Climate & Climate Change in the Bega Valley : Climate Smart Farming


Climate & Climate Change in the Bega Valley

The Bega Valley lies where the eastern and southern coasts of Australia meet. It has a unique climate, influenced by oceans to both the east and to the south of Australia and by the mountainous, Great Dividing Range, which lies to the Valley’s west. The nearby ocean reduces the extremes of temperature which are experienced inland and west of the Valley. But high summer temperatures, heat waves and winter frosts can still impact on agriculture and natural ecosystems in the Valley. Rainfall is variable. There are long dry periods and sometimes devastating droughts. Intense rainfall events also occur, sometimes contributing to extensive flooding. Extreme temperatures, heavy rainfall, floods, long dry periods and droughts can impact on the crops, livestock, native plants and animals, infrastructure and people of the Valley.

Climate change is likely to result in the following changes in the Bega Valley:

  • significant increases in temperature
  • longer dry spells
  • increases in storminess and winds
  • increased intensity of rainfall events
  • change in seasonal rainfall patterns
  • potential reduction in rainfall
  • decline in soil moisture and runoff

Step shifts in climate are more likely to occur than smooth and gradual changes. A period of relative stability in maximum temperatures may, for example, be replaced with a step increase to higher temperatures, which then becomes the new norm.

Climate variability is also likely to increase, changing the nature of storms and rainfall patterns, increasing the intensity and length of heat waves and the length and intensity of dry periods and drought.

Temperature changes are more certain than rainfall changes, although knowledge of how rainfall is likely to change is improving.

Climate changes are now being observed in the Bega Valley. Temperatures are increasing, including step wise increases punctuating periods of relative stability. The Valley is also experiencing increasing extremes in maximum temperatures and a lengthening of the warm season. There has been an intensification of long dry spells, with the most recent occurrence in the Millennial Drought between 1997 and 2009, and then again in 2017-2018. The Millennial Drought’s decline in cool season and autumn rainfall was unique and consistent with recent science on climate projections of seasonal rainfall changes.  It was the worst drought on record.

These climate changes, including the likely increase in extremes, and the potential for extremes to act together, as for example, in summer droughts, hot windy fire weather and increasing storminess with intense rainfall and strong winds are a risk to agricultural production and to the natural resources (water, soils and ecosystems) on which agriculture relies.

This summary was prepared by Louise Rose, using the following sources which provide further information on climate and climate change in the Bega Valley and surrounding region:

Alexander, L. V., & Arblaster, J. M. (2017). Historical and projected trends in temperature and precipitation extremes in Australia in observations and CMIP5. Weather and Climate Extremes, 15, 34-56. doi:https://doi.org/10.1016/j.wace.2017.02.001

Ayers, G. P. (2016). Australia’s Air Temperature Trend Reviewed. Journal of Southern Hemisphere Earth Systems Science, 66(3), 270-280.

Chiew, F., Potter, N., Vaze, J., Petheram, C., Zhang, L., Teng, J., & Post, D. (2014). Observed hydrologic non-stationarity in far south-eastern Australia: implications for modelling and prediction. Stochastic Environmental Research and Risk Assessment, 28(1), 3-15.

Dowdy, A. J., Grose, M. R., Timbal, B., Moise, A., Ekström, M., Bhend, J., & Wilson, L. (2015). Rainfall in Australia’s eastern seaboard: a review of confidence in projections based on observations and physical processes. Aust. Met. Oceanogr. J, 65, 107-126.

Evans, J. P., Argueso, D., Olson, R., & Di Luca, A. (2017). Bias-corrected regional climate projections of extreme rainfall in south-east Australia. Theoretical and Applied Climatology, 130(3), 1085-1098. doi:10.1007/s00704-016-1949-9

Freund, M., Henley, B. J., Karoly, D. J., Allen, K. J., & Baker, P. J. (2017). Multi-century cool-and warm-season rainfall reconstructions for Australia's major climatic regions. Climate of the Past, 13(12), 1751.

Grose, M., Abbs, D., Bhend, J., Chiew, F., Church, J., Ekström, M., . . . McInnes, K. (2015). Southern Slopes Cluster Report, Climate Change in Australia Projections for Australia’s Natural Resource Management Regions: Cluster Reports: CSIRO and Bureau of Meteorology, Australia.

Jones, R., & Ricketts, J. (2016). Atmospheric warming 1997–2014: hiatus, pause or regime?

Kirono, D. G. C., Hennessy, K. J., & Grose, M. R. (2017). Increasing risk of months with low rainfall and high temperature in southeast Australia for the past 150years. Climate Risk Management, 16, 10-21. doi:https://doi.org/10.1016/j.crm.2017.04.001

Lewis, S. C., & King, A. D. (2017). Evolution of mean, variance and extremes in 21st century temperatures. Weather and Climate Extremes, 15, 1-10. doi:https://doi.org/10.1016/j.wace.2016.11.002

Mummery, J., Weir, B., Grant, J., & Norman, B. (2017). Climate Change Adaptation in the Australian Capital Region: Emerging Issues in the Context of Regional Planning: University of Canberra.

Solman, S. A., & Orlanski, I. (2016). Climate change over the extratropical Southern Hemisphere: the tale from an ensemble of reanalysis datasets. Journal of Climate, 29(5), 1673-1687.

Timbal, B., Fiddes, S., & Brown, J. R. (2017). Understanding south‐east Australian rainfall projection uncertainties: the influence of patterns of projected tropical warming. International Journal of Climatology, 37(S1), 921-939. doi:doi:10.1002/joc.5047