In its most recent assessment on global warming, released in September, the IPCC stated that there were no identifiable long-term trends when it comes to tropical cyclones, which are also known as hurricanes or typhoons. However, there are fears that the strongest storms could grow even more destructive.
Tropical storms draw their energy from warm water. But the equation "warmer oceans equals more storms" doesn't hold true. The phenomenon known as wind shear as well as airborne dust particles can weaken them. Indeed, some have posited that reductions in air pollution in the Western world since the late 1970s have contributed to an increase in hurricane activity over the Atlantic since then.
In 2012, researchers from the University of Copenhagen reported that hurricane activity in the Atlantic had been rising for decades and had now grown as strong as it was at the end of the 19th century. However, the World Meteorological Organization (WMO) states that this trend was broken in the Atlantic at the turn of the millennium. The 2013 storm season, which ends in November, has so far been especially mild, with only two hurricanes, especially considering all the pessimistic forecasts published at the beginning of the year.
Fewer Storms, Higher Floods?
The WMO also reports that, over the last decade, there has been below-average tropical storm activity. In fact, Ryan Maue, a climate researcher at Florida State University, wrote in 2011 that worldwide tropical storm activity has reached a low point. Another study, from 2012, calculates that the number of storms has been declining since 1872.
Nevertheless, there is still the question of where things will go from here. The IPCC states that simulations predict there will be fewer tropical storms as the global temperature rises. But the most unsettling finding is that the strongest storms could get even stronger.
The consequences of this could be grave, writes Yale University researcher Robert Mendelsohn. According to his estimates, the strongest 1 percent of storms could cause more than half of the damage of all storm activity combined. However, since these giant storms come so infrequently, experts say it might be centuries before it is possible to actually measure the effects of climate change.
For the Philippines, other changes in the earth's climate might prove much more worrisome. For example, there are hardly any other places where the sea level is rising as quickly, and storm floods there continue to get higher. What's more, climate researchers expect to see more precipitation in a warmer world, as milder air can retain more moisture. As a result, typhoons could trigger even greater flooding.