The 2005 hurricane season was unlike any hurricane season before it. That year, there were fifteen hurricanes strong enough to be given a name. This was a record. Four were classified as Category 5 hurricanes on the Saffir-Simpson scale. The scale ranges from one to five and is based on wind speed. A Category 5 hurricane is the most severe hurricane possible. It has wind gusts measuring more than 251 kilometers per hour (156 miles per hour) and can cause terrible damage. Hurricane Katrina, a Category 3 storm that hit in 2005, changed New Orleans, Louisiana, forever. It killed more than 1,800 people and caused $162 billion in damages, making it the costliest hurricane in U.S. history. Later that same year, Hurricane Wilma became the strongest hurricane ever recorded. Its wind gusts reached speeds of 282 kilometers per hour (175 miles per hour). In 2005, two science papers said that the number and strength of hurricanes are linked to higher sea temperatures. What Is A Hurricane And How Does It Form? A hurricane is a tropical storm formed in the Atlantic Ocean, Caribbean Sea, Gulf of Mexico, or the Pacific Ocean. To form, hurricanes need warm temperatures. Ocean water above 27 kilometers per hour (80 degrees Fahrenheit) is considered ideal. Warm ocean waters provide fuel for the tropical storm. As warm ocean water evaporates into the air, it rises. At some point, the water vapor cools and condenses, forming precipitation in the form of rain, snow, sleet or hail. This cycle repeats, while inside the storm clouds, wind speeds increase. A storm is considered to be a hurricane once its winds reach a speed of 119 kilometers per hour (74 miles per hour). Hurricanes bring heavy rains and fierce winds. They can cause great loss of life and enormous destruction. What Does Climate Change Have To Do With Hurricane Formation? By studying records going back to 1880, scientists have determined that there has been a significant rise in global sea-surface temperatures. What is behind this? Scientists believe climate change is the cause. Human activities often rely on fossil fuels, such as coal and natural gas, to produce energy. However, burning fossil fuels releases gases into the environment. These gases stay trapped in the upper atmosphere. Over time, they trap heat from the sun, and this trapped heat causes temperatures to rise around the world. This leads to changes in weather patterns, sea levels, rainfall, and other phenomena. Scientists call this climate change. The steady rise in average air temperatures is called global warming. Warm ocean waters are essential to forming and maintaining a hurricane. Because of this, scientists have wondered if there might be a connection between warmer ocean temperatures and the increase in the number and strength of hurricanes. Some recent studies suggest there is indeed a link. One of these studies was conducted by scientist Ethan Gutmann. He found a way to show how climate change would affect hurricanes. Gutmann first created computer simulations of twenty-two named hurricanes that occurred from 2001 to 2013. His simulations recreated the formation and course of these hurricanes. Gutmann then raised the temperature in his simulations to match the expected changes from global warming. How did the hurricanes respond? They all had more rain and stronger wind speeds. Apart from that, each hurricane reacted differently. Still, scientists remain divided. Some now believe there is enough evidence to say climate change is the reason for the recent increase in the number and strength of hurricanes. Others are still unsure climate change is the only cause. They believe certain natural weather patterns that have nothing to do with human activity could also be a factor. One example is an El Niño or La Niña event. El Niño and La Niña events cause unusual warming or cooling of the ocean waters near the equator. That, in turn, affects weather patterns around the world. What Is The Future Of Hurricane Seasons? Some scientists think hurricane seasons with many strong storms could make the following year's hurricane season much calmer. A large, powerful hurricane takes a large amount of heat from the ocean to form and to grow. This means that, after a hurricane, the ocean waters are much colder than usual. As a result, it takes more time for the water to heat up enough to fuel other hurricanes. Scientists still do not have all the answers. Today, they are continuing to study possible links between climate change and the frequency and strength of hurricanes.