State of the Climate 2018

At the Bureau of Meteorology and CSIRO, we
monitor, analyse and explain observed and
future changes in Australia’s climate.
This is our fifth State of the Climate report.
It focuses on observations and data that show
how and why the climate is changing in Australia,
and around the globe.
Australia has warmed by just over one degree
since 1910, with most of that warming occurring
since the 1950s.
This means more frequent heatwaves, and increased
bushfire risk with more extreme fire weather,
and longer fire seasons, especially in southern
and eastern Australia.
Long-term changes in rainfall are also occurring.
In the past few decades, northern wet season
rainfall has overall been very much above
average.
Whereas across southern Australia, there has
been a decline in rainfall during April to
October.
These changes in temperature and rainfall
are projected to continue.
Overall temperatures will increase and periods
of extreme heat will worsen.
When combined with further decreases in rainfall,
drought will be more likely and more severe,
especially in parts of southern Australia
The warming trend is also observed in the
oceans.
The sea surface has warmed and contributed
to marine heatwaves, which have damaging impacts,
such as coral bleaching in the Great Barrier
Reef.
Below the surface, the oceans have absorbed
most of the extra heat in the Earth's system.
Australia's Southern Ocean is a particular
hot spot for heat uptake.
Sea levels have risen, and are projected to
rise further in the future, which will increase
coastal inundation and erosion, and risks
damaging coastal infrastructure.
The major driver of these changes to the climate
is the increase in greenhouse gas concentrations
in the air.
Carbon dioxide is now above the 400 ppm milestone,
and all greenhouse gases combined have just
crossed the milestone of 500 ppm equivalent
of carbon dioxide.
These increases have resulted from human activities.
For more information about our changing climate,
including projected changes in your region,
visit our websites
monitor, analyse and explain observed and future changes in Australia’s climate. This is our fifth State of the Climate report. It focuses on observations and data that show how and why the climate is changing in Australia, and around the globe. Australia has warmed by just over one degree since 1910, with most of that warming occurring since the 1950s. This means more frequent heatwaves, and increased bushfire risk with more extreme fire weather, and longer fire seasons, especially in southern and eastern Australia. Long-term changes in rainfall are also occurring. In the past few decades, northern wet season rainfall has overall been very much above average. Whereas across southern Australia, there has been a decline in rainfall during April to October. These changes in temperature and rainfall are projected to continue. Overall temperatures will increase and periods of extreme heat will worsen. When combined with further decreases in rainfall, drought will be more likely and more severe, especially in parts of southern Australia The warming trend is also observed in the oceans. The sea surface has warmed and contributed to marine heatwaves, which have damaging impacts, such as coral bleaching in the Great Barrier Reef. Below the surface, the oceans have absorbed most of the extra heat in the Earth's system. Australia's Southern Ocean is a particular hot spot for heat uptake. Sea levels have risen, and are projected to rise further in the future, which will increase coastal inundation and erosion, and risks damaging coastal infrastructure. The major driver of these changes to the climate is the increase in greenhouse gas concentrations in the air. Carbon dioxide is now above the 400 ppm milestone, and all greenhouse gases combined have just crossed the milestone of 500 ppm equivalent of carbon dioxide. These increases have resulted from human activities. For more information about our changing climate, including projected changes in your region, visit our websites

I’m Andrew Lenton and I’m a principal
research scientist at CSIRO’s Climate Science
Centre. I’m working on understanding the
role the oceans plays in the global climate
system.
The world’s oceans help regulate our climate
and slow down the rate at which the Earth’s
surface is warming, by absorbing more than
90 per cent of the extra heat from increased
greenhouse gases in the atmosphere.
However, this benefit comes at a price.
Globally, ocean temperatures are steadily
increasing. Some regions around Australia
are warming faster than the global average.
We know this because scientists have
been monitoring our oceans for decades.
There are several tools we use to observe
the ocean, such as specialised instruments
fitted to ships that allow us to measure temperature
and salinity at the sea surface, as well as
other instruments to measure the entire water
column.
Scientific moorings are installed around Australia,
collecting data and sending it back to researchers
in real-time.
With advances in technology, ocean observation
is increasingly moving towards remote sensing
and autonomous systems.
Satellites are used to collect data on ocean
surface temperature, ocean currents, sea level,

surface chlorophyll, ocean colour, wave and
wind speed, and salinity.
Autonomous sensing platforms such as 'Argo'
allow us to go to inaccessible, inhospitable
locations for extended periods of time, collecting
data that would otherwise be difficult or
impossible to obtain.
Ocean observations play a key role in providing
new insights, improving our models of the
oceans and climate, as well as enabling exciting
new research.
Perhaps most importantly, we’re better able
to track and understand changes in the ocean,
allowing us to look into the future of the
oceans and climate in ways that were previously not
possible.

Research scientists at the Bureau of Meteorology
are working to better understand climate extremes.
The Bureau's climate record comprises over
100 years of data from stations around Australia.
We analyse this climate record to understand
how changes are influencing extremes, including
hazardous weather events such as heatwaves,
bushfires and tropical cyclones.
Climate extremes are rare events that don’t
happen very often.
With Australia's temperature increasing by
over a degree, the frequency of extreme monthly
temperatures has risen from 2 per cent of
the time, to over 14 per cent—this is a six-fold
increase in only 50 years.
We can also use the Bureau's supercomputer
to examine the influence of climate change
on individual extreme events.
In October and November 2015, Australia experienced
record-warm daytime temperatures.
By running our models we show that the weather
systems in a CO2 environment typical of 1960
would not have led to the record-breaking
heatwaves that we saw.
More hot days can also mean more extreme fire
weather.
Our fire weather season has been starting
earlier and becoming more intense since the
1970s, particularly in southern and eastern
Australia.
Increases in the intensity and frequency of
many extreme events are projected to continue
and will have more severe impacts on Australians.
Although many extremes are becoming more severe
due to climate change, some extremes are expected
to become less frequent such as tropical cyclones
and East Coast Lows.
Research from the Bureau is helping us prepare
for a climate that is different to what we've
seen in the past.