4. Rising Carbon Dioxide Concentrations Flashcards

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1
Q

What can be deduced by drilling columns of ice in the Antarctic?

A

CO2 concentrations and temperatures of the past

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2
Q

How can CO2 concentrations and temperatures of the past be deduced by drilling columns of ice in the Antarctic?

A
  • 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
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3
Q

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)

A

fluctuated:

  • 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
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4
Q

What has happened to atmospheric carbon dioxide concentrations in the last 150 years?

A

they have risen above the normal range (considering where we are in the cycle)

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5
Q

Why have atmospheric carbon dioxide concentrations increased in the last 150 years?

A

due to the combustion of fossilized organic matter (coal, oil and gas)

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6
Q

When did the burning of fossil fuels really take off? What else has dramatically increased since this time?

A
  • industrial revolution 200 years ago
  • CO2 concentration

both are increasing faster and faster

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7
Q

How much have global temperatures increased by since the industrial revolution?

A

0.8°C with most of the increase coming since 1980

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8
Q

Are CO2 concentrations and global temperature directly proportional?

A

NO - they are correlated but there are other factors that affect global temperature so they are NOT directly proportional

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9
Q

There are other factors that affect global warming. What does this result in?

A

uneven temperature rises compared to CO2:

- there may be steady rises in CO2 concentrations, but sudden slows/ rapid increase in temperature

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10
Q

Apart from global warming, what else do CO2 concentrations effect?

A

the acidity of the sea and therefore coral reefs

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11
Q

“500 billion tonnes of CO2 has dissolved …. since the start of the industrial revolution.” Fill in the blank.

A

in the sea

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12
Q

How many tonnes of CO2 has dissolved into the sea since the start of the industrial revolution?

A

500 billion tonnes

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13
Q

How has the pH of the sea changed since the start of the industrial revolution?

A

ph drop from 8.25 to 8.14

represents 30% change in acidification

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14
Q

What marine animals are massively effected by increasing CO2 concentrations? Why?

A

reef-building corals:

  • they deposit calcium carbonate in their skeletons
  • so they need to absorb carbonate ions from seawater
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15
Q

Is the concentration of carbonate ions high or low in sea water? Why?

A

low

- they are not very soluble

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16
Q

How does carbon dioxide affect concentrations of carbonate ions?

A
  • CO2 + H2O –> carbonic acid
  • carbonic acid disassociates into hydrogen ions and hydrogen carbonate ions
  • hyrdrogen ions + carbonate –> hydrogen carbonate
  • thereby reducing carbonate concentrations
17
Q

How does carbon dioxide affect coral?

A
  • CO2 reduces concentration of carbonate ions in seawater
  • new calcium carbonate - the skeletons of coral - cannot be made
  • additionally, the existing calcium carbonate dissolves in carbonic acid*

*carbonic acid formed by CO2 + H2O