Extreme weather: weather phenomena that are at the extremes of historical patterns, especially severe or off season.
Severe weather: weather conditions that are hazardous.
Climate extreme: is a significant departure from the normal state of the climate, irrespective of its actual impact on life or any other aspect of the Earth’s ecology.
Climatic disaster: a climate extreme that has an adverse impact on human well-being, which can be defined as an unforeseen and often sudden event that causes great damage, destruction and human suffering.
Examples of disasters include: drought, heat waves, thunderstorms, blizzards, ice storms, arctic cyclones, cyclones, monsoons, tornadoes (twisters), tropical cyclones (hurricane, typhoon or “cyclone”), tsunamis, floods, forest fires, landslides, mudslides, avalanches and derechos.
Weather catastrophes: events that result from the combination of extreme weather and high population density.
When discussing future climate, it has been addressed that climate is changing more dramatically and faster than it should be, due to human action. Any shift in average climate will almost inevitably result in a change in the frequency of extreme events. Frequent reports of record-breaking events suggest that climate extremes are becoming more common, but scientists affirm that there is no scientific evidence of an increased frequency of extreme weather events, given the above mentioned natural variability in climate. However, just as an example, the number of weather-related disasters during the 1990s was four times that of the 1950s. In 1975, United Nations registered 75 disasters, 150 in 1982, 225 in 1994 and 546 in 2000. A recent UN report, prepared for the World Conference for Disaster Reduction, celebrated in January 2005, in Kobe, Japan, estimated that from 1994 to 2003, 609.638 died in natural catastrophes and at least 2.700 million were affected, doubling the figures of the precedent decade. This could be mere coincidence, but it may have to do with human induced climatic change. The same group of specialists thinks that a more likely explanation for this kind of disasters is that increased human vulnerability to climate extremes, particularly in developing countries, is transforming extreme weather events into climatic disasters. The communications’ revolution has also enhanced people awareness of the occurrence of extreme events and of their impact.
Anyhow, what is true is that any change in climate will affect society much more through extreme weather events rather than through subtle changes in climate averages.