Topic: Abrupt Climate Change

Abrupt climate change is here. Robert Hunziker, Counterpunch. Feb. 2, 2015.

Abrupt climate change. Q&A. Earth Institute at Columbia University.

Could abrupt climate change lead to human extinction within 10 years? Charlie Smith, straight.com. Feb. 11, 2017.



Abrupt climate change: past, present and future. Jim White, via youtube. Dec. 2014.

Scientific articles:

Abrupt Climate Change. Stefan Rahmstorf, Elsevier. 2009.

Introduction  

High-resolution paleoclimatic records from ice and sediment cores and other sources have revealed a number of dramatic climatic changes that occurred over surprisingly short times – a few decades or in some cases a few years. In Greenland, for example, temperature rose by 5–10 1C, snowfall rates doubled, and windblown dust decreased by an order of magnitude within 40 years at the end of the last glacial period. In the Sahara, an abrupt transition occurred around 5500 years ago from a relatively green shrubland supporting significant populations of animals and humans to the dry desert we know today. 

One could define an abrupt climate change simply as a large and rapid one – occurring faster than in a given time (say 30 years). The change from winter to summer, a very large change (in many places larger than the glacial–interglacial transition) occurring within 6 months, is, however, not an abrupt change in climate (or weather), it is rather a gradual transition following the solar forcing in its near-sinusoidal path. The term ‘abrupt’ implies not just rapidity but also reaching a breaking point, a threshold – it implies a change that does not smoothly follow the forcing but is rapid in comparison to it. This physical definition thus equates abrupt climate change with a strongly nonlinear response to the forcing. In this definition, the quaternary transitions from glacial to interglacial conditions and back, taking a few hundred or thousand years, are a prime example of abrupt climate change, as the underlying cause, the Earth’s orbital variations (Milankovich cycles), have timescales of tens of thousands of years. On the other hand, anthropogenic global warming occurring within a hundred years is not as such an abrupt climate change as long as it smoothly follows the increase in atmospheric carbon dioxide. Only if global warming triggered a nonlinear response, like a rapid ocean circulation change or decay of the West Antarctic Ice Sheet (WAIS), would one speak of an abrupt climate change.

Abrupt Climate Change. R.B. Alley et al, Science. March, 2003.

Abstract:

Large, abrupt, and widespread climate changes with major impacts have occurred repeatedly in the past, when the Earth system was forced across thresholds. Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events. Were such an event to recur, the economic and ecological impacts could be large and potentially serious. Unpredictability exhibited near climate thresholds in simple models shows that some uncertainty will always be associated with projections. In light of these uncertainties, policy-makers should consider expanding research into abrupt climate change, improving monitoring systems, and taking actions designed to enhance the adaptability and resilience of ecosystems and economies.

Rapid climate change: lessons from the recent geological past. Jonathan Holmes et al, Science Direct. Dec. 2011.

Abstract 

Rapid, or abrupt, climate change is regarded as a change in the climate system to a new state following the crossing of a threshold. It generally occurs at a rate exceeding that of the change in the underlying cause. Episodes of rapid climate change abound in the recent geological past (defined here as the interval between the last glacial maximum, dated to approximately 20,000 years ago, and the present). Rapid climate changes are known to have occurred over time periods equal to or even less than a human lifespan: moreover, their effects on the global system are sufficiently large to have had significant societal impacts. The potential for similar events to occur in the future provides an important impetus for investigating the nature and causes of rapid climate change. 

Holocene climate variability. Paul A.Mayewski et al, ScienceDirect. Nov. 2004.

Although the dramatic climate disruptions of the last glacial period have received considerable attention, relatively little has been directed toward climate variability in the Holocene (11,500 cal yr B.P. to the present). Examination of ∼50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000–8000, 6000–5000, 4200–3800, 3500–2500, 1200–1000, and 600–150 cal yr B.P. Most of the climate change events in these globally distributed records are characterized by polar cooling, tropical aridity, and major atmospheric circulation changes, although in the most recent interval (600–150 cal yr B.P.), polar cooling was accompanied by increased moisture in some parts of the tropics. Several intervals coincide with major disruptions of civilization, illustrating the human significance of Holocene climate variability.

Policy tradeoffs under risk of abrupt climate change. Yacov Tsura and Amos Zemel, Journal of Economic Behaviour and Organization. Dec. 2016.

Highlights

• Serious threats of climate change are associated with abrupt catastrophic events.
• Mitigation efforts delay the event occurrence.
• Adaptation efforts minimize the damage inflicted upon occurrence.
• The role of climate policy is to balance between mitigation and adaptation efforts.

Abstract

By now it is widely recognized that the more serious threats of climate change are associated with abrupt events capable of inflicting losses on a catastrophic scale. Consequently, the main role of climate policies is to balance between mitigation efforts, aimed at delaying (or even preventing) the occurrence of such events, and adaptation actions, aimed at minimizing the damage inflicted upon occurrence. The former affects the accumulation of greenhouse gases in the atmosphere; the latter determines the impact of loss once the event occurs. This work examines the tradeoffs associated with these two types of policy measures by characterizing the optimal mitigation–adaptation mix in the long run.