climate suprises Flashcards

1
Q

Thresholds and tipping points

A
  • A point where there is a change in the system that can be reversed
  • The climate system can switch into a new state very quickly once a threshold has been passed
  • A threshold can become a tipping point that, when crossed means the system moves into a new state, this is irreversible
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2
Q

examples of tipping points

A
  • ENSO changes
  • Permafrost loss
  • Runaway positive feedback loop of Ch4 release triggered by increase in temperature
  • Boreal forest dieback
  • Arctic sea ice loss
  • Greenland ice sheet melting, could increase sea level rise by 7m and disrupt Atlantic deepwater formation
  • Amazon rainforest dieback, hypernino from climate change would result in long dry spells in Amazon
  • Instability of West Antarctic Ice Sheet, could increase sea level rise by 8.5m and disrupt AABW formation
  • Sahara greening
  • West African monsoon shift
  • SE Asian monsoon instability
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3
Q

linear but delayed response of system to climate forcing

A
  • Magnitude is proportional to the additional forcing
  • Initial delay
    E.g. heating of the oceans, takes a lot of energy to increase temperature at first due to inertia but then steadily rises
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4
Q

Muted or limited response of system to climate forcing

A
  • Effect is not directly linked to additional forcing
  • Relevant part of climate system is buffered in some way
    E..g East Antarctic ice sheet has remained stable in much warmer periods of geological history (on land, so more stable)
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5
Q

Delayed and non-linear response of system to climate forcing

A
  • Climate system may have an initial slow response, but then responds in a non-linear way
  • Related to positive feedback mechanisms e.g. albedo lost as ice sheets melt
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6
Q

Threshold response of system to climate forcing

A
  • Very little response until it reaches a threshold
  • The response then takes place over a very short period of time
    E.g. if the Greenland ice sheet starts to melt, the melting could start to accelerate causing a catastrophic collapse
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