Tuesday, March 13, 2018

Hurricanes and Social-Ecological Systems: What Climate Change Means to Both


Post by: Luke Lamb-Wotton
 
A satellite image from the 2017 Atlantic season. Pictured are Hurricanes Katia (left), Irma (center), and Jose (right). Credit: Wikimedia Commons.  


For all of us living in coastal areas susceptible to high-energy storms, we all know too well the mayhem and devastation that can be associated with major landfalling hurricanes (category 3+). It took me a mere 3 months living in South Florida to experience my first run-in with one of these wicked storms. 

On September 10th, 2017, after Hurricane Irma swept through Cuba and prompted a mandatory evacuation order for the Florida Keys, Irma came screaming towards South Florida, originally predicted to make a direct hiton Miami-Dade but opted (to Miami-Dade’s relief) to take a more south-westerly track towards Tampa Bay. Regardless of the exact track, Irma’s expansive wind-field and storm surge still wreaked havoc on Miami-Dade’s infrastructure (some images can be found here), contributing to Irma’s ranking as the 5thcostliest U.S. hurricane on record, as reported by NOAA’s National Hurricane Center, reaching an estimated $50,000,000 in damages. 

In general, the 2017 Atlantic hurricane season was one for the record books, ranking 7th in terms of annual U.S. hurricane activity. Beginning August 27th, the U.S. got hit with the 30 dayhurricane three-piece as Hurricane’s Harvey, Irma, and Maria made landfall, the first Atlantic hurricanes to do so since Hurricane Wilma in 2005. Hurricane Harvey brought devastating rainfall to Houston, ranking by one weather historian as, “the most extreme precipitation event to hit a major U.S. city.” Hurricane Irma broke a whole slew of records- including the world record for time maintained at peak intensity (185 mph). Irma also leveled the island of Barbuda, which may force Barbuda into the modern world, as told by the Washington Post. Last but not least we can’t forget about Hurricane Maria, the storm that ransacked the Caribbean and started a national discussion about the speed of the ongoing federal hurricane relief. 

While it is easy to start pointing fingers and proclaim, “it’s climate change”, we need to be careful with these words (a lesson I surely learned during Dr. Joel Trexler’s Advanced Ecology course). A quick Google search makes it evident that the hurricane-climate change discussion is a hot topic. So, what do the experts think?

Two reports, one from NOAAand the other from NASA, generally conclude the same, and can be summarized succinctly with a quote from the NOAA report (linked above):

A future increase in tropical cyclone precipitation rates is likely; an increase in tropical cyclone intensity is likely; an increase in very intense (category 4 and 5) tropical cyclones is more likely than not; and there is medium confidence in a decrease in the frequency of weaker tropical cyclones.”

Yikes! The above quote likely sounds alarming to those who live within hurricane affected areas but one point should be clarified: this is referring to changes in globalhurricane activity and trends at global-scale often aren’t applicable at smaller spatial scales, a trap I often fall into in my research.
In that same NOAA report, the authors explain that little correlation between greenhouse gas emissions and hurricane activity exists for Atlantic basin hurricanes over the 120+ years of record. If a change in activity is to occur in the Atlantic basin, it likely wouldn’t even be detectable until the latter half of the century.

So, what to make of all this? When hurricane activity is aggregated across all the different basins of activity, increases in activity and intensity are very likely, but basin specific changes will be variable. While it is difficult to discern regional variability, preparing for the worst-case scenario might not be a terrible idea. 

In a 2005 paper, Adger et al. describe what they call social-ecological resilience to natural disasters and use case-studies to show how some regions exhibit more resilience than others. The authors define resilience in this usage as, “the capacity of linked social-ecological systems to absorb recurrent disturbances such as hurricanes and floods so as to retain essential structures, processes, and feedbacks.”

Adger and colleagues go on to describe an example of how varying levels of social-ecological resilience in South and Southeast Asia led to some areas being disproportionately affected by the 2004 Asian tsunami, caused by the second largest earthquake ever recorded. Contrary to what one might think, islands with high-levels of local knowledge and preparedness survived and were returned to some sort of normalcy faster than some mainland areas. 

While it is a good strategy to think about social resilience to natural disasters, some of the leaders in the field of Urban Ecology recently applied a conceptual framework to describe disturbance events and their impacts on “social-ecological-technological systems” (Grimm et al. 2017). 

By applying model specifications for describing disturbance events in urban settings, urban practitioners can focus their efforts on improving the resilience of their respective urban settings by identifying outcomes and vulnerabilities based on a standard set of criteria (Grimm et al. 2017). This is an important step in the right direction towards minimizing the catastrophic nature of hurricanes on cities and societies in an era of global increases in hurricane activity.

While I know that I have two paragraphs above discussing social-ecological resilience, one point I did want to make was that it was refreshing to see Grimm et al. make a focused effort on defining the entirety of the disturbance event without framing the discussion with a “let’s build resilience” narrative. While it is an important topic to consider (one of the first words you see when going to FIU’s Sea-Level Solutions Center webpage), it strikes me as an overused framework.
While I don’t mean to say “resiliency” is a bad framework in and of itself when discussing these issues. However, it seems to me that it could be perceived by some that by “building resilience” to climate change related events means climate change isn’t here yet and it most certainly is.

The complexities of society are only going to increase in an age of globalization and it would appear that hurricanes (and other natural disasters), will increase as well. Since certain regions will be better equipped than others to deal with this, I’d like to leave y’all with one final thought: As a global society, I think we can all agree that we still have a ways to go in figuring out how to distribute pockets of regional resilience across all parts of this spinning rock we call Home.

References
1.      Direct link to NOAA report: https://www.gfdl.noaa.gov/global-warming-and-hurricanes/
2.      Adger, W. Neil, et al. "Social-ecological resilience to coastal disasters." Science 309.5737 (2005): 1036-1039.
3.      Grimm, Nancy B., et al. "Does the ecological concept of disturbance have utility in urban social–ecological–technological systems?" Ecosystem Health and Sustainability3.1 (2017).

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