By Physicist Dr. Ralph Alexander
In a world that routinely hypes extreme weather events, it’s no surprise that the mainstream media and alarmist climate scientists have declared this year’s Atlantic hurricane season “unprecedented” and “record-shattering.” But the reality is that the season was merely so-so and no records fell.
While it’s true that the very active 2020 season saw a record-breaking 30 named storms, only 13 of these became hurricanes. That was fewer than the historical high of 15 recorded in 2005 and only one more than the 12 hurricanes recorded in 1969 and 2010, according to NOAA (the U.S. National Oceanic and Atmospheric Administration). The figure below shows the frequency of all Atlantic hurricanes from 1851 to 2020.
Of 2020’s 13 hurricanes, only six were major hurricanes, less than the record eight in 1950 and seven in 1961 and 2005, as shown in the next figure. A major hurricane is defined as one in Category 3, 4 or 5 on the so-called Saffir-Simpson scale, corresponding to a top wind speed of 178 km per hour (111 mph) or greater. Although it appears that major Atlantic hurricanes were less frequent before about 1940, the lower numbers reflect the relative lack of observations in early years of the record. Aircraft reconnaissance flights to gather data on hurricanes only began in 1944, while satellite coverage dates only from the 1960s.
Despite the lack of any significant trend in Atlantic hurricanes in a warming world, the frequency of hurricanes globally is actually diminishing as seen in the following figure. The apparent slight increase in major hurricanes since 1981 has been ascribed to improvements in observational capabilities, rather than warming oceans that provide the fuel for hurricanes and typhoons.
As further evidence that recent hurricane activity is nothing unusual, the figure below depicts what is known as the ACE (Accumulated Cyclone Energy) index for the Atlantic basin from 1855 to 2020. The ACE index is an integrated metric combining the number of storms each year, how long they survive and how intense they become. Mathematically, the index is calculated by squaring the maximum sustained wind speed in a named storm every six hours that it remains above tropical storm intensity and summing that up for all storms in the season.
For 2020, the Atlantic basin ACE index was 179.8, which ranks 13th behind 2017, 2005, the peak in 1933 and nine other years. For comparison, this year’s ACE index for the northwestern Pacific, where typhoons are common, was 148.5. The higher value for the Atlantic this year reflects the greater number of named storms.
NOAA attributes the enhanced number of atmospheric whirligigs in the Atlantic in recent years to the warm phase of the naturally occurring AMO (Atlantic Multi-Decadal Oscillation). The AMO, which has a cycle time of approximately 65 years and alternates between warm and cool phases, governs many extremes, such as cyclonic storms in the Atlantic basin and major floods in eastern North America and western Europe. The present warm phase began in 1995, marking the beginning of a period when both named Atlantic storms and hurricanes have become more common on average – as seen in the first two figures above.
Another contribution to storm activity in the Atlantic comes from La Niña cycles in the Pacific. Apart from a cooling effect, La Niñas result in quieter conditions in the eastern Pacific and heightened activity in the Atlantic. The current La Niña started several months ago and is expected to continue into 2021.
Despite NOAA’s recognition of what has caused so many Atlantic storms in 2020, activists continue to claim that climate change is making hurricanes stronger and more destructive and increasing the likelihood of more frequent major hurricanes. Pontificates Michael “hockey stick” Mann: “The impacts of climate change are no longer subtle. We’re seeing them play out right now in the form of unprecedented wildfires out West and an unprecedented hurricane season back East.”
Clearly, there’s no evidence for such nonsensical, unscientific statements.