Posted on October, 25 2005

While many people in the New Orleans region are still suffering from the destruction caused by hurricane Katrina, new hurricane Wilma threatens parts of Mexico and Florida. WWF picks up the question many people are asking these days and explains the link between climate change and the devastating hurricanes.

Climate change has increased the earth’s average temperature on land and sea surface by 0.6°C over the 20th century. Warmer sea surface temperatures are projected to continue to increase through the 21st century. According to scientists, this will likely increase the intensity and perhaps the frequency of hurricanes and tropical storms. It is also expected that rainfall from hurricanes and tropical storms could increase appreciably.

The rate of global mean sea level rise during the 20th century is between one and two millimeters per year. This rise is expected to continue throughout the 21st century, resulting in a global mean rise of between 0.09 to 0.88 meters by 2100. This sea level rise will lead to larger hurricane storm surges, with low-lying, coastal areas being at highest risk.

Hurricane intensity has increased: recent scientific findings show that there has been a substantial increase in net hurricane power, both longer storm lifetimes and intensities over the last thirty years. However, historical data from the past several decades do not show an increased trend in the frequency of hurricanes and tropical storms. Scientists disagree on the question whether global warming results in an increase in the frequency of hurricanes and tropical storms or not.

Even if the frequency of hurricanes does not change because of human-induced climate change, the increased intensity that has been measured and is expected to continue will likely lead to storms of the highest categories. These storms will undoubtedly have highly destructive impacts on natural and human systems.

Such powerful hurricanes will likely have stronger winds, larger storm surges, and heavier precipitation events, increasing risk to human life, damage to infrastructure and coastal property, and more destruction and disturbance to coastal ecosystems such as mangroves, river deltas and coral reefs.

The 2005 hurricane season is predicted to become the worst in U.S. history. Already in 2004, nine hurricanes affected the U.S. causing an estimated US$42 billion dollars in damage. 

Scientists say that global warming is a result of man-made greenhouse gas emissions, especially carbon dioxide (CO2). The biggest contributor to man-made CO2 emissions – globally 37% – is the power sector. Many power stations burn fossil fuels, mainly CO2-intense coal, to generate electricity.

WWF’s global PowerSwitch! campaign urges governments around the world to cut CO2 pollution produced by coal power stations and force a switch to clean, more efficient power.