100 likes | 257 Views
Environmental Problems. And how to fix them… Chapter 55. Deforestation – where and why?. In the past – deciduous forests have been impacted Today, it is more a problem in the tropics Subsistence agriculture – a family produces just enough food to feed itself
E N D
Environmental Problems And how to fix them… Chapter 55
Deforestation – where and why? • In the past – deciduous forests have been impacted • Today, it is more a problem in the tropics • Subsistence agriculture – a family produces just enough food to feed itself • Practice slash-and-burn agriculture: tropical soils are infertile and cannot be used to grow crops for more than one season • Provide range land for cattle: overgrazing can cause desertification
Deforestation – why is it a problem? • Increases soil erosion decreases fertility, increases sedimentation of waterways • Loss of biodiversity – for both native species and migratory ones • Increases risk of flooding in low lying areas • Reduces transpiration impacts hydrological cycle • Reduces photosynthesis impacts global warming
Global Warming – How and why? • Greenhouse gases: CO2, methane, surface ozone… • Greenhouse effect: Solar energy passes through, heat energy cannot pass out; this is necessary for life on Earth • Enhanced greenhouse effect: additional warming due to addition of greenhouse gases to the atmosphere
Global Warming - Predictions • Rise of sea level • Changes in precipitation patterns • Changes in the range of organisms • Impact on human health • Impact on agriculture
The ‘Hole’ in the Ozone Layer • The ozone layer helps protect Earth from much of the sun’s UV radiation • There has been a thinning of this layer due to the use of certain chemicals • CFCs = chlorofluorocarbons and other industrial chemicals which destroy ozone
Why is this ‘hole’ a problem? • More UV radiation will reach surface • Human health: • Skin cancer, cataracts • Photosynthesis impacts