Climate Tipping Points

From a systems perspective, the reason to stabilize our climate as soon as possible is to avoid the reinforcing biogeochemical feedback loops that could drive catastrophic, runaway climate change.  

We made our own causal loop diagram of many of the most important feedback loops.  You can see it below.

(Notice the big “balancing loop” to the far left.  THAT’S YOU and ME!!)

To learn more about them (not fun, but important…), check out this excellent animation: Wake Up, Freak Out – then Get a Grip from Leo Murray on Vimeo.


Comments

  1. says

    One note:

    The ice-albedo loop may operate more through local (polar) effects than through its effect on global temperature. At least, that’s my hypothesis, based on the fact that there’s not a lot of insolation at the poles, and thus not a major contribution to the global budget. I would expect the effect on the local heat budget to be larger. I’d be interested to know what the literature says on this.

    Some other feedbacks:

    Tropical forest dieback involves regional scale tipping points (forest cover affects microclimate and precipitation, and vice versa). It could also contribute carbon to the atmosphere, furthering warming and precip changes, in which case it’s a positive feedback. However, there are also albedo and wind effects – not sure whether the balance is still positive.

    Temp and precip changes also affect temperate forests, through increased pest and fire frequency and intensity. That releases carbon, another positive feedback.

    Trees lost at the southern margin of the temperate forests might eventually be replaced at the northern margin, a negative feedback. However, that will take a long time because there’s not much soil on what is now tundra, and soil formation takes a long time.

    Methane release from permafrost (shown above) is paralleled by carbon release from soils and methane release from undersea clathrates, all driven by and contributing to warming.

    Increasing temperatures suppress biological activity, reducing formation of cloud condensation nuclei. Less CCN means fewer clouds and more water vapor in the air, increasing temperature. (This is the speculative Cretaceous super-greenhouse effect).

    Freshwater outflows from melting ice influences thermohaline circulation (though this may be offset by increasing winds). There are potential + feedbacks, but the net sign of the effect is currently ambiguous.

    Rising sea level buoys ice sheets, possibly contributing to breakup and destabilization of continental outlet glaciers, further increasing sea level.

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