14th Austin Roberts Commemorative Lecture 2020

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It’s time to get real about the climate crisis in Southern Africa.

Stephan Woodborne

iThemba LABS

Climate change is an invidious process that has society lured into a sense of security because of its perceived glacial pace. There are different perspectives on climate change. These range from denialism, that in its most extreme form considers it to be a “hoax”, through a kind of inconsistency that arises because the evidence does not seem to be relevant where one lives. It is also perceived as a “natural process” while some  consider climate change to be one of the most important crises that need to be addressed by society. 

The presentation will show evidence of natural climate change, which has taken place in southern Africa in the past. The time scales range over hundreds of thousands to millions of years - but when the focus is on the last 1000 years, the evidence becomes tangible as it becomes evident on a scale that humans can relate to and will experience in their lifetime.

One example is to analyze baobab tree growth rings across southern Africa. It has been possible to produce a time map of rainfall variability over the last millennium. This evidence alone should startle us into action, because even the natural climate fluctuations in the last 1000 years include episodes that would cripple our modern economy. 

Anthropogenic (human) impacts on climate change just exacerbate this. This record allows scientists to bridge the past reality with future climate projections by providing a test for models. The same models that simulate future climate change have been run for the last 1000 years and compared with the paleo (older) record as a form of “calibration”.

The results show that the models accurately capture the effects of all the major forces of climate in southern Africa. This gives society a unique opportunity. Instead of waiting for climate change to play out its script, we can fast-forward to see what our future may relatively look like.

The presentation will show examples of contemporary effects due to climate change, and look into the future to explore the impacts of higher temperatures as well as how this may lead to extinctions in our lifetime or that of our children. The most important impact is the human dimension: our society must begin to develop resilience to the way in which a possible human tragedy will unravel if nothing is done.