Climate and Weather
Melbourne City is classified as having a temperate climate. It is not a typical Mediterranean climate as some might think. A temperate climate is generally characterised as having on average relatively even monthly rainfall and mild temperatures without frequent extremes of very cold or very hot weather. A Mediterranean climate is more typical of that experienced in Adelaide with marked relatively high winter rainfall and dry, hot summers.
The Royal Botanic Gardens provides weather information to the Victorian Bureau of Meteorology (BOM) from both Melbourne and Cranbourne sites.
RBG Melbourne Automatic Weather Station
An automatic weather station based at the Royal Botanic Gardens Melbourne provides the means for long term monitoring of climate and studying influences from changes to the urban environment surrounding the Gardens.
The impacts of climate change on Victoria will likely include changing weather conditions from what we might have normally experienced. These could include higher average annual temperatures; reduced, and more erratically distributed annual rainfall; and a greater incidence of extreme weather events. Increasing temperature and water scarcity will be unfavourable to plants native to temperate regions; for example, Northern Hemisphere trees such as elms, ashes, birches etc. and rhododendrons, ferns and some lawn grasses, but will favour plants indigenous to southern Australia and exotic plants from geographical areas with comparable climates (homoclimes).
More detailed information on RBG weather and climate including projected changes can be found in Royal Botanic Gardens Melbourne Climate Statistics from 2000 to 2010 (WORD - 96kb).
To ensure the preservation of RBG Melbourne’s unique living landscape into the future, the Gardens has developed a range of strategic responses to climate change projections. In the short to medium term, works associated with the Working Wetlands project are underway to capture and treat stormwater to maintain the health of the Ornamental Lake. Once funded, a second stage of the project will build the means to treat some of the lake water and use this for irrigation of the landscape.
However, a greater challenge is seeking to manage the Gardens during increases in average temperature from global warming. While it is normal for the climate to show natural variability with some years cooler and some years hotter, a gradual temperature rise is more likely to increase the chance of more extreme daily temperatures. Increases in both average and extreme daily temperature will place many of our plants under unsustainable stress.
Scorching of plants after three consecutive days greater than 43 degress Celsius (oC) from 28-30 January 2008 and a record breaking 46.7 oC on 7 February 2009. The relative humidity dropped to 8-10% on these days.
As stewards of the heritage gardens we all enjoy today, the RBG has a responsibility to maintain the landscape style under water scarcity and increasing temperatures. Ultimately, this will be most successful if the type of plants that we grow can be gradually changed to those more adapted for future climates.
Guilfoyle’s Volcano – many of the plants selected for this landscape will likely be more adapted to the climate of the future
Long-term landscape planning is essential, and the Gardens has reviewed its Master Plan and Living Plan Collections Plan to consider the projected climatic conditions. Our most valuable living assets are those that are long-lived such as the trees which take many years to reach maturity. From this perspective, RBG management is considering climate change projections for 2070 when selecting plants for the future.
More information on climate change and landscapes:
- Botanic Gardens and New Zealand 2009 Congress
- Rethinking Botanic Gardens in the Face of Climate Change – Perspectives on Planning, Landscape Design, and Implementation
- Botanic Gardens Conservation International Fourth Global Botanic Gardens Congress 2010 - Theme 5 - Addressing climate change through botanic gardens
Last updated 13 Jan 2011