Hurricane Havoc: Is Global Warming To Blame?
Hurricane Havoc: Is Global Warming To Blame?
By Norm Dixon
Green Left Weekly
The terrible devastation wreaked on New Orleans by Hurricane Katrina in late August, which took the lives of at least 964 people, and the subsequent political crisis caused by the failure of US President George Bush’s government to adequately respond to the disaster, catapulted the issue of industry-induced global warming into the headlines again.
A debate has erupted over whether world capitalism’s unprecedented emissions of industrial carbon dioxide into the atmosphere was directly responsible for Katrina, and the record-breaking number of fierce storms during this year’s Atlantic Ocean hurricane season.
When the season officially ended on November 30, there had been 26 named tropical storms since the season began on June 1, 14 of which reached hurricane strength (meaning they generated wind speeds in excess of 119 kph).
While Katrina was the most devastating hurricane and its impact on the United States ensured it received saturation media coverage, there were other disastrous storms. Between September 18 and 26, Hurricane Rita slammed into Florida, southeastern Texas and southern Louisiana. In early October, Hurricane Stan struck Mexico and Central America, killing more than 655 people in Mexico and another 130 or so in Guatemala, El Salvador, Nicaragua, Honduras and Costa Rica. Hurricane Wilma developed in mid-October, causing extensive damage in Florida and Mexico’s tourist centre of Cancun. Around 25 deaths in the Caribbean islands, Florida and Mexico were attributed to Wilma.
There were so many significant Atlantic tropical storms this year that weather bureaus used up all available letters from the English alphabet to name them (each year 21 names are reserved for Atlantic hurricanes, arranged alphabetically but skipping some letters) and for the first time had to supplement them with letters from the Greek alphabet.
The 24th named storm, tropical storm Gamma (it failed to reach hurricane strength), struck Honduras and Belize around November 20 killing at least 12 people. Tropical storm Delta developed off the Canary Islands, near the West African coast, and reached wind speeds of 110 kph on November 27. Tropical storm Epsilon formed on November 29 about 1000 kilometres east of Bermuda, in the Caribbean, and developed into a hurricane on December 2.
The previous record in an Atlantic hurricane season was 21 named storms in 1933. Records began to be kept in 1851. According to the US government’s National Weather Service, based on the average for the last 40 years, an Atlantic season normally sees 10 or 11 named storms, of which six can be expected to develop into hurricanes. Records also show that hurricane activity in the Atlantic has been higher than normal in nine of the past 11 years.
Inevitably, all this has raised understandable suspicions that global warming fuelled by industrial carbon dioxide emissions and other greenhouse gases played a direct role in the devastation caused by hurricanes Katrina, Rita and Wilma. Newspaper editors across the US have been quick to attempt — largely without success — to seek out climate scientists prepared to rashly attribute these specific storms directly to global warming and engineer a “debate” by giving equal space to the handful of industry-funded greenhouse denialists who dismiss any possible link at all, now or in the future.
The vast majority of climate scientists, who are certain of the reality of CO2-induced global warming, are very careful to point out that it is scientifically impossible to conclusively attribute any single weather event, such as a hurricane or a heat wave, directly to global warming.
There are too many random variables, as well as long-term countervailing or parallel cyclical oceanic and atmospheric processes to take into account. But for the same reason, it is also impossible to definitively rule out that global warming is not a factor in these individual events. As Dr. Brenda Ekwurzel, a climate scientist and a member of the 50,000-strong US Union of Concerned Scientists, explained in an October 27 article on the Countercurrents.org website, “This is because weather is not [the same as] climate. Climate represents average conditions over multiple seasons or decades. A longer perspective is essential to see climate shifts above the natural variation.”
And from that vantage point, there is good scientific evidence that global warming is having, and will increasingly have, an impact on the overall intensity and frequency of tropical storms. On July 31, the online edition of Nature magazine published the findings of Massachusetts Institute of Technology meteorology professor Kerry Emanuel, which revealed that over the past 50 years the average duration and intensity of Atlantic hurricanes and Pacific cyclones have increased significantly. This is linked to the increase in sea surface temperatures over the last 30 to 50 years of about 0.5 degrees Celsius. There has been a sustained upswing in sea surface temperatures since 1975. Emanuel found that hurricane and cyclone durations have increased by 60% since 1949 and that average peak storm wind speeds have jumped 50% since the 1970s.
According to the October 13 Washington Post, a US National Oceanic and Atmospheric Administration study has determined that sea surface temperatures in the Gulf of Mexico were higher in August than at any time since 1890.
Another recent study by Georgia Institute of Technology scientist Peter Webster has shown that the number of category 4 and 5 hurricanes (the most powerful and destructive, with winds in excess of 210 kph and 250 kph respectively) have almost doubled in the last 30 years, while there are proportionally fewer category 1, 2 and 3 hurricanes (wind speeds of 119-153 kph, 154-177 kph and 178-209 kph respectively). In the 1970s, 20% of storms were category 4 or 5. By the 1990s, it was 35%.
This trend of increasingly intense storms has been reflected in 2005. Hurricane Dennis achieved category 4 intensity on July 7, which is the earliest in the season on record for a storm of that strength, according to the US National Hurricane Centre. Category 5 Hurricane Wilma became a category 1 hurricane on October 18 and by October 19 was registering at 882 millibars, the lowest minimum pressure ever recorded in an Atlantic hurricane, and generated winds of more than 280 kph. Katrina was a category 1 hurricane as it crossed Florida on August 25 but by August 28 it had escalated into a category 5 hurricane, with wind speeds of 280 kph, as it picked up force from the hot Gulf of Mexico waters. At 902 millibars, Katrina was fifth most intense Atlantic hurricane ever recorded.
Similarly, Hurricane Rita intensified from a category 2 to a category 5 storm in the space of 24 hours, with winds reaching 265 kph on September 21 and 280 kph on September 22. Rita was fourth most intense Atlantic storm ever recorded (897 millibars).
That warmer sea and air temperatures generate more powerful and destructive storms is an undisputed scientific fact. NASA's David Adamec explained to the US NBC News on September 21 that, “if you think of a hurricane like as car, there are a lot of parts that keep it going ... the sea surface temperature and the heat that is provided by the ocean, that is the gasoline that fuels it.”
Kevin Trenberth, a climate expert from the US National Centre for Atmospheric Research, told the August 30 Los Angeles Times: “It's ocean temperatures and sea surface temperatures that provide fuel for hurricanes. It's the big guys, the more intense storms, that have been increasing ... in the Atlantic. But if you look more broadly, at what has been happening in the Indian Ocean and the Pacific Ocean, there is a clear trend.”
There is now overwhelming scientific evidence that global warming is taking place. The concentration of industry-generated greenhouse gases — most significantly carbon dioxide from the burning of fossil fuels to generate electricity and fuel transportation — in the atmosphere is rapidly rising, trapping heat like a greenhouse.
The average global temperature is already 0.6°C hotter than at the end of the 19th century. In 2001, the 2500 international scientists of the Intergovernmental Panel on Climate Change warned that unless CO2 levels are stabilised at around twice the pre-industrial level, the Earth's average atmospheric temperature will rise 1.4-5.8°C by 2100. On October 13, the Washington Post reported that data collected by climatologists at NASA's Goddard Institute for Space Studies (GISS) show that 2005 is on track to become the hottest year on record, surpassing the previous hottest year in 1998. It also found that, based on readings from 7200 weather stations around the world, the average global temperature is 0.75°C above the average between 1950 and 1980. It also found that warming is greater in the northern hemisphere.
GISS scientists point out that the 1998 temperature record came on top of the 1997-98 “El Nino of the century”, which was also upwardly affecting temperatures. In 2005, the record is likely to be broken without the help of a large El Nino, the cyclical warming of the ocean that has occurred 10 times in the past 40 years.
Meanwhile, as the huge fossil fuel and energy corporations continue to deny that there is any link between mounting industrial CO2 emissions and climate change, including more frequent and powerful storms and other weather-related catastrophes, other sections of the capitalist class whose profits are directly affected by global warming are sounding alarm bells. Peter Hoeppe of Munich Re, the largest insurer of insurance companies in the world, estimates that the impact of global warming-linked weather disasters is already taking a toll on the insurance industry, and this impact will be much greater as time goes by if action is not taken by governments to reduce global greenhouse-gas emissions.
According to Munich Re, insured disaster losses in 2004 were US$44 billion, the most expensive year ever for the insurance industry. Total disaster losses, insured and uninsured, were $114 billion. This compares to $40 billion (in 2004 dollars) in 1980 and $10.5 billion in 1951. Hurricane Katrina alone may result in personal and commercial property loss claims of $35 billion. Munich Re estimates that between 1994 and 2003 there were almost three times as many weather-related natural disasters as in the 1960s.
“Single events can never prove climate change. But like a stone in a mosaic, if you get enough of them, you begin to see the full picture”, Hoeppe told the July 3 Los Angeles Times. “We have seen dramatic increases in damage from weather events. Something is changing in the atmosphere. There is no other explanation.” Hoeppe attended a conference in Melbourne on November 11 sponsored by the Insurance Council of Australia, where he told delegates: “Natural catastrophes are increasing dramatically in number and magnitude. The insurance industry has to consider climate change in its risk models.”
Munich Re has assembled a team of 25 meteorologists, geologists, hydrologists and economists to study the likely consequences of global warming. Swiss Re, another reinsurance corporation, is funding studies to determine how rising global temperatures could increase the spread of diseases and allergens, which would negatively affect the profits of health insurance and life insurance companies.
In June, the Association of British Insurers, which represents 400 insurance companies, warned that the annual global cost of storm damage to the industry could rise by up to two-thirds by 2080, to £82 billion (A$192 billion) a year.
Green Left Weekly, December 7, 2005.
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