Drought Drought Reading Smith Ch 12 Drought A
- Slides: 66
Drought
Drought • Reading: Smith Ch 12
Drought • A slow-acting, often long-term hazard • Geographically widespread and territorially large
Niger, 1983
African Sahel Famine 1984 -5 • Followed 16 dry years from 1968 onwards • 2/3 of Africa is dryland, • 70% of its dryland farming areas are degraded
Drought • MDCs: – Drought is costly, but not deadly • LDCs: – Drought is frequently deadly – food supplies are fragile, malnutrition is “normal”, the poor can be killed quickly in famine
Drought • Most famine deaths in sub-Saharan Africa
Mid 1980 s African Drought • Affected 20 countries, 150 million people • 30 million in urgent need of food aid • 10 million refugees seeking food and water • 100, 000 to 250, 00 deaths
Africa • Current drought conditions in southern Africa – 14 million in 6 countries face starvation – Botswana refusing food aid from US and EU: • fears about genetically modified food.
Victoria Falls, Dry Season
Ethiopia • Drought and war brought famine in 1984 – 1 million deaths in Ethiopia • Now in Ethiopia – 6 million require food aid, – 15 million face starvation by the end of 2002 – 10% of government revenues spent on foreign debt repayments – Will require 200 million tonnes of food aid
1984 Ethiopian Famine
Australia 1979 -83 Drought • No-one died of famine • Several died in bushfires • Drought affected – 50% of farms – 60% of livestock – economic hardship – permanent environmental damage?
Drought • Effects are relative – Drought for a wheat farmer may not affect livestock farms – Balance of moisture and evaporation – Long-term drought management can reduce vulnerability
Meteorological Drought • Shortfall of precipitation • Link between precipitation and useful moisture is indirect
Hydrological Drought • Reduction of stream-flow or groundwater levels • Important impacts on urban areas • Reduces available reserves of accessible water
1971 Frostproof Florida
Agricultural Drought • Reduction in soil moisture available for plant growth • Reduced crop growth and output
Summer Drought in Toronto • Lawns absorb 1/2 of domestic water consumption • Most water pumped from Lake Ontario • Drought increases demand for water • To reduce demand: – better conservation – increase cost
Agricultural Drought • Australia 1982 drought – Wheat production down 37%, Livestock slaughtered • USA 1988 drought – 31% drop in corn yield, 1/3 of crop destroyed – Losses of $4. 7 billion USD – World grain reserve drops to 288 million tonnes or 63 days supply
US Corn Belt Drought 1988
Agricultural Drought • Southern Africa 1990 -2 – 30 -80% harvest failure – 86 million people affected over 7 million km 2
Agricultural Drought • NE Brazil 1985 – 1 million men abandon farms, head to cities to seek work
• Fleeing famine in Ethiopia, 1984
Famine Drought • Drought a physical hazard • Famine a cultural hazard • Famine sometimes found in extreme agricultural drought conditions. • Most deaths in famine are from disease, lack of access to clean water
Physical Causes • Drought more likely in drier climates – low annual precipitation – high variability – rains unreliable
July
October
Wet/Dry Seasons, Thailand
Thailand Dry season
US Great Plains • Dry to semi-arid climate – Major droughts every 20 years or so • 1890 s, 1910 s, 1930 s, 1950 s
US-Canada Dust Bowl 1930 s • Cyclical drought • Botched dry-farming techniques • Depressed economy
Palliser’s Triangle
Destroying Grassland 1900 • Oxbow SK
Saskatchewan 1930 s
Saskachewan 1930 s • 70% contraction in Provincial revenues • Mass emigration of Saskatchewaners to BC
Swift Current SK
Sahel • Rainfall low (100 mm to 800 mm p. a. ) – declines northwards • Rainfall reliability variable – becomes less reliable northwards • Rainfall highly seasonal – 80% falls in July-August
Rain in Nigeria
Niger River, Mali
Sahel • Desertification – immediate economic needs force overgrazing – demand for firewood destroys tree-cover – land degradation
Physical Causes • Risk of African and other tropical droughts increased by El Nino • Global atmospheric and ocean circulation rhythms involved • Dust storms and dry soils alter albedo – may accentuate drought
Broken Hill dust storm
Asian dust over California
Dust Storm, Canary Islands
Human Causes • Land degradation due to population pressure – 90% of Africa’s energy needs come from wood – Urban shadow denuded of trees around most cities
China’s Great Leap Forward • Mao’s efforts at a crash programme of industrialization and forced collectivization – disrupted rural life and food-producing systems – mild drought in northern China
China’s Great Leap Forward • 20 -30 million died of starvation 1959 -61 • End of Mao’s economic leadership – Mao tried to regain control via the Cultural Revolution. . .
Senegal • Senegalese change habits when they move to the city – Eat more rice: demands water – Cook, heat with Charcoal not wood: stresses the forests • Increases pressure on the water-resources
Human Causes • Role of colonialism and global trading system?
Assignment 2 • Due date 28 November • To get it back – Provide a stamped, addressed envelope with sufficient postage – collect it during Dr Anderson’s office hours next term
Exam • Wednesday December 11, 3: 30 -5: 30 p. m. Curtis Lecture Hall D • Format: – Choice of essay questions, do two in 2 hours
- While reading activities
- World, drought monitor
- Drought usaco
- Vermont drought monitor
- Drought sentence
- Jordan drought
- Drought presentation
- Utah drought map
- Types of drought
- Drought present tense
- Anasazi drought
- Drought stopper system
- Bibliography of drought in south africa
- What are solutions of drought
- Drought and desertification
- Conclusion on drought
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- Types of reading skill
- Round robin reading vs popcorn reading
- Critical reading is an active and reactive process.
- Aims and objectives of reading
- Intensive reading and extensive reading
- What is intensive reading
- Extensive reading
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