The typhoon that has scientists’ heads SPINNING
Will a typhoon like Haiyan happen again?
Very likely – and it may be worse, say experts.
The typhoon that hit the Philippines, clocked with almost 200-mile-an-hour winds, has gone down as possibly the worst in history. And it may be only the beginning of more horrendous storms to come because of global warming.
Typhoons gain their strength by drawing on ocean heat and intensify when combined with cool air.
While the Pacific this time of year is ripe for the worst – a Category 5 – kind of typhoon, it usually peaks before reaching land. However, that was not the case with Haiyan. According to experts, the ferocity of the winds accompanying the storm whipped it to a greater frenzy. Coupled with the deluge of rainwater accumulated by mountainous regions then dumped, the result was what Massachusetts Institute of Technology scientist Kerry Emanuel called “a triple whammy,” resulting in this typhoon possibly being the worst on record.
The closest to this kind of storm was 1969’s hurricane Camille, which struck the Gulf Coast of the United States with 190-mile-an-hour winds. However, the size of that storm was only one fifth the size of the one that hit the Philippines. This storm got so strong because “it had everything working for it,” tropical weather expert Brian McNoldy told Science magazine. Other scientists have blamed the storm’s intensity on a series of bad coincidences coming together – warmer than usual water, late peaking, extremely high winds and heavy rainfall. “This is the top end of any tropical system that we have seen on our planet,” said Weather Channel hurricane specialist Bryan Norcross.
Typhoons are similar to hurricanes, except they originate in the Pacific. Two major components must be present: the ocean and warm air. Because heat rises, warm air is pushed upward, into the sky, causing a large swirling action. The moister the ocean and the hotter the air, the more the typhoon keeps growing, which was the case in the Philippines.
Typhoons, similar to hurricanes, are formed by a combination of water vapor and thermal energy, but six things have to happen to create the intensity and subsequent devastation wrought by Haiyan: warm sea temperatures, atmospheric instability, high humidity in the troposphere (lower region of the earth’s atmosphere), a pre-existing low level of disturbance, low vertical wind shear and what is called the Coriolos effect, which is responsible for the rotation of large cyclones or typhoons.
Although strong activity in the past has been associated with warming of the Pacific due to el Nino, that did not occur in this case. Scientists attribute the intensity of the storm to a phenomenon called “Madden-Julian oscillation,” which is a periodic increase in the uplift of warm, wet air from the ocean., which spawns such storms. Some scientists have said that this effect is likely to increase dramatically due to global warming.
This catastrophe was also enhanced by the island nation’s poor infrastructure of poor building materials used to build many homes. “Weak connections between roofs and walls expose the buildings to consistent extreme wind force,” said Norman Cheung, an environmental hazards expert at London’s Kingston university. “The marked change of internal and external pressure made them collapse completely.”
Some believe that such storms, including hurricanes in the Atlantic, such as Hurricane Sandy that hit the Northeast coast of the United States last year, are getting worse? While it is plausible to assume so, most scientists see their frequency dissipating but their strength growing.
Said MIT’s Emanuel: "The weaker storms might be less frequent, but it's not the weaker storms that do the damage. In the end, we're much more concerned about what happens at the high end. It's those guys that do all the terrible destruction."
Whether the change in storm activity is attributed to global warming “is the one-million-dollar question,” says author Quirin Schiermeier of Nature magazine. “Storms receive their energy from the ocean, so it would seem logical that they would get stronger, and perhaps also more frequent, as the upper layers of the tropical oceans warm. Indeed, the potential intensity of tropical storms does increase with warmer sea-surface temperatures.”
However,he continued, “ the effect of warming seas could be counteracted by the apparent increase in the strength of shear winds—winds blowing in different directions and varying strength at different altitudes. Shear winds tend to hinder the formation of storms, or tear them apart before they can reach extreme strength.
On balance, many climate researchers think it is plausible to assume that tropical storm activity will rise. Some evidence exists that storm intensity has indeed increased, but it is limited to the North Atlantic, where observations are most abundant. In other places, the available evidence is not yet conclusive. However, note climatologists, this is the third time such disaster has hit the Philippines in less than a year. A typhoon last December killed 2,000 – albeit low in comparison to the anticipated death toll of 12,000 this time around. This does not take into consideration the devastating economic impact to the country estimated to be about $14 billion.
Climatologists have said we should assume that tropical storm activity around the globe will increase. However, until this past week, it was assumed that the proliferation of such activity would be in the Atlantic.
The devastation of the past week now has everyone going back to the drawing boards.
(This story is based on reports by Toronto’s Globe and Mail, Nature and Science magazines, the Weather Channel, Bloomberg News and Associated Press and other news sources.)