- While climate change is not producing more hurricanes overall, it is making the most powerful ones more likely and bringing heavier rainfall
- The forecast suggests that the 2024 Atlantic hurricane season could come close to the record of seven major hurricanes set in 2005 and 2020
- Warmer ocean temperatures provide more energy for storms to grow and intensify as they track westward.
The National Oceanic and Atmospheric Administration (NOAA) has sounded the alarm on a potentially record-breaking Atlantic hurricane season in 2024, forecasting up to seven major hurricanes, more than double the typical number. While climate change may not be directly increasing the frequency of hurricanes, it is undoubtedly intensifying the most powerful storms and exacerbating their rainfall.
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Meanwhile, the Bay of Bengal is being battered by Cyclone ‘Remal’. Remal, a low-pressure system over the Bay of Bengal is anticipated to intensify into a severe cyclonic storm, reaching the coasts of Bangladesh and West Bengal, India by Sunday evening.
Factors Behind the Forecast
Two key factors are driving the forecast for an intense hurricane season. Firstly, there is the likely switch from El Niño to La Niña within the coming months, which helps these storms to grow more easily. Secondly, sea surface temperatures are much warmer than usual in the main hurricane development region in the tropical Atlantic. Warmer waters provide more energy for storms to grow as they track westwards.
“All the ingredients are in place” for an intense hurricane season, said Ken Graham, director of the US National Weather Service.
Is Climate Change Making Hurricanes Worse?
On average, the Atlantic basin – which includes the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico – experiences 14 named tropical storms a year, of which seven are hurricanes and three are major hurricanes. Tropical storms become hurricanes when they reach peak sustained wind speeds of 74mph (119km/h). ‘Major’ hurricanes (category three and above) are those reaching at least 111mph (178km/h).
In total, NOAA expects between 17 and 25 named tropical storms, of which between eight and 13 could become hurricanes and between four and seven could become major ones. The highest number of major hurricanes in a single Atlantic season is seven, seen in both 2005 and 2020. NOAA’s forecast suggests that 2024 could come close to that record.
The Impact of Global Warming on Hurricanes
To highlight the way global warming is making the highest-intensity storms more likely, a recent study explored the possibility of creating a new category sixth level. This “would alert the public that the strongest tropical cyclones that we are now experiencing are unprecedented and the reason for that is the warming of the surface oceans because of climate change,” explained study lead author Michael Wehner, senior scientist at Berkeley Earth.
Hurricane categories only account for wind speeds. However, these storms pose other major hazards, such as rainfall and coastal flooding, which are generally worsening with climate change. Warmer air can hold more moisture, increasing the intensity of rainfall. Meanwhile, storm surges – the short-term increases to sea level from hurricanes – are now happening on top of a higher base due to rising sea levels, principally caused by melting glaciers and warmer seas.
“Sea-level rise increases the total flood depth, making today’s hurricanes more damaging than prior year’s storms,” says Andrew Dessler, a professor of atmospheric science at Texas A&M University.
How do hurricanes form?
Hurricanes, typhoons, and cyclones have their origins in atmospheric disturbances, such as tropical waves or areas of low pressure, where thunderstorms and clouds develop. This is the initial spark that can potentially ignite a powerful storm.
As warm, moist air rises from the ocean’s surface, winds within the storm cloud begin to spin. This rotating motion is linked to the Earth’s rotation, which affects wind patterns in tropical regions just away from the equator.
However, for a hurricane to fully develop and maintain its spinning intensity, specific conditions must be met. The sea surface temperature generally needs to be at least 27°C (80.6°F) to provide enough energy to fuel the storm. Additionally, the winds must not vary significantly with height in the atmosphere.
When these factors align perfectly – warm ocean temperatures, rising moist air, and consistent wind patterns – an intense hurricane can form. However, the exact causes behind the formation of individual storms remain complex and involve intricate atmospheric dynamics.
How might hurricanes change in the future?
While the total number of tropical cyclones globally is unlikely to increase, the Intergovernmental Panel on Climate Change (IPCC) warns that hurricanes are ‘very likely’ to undergo significant changes as the planet continues to warm.
As temperatures rise, hurricanes are expected to pack higher rates of rainfall and reach higher maximum wind speeds. This means a higher proportion of storms would escalate to the most intense categories – 4 and 5 on the Saffir-Simpson Hurricane Wind Scale.
The IPCC predicts that the proportion of category 4 and 5 hurricanes may increase by around 10% if global temperature rise is limited to 1.5°C above pre-industrial levels. This proportion could climb to 13% at 2°C of warming and a staggering 20% at 4°C, although exact numbers remain uncertain.
Oceans suffer from record-breaking year of heat
A BBC analysis has found that fueled by climate change, the world’s oceans have broken temperature records every single day over the past year. Nearly 50 days have smashed existing highs for the time of year by the largest margin in the satellite era. While planet-warming greenhouse gases are primarily responsible, the natural weather event El Niño has also contributed to warming the seas. These super-heated oceans have taken a severe toll on marine life and driven a new wave of coral bleaching. The alarming data, based on the EU’s Copernicus Climate Service, underscores the oceans’ struggle to cope with the relentless heat absorption caused by human-induced climate change, raising grave concerns about the severe consequences if this trend continues unabated.
Depression in Central Bay of Bengal
A brewing depression over the central Bay of Bengal is rapidly intensifying, poised to escalate into a severe cyclonic storm christened ‘Remal.’ According to the Bangladesh Meteorological Department (BMD), the well-marked low pressure over the west-central and adjacent area of the south Bay of Bengal has strengthened into a depression over the past 12 hours and could become a cyclone by Saturday morning, according to the Met office.
It is expected to continue moving northeastwards and intensify into a cyclonic storm over the east-central Bay of Bengal by the morning of May 25.
Subsequently, it will likely move northwards and intensify into a severe cyclonic storm by the evening of May 25.
Continuing its northward movement, it is expected to cross the coasts of Bangladesh and adjoining West Bengal between Khepupara and Sagar Island around midnight on May 26 as a severe cyclonic storm.
Named by Oman, Cyclone Remal marks a formidable start to the pre-monsoon season in the region, underscoring the need for heightened preparedness and swift emergency response measures to safeguard lives and property in the cyclone’s projected path.
Deadliest cyclones in Bangladesh
As Bangladesh braces for another cyclone, reflecting on past tragedies is sobering. Among the deadliest were the 1970 Bhola Cyclone and the 1876 Great Backerganj Cyclone, claiming 500,000 and around 200,000 lives respectively. Other devastating cyclones include the 1991 Bangladesh Cyclone and the 1965 cyclone, each with significant loss of life. Despite advancements, recent cyclones like Sidr in 2007 continue to inflict substantial damage, underscoring the ongoing vulnerability of the region to nature’s fury.
Crucially, the more global temperatures continue to rise, the more extreme these changes in hurricane behavior will tend to become. As the world grapples with climate change, coastal communities must brace for the prospect of increasingly destructive and rainfall-intense hurricane seasons in the future.
