The Bureau of Meteorology and CSIRO have just released their updated ”State of the Climate’ report. This is produced every two years and provides an update on what is happening with the latest climate science. As in previous report’s, the impacts of climate change on the Australian landscape are clear. There are also some specific details for people concerned about mountain environments.

In general terms, the impacts of climate change on Australia are clear:

  • Australia’s climate has warmed on average by 1.44 ± 0.24 °C since national records began in 1910, leading to an increase in the frequency of extreme heat events.
  • There has been a decline of around 16% in April to October rainfall in the southwest of Australia since 1970. Across the same region May–July rainfall has seen the largest decrease, by around 20% since 1970.
  • In the southeast of Australia there has been a decline of around 12% in April to October rainfall since the late 1990s.
  • There has been a decrease in streamflow at the majority of streamflow gauges across southern Australia since 1975. 
  • Rainfall and streamflow have increased across parts of northern Australia since the 1970s. 
  • There has been a decrease in the number of tropical cyclones observed in the Australian region since 1982. 
  • Oceans around Australia are acidifying and have warmed by around 1 °C since 1910, contributing to longer and more frequent marine heatwaves. 
  • Sea levels are rising around Australia, including more frequent extremes, that are increasing the risk of inundation and damage to coastal infrastructure and communities. 

The report is available here.

As expected, the news for us snow and mountain lovers is not great:


Snow pack

The report says:

‘Downward trends in maximum snow depth have been observed for Australian alpine regions since the late 1950s, with the largest declines during spring and at lower altitudes’.

This is, of course, not ‘new’ news. See for instance this piece on snow pack decline in Australia.

The report also notes:

‘Snow depth is closely related to temperature, and the observed declines are associated with the observed warming trends. Maximum snow depth remains highly variable and is strongly influenced by rare heavy snowfall days, which have no observed trends in frequency. Several heavy snowfall events contributed to average to high maximum snow depths in the seasons from 2017 to 2019’. 

Fire

We know that fire seasons are becoming longer and more intense and this is having a devastating impact on mountain forests, especially Alpine Ash and Snow Gums.

The report says:

‘The frequency of the most dangerous 10 per cent of fire weather days has increased significantly in recent decades across many regions of Australia, especially in the south and east. These increases are particularly evident during spring and summer and are associated with an earlier start to the southern fire weather season. Climate change is contributing to these changes in fire weather including by affecting temperature, relative humidity and associated changes to the fuel moisture content. Considerable year-to-year variability in fire weather also occurs. La Niña years, for example 2010–11 and 1999–2000, are associated with wet and cool climate anomalies and a lower number of days with high FFDI values. 

Dry lightning that occurs without significant rainfall is the primary
source of natural ignition for bushfires. Understanding changes to bushfire ignition in Australia is a current area of active research, including the frequency of dry lightning. 

There is a significant trend in some regions of southern Australia towards more days with weather conditions conducive to extreme bushfires that can generate thunderstorms within their smoke plumes. These fire-generated thunderstorms can lead to extremely dangerous fire conditions, as observed during the 2019–20 summer, and for the Canberra (2003) and Victorian Black Saturday (2009) fires. In some cases, the lightning strikes produced from the smoke plumes generate new fires.’ 

Stream flow

As noted above, the south east is already receiving less stream flow. The river systems of The Australian Alps are the headwaters of many of our key rivers in the south east, and less stream flow impacts all the way downriver, from the forested high country and into farming country and the ecosystems of the inland rivers.

  • In the southeast of Australia there has been a decline of around 12% in April to October rainfall since the late 1990s.
  • There has been a decrease in streamflow at the majority of streamflow gauges across southern Australia since 1975. 

Action is always the Antidote to Despair

This report is yet another good reason to get active with a climate change group and do what you can at home and in your workplace to reduce greenhouse emissions.


We certainly need better air capacity to fight the fires that we are experiencing across mountain and other natural areas. Please sign this letter to the prime minister calling for a publicly-owned national air fleet.