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
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
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
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)
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
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