries. Donald Trump, president of America, is the most famous deniers of all, mainly because America is the second largest polluter of the world and to limit polluting activities would cost America a lot. And hence denying the whole thing is the easy option. Pursuing such damaging policy, America, under Donald Trump, had withdrawn from the Paris Agreement in 2017.

The Paris Agreement of 2015 aims to limit global warming to 1.5ºC relative to a pre-industrial baseline. Its precise commitment is:

Holding the increase in the global average temperature to well below 2℃ above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5℃ above pre-industrial levels, recognising that this would significantly reduce the risks and impacts of climate change.

We all live in the same planet. If one country i.e. America, the second largest polluter, keeps damaging the planet for its own benefit, that would wipe out the sacrifices of large number of countries. America is pushing the Earth to a precipice for their selfish interests.

(The next Part (Part II) will deal with the likely consequences of the present predicament and the most likely prediction of the future scenario.)


  • Dr A Rahman is an author and a columnist
Cultural, Environmental, International, Life as it is

America’s ‘Last Frontier’ becoming the ‘Lost Frontier’

Missing glaciers at Denali, Alaska

Nick-named the “Last Frontier”, Alaska is the largest state (in area) of the United States. It is also one of the richest states; thanks to its abundance of natural resources, such as oil, natural gas, gold and fish. The state is home to a vast expanse of pristine wilderness, towering mountains, breathtaking glaciers and big game animals.

Alaska may not fit the bill for what most people envisage as a vacation spot, but it has been on my family’s bucket list for a long time. Finally, our 10-day jaunt started on July 1, 2019 in Anchorage, the largest city in Alaska. We visited three national parks: Denali Wilderness in central Alaska, Tidewater Glaciers on the Prince William Sound and Kenai Fjords near Seward.

We also took a 90-minute flight-seeing tour of Mount Denali followed by landing and strolling on a glacier at 1,750 metres. At 6,200 metres, Denali is the highest peak in North America. A panoramic cruise through the Orca Inlet at Cordova allowed us to see the highest concentration of sea otters in the world. We saw the midnight sun at Anchorage and basked in 24 hours of sunshine at Healy, a backwood small town close to the Arctic Circle.

Besides appreciating the awesome natural beauty of Alaska, what struck me most during the trip is how global warming has pushed this Arctic region into an entirely new climate regime, one that is outside the experience of the aboriginals and native wildlife.

Climate change is occurring faster in high-latitude regions–twice as fast as the rest of the world–due to the phenomenon of “Arctic Amplification,” which is the self-reinforcing process that warms the Arctic and subarctic regions much faster than the rest of the world. Being located on both sides of the Arctic Circle, effects of climate change in Alaska are no longer yearly anomalies; rather, they are daily occurrences.

Over the past 60 years, the average temperature across Alaska has increased approximately by 1.7 degrees Celsius. Warming in the winter has increased by more than three degrees. Temperature in Anchorage three days after our arrival was 32 degrees.

As Alaska continues to warm, average annual temperatures are estimated to increase by an additional 1-2 degrees by the middle of this century, while precipitation is projected to increase during all seasons by the end of this century. Despite increased precipitation, Alaska is likely to become drier due to greater evaporation caused by warming temperatures and longer growing seasons.

With rising temperatures, the threat of massive wildfires continues to grow over time across Alaska all the way to the Arctic. During our stay, about 350 wildfires were raging in south and south central Alaska. Smoke from the fires made driving hazardous, particularly through the scenic backroads.

Warmer temperatures have left vegetation more susceptible to parasites and spruce bark beetles. They have killed more than four million acres of trees in Alaska. Indeed, we saw thousands of dead trees in the Denali Wilderness.

Alaska is full of eye-catching glaciers adorning majestic mountains, but most of them are melting at an accelerated rate. The US Geological Survey estimates that Alaska is losing 75 billion tonnes of glacier a year. Melting glaciers have implications for hydropower production, ocean circulation patterns and global sea-level rise. In addition, glacial meltwater from tidewater glaciers, which are valley glaciers that flow far enough to reach out and calve into the sea, has chemical properties that can exacerbate ocean acidification that is already threatening the fishery industry.

As we cruised on the Prince William Sound, arguably the best place in Alaska to see spectacular tidewater glaciers, we saw fewer glaciers due to warmer temperatures. The largest glacier accessible by car, Matanuska Glacier near Anchorage, is shrinking dramatically at its toe. Furthermore, during the flight-seeing tour of Denali, we saw many mountains with barren slopes and valleys. According to our pilot, they were once packed with glaciers.

Nearly 80 percent of Alaska’s surface lies above permafrost—frozen ground that is typically located a few feet below the soil surface in extremely cold regions and remains frozen year-round. However, as air temperatures are rising, permafrost is thawing in many areas, causing the soil above to sink, resulting in ground subsidence that is damaging highways, railroads, airstrips, homes and other structures. Moreover, shrubs and spruce that previously could not take root on the permafrost now dot the Alaskan landscape, potentially altering the habitat of the native animals.

Because of melting permafrost and subsequent caving of the road, we could not drive from Healy to Valdez via the scenic Denali Highway. Instead, we had to take a 320km detour.

Arctic permafrost acts like a gigantic cap over mineral resources and fossil fuels containing greenhouse gases. But melting permafrost is releasing these gases, particularly methane trapped in ice. Clearly, the loss of permafrost and glaciers is opening new pathways for greenhouse gases, constituting a newly identified, powerful feedback to global warming.

Erosion of Alaska’s coastline is increasing due to the decline in sea ice that protects the coast from storms and tidal surges. The coastal areas are now more vulnerable to devastating storms and heavier rainfall.

The ripple effect of ice loss does not stop here. In the sparsely populated areas, where roads are few and far between, frozen rivers are indispensable for transporting goods, visiting family and taking children to school. With the loss of ice, their communication routes are cut off. Additionally, many people in northern Alaska depend on hunting on the ice. They no longer have access to traditional hunting areas, or access is much more dangerous because the ice is less stable.

Although climate change is having deleterious effects on people all over Alaska, those most affected are the Alaska Natives. Since they live so closely with the land and nature, small shifts in the ecosystems can perturb their way of life. Also, they get food mostly through fishing and hunting, including animals like polar bears, walruses and seals. Changing climate has resulted in the habitat destruction of these animals.

In summary, climate change in Alaska is not a distant or abstract concern, as some would like us to believe. It is real—simply because there is water where there was once ice. Hence, with a gloomy, disaster-prone future, it seems America’s “Last Frontier” will eventually become the “Lost Frontier.”

  • Quamrul Haider is a Professor of Physics at Fordham University, New York.

Environmental, Life as it is, Religious

Where land and sea mingle

We are used to visualising sea at the end of a land or a land at the end of a sea, but this stereotypical image gets knocked on its head when we go to the western outskirts of Scotland called Hebrides. Hebrides – both Inner and Outer – on the western edges of Scotland offer the spectacle of land, lochs, sea and islands embracing each other in a spectacularly serene landscape.

The start of a sea in Hebrides does not preclude any further land, as just a few miles of sea will usher in an island and then a few miles of land of the island will lead to another stretch of sea or a loch or a lochan (a small loch) and the pattern repeats few more times. Land and sea truly intertwine there. It is estimated that there are over 31,000 lochs and lochans in Scotland alone. Loch is a Gaelic word for lake.

We started our journey by road from a bus station just outside Queen Street Railway Station in Glasgow heading towards Oban on the west coast of Scotland. We skirted along Loch Lomond and evaded few other lochs on our journey and, needless to say, the landscape was spectacular. On the way we stopped at Inveraray (the ancestral home of Duke of Argyll) for lunch and then proceeded towards Oban. Oban is the major ferry port connecting almost all the outlying islands in Hebrides.  

From Oban we took a ferry to go to Craignure, a ferry port, on the Isle of Mull. Mull is the second largest island (area=875 and about 45km long) in the Inner Hebrides with a population of just over 2,500 people. The island had seen better days a couple of centuries ago when the population was over 7,000 and there were trade links with Ireland and other Outer Hebrides islands. The Vikings were regular visitors to these shores plundering the island. The Norse influence in local language, culture etc is clearly evident here. Our hotel was situated at the edge overlooking the wider stretch of the sea. Just a short distance away from our hotel is the water stretch that is called the Sound of Mull. The name ‘Sound of Mull’ comes from the fact that in the olden days people from Mull used to shout out a message or call for a ferry across the narrow stretch of water from the mainland and the mainland people used to say they received the Sound of Mull.

The following day we travelled by coach through the spectacularly scenic road (mostly single tracks with ‘passing places’) in Ross of Mull to Fionnphort to take a ferry to Iona. The name Iona in Gaelic means ‘sacred isle’. It is truly a place where serenity merged with numinosity overwhelmed people. The most famous landmark in the island is the Iona Abbey, which was established by St. Columba in 537AD (even before Islam was proclaimed in the deserts!). John Smith, the Labour politician and the leader of the party who could have been the British prime minister if he would have lived a few more years, when he died in a heart attack in 1994, is buried just outside the Abbey. When I asked, why his grave is out in the open, whereas quite a few graves are sheltered inside the Abbey, I was told that only ‘noble people’ are buried inside the Abbey. Scottish feudal system is very much alive and kicking out there. We were also told that special permission was required for John Smith to be buried in the island. Next to the Abbey is the Nunnery where more than 100 nuns used to live at any time (until 19th century) and devoted their entire lives in the service of God!

After spending the whole day mulling over the relics left behind by those who served God to the best of their abilities, we left the isle of Iona by crossing the ‘Sound of Iona’ to come back to Mull and then to our hotel. Whereas Isle of Mull was one of the major trade posts for the Vikings, isle of Iona was distinctly a devotional place.

The following day, we set off in the northerly direction through single track roads to come to Tobermory, the ‘capital’ of the island. This capital is not a hustling and bustling city, but a sleepy little village of about 700 people. There is one main road by the sea having about 10 or 12 shops and, of course, a distillery producing Scottish whiskey. They are extremely proud that their whiskey is exported to as far a place as Japan.

Mackinnon’s Cave and Fingal’s Cave in Staffa

At about 10:30 we took a ferry to go to a small island called Staffa. After about one hour of boat trip we reached the point where a ferry could dock. Staffa is a volcanic island with basalt columns and natural caves. The famous caves are ‘Mackinnon’s Cave’ and the ‘Fingal’s Cave’. Staffa is also a National Nature Reserve where birds have sanctuary to breed in peace. Round the edges of the columns, there are perilous wooden steps to go up to top to see birds in natural habitat. But this climb is not for faint-hearted.

After spending a couple of hours there, we set off for another, even smaller, island called Lunga, which is in the range of Treshnish isles. This island, as well as Staffa, are uninhabited and hence it is an ideal place for bird sanctuary. Puffins are there in large numbers at the top of the island hatching their eggs. Our guide told us that in about two months’ time, parent puffins will fly off to warmer islands in the south, leaving the chicks to fend for themselves and then fly off to the south.

Puffins in Lunga

On the last day of our trip, we left our hotel early in the morning to visit the Duart Castle, the 13th century home of the Chief of MacLean Clan. In the Scottish feudal system, MacLean Clan as well as McDonald Clan were at the top hobnobbing with British and foreign Royalties. But as usual, they were also bitter enemies and rivals for centuries. If one Clan became Royalist, the other would be anti-Royalist and vice-versa.

On our journey back, we crossed the Fishnish to Lochaline ferry and then drove through the magnificent Morvern mountains to come to another ferry crossing. After that we went through Glen Coe and Loch Lomond. Glen Coe is the most famous glen in Scotland with deep glacial valleys and towering mountains. Scotland has some of the skiing slopes in these mountains. After that we followed the road along Loch Lomond to come back to Glasgow Railway Station. 

Altogether it was a magnificent tour not only because it took us through magnificent landscape but also it allowed a glimpse to the Scottish heritage and hierarchy.

  • Dr A Rahman is a writer and a columnist.      

Bangladesh, Economic, Environmental, International, Life as it is, Technical

Our oceans: The ultimate sump

Plastic pollution

Today is “World Oceans Day,” a day observed worldwide to raise awareness about the crucial role the oceans play in sustaining life on Earth. It is also a day to appreciate the beauty of the oceans that “brings eternal joy to the soul.”

The oceans are among our biggest resources and also our biggest dumping grounds. Because they are so vast and deep, many of us believe that no matter how much garbage we dump into them, the effects would be negligible. Proponents of dumping even have a mantra: “The solution to pollution is dilution.” Really! In case they don’t know, garbage dumped into the oceans is continuously mixed by wind and waves and widely dispersed over huge surface areas.

There is a zone in the Pacific Ocean, called The Great Pacific Garbage Patch, which is a gyre of marine garbage twice the size of Texas. The garbage, mainly microplastics, were carried there by strong currents from other parts of the ocean. This is not the only floating garbage in our oceans. The Atlantic and Indian Oceans have their own garbage patches. Worse yet, the sheer size of the patches is making clean-up efforts an extremely difficult task.

Surely, human activities are impacting the oceans in drastic ways. Some of the anthropogenic environmental issues that are affecting the oceans are plastic pollution, oil spills, climate change and noise. One of the most dangerous threats the oceans may face in this century is radioactive pollution.

Each year, we dump nearly eight million tonnes of plastic—mostly grocery bags, water bottles, yogurt cups, drinking straws and plastic utensils—into the oceans. Recently, plastic has been discovered in the deepest part (11 kilometres) of the world’s oceans, Mariana Trench in the Pacific Ocean. Extremely elevated concentration of PCBs, an environment-damaging chemical banned in the 1970s, have also been found within the sediment of the trench.

While it takes hundreds of years for plastics to decompose fully, some of them break down much quicker into tiny, easy-to-swallow particles that can easily be ingested by marine species causing choking, starvation and other impairments.

Pollution of the oceans by oil spills has been one of the major concerns for a long time. The primary source of spill is offshore drilling. The process is inherently dangerous and thus, is prone to accidents. When accidents happen, and they do happen without warning, they cause massive damage to the environment—aquatic and shore—that persists for decades to come. Some oil spills happen when tankers transporting petroleum products have accidents.

If the layer of the oil is thick enough, it smothers creatures unable to move out from under it. Besides, swimming and diving birds become covered with oil, which mats their feathers, reducing their buoyancy and preventing flight. The insulative value of feathers is also lost and the birds quickly die of exposure in cold water.

The world’s largest oil spill was not an accident; it was the result of the Persian Gulf War in 1991. The second worst disaster was the spill by BP’s Deepwater Horizon offshore rig in the Gulf of Mexico in April 2010. Both incidents killed tens of thousands of birds, marine mammals, sea turtles and fish, among others.

Land and oceans together absorb slightly more than half of all the carbon dioxide emissions, with the oceans taking a greater share. When carbon dioxide dissolves in water, it forms carbonic acid. Various studies estimate that if we keep on pumping carbon dioxide into the atmosphere at the current rate, then by the year 2100, the water of the oceans could be nearly 150 percent more acidic than they are now. Such a large increase in acidity would upset the productivity and composition of many coastal ecosystems by affecting the key species at the base of the oceanic food webs. It would also reduce calcium carbonate, which is essential for building the shells and skeletons of creatures like mussels, clams, corals and oysters.

Because oceans absorb more than 90 percent of the heat that is added to the climate system, sea level is changing, albeit unevenly. It is changing unevenly as oceans do not warm uniformly across the planet, with the southern oceans warming at a faster rate. In addition, global reef systems are slowly migrating poleward as oceans around the world continue to warm.

The single most significant contribution to rising sea level is from the thermal expansion of water. Melting ice makes the second most important contribution, but only melting of land-based ice—glaciers, ice caps and ice sheets—is significant. Ice that is already floating in the water—iceberg—makes essentially no change in sea level when it melts, because the greater density of water offsets the volume of ice that is not submerged. Other factors that contribute to the rise in sea level include wind and ocean circulations, depth of the oceans, deposition of sediments by river flows and alteration of the hydrologic cycle by humans.

According to some studies, global sea level rose by about 18 cms during the last century. In the worst-case scenario, sea level could rise by two metres by the end of the year 2100. Arguably, rising sea level is among the potentially most catastrophic effects of human-caused climate change.

The oceans are no longer “The Silent World” of the famous oceanic explorer Jacques Cousteau. Today, they are being acoustically bleached by noise from seismic blasts used for offshore oil and gas exploration, marine traffic and military sonar.

Unlike plastic pollution, noise pollution does not have the visual impact that is needed to spark an outcry and force action. It is an invisible menace that is drowning out the sounds of many marine animals, including fish, use for navigation, communicating with each other, finding food, choosing mates and warning others of potential dangers.

Whales and dolphins are particularly vulnerable to noise pollution. The deafening seismic blasts and the ping of sonar are responsible for the loss of their hearing and habitat, and disruption in their mating and other vital behaviours. The disappearance of beaked whales in the Bahamas in recent years have been attributed to testing of US Navy sonar systems in the region.

From 1946 through 1993, nuclear countries used the oceans to dispose of radioactive wastes. The United States alone dumped more than 110,000 containers of nuclear material off its coasts. Russia dumped some 17,000 containers of radioactive wastes and several nuclear reactors, including some containing spent nuclear fuel.

It is highly likely that radioactive wastes would eventually leak out of the containers because of poor insulation, volcanic activity, tectonic plate movement and several other geological factors. Indeed, last month, UN Secretary General Antonio Guterres confirmed that a Cold War era concrete “coffin” filled with nuclear waste is leaking radioactive material into the Pacific Ocean. Since radiation from nuclear wastes remains active for hundreds of thousands of years, their dangerous effects will linger for a long time and will have lethal impact on marine life.

Furthermore, six nuclear submarines — 4 Russian and 2 American — lost as a result of accidents are lying at the bottom of the oceans. They represent serious threat of radioactive contamination of the oceans, too.

One of the biggest contaminations due to radiation was caused by a series of nuclear tests conducted by the USA on the sea, in the air and underwater at Bikini Atoll in the North Pacific between 1946 and 1958. The French nuclear tests carried out during 1966-1996 in French Polynesia are responsible for other cases of intense radioactive pollution of marine ecosystems.

Clearly, we are using the oceans as the ultimate sump, partly because their very immensity seems to preclude any long-term effect, and partly because they belong to no one. This cannot continue indefinitely because in order for us to survive, we have to protect the oceans. Lest we forget, life emerged from the oceans and the source of most of the oxygen we breathe are the oceans. They have been an endless source of inspiration to humankind.

Quamrul Haider is a Professor of Physics at Fordham University, New York.

Advanced science, Bangladesh, Environmental, International, Life as it is, Technical

Cyclone Fani and global climate change

The temperature of the Earth changes over geologic time. During periods of glaciation, it was about five degrees Celsius cooler and in the interglacial period about five degrees warmer. The last glaciation period was 100,000 years ago. Since then, there have been fluctuations of a few degrees, the period of 1430 to 1850 being one of particularly low temperatures in Europe. Although there were fluctuations from year to year, it seems evident that there has been a steady increase in average global temperature since the Industrial Revolution. According to the World Meteorological Organization, average global temperatures will reach a new milestone this year—one whole degree higher than temperatures before industrialisation.

In the early 1990s, when concern about climate change caused by the rise in temperature became widespread, the “signal” of anthropogenic effects hadn’t unambiguously emerged from the “noise” of natural climate variability. However, we now know that most of the climate-related changes observed over the past 50 years is attributable to human activities. In fact, by burning prodigious amounts of fossil fuels that emit carbon dioxide, which is the principal greenhouse gas, we humans have taken Earth’s atmosphere in general and global temperature in particular into a regime that our planet hasn’t seen for millions of years.

Although the interplay between carbon dioxide and temperatures is complex and not necessarily 100 percent predictive, nevertheless, the obvious correlation between the two variables suggests that we might expect a significant adverse climatic response to the industrial-era surge in fossil fuel derived atmospheric carbon dioxide. Undeniably, the effects of this interplay are manifested in the increase in the ferocity of storms, floods of biblical proportions, spike in the number of unusually hot days, melting of the glaciers, drought, desertification and deforestation, polar vortex, uncontrollable forest fires, degradation of the coral reefs, habitat loss and rise in the sea level, to mention a few.

Today, because of global warming, intense storms are occurring in many parts of the world. If they form in the Atlantic or Caribbean, they are known as hurricanes, and in the Pacific or China Sea as typhoons. If they develop off the coast of Indian Ocean or the Bay of Bengal, we call them cyclones. These storms are one of the most awe-inspiring displays of the raw power of nature. They are also among the deadliest and costliest natural disasters we have to contend with routinely.

After churning through the Bay of Bengal for several days, gathering immense amount of energy along the way, cyclone Fani roared through Bangladesh on May 4, 2019, leaving behind a massive trail of destruction—killing more than a dozen people, knocking out power, shredding roofs and leaving hundreds of thousands homeless. Classified by meteorologists as the equivalent of a Category 4 hurricane, it was one of the most intense cyclones in 20 years in the region.

Cyclones batter Bangladesh at regular intervals, mainly in April/May or October/November, when weather conditions align in a manner most favourable for storm origination and sustenance. As examples, cyclones Aila struck southern Bangladesh on May 27, 2009 and Sidr made landfall on November 14, 2007. The occurrence of these and other cyclones in close succession is a reminder of the country’s extreme vulnerability to the devastating effects of human-induced climate change.

The 1970 cyclone that hit Bangladesh on November 12 and raged the strongest on November 13 was the worst natural disaster we have witnessed so far. The resulting storm surge, more than 20 feet high and topped by huge tidal waves, washed over offshore islands and carried water from the sea many miles inland. The cyclone and flood destroyed the entire infrastructure of the country’s southern coast and killed an estimated half a million people, though some researchers estimate that the death count was close to a million. The failure of the Pakistani government to respond quickly to the crisis, among other things, contributed to the political turmoil that led to an independent Bangladesh in 1971.

Tropical cyclones are influenced by many factors, but the role of warm sea-surface temperatures is the primary source of energy for cyclones. In particular, a cyclone gets most of its energy from the latent heat of condensation and the moisture generated from the sea. Thus, for the genesis of cyclones, temperature of water near the surface of the sea must be higher than 27 degrees to a depth of at least 150 feet. Additionally, heat from the sea and Earth’s counter-clockwise rotation conspire to create the cyclone’s spin and propulsion. Furthermore, rising sea levels mean that surges produced by cyclones are much more powerful, thereby increasing the risk of inland flooding.

Moreover, cyclones need to be at least 300 miles from the equator, where a deflective force known as Coriolis force resulting from Earth’s rotation begins to take effect. When cyclones reach land, or cooler water, they lose energy as the conditions necessary to reinforce them are no longer present.

As a result of global warming, temperature near the surface of the Bay of Bengal varies from 27 degrees in January to more than 31 degrees in May. The unusually warm water, together with geographical and environmental factors, make the Bay of Bengal a hot spot for cyclonic activity.

Can changes in frequency and intensity of cyclones observed so far be attributed solely to anthropogenic global warming as against long-term periodic natural variations? Cyclones are affected by natural fluctuations too, driven by external factors, such as solar variability and volcanic eruptions, natural internal variations of the complex physical, chemical, and biological systems of Earth.

Additionally, research has shown that urbanisation significantly contributes to the amount of rainfall dumped, as evidenced by over 130 centimetres of rain that fell on the Houston region during hurricane Harvey in 2017. This is because the “roughness” of the city—as in the buildings and infrastructure—creates a drag on the storm system, causing it to slow down, resulting in more rain over the city area.

Climate models predict that global warming could spawn more bizarre and violent weather, notably cyclones and severe floods in the future. Indeed, while people are trying to come to grips with the effects of Fani, meteorologists have warned that Bangladesh is likely going to experience another cyclonic storm called Vayu some time later this month.

The models also predict that by the end of this century, global warming effects could increase a cyclone’s intensity by about 20 percent, making them more destructive than ever. The amount of rainfall would also increase substantially. Other estimates predict that a doubling of carbon dioxide concentration would result in a 40-50 percent increase in destructive cyclones.

So, what should we do to keep our planet in the so-called Goldilocks zone of the solar system? We have to make a concerted effort to end our dependence on fossil fuels. We have to replace them with non-polluting, renewable sources of energy. We have to develop more carbon-free energy technologies. We have to sequester carbon dioxide emissions using the available technology. More importantly, we have to shun the “business as usual” attitude. In short, we will have to build a sustainable future. Otherwise, climate change will cause our civilisation to collapse.

Quamrul Haider is a Professor of Physics at Fordham University, New York.