Lesson 3: Climate Change Flashcards
what does anthropogenic climate change mean?
climate change caused by human activity
What two gasses have the biggest impact on the greenhouse effect?
carbon dioxide and water vapour
Why is too much methane problematic?
Methane oxidises in the atmosphere which produces CO₂ and water
How do greenhouse gasses cause global warming (explain in terms of wavelength of radiation)?
Short wave length radiation from the sun passes through the ozone layer and is absorbed by the earth.
The short wavelengths are converted into longer wavelengths (IR).
IR is given off by the earth.
Parts of the IR is escapes into space,
Most get trapped on earth by greenhouse gasses and heat is re-emitted onto earth’s surface. This is GLOBAL WARMING.
What is the issue with this graph?
Too simplistic. Not all peaks in global temperature correlate with higher CO₂ levels.
What other factors could cause an increase in average global temperature?
sunspots
variation of the earth’s orbit.
What are some consequences of global warming?
Climate change
higher temp. = more evaporation of water = extreme rainfall. Changes in wind + ocean currents = more hurricanes
Rising seawater
melting of polar ice caps
loss of habitats
loss of arctic and coastal habitats
changes in biotic factors
temperate animals moving to previously arctic conditions —> more competition —> disruption of food chains.
How are rising CO₂ levels affecting the formation of coral reefs?
CO₂ dissolves in water and forms H₂CO₃ (carbonic acid). The molecule easily dissociates into H⁺ and HCO⁻. The H⁺ makes the water acidic (ocean acidification). This increase the solubility of calcium carbonate so less CaCO₃. Exoskeletons will dissolve so they become less resilient.
what impacts does melting ice have on a polar bear’s ability to survive?
longer swimming distances
loss of hunting grounds
habitat fragmentation → isolate bear populations → less genetic diversity
What is the positive feedback cycle of global warming in terms of sea ice?
Increase in temperature → snow + ice melts → Darker surfaces are revealed → albedo reduced → increased absorption of radiation → accelerates temp. and melting of snow.
what is peat?
an accumulation of partially decayed organic matter.
What conditions does peat form in?
waterlogged (very wet) + acidic
Why is peat important?
sequesters carbon
has a net cooling effect on the climate
slow the flow of water, cleaning it naturally and reducing flood risk
What is the positive feedback cycle of global warming in terms of peat?
rise in temperature → more microbial activities → accelerated decomposition of organic matter → releases a lot of carbon dioxide + methane → further increase in temp.
what are three approaches to increasing carbon sequestration?
afforestation
restoration of peat-forming wetlands
forest regeneration
