Does Climate Change Affect Hurricanes?

Atmospheric Composition by Molecular Count (not including water vapor)

Source: iea.org/weo

In the distant past, the earth's orbital eccentricity, variance of the tilt and wobble have led to periods of warmer and colder weather. Even though the solar energy from the sun is considered a constant, a slight change could cause temperature fluctuations. Recently, Mars has also shown a decrease in ice coverage without greenhouse gas changes (Fenton, 2007). The cause for the reduction in aerial coverage and possibly warming may be from dust (Kahn, 1992).

As populations increase, it promotes changes in land type such as the massive grasslands of the central United States of the 19th century changing to mostly agriculture or arid land. Another example is the great tropical forecasts of the Amazon being transformed into agricultural lands. Removing trees does lessen amounts of CO₂ being converted to oxygen, but a likely greater effect is the changing of the albedo increasing heat absorption of the land.

Related to this subject there is another possible influence to the earth's temperature. It is related to the solar wind and the earth's magnetic field. The magnetic field protects us from the harmful charged particles of the solar wind and radiation. Recent research is ongoing on how cloud formation is correlated to the charged particles. It is postalized that variance in solar cycles is related to variance in the amount of cloud cover. [4]

In summary, there are four main known mechanisms which would cause large scale climate change, and another possible cause. These mechanisims could allow for a warming (or even cooling) of the earth's average surface temperature. These are: (1) solar energy variance, (2) gradual changes in the earth's orbit, tilt, and wobble, (3) change in the earth's albedo, (4) greenhouse gas changes, and (5) magnetic field // cosmic radiation variance. Climate has always changed from various mechanisims. These mechanisims can work at different paces. Sometimes there are a combination of causes at work. We are in a warmer phase and the exact combinations for the cause(s) are not known.

A Brief Discussion on Temperature
The hypothesis of temperature increase (or decrease) causing changes in climate is a valid concern. Would a small temperature increase of 1-3 degrees F cause catestropic global climate change? Would glaciers rapidly disappear, polar ice caps collapse, severe weather increase including drought, floods, stronger and more hurricanes? Over the past decades certain scientists and politicians predicted that the Arctic polar ice would disappear during the summer by the mid 2010's which did not occur. Additionally, glaciers were predicted to have melted in Glacier National Park, U.S. by 2020 which did not occur. The media has also advertised that in the US climate change has caused a large upward trend in wildfires. As an example, the January 2025 wildfires in Southern California were determined to be caused by either by arson or faulty high power lines. Wildfires in the 1920's-1930's burned far more acreage and recent fires, despite the advancement in firefighting techniques.

Temperature is at the core of our discussion as it would influence changes in climate and specifically the concern here - tropical cyclones.

There is no doubt that changes in temperature can influence climate. Short term climate changes have been observed with volcanic eruptions injecting large amounts of material into the atmosphere. Crops have failed from the cooler temperatures which can last a year or longer. We can see micro climate change in effect as cities grow in size. This urban heat island effect does change the climate around cities. Rainfall can increase as well as winds being affected. Temperatures are also warmer, especially overnight lows being higher.

One other brief point about global temperature is with its map depiction. Maps of global temperature trends showing the red for warm and blue for cool over long periods of time. These maps should not be trusted if used well before the satellite era. Many times global temperature trends are dipicted from 1900 or earlier into the 19th century. Temperature data except for the United States and western Europe were very sparse and would be unwise to construct global representations this far into the past.

What are the Possible Effects of Climate Change on Hurricanes?
There is a common belief that because the global temperature has slightly increased, hurricanes also must increase in number and intensity. The primary factors in the ability of a hurricane to strengthen or weaken is the wind shear profile of the atmosphere, sea surface temperature, and dry mid troposphere air. Vertical or horizontal shear can tear a tropical cyclone apart keeping it from forming. Dry air can have similar effects. As for water temperature, it has been warm enough in the tropics to produce hurricanes for eons. The temperature for tropical cyclone formation equates to a sea surface temperature of about 80°F (26.5°C). If the behavior of hurricanes are studied, cases can be found where hurricanes have strengthened over cooler water and have weakened over warmer water. More commonly there can be a "boost" to a hurricane's strength as it moves over the Gulf Stream or smaller "loop currents" if upper air wind profiles do not change much.

The recent upturn in tropical cyclone activity was predicted long before Global Warming became a household name. Tropical cyclone activity in the tropical North Atlantic has been known to vary in cycles and an increase was anticipated. For the last approximately 125 years the long term average indicated that there were 11 tropical storms of which 6 became hurricanes. Over the last recent decades, there has been a marked increase to 14 tropical storms of which 7 became hurricanes on average. The 2013 season showed a slow down in numbers of tropical cyclones. In fact, only two hurricanes formed. This is the lowest number since 1982. Looking at the past century, there were other active periods such as the early to mid 1930's. In general the 1930's through the 1960's were an above average period.

Other considerations should take into account medium to long-term atmospheric - oceanic processes. El Nino Southern Oscillation (ENSO) is a well known process that has distinct effects on North Atlantic tropical cyclone activity. Kelvin waves and the Madden-Julian Oscillation are also currently being studied on their effects of tropical cyclone activity. The Pacific Decadal Oscillation PDO) also may be connected. There are many different types of waves or oscillations in the atmosphere and ocean. There is much research to be done on how these processes contribute to tropical cyclone formation and rapid intensification.

Another factor in comparing long term tropical cyclone trends is the increase in technology. Tropical cyclone numbers were likely somewhat higher than what official data represent previous to the satellite era. Satellites did not exist and were not able to observe short lived, small, or remote tropical cyclones.