[ad_1]
Asking whether a climate event is influenced by climate change is tantamount to asking whether an air ball will be influenced by gravity. The planet has warmed significantly in recent decades and has caused changes in the environment in which extreme weather events occur.
Some of these changes are minor and inconsequential, and some, such as the shear of the wind that tears hurricanes, could actually be beneficial. But some have destructive consequences.
The year 2017 was the hottest ever recorded for the Earth's oceans, with a world heat record in the top 2,000 meters of the oceans. This year, the trend is even warmer, with the heat content of the oceans from April to June being the highest ever recorded.
"The heat feeds all kinds of storms and contributes to very heavy rains and floods," said Kevin Trenberth, a senior scientist with the National Center for Atmospheric Research.
"The observed increases in [ocean heat content] support higher sea surface temperatures and humidity, and feed tropical storms so that they become more intense, larger and more durable, thus increasing their potential for damage ", -he declares.
Florence's environment was warmer and wetter because of climate change, said Trenberth, which paved the way for what was to be the biggest threat of the storm: heavy rains and flash floods.
The warmer oceans mean more moisture available in a warmer atmosphere.
"It's one of the simplest relationships of any meteorology," said Michael Mann, professor of atmospheric science and director of the Earth Science Science Center at Penn State University.
For every degree Celsius (1.8 degrees Fahrenheit), there is 7% more moisture in the air. The ocean temperatures around Florence were higher than normal at 1.5 degrees Celsius (2.7 degrees F), contributing to about 10% more humidity in the atmosphere.
Highest level of the sea, stronger increase
Florence reached record levels in parts of North Carolina, although it weakened into a Category 1 storm with winds of 90 miles per hour on Friday morning.
The NOAA tide gauge at Wrightsville Beach, North Carolina, jumped more than 4 feet above normal on Friday when the storm landed, beating the record set by Hurricane Joaquin in 2015 by more than a foot.
Floods in Beaufort and Wilmington, North Carolina, were also marked by high tides of several decades.
Several factors have contributed to making Florence such a prolific coastal flooding threat. Its large size, slow movement and previous Category 4 intensity all accumulated an enormous amount of water.
But these features are mostly a product of the daily weather conditions around Florence and are somewhat random – a rolling weather dice, if you will.
But when a storm like Florence arrives ashore, the destruction is even worse than a few decades ago – one of the reasons why Category 1 hurricanes Matthew and Florence have produced higher water levels on the coast of North Carolina which was a category 3 when it landed in the same area.
Florence and Harvey should not be seen as an example of what man-made global warming could bring us at any given moment. They must be considered as regrettable examples of the fact that global warming, caused by the steady increase in greenhouse gas emissions, is causing the current storms.
It is therefore time to act now to solve the current problem, both with better coastal infrastructure and flood defenses and with an immediate reduction in greenhouse gas emissions to minimize the future threat.
The visit will again provide the President with evidence that climate change is already affecting the country.
Source link
