droughts Flashcards
What is a drought?
A long period when rainfall is below average.
What happens to water supplies during a drought?
Water supplies, such as lakes and rivers, become depleted due to continued use without replenishment from rainfall.
High temperatures increase evaporation, further depleting water supplies.
How long can droughts last in different regions?
Drought lengths vary, Britain lasted 16 months, while droughts in African countries can last for over a decade.
What are some causes of drought?
- Changes in atmospheric circulation (e.g. El Niño/La Niña) doesn’t rain much in an area for months/years
- Failure of annual rains, such as monsoons in India.
*high pressure weather systems block depressions
How has the frequency of droughts changed since 1950?
Globally, the frequency of droughts has varied year to year but overall has not changed much since 1950.droughts might become more frequent in the future due to climate change
Where are areas most at risk from drought?
Central and southern Africa, the Middle East, Australia, eastern South America, and parts of North America.
Locations affected by drought can change over time.
What trend has been observed in drought occurrences since 1950?
There have been more droughts in Africa, Asia, and the Mediterranean, and fewer in the Americas and Russia.
What is the effect of anticyclones on weather patterns related to drought?
Anticyclones can block depressions (weather systems that cause rain), leading to drought conditions.
Fill in the blank: Droughts are often accompanied by _______ temperatures, which increase the rate of evaporation.
[high]
