Tuesday, September 3, 2019

Hurricane Dorian Sets Records

Image credit KJCT 8 ABC.com
Hurricane Dorian is yet another wake-up call. Dorian has broken all kinds of intensity records including being the strongest storm ever to make landfall. Dorian slammed into the Bahamas as a category 5 storm bringing with it widespread flooding and wind speeds gusting up to 220 miles per hour.  In its wake buildings have been damaged and destroyed. Five people are known to have died but the casualty count could increase even thought the storm has weakened to a category 2 storm.

This slow moving storm still packs a punch with wind speeds exceeding 110 miles per hour. It is expected to move northwest towards Florida and work its way up the coasts of Georgia and South Carolina tonight. It could cause flooding on the US mainland with surges of up to 7 feet in some places.

Despite advances in attribution science we need to be cautious when linking this or any individual storm to global warming, however, we cannot discount the basic physics at play.

"Other influences being equal, warmer waters yield stronger hurricanes with heavier rainfall. The tropical Atlantic Ocean has warmed over the past century, at least partly due to human-caused emissions of greenhouse gases," National Oceanic and Atmospheric Administration (NOAA) said.

Heat is the fuel that powers storms and every month this year has been among the hottest on record. July 2019 was hottest month ever recorded and this year's high ocean temperatures have proven fatal to marine wildlife.

High sea surface temperatures, drive stronger winds, more evaporation, more atmospheric moisture and more heavy precipitation.  Heavy rainfalls are part of the new normal in a warmer world. NOAA made this point in a recent statement: "Most models agree that climate change through the twenty-first century is likely to increase the average intensity and rainfall rates of hurricanes in the Atlantic and other basins."

These storms are not just about destructive high winds and heavy downpours. They are also about storm surges that exacerbate sea level rise and cause widespread flooding.

We saw how warmer temperatures played a role in Hurricane Harvey which killed 68 people. The storm dumped 60 inches of rain over parts of Texas and storm surges of as much as 7 feet. The National Hurricane Center called it "the most significant tropical cyclone rainfall event in US history." It was also one of the most costly hurricanes in US history.

Hurricane Dorian is hardly the only extreme weather event we have seen in 2019. Cyclones Idai and Kenneth devastated parts of Mozambique alongside dozens of lower impact events that did not make international news.

Record breaking heatwaves and wildfires have been defining features of 2019. These events are becoming increasingly severe as have storms, floods and droughts. According to the UN there are now an average of four climate disasters every month.

Climate change is not a future nightmare it is a current reality. As explained by Mami Mizutori, the UN secrtary General's special representative on disaster risk reduction, "This is not about the future, this is about today."

Record breaking extreme weather is here to stay. We can prepare by planning and investing in adaptation and resilience, but just how bad it gets will depend on our climate mitigation efforts.

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