ability, in some areas, to provide multiple cropping opportunities within a single
year. As such, agricultural production is distributed geographically and across
different climatic zones. Much of the most productive arable land in QLD is located
in the south-east areas or closer to the coast, whilst western parts of the State are dry
and drought prone and more widely utilised for grazing purposes. In contrast, NSW’
most productive and diverse arable land is located in the south; however, some areas
in central and northern regions (like the Liverpool Plains) are considered some of the
most fertile agricultural land in the State. In terms of climate, northern QLD is
affected by the seasonal migration of the monsoon across the equator. This results in
a distinct dry season (May to September) and wet season (October to April), with the
latter part of the wet season characterised by monsoonal activity. The south-eastern
QLD region is characterised by a range of climates from subtropical in the north
through to temperate in the south, with a typically drier winter and wetter summer.
This area is also influenced by large-scale atmospheric circulation drivers, particularly the El Niño Southern Oscillation, leading to high variability and the occurrence
of droughts and floods (CSIRO 2012). On the eastern Australian coast (QLD and
down into NSW), the formation of ‘East Coast Lows’ can also have a significant
impact on water resources, resulting in intermittent large inflows into water catchments. This area has also been subject to considerable climate variability, including
the Millennium Drought and the two wettest years on record for Australia
(2010–2011) as a result of two strong La Niña events (CSIRO 2012). QLD is the
most natural-disaster-prone State in Australia (ABS 2012a; Davis 2016). With an
increasingly variable climate, impacts to agriculture will manifest, particularly in the
frequency and intensity of extreme weather events. These will range from longer
dryer periods, intense flooding, fewer frosts and warmer temperatures for longer and
increased maximums (WWF 2015).
Temperatures in Australia were relatively stable from 1910 to 1950. Since then,
both minimum and maximum temperatures have shown an increasing trend, with an
overall increase from 1910 to 2010 of approximately 0.8
C (ABS 2012a). Australia
has warmed by approximately 1
since 1910. The warming has occurred mostly
since 1950, and the frequency of daily temperature extremes has also changed since
1910 (Bureau of Meteorology 2017). The number of weather stations recording very
warm night-time temperatures and the frequency with which these occur has
increased since the mid-1970s. The rate of very hot daytime temperatures has also
been growing since the 1990s (Bureau of Meteorology 2017). According to the
fourth biennial State of the Climate report (CSIRO 2016), the duration, frequency
and intensity of extreme heat events have increased across large parts of Australia,
causing extreme fire danger and heat waves in many parts of the continent. Further,
there has been a decline of approximately 11% in April to October growing season
rainfall in the continental south-east since the mid-1990s (CSIRO 2016). Given the
changes in climate and the associated alteration to Australia’s rainfall patterns and
temperatures, many areas are becoming dryer and, in many cases, also warmer,
which in turn decreases agricultural water from run-off, surface water availability
and groundwater recharge. With the lower water availability, there have also been
decreases in dam and on-farm storage levels. Australia is committed to domestic and
7 Water Security: Challenges to the Irrigation Water-Energy Nexus in Australia
89
year. As such, agricultural production is distributed geographically and across
different climatic zones. Much of the most productive arable land in QLD is located
in the south-east areas or closer to the coast, whilst western parts of the State are dry
and drought prone and more widely utilised for grazing purposes. In contrast, NSW’
most productive and diverse arable land is located in the south; however, some areas
in central and northern regions (like the Liverpool Plains) are considered some of the
most fertile agricultural land in the State. In terms of climate, northern QLD is
affected by the seasonal migration of the monsoon across the equator. This results in
a distinct dry season (May to September) and wet season (October to April), with the
latter part of the wet season characterised by monsoonal activity. The south-eastern
QLD region is characterised by a range of climates from subtropical in the north
through to temperate in the south, with a typically drier winter and wetter summer.
This area is also influenced by large-scale atmospheric circulation drivers, particularly the El Niño Southern Oscillation, leading to high variability and the occurrence
of droughts and floods (CSIRO 2012). On the eastern Australian coast (QLD and
down into NSW), the formation of ‘East Coast Lows’ can also have a significant
impact on water resources, resulting in intermittent large inflows into water catchments. This area has also been subject to considerable climate variability, including
the Millennium Drought and the two wettest years on record for Australia
(2010–2011) as a result of two strong La Niña events (CSIRO 2012). QLD is the
most natural-disaster-prone State in Australia (ABS 2012a; Davis 2016). With an
increasingly variable climate, impacts to agriculture will manifest, particularly in the
frequency and intensity of extreme weather events. These will range from longer
dryer periods, intense flooding, fewer frosts and warmer temperatures for longer and
increased maximums (WWF 2015).
Temperatures in Australia were relatively stable from 1910 to 1950. Since then,
both minimum and maximum temperatures have shown an increasing trend, with an
overall increase from 1910 to 2010 of approximately 0.8
C (ABS 2012a). Australia
has warmed by approximately 1
since 1910. The warming has occurred mostly
since 1950, and the frequency of daily temperature extremes has also changed since
1910 (Bureau of Meteorology 2017). The number of weather stations recording very
warm night-time temperatures and the frequency with which these occur has
increased since the mid-1970s. The rate of very hot daytime temperatures has also
been growing since the 1990s (Bureau of Meteorology 2017). According to the
fourth biennial State of the Climate report (CSIRO 2016), the duration, frequency
and intensity of extreme heat events have increased across large parts of Australia,
causing extreme fire danger and heat waves in many parts of the continent. Further,
there has been a decline of approximately 11% in April to October growing season
rainfall in the continental south-east since the mid-1990s (CSIRO 2016). Given the
changes in climate and the associated alteration to Australia’s rainfall patterns and
temperatures, many areas are becoming dryer and, in many cases, also warmer,
which in turn decreases agricultural water from run-off, surface water availability
and groundwater recharge. With the lower water availability, there have also been
decreases in dam and on-farm storage levels. Australia is committed to domestic and
7 Water Security: Challenges to the Irrigation Water-Energy Nexus in Australia
89