O mundo está chegando ao fim mesmo...pelo menos é o que eu acredito. A cada dia um novo disastre acontece em algum lugar do mundo. Infelizmente, ás vezes, em um mesmo local vários disastres acontecem simultaneamente, como é o caso do Japão (terremoto + tsunami + acidente nuclear). Abaixo, preparei um glossário dos principais desastres naturais em inglês. Assim fica mais fácil entender a CNN!
Drought
In terms of a natural disaster, drought is rarely properly defined as "a lack or shortage of rainfall". Rather, economic and social factors influence the degree of susceptibility of the affected people, as does the physical situation of the affected area. Crop failure as a result of soil water stress and the associated economic difficulty is a key factor in defining a drought-stricken area, but this is only one category of drought definition (agricultural drought). Others include meteorological drought (which points to physical and natural atmospheric factors and their variability) and hydrological drought (a drought pertaining to a lack of 'terrestrial water' such as a reduction in stream flow and water levels in dams and lakes).
Earthquakes
A series of vibrations in the Earth's crust that are of such a magnitude that they can be observed or sensed without seismic instruments. Such disruptions are initiated along fault lines and have the ability to cause widespread damage as the geological structures that have been affected attempt to resettle after the disturbance. One of the worst earthquakes ever recorded occurred in Tangshan, China, on July 28, 1976. More than 250 000 people lost their lives and the city of Tangshan was reduced to rubble.
Famines
These are simply defined as the scarcity of food (mostly as a result of a physical obstacle in the food-production process), leading to malnutrition and starvation. Famines are commonly associated with drought, as this leads to crop failure and a decrease in food production, but other factors such as floods, diseases and pest plagues as well as political instability have been known to be the primary cause of large-scale famines - particularly on the African continent.
Floods
This type of hazard can have a primary effect (a dramatic increase in rainfall over a short period of time may cause a river to burst its banks or a similar heavy rainfall can inundate a low-lying area with a high water table etc) but more commonly, floods are secondary effects following some other natural disaster (an earthquake may damage a dam wall, or the rainfall associated with a hurricane can result in severe flooding etc.). Sometimes, conditions prior to a relatively limited rainfall event can cause as much damage: drought conditions can reduce soil quality and when this is eventually followed by a rainfall event, the water does not infiltrate the ground as it should, and hence, the runoff results in flooding in a lower-lying area. Floods are generally associated with disease outbreaks and nutrition problems in the short- to long-term phase.
Hailstorms
These thunderstorms are capable of destroying agricultural fields and property as well as damaging other infrastructure. The diameters of the hailstones can vary from 5 mm to golf ball size, and the damage on the ground is naturally proportional to the size. Crop failure is the most common result of severe hailstorms and this has far-reaching economic implications: In July 1990, a hailstorm in Denver, Colorado caused an estimated $625 million in damages, making it the costliest hailstorm in the history of the United States.
Heat waves
A heat wave is often characterised by an extreme heat event in a location where such a degree of heat (as well as the time span) are unusual. Various atmospheric factors contribute to such an extreme event, which is why they are not as common as some of the other natural disasters. The two most recent serious heat waves occurred in Chicago in 1995 (where more than 700 people died in one week as a result) and in Europe - the worst heat wave ever recorded, in terms of loss of life - in the summer of 2003. An estimated 19 000 people lost their lives over the four weeks between July and August.
Hurricanes
These are particularly powerful tropical storms, typified by high-speed wind velocities of up to 120 km/h and capable of causing loss of lives, widespread damage on land, and even pose a serious threat to shipping. Hurricanes are common in the southeastern states of the US between July and October, as the hurricanes originate in the 5° - 10° N and S latitude bands over warm, tropical ocean waters. The damage these storms cause is not limited to destructive high-speed winds that cause structural damage, but also includes the effects of a large amount of rain falling in a very short period of time. The damage inflicted by a series of hurricanes takes a long time to recover from and the costs are enormous: the 1998 US hurricane season cost American taxpayers over $450 million.
Ice storms
Unlike snowstorms, ice storms occur when precipitation falls over an area where the surface temperature is less than 0 °C. As the rain strikes the ground, the water droplets freeze and accumulate as ice crystals. This has the effect of damaging plants and trees (branches can even snap off under the pressure of contraction) and even breaking power lines. High latitude areas commonly experience this type of hazard due to their cold climates. The worst ice storm on record occurred over Eastern Canada in 1998, where despite a relatively mild winter, a single ice storm event claimed 35 lives and destroyed thousands of trees. The intensity and extent of this disaster made it Canada's number one news story of the year.
Lahars
A lahar is simply an avalanche of debris flow with more than 25 % volcanic material - the rest being mud and water. They occur as a result of volcanic activity, and typically in cold climates where ice cover provides the water component of the flow. These debris flows can reach relatively high speeds and have the ability to wash away towns and villages in their path.
Landslides and mudslides
Again, these types of disaster are more commonly secondary effects. Earthquakes, volcanoes or hurricanes have the ability to destabilise sections of ground on inclines. A relatively stable ground area is easily destabilised by vibration or by an increase in weight (which can be caused by an increase in water content). The force of gravity plays the largest role, and the effects of such mass wasting can be devastating to people (in the event of a mass wasting occurring in a populated area) and the environment that is altered irreparably.
Snowstorms
Storms that are associated with widespread snowfall and above-average wind speeds are classified as snowstorms. These can lead to widespread difficulties for the communities experiencing them. Communications are difficult in heavy snowstorm conditions and mobility is severely impacted, which makes rescue operations particularly difficult. Most high-latitude countries experience these hazards annually and therefore invest heavily in early-warning systems, rescue equipment and vehicles, community education and any other means that could potentially mitigate the expected disaster.
Tornadoes
These natural hazards are commonly described as violently rotating columns of air that are in contact with both the ground and an upper atmosphere cumulonimbus cloud. Tornadoes can reach wind speeds of up to 510 km/h and are known to be particularly destructive in terms of property, structures and the natural environment. One of the worst tornado incidents to strike the US occurred in 1925 and largely affected three states (Montana, Illinois and Indiana). No less than 689 people lost their lives, more than 2 000 were injured and the damages reached a shocking $16,5 million (for 1925!).
Tsunamis
Tsunamis are a type of natural disaster that wreaks havoc in coastal areas. Although the magnitudes of these seismic waves vary, their ability to destroy structures and claim lives is a constant threat to populations in oceanic-plate boundary areas, as they are usually caused by underwater earthquakes in seismically active areas. The greatest recorded tsunami occurred in late December 2004, when a quake just off Indonesia's Banda Aceh province caused powerful tsunamis to propagate towards the coasts of Indonesia, Thailand, Sri Lanka, India and even across the Indian Ocean to the African continent. It has been estimated that up to 300 000 people may have lost their lives in this tsunami disaster.
Volcanoes
Although some seismically active volcanic craters erupt on a daily basis with small, non-threatening episodes, the supervolcano eruptions are the ones that threaten lives, destroy whole settlements and natural environments. The largest and most destructive volcanic eruption in recent times was that of Mount Krakatoa (Indonesia) in 1883, which killed more than 36 000 people and destroyed 165 villages situated on the coast close to the volcano.
Wildfires
In certain cases, wildfires can be sparked by natural causes, such as the sun's heat. It is cases like these that naturally fall into the 'natural hazards' category, as opposed to those wildfires that are set by arsonists. Either way, vegetation that has been exposed to lengthy drought spells provides the perfect conditions for the rapid spread of a wildfire. The threat of an out-of-control wildfire is, of course, the widespread destruction of vegetation, property and the potential loss of life, but the greatest obstacle in controlling such a blaze is the speed at which it can spread. Australia's state of New South Wales has a long history of devastating wildfires: the "Black Christmas fires" of December 2001 and January 2002 destroyed more than 5 000 km2 of land and 150 homes (although no-one was killed). More than 80 individual fires tore through the state for eleven days, and it required more than 20 000 people in fire-fighting capacities to finally put the last embers out.
