Indirect Effects of Climate Change on Cyclones

Fiji was recently hit by Tropical Cyclone Tomas, a category four storm. Reports coming from the hardest hit areas indicate the effects were felt for four days, but that thankfully, there appear to be few fatalities. Was the cyclone caused by climate change? Not really. Were some of its impacts linked to climate change? Possibly.

Shorter-term factors like El Nino and local factors like sea surface temperatures and wind shear had a much more immediate impact on the strength and track of Tomas. In fact, the El Nino conditions were experiencing right now can increase the number of cyclones in the South Pacific and move their storm tracks northeast. Fiji sits right to the northeast of most storm tracks so its not surprising that a cyclone made landfall there.

Climate change and its effect on cyclones is a very "active" area of research. It just so happens the World Meteorological Organization (WMO) Expert Team on Climate Change Impacts on Tropical Cyclones recently updated their findings on tropical cyclones (or hurricanes or typhoons as you may know then in other parts of the world). There's two areas of strong agreement in their report. The first? No single event can be tied to climate change. Al Gore ran this problem using Hurricane Katrina in An Inconvenient Truth, and James Inhofe did the same in turn when he built a snow fort for Al Gore. The climate system is much too complex to consign single events to specific causes.

The second? The WMO Team makes it the last point in their report:

Despite the diversity of research opinions on this issue it is agreed that if there has been a recent increase in tropical cyclone activity that is largely anthropogenic in origin, then humanity is faced with a substantial and unanticipated threat.

While current research indicates climate change is not the direct cause of this (or any other) cyclone, its possible that result could change as research methods and data gathering improves. Rather than speculating on what that might mean, though, its worth examining some trends that more concretely relate anthropogenic climate change to cyclone damage.

Indirect Impacts of Climate Change on Cyclones

One of those connections is sea level rise. The IPCC is fairly certain sea levels will rise over the course of the 21st century. When sea levels increase, so too, does the damage from storm surges caused by tropical cyclones. Higher oceans mean higher storm surges that take longer to recede. This is not good: the leading cause of death from tropical cyclones is salt water flooding due to storm surges.

Also, one area of agreement is a likely increase in precipitation from storms. A warmer ocean allows for more convection, which means more moisture waiting to fall as rain. More rain can lead to greater flooding and increase the likelihood of water-borne diseases after a storm passes over.

Us and Cyclones

In addition to long term climate change and shorter-term variability, there's a third important factor that affects how much damage cyclones cause: where we choose to build. Coastal areas are become increasingly more populated. As more people move to these areas and insure homes (in the developed world at least), tropical storms are likely to cause greater damages and higher costs.

The climate system and human development are inherently tied together. A change in either one of them affects lives, property, and the environment. It?s not likely that coastal communities will be abandoned anytime soon. In light of this fact, it's important to adapt to current conditions and possible worse ones in the future. Better warning systems, stronger infrastructure and building codes, and better action plans will help protect lives and livelihoods.

Photo Credit: Flickr