Since starting this blog in June 2013, on at least five occasions I have posted about — or at least touched on — the topics of climate change and sea level rise. As my neighbors and I in South Florida recover from Hurricane Irma, and Texans from Hurricane Harvey, the experts are already running out of adjectives to describe these two storms. Harvey has been described by the National Weather Service as “unprecedented” and “beyond anything experienced”, and Irma was the largest ever-recorded Atlantic hurricane and set some impressive records: it remained a Category 5 (the strongest category) for more than three days, the longest duration for a Cat 5 in more than 50 years; Irma maintained a maximum sustained wind speed of 185 miles per hour for 37 hours, the longest of any cyclone ever recorded anywhere on earth; it generated the most accumulated cyclonic energy of any recorded Atlantic storm; and, it alone generated more accumulated cyclone energy than 18 of the 51 full hurricane seasons since 1966, thus meeting NOAA’s definition of an average full Atlantic hurricane season (June through November) in one storm!
Obviously, the role of climate change in these events is being widely discussed. As I have previously written, the scientific evidence of rising global temperatures is undeniable. The only question, hotly debated by politicians, is the impact of human activity to the phenomena. There can be no argument that sea levels are rising, and warmer ocean temperatures have certainly contributed to that rise. For example, according to Michael Mann, distinguished professor of atmospheric science at Penn State, there is a simple thermodynamic relationship that demonstrates a three percent increase in average atmospheric moisture content for each nearly 1°F (0.5°C) of temperature rise. Based on the increase in the Gulf’s surface temperatures from approximately 86°F to 87°F (30°C to 30.5°C), there was at least three percent more moisture in the atmosphere, a fact that clearly contributed to Harvey’s record breaking rainfall. That, coupled with the >6-inch (15 cm) higher sea level, made the storm surge from Harvey, and resulting destruction, even more deadly.
Climate scientists cite several anthropogenic activities as having contributed to the increase in local sea surface temperatures, including human-induced emissions of greenhouse gases and particulate pollution. In addition to the higher water temperatures, experts point to the coastal subsidence caused by human activities such as oil drilling, as contributing to the rise in sea level. According to Kevin Trenberth, with the Climate Analysis Section at the US National Center for Atmospheric Research, human impact could be responsible for as much as 30 percent of Hurricane Harvey’s rainfall. We’re still recovering from Irma (and, as I write this, watching Maria very closely), but I have no doubt that we’ll be seeing similar scientific analyses linking Irma’s strength to the warm water temperatures resulting from climate change.
Fortunately, here in Florida our building code was substantially revised after Hurricane Andrew, 25 years ago last August. It is almost certain that many areas are faced with the prospect of more intense storms occurring more frequently — Harvey caused the third “500-year” flood in three years (some meteorologists are calling it a “1000-year” event), the other two being the Memorial Day floods in 2015 and 2016 — and Houston had major flooding on an average of four-to-five days each year from 1996 to 2015. So, it may be time for states like Texas and Louisiana to take another look at their building codes.
Also, Property Assessed Clean Energy (PACE), about which I’ve also posted in this blog, considers hurricane hardening (roofs, impact doors and windows, etc.) as qualifying improvements here in Florida. This is also something that the Texas PACE Authority may wish to consider, since PACE is already helping with the restoration efforts here in Florida.
The author is principal at Sustainable Performance Solutions LLC, a south Florida-based engineering firm focusing on energy and sustainability. He can be reached at [email protected]