Climate change: What does the future hold?

Beate Hölscher, Research Administrator, SAEON

In March 2012, Dr Warren Washington, distinguished scientist from the National Center for Atmospheric Research, Boulder, Colorado presented a public talk at the National Research Foundation (NRF) entitled 20th and 21st Century Climate Change: Climate Modelling, Societal Impacts, and Environmental Justice. The event was hosted by SAEON and the Africa Centre for Climate and Earth Systems Science (ACCESS).

Dr Warren Washington (centre) with his wife Mary (right) and Dr Albert van Jaarsveld, CEO of the National Research Foundation (Picture: Patrick Saunders). View biographical information on Dr Washington.		In his talk Dr Washington highlighted the dangers posed by acidification of the world's oceans, and the possible disruptions of the climate feedback mechanisms - the worst case of which would be reaching a 'tipping point' which will have unprecedented consequences on the climate equilibrium.

Dr Washington succeeded in making a technical and much debated subject both fascinating and easily understandable.

The Anthropocene

The most recent Intergovernmental Panel on Climate Change Assessment Report (IPCC AR4) has convinced most climate scientists that humankind is changing the Earth's climate and that significant global warming is taking place. In fact, the term Anthropocene^* is now widely accepted, which refers to the era of a human-altered global environment that we are now in.

The talk gave a brief review of the history of global climate observations, followed by evidence of observed 20th century climate change in the form of interesting, albeit shocking graphs. Dr Washington also discussed and explained the views held by some scientists sceptical of the IPCC report, who advocate that the observed changes result from natural climate variability or other causes. However, a climate model using natural events only (volcanic eruptions and solar irradiance) does not show the climate warning trends.

Climate models

Dr Washington is widely regarded as the guru of climate models. In fact, as early as the 1960s he became one of the first developers of ground-breaking atmospheric computer models in collaboration with colleagues at the US National Center for Atmospheric Research (NCAR).

These models, which use fundamental laws of physics to predict future states of the atmosphere, have helped scientists understand climate change. (Prior to this, with the existing computing powers of the time, running the models took several days and rooms full of equipment!)

In his talk Dr Washington presented a series of the latest complex climate model simulations (from low and high carbon emission scenarios) which are projected into the 21st century and beyond in preparation for the next IPCC assessment. These simulations running in fast forward through the decades, depicted as pulsating and psychedelic clouds of colour, give viewers a chilling picture of how fast these changes are progressing.

Acidification of our oceans

Dr Washington also mentioned the dangers posed by acidification of the world's oceans, and the possible disruptions of the climate feedback mechanisms - the worst case of which would be reaching a 'tipping point' which will have unprecedented consequences on the climate equilibrium.

"It was indeed an honour to host a scientist of Dr Washington's calibre and to exchange questions and opinions on climate change in the South African context," said SAEON Managing Director Johan Pauw.

^* The Anthropocene is a recent and informal geologic chronological term that serves to mark the evidence and extent of human activities that have had a significant global impact on the Earth's ecosystems. The term was coined by ecologist Eugene F. Stoermer, but has been widely popularised by the Nobel Prize-winning atmospheric chemist Paul Crutzen, who regards the influence of human behaviour on the Earth's atmosphere in recent centuries as so significant as to constitute a new geological era for its lithosphere.