Why Hotter Really Matters

 

“Tracking hurricanes from the Cape Verde [Africa] formation zone gives me and other Caribbean people plenty of time to broadcast preparedness warnings.”

Caribbean resident and stormwatch volunteer, Jane Higgins  

Among climate change’s greatest symptoms is the length and severity of tropical storms. Intense winds are born of cold and warm fronts colliding, and as temperatures increase during the various storm seasons around the world, so do the wind forces behind the storms. Likewise, as the water beneath those storms gets warmer, especially ocean surface temperature north of 80 degrees Fahrenheit, the more water rises and is sucked up by the storm. This increases the volume of water now captured by the storm, leaving more to be dropped on human-inhabited land masses later, and the extra weight slows the forward progress of the tropic storm, letting it sit longer atop land mass to dump vastly more rainwater before lumbering on.

The wind velocity itself might not change from the extra water – just the vector of the storm itself – so you have the worst of two worlds: exceptionally high winds with vastly more concentrated rainwater, both hovering in place for longer times before moving on. The concomitant damage results in more intense storms (even as the number of tropical rampaging storms remains about the same) with much greater potential for torrential flooding.

This season’s Hurricane Laura, for example, generated surface water temperatures in the Gulf of Mexico were solidly between 86 degrees and 88 degrees. The odd after-effect of the passing storm was to churn up deeper water, bringing surface temperatures down to 82 degrees in Laura’s wake. We saw the same pattern in most recent severe Gulf hurricanes, where the Gulf surface temperature has been riding higher during the hurricane seasons from the last few years. Simply put, the severity of such storms seems to be increasing each year.

What is particularly interesting to those of us in the United States is the impact of serious excessive rising temperatures in West Africa (around Cape Verde) and how that impacts hurricane season in the US. “It turns out that about 83% of major hurricanes – categories 3, 4 and 5 – that hit North America share the same birthplace as [Hurricane] Irma. Those emerging from Cape Verde are among the most powerful and longest-lived tropical storms. This has led stormwatchers to look closely at the atmosphere above Africa for clues about what might be going on. What is it about the storms emerging from here that makes them so devastating? And is it possible to predict the most powerful hurricanes to give people in their path more time to prepare? …

“Typically, the Atlantic sees around six hurricanes a year. But 2020 is no average year – at the time of writing, 25 named tropical storms and nine hurricanes have already formed. After the 2019 hurricane season concluded with Storm Sebastian in November, the World Meteorological Organization’s list of 21 alphabetical names (Q, U, X, Y and Z are excluded) – which are used on a six-year rotation – became exhausted by mid-September. Instead the last four storms have been allocated Greek nomenclature – Alpha, Beta, Gamma and Delta.

“Among the nine hurricanes of 2020, four – including the two most powerful storms Laura and Teddy – can be traced back to Africa, where the seeds for their destructive power were first laid. Like all Cape Verde hurricanes, they began as disturbances high in the atmosphere above western Africa, known as African Easterly Waves. These are huge kinks in the stream of air that flows across Africa from east to west.

“This stream of air, known as the African Easterly Jet, is driven by the large temperature difference between the enormous expanse of the Sahara Desert and the semi-arid Sahel region to its south.

“The Sahara Desert – one of the driest regions on the planet – covers more than 3.3 million square miles (8.5 million sq km) and spans 11 countries in northern Africa. It produces a steady blast of hot, dry air into the atmosphere. ‘Obviously it’s always hot there, but in the summer it gets really hot,’ says Philip Klotzbach, an atmospheric scientist at Colorado State University, who issues seasonal forecasts on the Atlantic hurricane season. The summer heat increases the differences between the hot, dry Sahara and the cooler, wetter Sahel. The more pronounced the temperature gradient, the stronger the jet stream.

“As the hot Saharan air rises several kilometres above the surface, it turns southward to meet the cooler air above the Sahel and the Gulf of Guinea. The rotation of the Earth turns this air current westward to create a powerful jet of air across the continent and out into the Atlantic Ocean. ‘It’s a very strong blow out of the east at 15-20,000ft (4.5-6km),’ Klotzbach explains.” BBC.com, October 15^th. Higher heat thus means more intense winds and more water absorbed into the hurricane vortex. The perfect storm has become the routinely perfect storm.

Some scientists believe that giant pumps could be used to bring colder water from deep beneath the surface of the Gulf of Mexico to the surface to reduce that absorption of warmer water to help reduce the impact of Gulf-related hurricanes. Perhaps, but not only is this exceptionally costly and complex, it is like trying to put a band aid on a massive gaping wound. We just keep sidestepping the dire necessity of dealing with climate change as a whole, noting that hurricanes are one huge, but relatively small, part of the overall damage caused by our failure to contain greenhouse gasses.

Or we can continue to watch once productive agricultural land dry up and turn fallow, disease carrying insects migrate to regions where there is no immunity against those diseases, watch precious forest land burn into oblivion, observe rising seas and massive coastal erosion and uncontrolled flooding decimate man and animal alike. Add the wars resisting unwanted drought-driven migrants, conflicts over increasing resource scarcity and the tens of trillions of dollars of lost values and opportunities. We have been making the wrong economic/business friendly choice.

            I’m Peter Dekom, and the most basic economic principles tell you that ignoring the containment of climate change is probably the most destructive policy possible when it comes to measuring near-term and long-term job growth and sustaining business values and profitability.