15 July 2014

Australian Drought Is Likely Result of Rising Greenhouse Gases

Posted by Dan Satterfield

regional_rainfall_declineA new paper in Nature Geoscience has found that the increasing drought in Australia is very likely due to rising greenhouse gases, and dropping levels of stratospheric Ozone in the atmosphere, and NOT a normal climate fluctuation. Model data also showed that it will likely get worse as greenhouse gases increase over the next century.

Key Findings (from GFDL release-see link below)

  • An important new tool for prediction of regional-scale climate change has been developed at GFDL: a new high-resolution climate model (CM2.5), able to simulate regional-scale precipitation with fidelity that is considerably better than previous generation models.
  • Model simulations show that the observed long-term decline in winter rainfall over parts of southern Australia, especially southwestern Australia, is a response to anthropogenic increases in greenhouse gases and reductions in stratospheric ozone.
  • Model projections indicate an amplification of this drying trend, in both magnitude and spatial extent, through the 21st century.

A good summary of the paper is here from the Geophysical Fluid Dynamics Lab. Abstract and paper is here.

The authors ran the model with changes in natural forcings like solar output/volcanoes etc. and could not reproduce the observed spatial and temporal pattern of drying. Rising greenhouse gases and lower ozone in the straosphere DID.