Climate Change Flashcards
Define global warming
Increase in global mean surface temperature, thought to be as a result of the greenhouse effect
Describe the greenhouse effect and how it leads to global warming
- some solar radiation is reflected by the Earth and atmosphere
- most is absorbed by the Earth’s surface
- infrared radiation may pass through atmosphere; some may be absorbed and re-emitted in all directions by greenhouse gas molecules
- this warms the Earth’s surface and lower atmosphere
Give examples of greenhouse gases
CO2 and methane
What effect do greenhouse gases have on the atmosphere?
Trap infrared energy into atmosphere
What is the effect of global warming on photosynthesis?
~ Rate may increase due to greater amount of CO2 and higher temps
~ = increase in plant productivity and food production
~ may also cause a shift in climactic zones; temps become warmer so different crops grow
What is the effect of global warming on distribution?
~ plants and animals cannot cope with high temperatures so many may migrate to cooler temperature areas (northwards)
~ creates greater competition, may lead to a reduction in the number of species
What is the effect of global warming on changing development?
~ Sex of reptile embryos is determined by temperature
~ global warming = changes in sex ratio
~ this means reduced breeding success which may lead to extinction
What is the effect of global warming on life cycles?
~ animal life cycles are synchronised with the changing seasons
~ may lead to a disruption in mating, hibernation, laying of eggs, plant flowering, etc.
Describe some of our evidence for global warming
• Records of CO2 levels = increasing levels of CO2 in atmosphere which contribute to greenhouse effect
• Temperature records = show raise of 1 degree, correlated with CO2 levels
• Pollen in peat bogs = pollen grains preserved in peat bogs, analysis of these can help us see plants present at the time of the peat’s formation (deeper layer = older)
• Dendrochronology = study of tree rings, size of these is affected by temperature (wider =warmer)
• Ice cores = can look at oxygen isotopes in bubbles to determine temperature and atmospheric CO2 throughout time; deeper into ice = longer ago
What can past evidence of global warming be used for?
To make predictions which can be used to create models for future climate change (however these do not include factors like human efforts to reduce climate change)
Describe the main methods to reduce climate change
Biofuels
- fuels produced by biomass
- carbon neutral as CO2 released by burning the fuel is removed by the plant it is made from
Reforestation
- planting new trees in depleted forests
- leads to more photosynthesis, reduction in CO2
Renewable energy
- wind, tidal and solar energy
How can future climate change be predicted + issues with this?
Using data from greenhouse gas concentrations to make models of future climate change
- could continue to increase, eventually level off or decrease
Issues
- don’t know how much global surface temp will increase due to elevated emissions
- don’t take into account changes in greenhouse gas concentrations occurring due to natural causes
- cannot say the exact effect of increased emissions
Generally describe the carbon cycle
CO2 released into atmosphere by respiration and combustion of fossil fuels; absorbed by plants and converted to glucose; plants eaten by animals who use carbon to synthesise organic molecules; when plants/animals die, decomposers break down + respire organic molecules , adding CO2 back to atmosphere
How are fossil fuels made?
In carbon cycle, in absence of decomposers (deep ocean, bog peats) carbon compounds are converted to fossil fuels by high temps and pressures over millions of years
How can knowledge of the carbon cycle help reduce CO2 levels?
~ Minimising the amount of carbon dioxide released in combustion reactions (burn less fossil fuels)
~ Maximising the amount of carbon dioxide absorbed for photosynthesis (plant more trees).
