global warming Flashcards
(31 cards)
global warming
gradual increase in temperature of the earth’s surface/ process by which average global surface temps are rising
enhanced greenhouse effect
climate change
changes in weather patterns in regions over time
greenhouse effect
greenhouse gases accumulate in the upper atmosphere & relect infrared rays back onto earths surface many times instead of the if rays being reflected into space
reduces amount of IR RADIATION lost from earths surface
natural phenomena
heats up the earths surface
CO2 , nitrous oxide, methane
greenhouse effect steps
–infrared radiation through earths atmosphere from sun
-warms surface of the earth
-reflects up off surface and bounces off greenhouse gases in upper atmosphere
-bounces down onto the earth again warming it further
-some irr does get reflected back into space
how has the greenhouse effect been essential for life on earth
greenhouse gases have trapped infrared radiation keeping the earth warm enough to support life
differences between natural and anthropogenic greenhouse effect:
natural: more heat escapes into space
less heat is re-radiated onto the earth’s surface
a greenhouse gas
a gas that traps re radiated intfrared radiation in the atmosphere keeping the earth’s surface warm & making it so that the re radiated infrared radiation isnt lost to spacw
explain why the greenhouse effect is vital for life on earth
-re radiated infrared radiation being trapped in the atmosphere keeps the earths surface warm
-this provides optimal temperature for enzyme activity, important physiological processes depend upon enzyme-controlled reactions
-ensures that most water on earth remains in liquid form, water is an important transport medium for plants and essential to many organisms
-large daily temperature fluctuations, atmosphere mediates temperature swings
lunar surface can reach 134degrees during the day and -153 degrees at night, this is hostile to most life form
evidence of global warming
-temp records
-dendrochronology
-pollen
-ice cores-air bubbles trapped inside can give an indication of atmospheric composition including concentration of greenhouse gases
-records of lake levels
peat bogs and pollen
peat bogs are waterlogged ECOSYSTEMS which have acidic and anaerobic conditions
pollen and other organic material doesnt decay in peat bogs dont decay or decay very slowly
why is this
because decomposers lack the O needed for respiration and any enzymes they do release which would catalyse reactions in decomposition are denatured by low ph in the acidic conditions
how can analysing pollen grains in peat bogs givean indication of previous atmospheric conditions
-the pollen is well preserved due to the anaerobic and acidic conditions
-the climate affects which species thrive in an environment
-the depth of the peat correlates with when the pollen was produced, deeper the depth the older the pollen
-changes in pollen indicate that the climate has warmed over time
pollen studies provide info form 20k years ago
dendrochronology
-trees are sensitive to local climate conditions such as rain and temperature
-so they can give us an indication of an area’s local climate in the past
-very old trees can give an indication on how a climate has changed over a span of 1000 years
-tree rings grow Wider in Warmer Wet years and thinner in colder dry years
-if the tree has experienced stressful conditions such as drought they may hardly grow in these years
can also show different isotopes of carbon
more c12 isotopes in tree rings are an indication that fossil fuel emmissions have become more common in the atmosphere as fossil fuels contain less c13 and c14
most common info gathered by tree rings
-age
-rate of growth
-indicator of climate
back up to 3000 years ago
temp records
long data sets are available
e.g. central england in 1659
ice core
-dif carbon isotopes in air bubbles can indicate the source of co2 in the atmosphere
c13 and 14 unlikely to be from fossil fuels
analysis of air bubbles can also provide info on co2 concentrations in the atmosphere the year the snow fell trapping those air bubbles
predicting future climate change
extrapolation- existing data on global warming can be used to make predictions on future global temps
extrapolation is effectively a line of best fit
extrapolated data can be used to produce models that show how the climate may change in the future
what can global warming predictions be useful for?
to plan for the future such as by building flood defences
encourage people to change their activities
such as by increasing the use of remewable resources of energy such as solar and wind
limitations of predictions models
future technologies may or may not be successful at removing carbon from the atmosphere
global climate patterns are complex and therefore difficult to predict
the past isnt necessarily a guide to the future and therefore extrapolation may be inaccurate
tipping point is possible such as melting of permafrost causing sudden increase in atmospheric methane
factors other than human activity may affect climate change such as volcanic eruption releasing ash into the atmosphere which could reflect radiation back into space and cool the earth
solutions
-replacing the use of fossil fuels with biofuels (produced from biomass)
-reforestation to increase the amount of carbon taken in by plants for photosynthesis
biofuels
-carbon neutral as no net increase in the conc of carbon dioxide in the atmosphere
pros
-renewable and sustainable, plants can be regrown
-carbon net 0
-energy unit price quite low
-large amounts of biomass available on a global scale
-scalable and flexible
-no long transportation distances
-local jobs created
cons
-biodiversity may be lost from deforestation or monocultures to grow plants for biofuels
-greenhouse gas emmissions from production and transportation
-production of biofuels can be inefficient
-large amounts of raw materials used
-use of chemical fertilisers and pesticides may harm local wildlife
-large areas of land needed for biofuel production
-high initial investment required
reforestation
increases number of plants
increases vol of co2 taken in for photosynthesis
reduction in carbon dioxide in atmosphere will reduce global warming as it will decrease the enhanced greenhouse effect
