droughts
Droughts are unusually long periods of insufficient rainfall.
Since ancient times droughts have had far-reaching effects on humankind by causing the failure of crops, decreasing natural vegetation, and depleting water supplies. Livestock and wildlife, as well as humans, die of thirst and famine; large land areas often suffer damage from dust storms or fire. What cause droughts?
Droughts and famines:
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floods |
Flood can happen very quickly when lots of heavy rain falls over a short period of time. It will wash out the crops and the nutrient from the soil. Crops die because of too much water and no oxygen. After flood, farmers cannot farm anymore, so there are no grain and people start to starve.
What cause floods?
Flood and Famine:
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Storm
Storm is another cause of famine. A storm is a disturbed state of an environment affecting earth's surface. It may causes strong wind, hail, heavy precipitation, heavy freezing rain, strong winds, dust storm, blizzard, sandstorm, etc. All of these factors may cause crop failure. Wheat, corn, soybeans, and tobacco are the most sensitive crops to hail damage.
Storm and Famine:
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insect plagues & plant disease |
Locusts, termites, fire ants, killer bees are the insects can cause insect plagues. A big group of harmful locusts will bring a serious damage to crops. This kind of insect feeds on crops and devours all vegetation. Locusts occur on nearly every continent. Most of time insect plagues happen right after other natural disasters. Droughts can cause insect plagues easily.
The great change of environment will cause plant disaster. Nuclear radiation or other disasters will cause plant ’s gene mutation. The variable grains are harmful to humans’ bodies or it will cause grain dies easily. Then plant disaster will happen easily. Insect plagues and Famine:
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