Age of Super-Storms; Bane of Climate Change
Have hurricanes become more dangerous due to climate change?
It was an April morning and I was sipping my morning coffee sitting on the balcony of my apartment. Across the street there is a large mango grove belonging to a Temple. The many young and unripe mangoes hanging on the branches swinging to the tune of the gentle breeze was a pleasant sight. It was mid-summer and the leaves all were somewhat dreary and frail. Yet they were happily swaying in the placid and pleasant breeze and appeared to be beckoning me. I felt little perturbed fearing what would befall on those beautiful trees in a day or two. Cyclone Fani is supposed to make landfall on the Chennai coast within the next two days. Yet they were playing in the gentle wind so blissfully oblivious of the dreadful fate awaiting them.
More than two years ago, on December 12, 2016, I was standing on the same balcony helplessly watching many of the mango trees in the orchard getting pitilessly uprooted by the fury of Cyclone Vardah. Center for Climate Change and Adaptation Research of Anna University estimates that Cyclone Vardah uprooted 172000 trees and caused a 25% decline in the city’s green cover and its suburbs. It left a trail of destruction across Chennai and entire coastal Tamil Nadu. Now Cyclone Fani is happening in the middle of summer towards the end of April and it itself is somewhat unusual. According to weathermen, it was in 1966 that a cyclone reached Chennai’s shore last in an April month.
But then such extreme weather anomalies are becoming the order of the day. It was just 10 days ago, more than 64 people died in India due to nonseasonal April rains which unleashed heavy hail, thunder storms and high winds. Typhoon Nangka battered Marshall Islands and Guam in July 2015 causing extensive losses. And July is not typically typhoon season for the western Pacific nation. Nonseasonal and unprecedented are fast becoming the two most common adjectives to describe the hurricanes, typhoons and cyclones blowing across the world as their unpredictability and fierceness reach uncharted territories at increasing frequencies.
Super storms are becoming super stronger too with the changing climate. Typhoon Mangkhut which lashed China’s southern coast and Philippines in September 2018 at 180 miles per hour was one of the fiercest storms that ever hit those countries. Typhoon Jebi which battered Japan in the first week of September 2018 was the strongest typhoon hitting the country in the last 25 years. Typhoon Rumbia which pounded China’s Zhejiang Province in August affected nearly 9.5 million people. The 2018 Pacific typhoon season saw a total of 29 storms of which 13 were typhoons and 7 were super typhoons. Not many of us have heard of Super Typhoon Yutu which made landfall in October, 2018 on the remote American islands, the Mariana Islands in the Pacific. With winds of 180 mph and coastal flooding in excess of 15 feet the storm caused total mayhem and devastated the lives of 50000 inhabitants of the islands. Yutu is the 5th tropical cyclone classified category 4 or 5 which lashed U.S. coastline in the past 15 months, an alarming frequency so far not seen in nearly 170 years of recorded weather history. It might be an oddity now, but it will be the certainty not too distant into the future. Do you dare to imagine a super storm like Yutu hitting any large city on the American West Coast? Soon, this might be the dreaded reality we have to live with.
According to the National Oceanic and Atmospheric Administration (NOAA), hurricanes Harvey, Irma and Maria of 2017 are among three of the five costliest hurricanes in U.S. history with total losses amounting to $265 billion. Four named storms Florence, Helene, Isaac and Joyce were active at the same time during the 2018 hurricane season. It was the first since 2008 and may be indicative of the things to unfurl in the future. Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) has warned about the impact climate change has on tropical cyclones and hurricanes. The report envisages that the frequency of high intensity super storms, category 4 or 5 will increase considerably due to the effects of climate change. Cyclone Kenneth, a Category 4 storm lashed Mozambique within six weeks of Cyclone Idai, another powerful storm which devastated Mozambique, Malawi and Zimbabwe, killing more than 1000.
A study by the veteran climate expert Peter J Webster examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity from 1970 to 2005. They found a large increase in the number and proportion of categories 4 and 5 hurricanes which was consistent with the increase in sea surface temperature. In 2010, another study projected significant increase in the frequency of very intense Atlantic hurricanes due to anthropogenic warming of oceans. Scientists from the University of Melbourne in Australia used 33 years of satellite data between 1985 and 2018 to monitor wave and wind patterns in the ocean. The alarming finding from their analysis is that the fastest winds and largest waves increased in their intensities. Speed of the top 10% of winds increased by 4.9 feet and height of the top 10% of waves increased a foot over the study period. This corresponds to 8% increase in the speed of fastest winds, and a 5% increase in the height of largest waves. There is growing evidence that over the past 25 years, there has been a global increase in wind speed and possibly wave height. The overall consensus among scientists is that the frequency of strong storms is going to increase as the planet warms. The intensity of rainfall associated with storms also will be on the rise due to the higher moisture carrying capacity of warmer air. Water vapor increases by 7% for every degree centigrade of warming. This coupled with the strengthened storm surge due to the sea level rise will cause inundation of coastal areas much farther inland.
There is still a large minority questioning the anthropogenic origin of climate change, but a recent analysis states that warming of the world’s oceans occur at as much as 40 percent faster than what the United Nations estimated in 2015. It is estimated that around 90% of the heat gained by earth between 1971 and 2010 was absorbed by the oceans. The top 2000 meters of the ocean took up 240 ZJ (1 zettajoule is equal 1000 000 000 000 000 000 000 joules, an amount not comprehensible to most of us) of heat energy between 1955 and 2010 but resulted only in a nominal temperature rise. It is because of ocean’s high heat capacity. Nevertheless it is sufficient to cause all the serious problems associated with climate change we experience now. Had the lower 10 km of the atmosphere absorbed the same quantity of heat, earth would have been warmer by at least 36°C. It is frightening even to imagine such a situation. What would be the force and fury of the super storms arising under such a scenario? Thanks to the mighty oceans, we are somewhat safe as of now. But for how long? Warming occurs unrestricted, and all the warnings by IPCC and other competent agencies go unheeded. If it continues like this, the future of people living on the coasts looks very miserable. Prioritized and concerted action by all the concerned parties to lessen climate change is the only solution. And it is not an easy solution either.
