Warming likely to continue
Greenhouse gas emissions are continuing to increase.
Due to the long time these gases remain in the atmosphere, we expect the warming trend of the past century to accelerate throughout this century.
We also expect changes to rainfall patterns and to the frequency of extreme weather events such as cyclones and droughts.
Greenhouse gas concentrations will affect the future climate
The Earth's future climate will depend on whether the world’s population manages to slow or even reduce greenhouse gas emissions.
Since greenhouse gases have a long lifetime in the atmosphere, even a reduction in emissions will see atmospheric concentrations continue to increase, leading to further climate change for many decades.
To understand how our climate may change in future, scientists have developed different greenhouse gas emissions scenarios based on assumptions about future demographic change, economic development and technological advances.
Based on these ranges of emissions, the concentration paths are similar up to about 2030, and then diverge markedly.
For more information on greenhouse gas scenarios visit the Climate Change in Australia website.
Future global warming
In its most recent climate projections in 2014, the United Nations Intergovernmental Panel on Climate Change (IPCC) projected a global warming increase by 2100 of between 0.3 and 4.8 °C (relative to 1986-2005), depending on the emission scenario.
Specifically, the planet could warm by between 0.3 °C and 1.7 °C for a scenario where emissions of greenhouse gases are low following extensive global efforts to reduce emissions, or it could warm by 2.6 °C to 4.8 °C if there is little global action to reduce greenhouse gas emissions.
The world is tracking along a path that is more like a medium to high emissions scenario, where the planet could warm by 1.4 to 3.1 °C.
Australia's future climate
As with the world as a whole, Australia over the coming decades is expected to experience continued warming, with more extremely hot days and fewer extremely cool days.
Hotter weather would bring a longer fire season for the south and east and an increase in the number of dangerous fire weather days.
Based on global warming projections, and the observed ratio of Australian to global temperature of around 1.4, Australia could be expected to warm by between 0.4 and 6.78 °C (relative to 1986-2005) by 2100.
While Australia’s current decade is warmer than any other decade over the past century, it is likely to be the coolest decade for the century ahead.
Rainfall in southwest and southeast Australia has been declining in recent decades and is projected to likely decline further.
Climate models show that there may be a decrease in cool season rainfall across many parts of south and east Australia, likely leading to more time spent in drought.
Climate models suggest that rainfall near the equator will increase globally, but it’s not clear how rainfall may change in northern Australia.
Australia will experience climate-related changes to extreme weather events.
Throughout the country, intense short-duration heavy rainfall events will become more frequent and extreme.
Droughts will become more frequent, more intense and will last for longer.
Fire-weather risk is also likely to increase, fire seasons will be longer, and bushfires will affect expanded areas.
Although it is likely that there will be fewer tropical cyclones in the Australian region, the proportion of intense cyclones may increase.
For most of the Australian coast, extreme sea levels that had a probability of occurring once in a hundred years are projected to become an annual event by the end of this century with lower emissions, and by mid-century for higher emissions.