Global Warming: Its Influence on Floods and Hurricanes

11/17/20221 min read

In the aftermath of Hurricane Katrina in 2005, the disastrous loss of human life amounted to 1,833 people and hundreds missing in the US states of Louisiana, Mississippi, Florida, Georgia, and Alabama (Knabb et al 2006), with economic loss and damage estimated at USD186.3 billion (NCEI 2022).

Tropical waves, warm waters, thunderstorm activity, and a sudden or sharp uptake in wind speed or direction, can combine to form a hurricane (NOS). As global temperatures increase and the oceans warm, this results in expansion of waters, deglaciation, and loss of snow cover, and consequently an average increase in sea levels all over the world (Irish et al 2014).

By studying historical records over the past 100 years,, researchers calculate that in that period, the global sea levels have risen at an annual rate of approximately 1.7 to 1.8mm (Irish et al 2014).

Global warming has influenced hurricane intensity significantly. Irish et al consider that if Hurricane Katrina had happened in 1900, with its cooler climate and lower sea level, floodwaters would have been 15 to 60% lower and there would have been much damage (Irish et al 2014).

As the Earth continues to heat up, coastal communities, especially those in low-lying areas, are in great danger of flooding and storm surges.

Apart from causing sea level rise, warmer sea surface temperatures also lead to more intense hurricanes and storms, and higher levels of storm surge (Irish et al 2014). For every 1 degree Celsius increase in sea surface temperatures occasioned by greenhouse gas emissions, we can expect an average of 8% increase in the pressure differential, and 3.7% higher windspeeds, of cyclones and hurricanes (Irish et al 2014).

References:

  • Knabb, R.D., Rhome, J.R., Brown, D.P. (2006). ‘Tropical Cyclone Report - Hurricane Katrina - 23-30 August 2005’. National Hurricane Center. 10 August 2006. https://www.nhc.noaa.gov/data/tcr/AL122005_Katrina.pdf

  • NOAA National Centers for Environmental Information (‘NCEI’). (2022). ‘U.S. Billion-Dollar Weather and Climate Disasters (2022)’. https://www.ncei.noaa.gov/access/billions/ DOI: 10.25921/stkw-7w73

  • National Ocean Service (‘NOS’). National Oceanic and Atmospheric Administration. ‘How do hurricanes form?’ https://oceanservice.noaa.gov/facts/how-hurricanes-form.html

  • Irish, J. L., Sleath, A., Cialone, M.A., Knutson, T.R., and Jensen R.E. (2014). ‘Simulations of Hurricane Katrina (2005) under sea level and climate conditions for 1900’. Climatic Change 122(4) 2014, pp.635–649.