Cyclic Theory

Some climatologists view the incidences of hurricanes as part of a natural cycle. Some researchers at NOAA and Colorado State University have conducted studies that support the theory that the number and intensities of hurricanes follow in 50- to 70-year cycles called the Atlantic Multidecadal Oscillation (AMO). They believe the AMO is controlled by gradual changes in the North Atlantic Ocean currents.

The AMO controls the flow and direction of the major wind systems. When the trade winds blow steadily from the east, they produce excellent conditions for hurricanes to form. Right now Earth is in the AMO, which is why there are presently so many hurricanes. When the strength of the ocean currents changes and causes the westerlies to move southward toward the trade winds, this keeps hurricanes from forming. During these times of the cycle, there are not many hurricanes.

It has also been suggested that El Niño events in the Pacific, which occur every four to seven years, tend to keep hurricanes from forming in the Atlantic, especially strong hurricanes of category 3 or higher. El Niños occurred in the Pacific in 1997 and 2006. These two years also had very little storm activity in the Atlantic.

The 2004-05 hurricane season spurred much debate among climate scientists. Kevin Trenberth at the National Center for Atmospheric Research located in Boulder, Colorado, believes that half of 2005's extra ocean warmth was due to global warming. Clifford Jacobs at the National

Science Foundation (NSF) calls the situation a "raging scientific debate." According to the National Research Council, the past few decades have been the warmest on Earth in the last 400 years, if not the last several thousand years. One of the panel members of the National Research Council, Kurt Cuffey, believes there is an overwhelming amount of evidence that human activities—such as deforestation, farming practices, and the burning of fossil fuels—have significantly contributed to global warming and thus to the number of hurricanes per year.

One of the critical aspects of hurricanes is the amount of destruction they cause. The harm to people and damage to property can be enormous if they strike heavily populated areas. Unfortunately, coastal areas are some of the most desirable places to live, as evidenced by some of the United States's most populated cities: New York, Los Angeles, Miami, and New Orleans.

The remains of the middle school in Pass Christian, Mississippi, September 19, 2005. Hurricane Katrina caused extensive damage all along the Gulf Coast. (Mark Wolfe, FEMA)

Biloxi, Mississippi, April 1, 2006. After Hurricane Katrina, demolition was the only choice for many buildings such as this one along Highway 90. After seven months, it was still difficult to comprehend the degree of devastation the Mississippi coast area sustained. (George Armstrong, FEMA)

The period from 1970 to 1994 was a relatively quiet period in terms of tropical cyclone activity. In fact, relatively few actually made landfall anywhere in North America. During this time, the United States's population was beginning to grow, and expansion of settlements along the nation's coasts was enormous. Similar tendencies of population growth along coasts has occurred worldwide.

When major hurricanes hit populated areas the effects can be disastrous. Even people that have "hurricane proofed" their homes with cement reinforcement and hurricane shutters have returned after a storm to find their house completely gone. Some residents who lose their homes after major hurricanes never rebuild but move from the area instead. (This was the case after Katrina, which hit the U.S. South-

Pass Christian, Mississippi, October 4, 2005. An aerial photo of destroyed Mississippi Gulf Coast Highway I-90 as a result of winds and tidal surge from Hurricane Katrina. This section of the bridge connected Pass Christian, near Gulfport, to Bay St. Louis. (John Fleck, FEMA)

Punta Gorda, Florida, in 2004 after Hurricane Charley swept through

(Andrea Booher, FEMA)

Punta Gorda, Florida, in 2004 after Hurricane Charley swept through

(Andrea Booher, FEMA)

east in 2005.) Others, who return, face major reconstruction. Often those who do not lose their house have to deal with the eventual invasion of indoor mold due to the moisture from the storm, causing them to evacuate later. Whether storm victims relocate, rebuild, or choose some other alternative, the impact has a financial, emotional, logistical, and psychological cost. Family members are often lost, as well as property and other personal items.

When people rebuild, not only is it very expensive, but families must also find temporary places to live in the meantime. New construction can take months, or even years, to complete. Some people have had to find nearly three years of temporary housing before they have a permanent home to live in once again.

It is important to understand, too, that just because most recent hurricane activity has occurred in the southeastern portion of the United States in the past few years, hurricanes can also travel up the eastern seaboard to areas such as New York, as well as west to Texas, for example especially with the increasing effects of global warming and the changing character of recent weather patterns.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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