Nonlinear Impacts of Global Environmental Change

In this post I would like to put the focus on nonlinear impacts of the global environmental change. In my previous posts I have (hopefully) already pointed out, that the described and predicted effect on the human population are based on a wide range of scenarios.
But even this wide range of scenarios is not something to rely on too much. In most cases the scenarios do give a good idea about what could happen, but in many cases these scenarios are not very informative in terms of nonlinear impacts.

I came to this topic through a recently published article by the world bank about climate change impacts (Link). In this short article it was state that especially at an increase of more than 2 degrees, "there is a risk to trigger nonlinear tipping elements". Examples are also given: disintegration of West Antarctic ice sheet leading to a even faster sea-level rise, or large-scale Amazon dieback (with effects on the ecosystem, rivers, agriculture, energy production and livelihoods). All the named factors that could occur out of a Amazon dieback or the processes at the Antarctic ice shield show the wide range of effects not only on biodiversity and nature, but also directly on humans. 

While digging through articles and publications about this topic I found a very interesting article by Stephen Schneider, which was published already in 2004 in Global Environmental Change (Link to article).
Schneider states that a nonlinear outcome, therefore a surprising outcome is a "climate change-induced phenomenon with a very low probability of happening became reality or if an event never before imagined took place". Such nonlinear outcomes are possible due to the current situation, that many of the global systems and connections between the different systems are simply unknown or not yet understood. Examples for these systems are the oceanic-, the atmospheric- and the terrestrial-system.
Schneider writes that most climate change models rarely consider high-consequence extreme events with a low probability. And even the fact that these events are happening with a low probability is not certain, because to the lack of understanding and knowledge about the systems and effects. 

Some other quite popular examples (gladly picked up by media all around the world) of nonlinear effects that some people predict to maybe happen are a change of the Gulf Stream or a change to the so called El-Nino phenomena. 

This was one of my shorter articles, but I think it was about one of the most important things that always has to be kept in mind when talking about global environmental change and the effects of it. 

If your are interested in further reading I highly recommend you the linked article by Stephen Schneider.