Chapter 6 investigates and debunks the widespread fears that global warming might cause more extreme weather. The IPCC claims global warming will cause (or already is causing) more droughts, floods, hurricanes, storms, storm surges, heat waves, and wildfires. We find little or no support in the peer-reviewed literature for these predictions and considerable evidence to support an opposite prediction: That weather would be less extreme in a warmer world.

• The IPCC predicts that a warmer planet will lead to more extreme weather, characterized by more frequent and severe episodes of drought, flooding, cyclones, precipitation variability, storms, snow, storm surges, temperature variability, and wildfires. But has the last century - during which the IPCC claims the world experienced more rapid warming than any time in the past two millennia - experienced significant trends in any of these extreme weather events?

• Droughts have not become more extreme or erratic in response to global warming. Real-world evidence from Africa, Asia, and other continents find no trend toward more frequent or more severe droughts. In most cases, the worst droughts in recorded meteorological history were much milder than droughts that occurred periodically during much colder times.

• Floods were more frequent and more severe during the Little Ice Age than they have been during the Current Warm Period. Flooding in Asia, Europe, and North America has tended to be less frequent and less severe during the twentieth century.

• The IPCC says “it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increase of tropical sea surface temperatures.” But despite the supposedly “unprecedented” warming of the twentieth century, there has been no increase in the intensity or frequency of tropical cyclones globally or in any of the specific oceans.

• A number of real-world observations demonstrate that El Niño-Southern Oscillation (ENSO) conditions during the latter part of the twentieth century were not unprecedented in terms of their frequency or magnitude. Long-term records suggest that when the earth was significantly warmer than it is currently, ENSO events were substantially reduced or perhaps even absent.

• There is no support for the model-based projection that precipitation in a warming world becomes more variable and intense. In fact, some observational data suggest just the opposite, and provide support for the proposition that precipitation responds more to cyclical variations in solar activity.

• As the earth has warmed over the past 150 years, during its recovery from the global chill of the Little Ice Age, there has been no significant increase in either the frequency or intensity of stormy weather.

• Between 1950 and 2002, during which time the air’s CO2 concentration rose by 20 percent, there was no net change in either the mean onset date or duration of snow cover for the continent of North America. There appears to have been a downward trend in blizzards.

• Storm surges have not increased in either frequency or magnitude as CO2 concentrations in the atmosphere have risen. In the majority of cases investigated, they have tended to decrease.

• Air temperature variability almost always decreases when mean air temperature rises, be it in cases of temperature change over tens of thousands of years or over mere decades, or even between individual cooler and warmer years when different ENSO states are considered. The claim that global warming will lead to more extremes of climate and weather, including more extremes of temperature itself, is not supported by real-world data.

• Although one can readily identify specific parts of the planet that have experienced both significant increases and decreases in land area burned by wildfires over the last two to three decades of the twentieth century, for the globe as a whole there was no relationship between global warming and total area burned over this period.

Chapter 6. Observations: Extreme Weather (PDF, 497 kb)

     6.1. Droughts (PDF, 167 kb)
            6.1.1. Africa
            6.1.2. Asia
            6.1.3. Europe
            6.1.4. North America

     6.2. Floods (PDF, 89 kb)
            6.2.1. Asia
            6.2.2. Europe
            6.2.3. North America

     6.3. Tropical Cyclones (PDF, 155 kb)
            6.3.1. Atlantic Ocean
            6.3.2. Indian Ocean
            6.3.3. Pacific Ocean
            6.3.4. Global

     6.4. ENSO (PDF, 84 kb)
            6.4.1. Model Inadequacies
            6.4.2. Relationship to Extreme Weather
            6.4.3. Relationship to Global Warming

     6.5. Precipitation Variability (PDF, 67 kb)
            6.5.1. Africa
            6.5.2. Asia
            6.5.3. North America

     6.6. Storms (PDF, 72 kb)

     6.7. Snow (PDF, 73 kb)

     6.8. Storm Surges (PDF, 45 kb)

     6.9. Temperature Variability (PDF, 66 kb)

     6.10. Wildfires (PDF, 76 kb)