Flashcards in 4. Rising Carbon Dioxide Concentrations Deck (17):
What can be deduced by drilling columns of ice in the Antarctic?
CO2 concentrations and temperatures of the past
How can CO2 concentrations and temperatures of the past be deduced by drilling columns of ice in the Antarctic?
- ice has built up over 1000s of years
- ice deeper down is older than surface ice
- bubbles of air in ice can be extracted and CO2 concentration tested
- global temperatures can be deduced from ratios of hydrogen isotopes in water molecules
What has happened to CO2 levels and global temperatures over the last 800,000 years? What can we say about the relationship between the two? (p.61)
- rapid increasing, followed by longer periods of decreasing
- rapid warming, followed by longer periods of cooling
- correlates very strongly...
- correlation does not equal causation
- but from previous research, we know that carbon dioxide is a greenhouse gas...so some of the temperature variation is due to variation of atmospheric carbon dioxide concentrations
What has happened to atmospheric carbon dioxide concentrations in the last 150 years?
they have risen above the normal range (considering where we are in the cycle)
Why have atmospheric carbon dioxide concentrations increased in the last 150 years?
due to the combustion of fossilized organic matter (coal, oil and gas)
When did the burning of fossil fuels really take off? What else has dramatically increased since this time?
- industrial revolution 200 years ago
- CO2 concentration
both are increasing faster and faster
How much have global temperatures increased by since the industrial revolution?
0.8°C with most of the increase coming since 1980
Are CO2 concentrations and global temperature directly proportional?
NO - they are correlated but there are other factors that affect global temperature so they are NOT directly proportional
There are other factors that affect global warming. What does this result in?
uneven temperature rises compared to CO2:
- there may be steady rises in CO2 concentrations, but sudden slows/ rapid increase in temperature
Apart from global warming, what else do CO2 concentrations effect?
the acidity of the sea and therefore coral reefs
"500 billion tonnes of CO2 has dissolved .... since the start of the industrial revolution." Fill in the blank.
in the sea
How many tonnes of CO2 has dissolved into the sea since the start of the industrial revolution?
500 billion tonnes
How has the pH of the sea changed since the start of the industrial revolution?
ph drop from 8.25 to 8.14
represents 30% change in acidification
What marine animals are massively effected by increasing CO2 concentrations? Why?
- they deposit calcium carbonate in their skeletons
- so they need to absorb carbonate ions from seawater
Is the concentration of carbonate ions high or low in sea water? Why?
- they are not very soluble
How does carbon dioxide affect concentrations of carbonate ions?
- CO2 + H2O --> carbonic acid
- carbonic acid disassociates into hydrogen ions and hydrogen carbonate ions
- hyrdrogen ions + carbonate --> hydrogen carbonate
- thereby reducing carbonate concentrations