Climate Change in the ACT

Are severe weather events linked to climate change?

 

Determining whether a specific, single extreme event is due to a specific cause, such as increasing greenhouse gases, is difficult, if not impossible, for two reasons: 1) extreme events are usually caused by a combination of factors; and 2) a wide range of extreme events is a normal occurrence even in an un-changing climate. 

 

Nevertheless, analysis of the warming observed over the past century suggests that the likelihood of some extreme events, such as heatwaves, has increased due to green-house warming, and that the likelihood of others, such as frost or extremely cold nights, has decreased.

 

Extreme events usually result from a combination of factors. Because some factors may be strongly affected by human activities, but others may not, it is not simple to detect a human influence on a single, specific extreme event.

 

Nevertheless, it may be possible to use climate models to determine whether human influences have changed the likelihood of certain types of extreme events.

 

• Source: FAQ # 9.1; IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

 

A changing climate leads to changes in the frequency, intensity, spatial extent, and duration of extreme weather and climate events. These include extreme temperatures, heatwaves, drought, flooding, bushfires, tropical cyclones, and storm surges.

 

The natural climate variability that underlies all extreme weather events is now influenced and altered by the effect of human-induced warming of the climate system. 

 

Future climate change impacts will be experienced mostly through extreme events rather than gradual changes in mean temperature or rainfall.

 

Heatwaves, floods, fires and southern Australian droughts are expected to become more intense and more frequent. Frosts, snow and cyclones are expected to occur less often.

 

• Source: CSIRO Questions and answers about climate change; What is extreme weather and how is it changing?