Science Saturday: Climate Change and Hurricanes
This past August marked the 10th anniversary of Hurricane Katrina, with extreme weather events and climate change coming back to the forefront of discussions (slightly). It is, however, wrong to consider a specific weather event to be indicative of climate change. Even a weather event as extreme as Katrina needs to be analyzed in the context of long-term hurricane patterns and trends in the global climate system.
See some sattelite photos of Hurricane Katrina from NASA Goddard
There are a few facts that research and data tell us about future hurricanes and predictions. According to the National Oceanic and Atmospheric Administration (NOAA), the two variables that are most considered when predicting future hurricane trends are their intensity and frequency. When commenting on the effects of climate change, most people say, more off-handily than not, that both intensity and frequency will rise in the future because of global climate change.
This assumption is misguided.
From a NOAA review of existing studies, it is concluded, “It is likely that greenhouse warming will cause hurricanes in the coming century to be more intense globally and have higher rainfall rates than present-day hurricanes.”
This question of frequency and intensity also depends on which region of the world we are focusing on. NOAA’s regional model for the Atlantic hurricane and tropical models show that the number of hurricanes and tropical storms falls for the average 21st century climate change projected by their current models. However, NOAA also predicts the rate of rainfall will be higher in the event of tropical storms.
Another important issue in the topic of hurricanes is the challenge of forecasting future damage, which is linked to the question of how society should respond. Here I will quote NOAA extensively:
“In the Bender et al. 2010 study, we estimate that the effect of increasing category 4-5 storms outweighs the reduction in overall hurricane numbers such that we project (very roughly) a 30% increase in potential damage in the Atlantic basin by 2100. This estimate does not include the influence of future sea level rise or other important factors such as coastal development or changes in building practices.”
It’s important to note a couple of things with this statement. One is the rough estimate of increase in potential damage and the difficultly of putting a number to it. And two, though this estimate was given a number, it does not factor in many important factors environmental and anthropological factors that will matter quite a lot when evaluating damage from hurricanes. This really goes to show that predicting weather and its interaction with human structures, like buildings and infrastructure, is very complex.
While scientists are still trying to form a better picture of the future of hurricanes, this does not mean that this research is not useful. Erring on the side of caution with tropical storms that could be more intense should always be the first step to disaster preparedness. This should be our biggest lesson from Katrina: though individual hurricanes cannot be stopped, people and government need to be mobilized to preserve safety and order.
