What can humans do to reduce the impact of climatic hazards? Flashcards
Causes of global warming:
- Burning fossil fuels produces carbon dioxide
- Transport producing carbon dioxide and nitrous oxide
- Farming – cattle, rice paddy producing methane (a major greenhouse gas
- Deforestation – less carbon absorbed and often cleared by burning
- Waste tips producing hydroflourocarbons
- Melting permafrost releasing methane and carbon dioxide
Efffects of global warming:
- Sea level rise leads to flooding of low-lying coastal areas and increased coastal erosion
- Increased flooding (coastal and river)
- Increase in extreme weather as more energy in atmosphere, leading to increased storms and hurricanes
- Changes in crop patterns, leading to increased risk of famine
- Reduced rainfall in some areas, leading to spread of deserts and droughts
- Change in natural vegetation
- Change in economic activity
- Wildlife will adapt or become extinct; pests and diseases will spread (e.g. malaria in Europe)
Causes of global dimming
- Heavy industry producing particulates means that more clouds form
- Heavy industry producing sulphate pollution that reflects sunlight
- Could be a side effect of global warming
Effects of global dimming
- May offset global warming
- Reduced effectiveness of solar power
- Slower growth of crops and lower yields
- Human health problems – Seasonal Affective Disorder (SAD) and lack of vitamin D
Causes of acid rain
- Air pollution caused by emissions of sulphur dioxide, nitrogen oxides and ammonia is responsible for acid rain
- In the atmosphere these pollutants combine with water droplets to form sulphuric acid and nitric acid
- Eventually the chemicals reach the ground in rain and snow, or as dry depositions
- Acid rain is an unwanted side effect of industrial development, and specifically the burning of fossil fuels
- Man-made emissions of sulphur rose sharply from 1945 to the early 1970’s
- Coal fire power stations and heavy processing industries such as iron and steel produce large amounts of sulphur dioxide
- More than half of all nitrogen oxide emissions come from exhaust gases from motor vehicles
- Ammonia is largely derived from intensive livestock farming and organic fertilisers
The effects of acid rain:
o The acidification of lakes, streams and soil
o The deconstruction of forests and wildlife (in aquatic habitats)
o The corrosion of buildings and stone monuments, especially those of limestone and sandstone
• When soil becomes acidified essential nutrients are leached out and toxic metals such as aluminium threaten wildlife and enter food chains
o For example, dissolved aluminium and acid waters kill aquatic invertebrates such as water snails, mayfly larvae and dragonflies that support birds, fish and aquatic mammals
When was acid rain recognised as a global problem?
Acid rain was only recognised as a global problem in 1979 when the Convention on Long Range Transboundary Air Pollution was signed
Problems due to acid rain in Europe around 1979:
• In Europe, Norway and Sweden were badly affected
• They were net importers of acid rain originating in neighbouring states such as Germany, the UK and Poland
• Around 14,000 lakes in Sweden were so badly affected that sensitive organisms could no longer survive in them
• Increases in soil acidity disrupted soil chemistry and nutrient cycles, and leached out essential plant nutrients such as calcium and magnesium
o These processes caused forests to die
Responses to the acid rain problem in Europe:
- In Europe concerted actions by governments to tackle the problem of acid rain began in the mid 1980’s – agreements signed in these years committed countries to make significant reductions in sulphur emissions
- Binding emissions ceilings were set in the Göteborg Protocol of 2001 and were to be achieved by each EU state by 2010
- They covered the three pollutants mainly responsible for acid rain: sulphur dioxide, nitrogen oxides and ammonia
Success of reducing acid rain problem in Europe:
o Between 1980 and 2003 emissions from land-based sources in Europe fell by almost 75%
o UK emissions of chemicals that can cause acid rain fell by 52% between 1990 and 2004
o Many of the UK’s most acidified upland lakes and streams have begun to recover from the effects of acid rain – as acidity declined wildlife started to reappear with sensitive indicator species such as brown trout making a comeback
Background - Acid rain in China
- 2003 – caused US$13 billion losses
- 33% of China suffers acid rain
- Worst in south, with rain with a pH of 5
Causes of acid rain in China
- Increased car ownership
- High usage of coal
- Rapid industrialisation
- Over-use of nitrate fertilisers
- Rapid urbanisation
- Lax anti-pollution laws and little environmental protection
Impacts of acid rain in China
- Increased chemical weathering – buildings, roads, etc.
- Rail and power lines corroded and fail
- Soils increase acidity = reduce crop yields
- Loss of forests = increased soil erosion
- Rivers and lakes increase acidity = damage to wildlife and fish farming
- Eye and respiratory problems increase
- Ancient buildings corrode
How is acid rain is part of the environmental cost of China’s soaring economic growth?
o The speed of China’s industrialisation has simply outpaced environmental protection
o The economic and environmental costs are considerable: an estimated US$13 billion a year or 3% of GDP
Tackling acid rain pollution in China
• Since 1996, the United Nations Development Programme has provided US$3.6 million to fight acid rain in Guiyang in southwest China
