March 24, 2012

Commonwealth Science and Industrial Research Organisation

Green Army: Research and Development


State of the Climate 2014

  • {2013 was Australia’s warmest year on record …}
  • Australia’s climate has warmed by 0.9°C since 1910 …
  • Global mean temperature has risen by 0.85°C from 1880 to 2012. …

Extreme fire weather has increased, and the fire season has lengthened, across large parts of Australia. …
Atmospheric greenhouse gas concentrations continue to rise and continued emissions will cause further warming over this century.
Limiting the magnitude of future climate change requires large and sustained net global reductions in greenhouse gases.
(p 3-4)


Australian Climate

  • Seven of the ten warmest years on record have occurred since 1998.
  • Over the past 15 years, the frequency of very warm months has increased five-fold and the frequency of very cool months has declined by around a third, compared to 1951–1980. …

Since 2001, the number of extreme heat records in Australia has outnumbered extreme cool records by almost 3 to 1 for daytime maximum temperatures, and almost 5 to 1 for night-time minimum temperatures.
(p 5)

[Overall,] Australian average annual rainfall has increased since national records began in 1900, largely due to increases in rainfall from October to April, and most markedly across the northwest. …
[However, since] 1970 there has been a 17% decline in average winter rainfall in the southwest of Australia.
{In the far southwest, streamflow has declined by more than 50 percent since the mid-1970s.}

The southeast has experienced a 15% decline in late autumn and early winter rainfall since the mid-1990s, with a 25% reduction in average rainfall across April and May. …
[And in] the far southeast, streamflow during the 1997–2009 Millennium Drought was around half the long-term average.
(p 6)



Number of days each year where the Australian area-averaged daily mean temperature is above the 99th percentile for the period 1910–2013. …
This metric reflects the spatial extent of extreme heat across the continent and its frequency.
Half of these events have occurred in the past twenty years.


Recent studies examining heavy monthly to seasonal rainfall events that occurred in eastern Australia between 2010 and 2012 have shown that the magnitude of extreme rainfall is mostly explained by natural variability, with potentially a small additional contribution from global warming. …

The research on cyclone frequency in the Australian region is equivocal, with some studies suggesting no change and others a decrease in numbers since the 1970s.
(p 8-9)


Global Atmosphere and Cryosphere

  • Ice-mass loss from the Antarctic and Greenland ice sheets has accelerated over the past two decades.
  • Arctic summer minimum sea-ice extent has declined by between 9.4 and 13.6% per decade since 1979, a rate that is likely unprecedented in at least the past 1,450 years.
  • Antarctic sea-ice extent has slightly increased by between 1.2% and 1.8% per decade since 1979.

The mean estimated rate of ice loss from the Antarctic ice sheet has increased nearly five-fold from an estimated mean of 30 gigatonnes per year (Gt/yr) for the period from 1992 to 2001, to 147 Gt/yr for the period 2002 to 2011.
The rate of ice loss from the Greenland ice sheet has increased [more than six-fold] from 34 to 215 Gt/yr over the same period.

The average rate of ice loss from glaciers around the world, excluding glaciers on the periphery of the ice sheets, was
  • very likely 226 Gt/yr over the period 1971 to 2009, and
  • very likely 275 Gt/yr over the period 1993 to 2009. …

The [slight] increase in Antarctic sea-ice extent has been linked to several possible drivers, including
  • freshening of surface waters due to increased precipitation and the enhanced melting of ice shelves, and
  • changes in atmospheric circulation resulting in greater sea-ice dispersion.
(p 10)


Oceans

  • Global mean sea level … in 2012 was 225 mm higher than in 1880. …
  • Ocean acidity levels have increased [by 26% since 1750.]

Warming of the world’s oceans accounts for more than 90% of additional energy accumulated from the enhanced greenhouse effect …
The ocean today is warmer, and sea levels higher, than at any time since the instrumental record began.
  • The upper layer of the ocean, from the surface to a depth of 700 metres, has increased its heat content by around 17x10^22 joules since 1971, accounting for around 63% of additional energy accumulated by the climate system.
  • Warming below 700 metres over the same period accounts for approximately 30% of additional energy.
  • The remaining 7% has been added to the cryosphere, atmosphere and land surface.



Change in ocean heat content (in joules) from the full ocean depth, from 1960 to present.
Shading provides an indication of the confidence range of the estimate.
(p 11)

Global sea level fell during the intense La Niña event of 2010–2011.
This was ascribed partly to the exceptionally high rainfall over land which resulted in floods in Australia, northern South America, and Southeast Asia.
[And] was compounded by the long residence time of water over inland Australia.
Recent observations show that sea levels have rebounded in line with the long-term trend.
(p 12)


Greenhouse Gases

  • [Global] mean CO2 levels [reached] 395 ppm in 2013 [— likely the highest level in at least 2 million years. …]
  • The increase in atmospheric CO2 concentrations from 2011 to 2013 is the largest two-year increase ever observed.

Global anthropogenic CO2 emissions into the atmosphere in 2013 are … about 46% higher than in 1990.
Global CO2 emissions from the use of fossil fuel are estimated to have increased in 2013 by 2.1% compared with the average of 3.1% per year from 2000 to 2012.
(p 13)

Global atmospheric CH4 … and N2O [concentrations] are at their highest levels for at least 800 000 years.

[The combined] ‘equivalent CO2’ atmospheric concentration [of all GHGs] reached 480 ppm in 2013.
(p 14)


Future climate scenarios for Australia

  • [An up to 3-fold] increase in the number of extreme fire-weather days is expected in southern and eastern Australia [by 2015,] with a longer fire season in these regions. …
  • The frequency and intensity of extreme daily rainfall is projected to increase. …
  • Projected sea-level rise will increase the frequency of extreme sea-level events.

[Between] 1910 to 1990 [Australia] warmed by 0.6°C.
Warming by 2070, compared to 1980 to 1999, is projected to be
  • 1.0 to 2.5°C for low greenhouse gas emissions and
  • 2.2 to 5.0°C for high emissions [ie business as usual. …]

Further decreases in average rainfall are expected over southern Australia …
[Consequently, droughts] are expected to become more frequent and severe in southern Australia. …

Reductions in global greenhouse gas emissions would increase the chance of constraining future global warming.
Nonetheless adaptation is required because some warming and associated changes are unavoidable.
(p 15)





State of the Climate 2012


NASA, the US National Climatic Data Centre, and the UK Hadley Centre have each produced global temperature datasets.
The graph shows the annual means calculated from the three datasets.
Years beginning with an El Niño (orange) and La Niña (blue) are shown after suitable data became available in 1950 …
(p 10)


State of the Climate 2010


Since 1960 the mean temperature in Australia has increased by about 0.7°C. …
Some areas have experienced warming since 1960 of up to 0.4 °C per decade [3 times the global average] resulting in total warming over the five decades of 1.5 to 2ºC.
(p 1)


Contents


No profit in climate change research

Australian attitudes to climate change and adaptation: 2010-2014

State of the Climate 2014

State of the Climate 2012
Climate Science and Solutions
Would you like to know more?


THE COMMONWEALTH SCIENCE AND INDUSTRIAL RESEARCH ORGANISATION (CSIRO)

  • Australian attitudes to climate change and adaptation: 2010-2014, 2015.
    Z Leviston, M Greenhill, & I Walker.

    Do you think that climate change is happening?
    (Adapted from Figure 1, p 3)
    Yes78%
    No22%


    What best describes your thoughts about climate change?
    (Adapted from Figure 2, p 4)
    Happening84.5%
        Human induced45.9%
        Natural fluctuation38.6%
    Not happening / Don't know15.6%

    [Of those who thought climate change was happening 54.3% attributed it to human activity and 45.7% to natural variation.]


    Percentage agreeing that human-induced climate change is happening
    (Adapted from Figure 42, p 45)
    Voting behaviour at the last federal electionN=3789 (100%)
    Liberal28%1616 (43%)
    Labor59%1406 (37%)
    Green76%437 (12%)
    Independent46%172 (5%)
    National22%158 (4%)

    On average, participants with more left-wing orientations were more likely to be sure climate change was happening, were more worried about it, and thought it more important.
    However, the strength of the relationship between political orientation and individual climate-relevant behaviours was very small.

    [Of the 269 people who responded to all five surveys, nearly] half (48.5%) changed their selection at least once [between 2010 and 2014.]
    Between 2013 and 2014, the percentage of repeat respondents changing their selection was 29%.
    (p 11)

    The most common shift [between 2010 and 2014] was to move from the opinion that climate change was human-induced to the opinion that it was happening, but natural (11.2% of respondents).
    [By contrast, 5.6% switched from natural to human induced.
    There was, therefore, a net reduction of 5.8% in the human induced cohort (48.0% to 42.4%).] (p 12)

    Those who thought climate change was not happening (7.9% of respondents from Figure 2) strongly overestimated the prevalence of their own opinion (49.1%) [among the broader community.
    Whereas, those] who thought that climate change was [happening slightly underestimated] the broader prevalence of their own opinions.
    Every group overestimated the percentage of people who denied climate change was happening.
    (p 6, emphasis added)

    Overall, respondents estimated that 61.5% of climate change was attributable to human activity.
    [Remarkably,] even those who thought climate change was not happening at all thought [that] roughly a third of climate change was attributable to human activity.
    (p 7)

    [This] suggests that people's basic opinions do not represent a static belief, but rather might best be viewed as a 'positioning statement' that gives a broad indication of the perceived threat posed by climate change, and the urgency and magnitude with which a person feels it should be addressed.
    (p 64)

    Those who think climate change is human-induced were more likely to say ‘scientific research’ was the main basis for their opinion.
    Those who thought climate change was not happening, or caused by natural processes, were more likely to select ‘common sense’, ‘the weather’, or ‘historical events’ as their basis.
    Very few selected ‘politicians and government’ or ‘news and media’.
    (p viii)

    People’s engagement in individual climate-relevant behaviour has reduced in 2014.
    (p ix)

    Between 2010 and 2014,
    • 48% of repeat respondents’ pro-environmental behaviour scores decreased,
    • 19.3% remained steady, and
    • 32.7% increased.
    (p 26)

    People tend to overestimate how much they do compared to others.
    More than 90% of respondents estimated they engaged in the same or more behaviours than other Australians.
    Less than 7% thought they did less than other Australians. …
    (p ix)

    More than half of respondents reported experiencing at least some [personal] injury, loss, or damage as a result of
    • extreme high temperatures (61%),
    • heatwaves (61%),
    • heavy rain (59%),
    • drought and water scarcity (57%), or
    • hailstorms (51%).
    (p 35)

    There is little familiarity with climate change terminology, but this is improving.
    [In 2014, roughly] one in five respondents had heard of ‘climate mitigation’ [— 21% vs 18% in 2013;] while nearly one in three had heard of ‘climate adaptation’ [— 31% vs 19% in 2012.]
    (p ix)

    There is broad support for a wide range of adaptation initiatives.
    Most support was given to
    • investment in renewable energy resources,
    • protection from invasive species,
    • increased investment in public transport, and
    • restrictions on development in vulnerable areas.
    Least support was given to
    • investment in nuclear power stations and
    • increased aid to overseas countries impacted by climate change. …

    Anger, fear, and powerlessness were rated as the most commonly felt emotion in response to climate change.
    (p x)

  • State of the Climate 2012, CSIRO / Australian Bureau of Meteorology, 13 March, 2012.

    TEMPERATURE


    Australian average temperatures over land

    Each decade has been warmer than the previous decade since the 1950s. …
    [Daily] maximum temperatures have increased by 0.75 °C [and] overnight minimum temperatures have warmed by more than 1.1 °C …
    2010 and 2011 were Australia’s coolest years recorded since 2001 due to two consecutive La Niña events. …
    The average temperature [over the last decade] has been more than 0.5 °C warmer than the … 1961-1990 long-term average.
    (p 3)

    The rate of very hot (greater than 40 °C) daytime temperatures has been increasing since the 1990s.
    (p 4)


    Rainfall


    A very strong La Niña event in 2010, followed by another La Niña event in 2011, brought the highest two-year Australian-average rainfall total on record. …
    [Despite this] Southwest Western Australia experienced its lowest rainfall on record in 2010 and only average rainfall during 2011 …
    (p 5)


    OCEANS

    Global-average mean sea level for 2011 was 210 mm above the level in 1880.
    Global-average mean sea level rose faster between 1993 and 2011 [3 mm/year] than during the 20th century as a whole [1.7 mm/year].

    Rising global-average mean sea level


    The observed global-average mean sea-level rise since 1990 is near the high end of [the IPCC AR4] projections …


    Rising sea level around Australia


    Since 1993, the rates of sea-level rise to the north and northwest of Australia have been 7 to 11 mm per year, two to three times the global average, [while] rates of sea-level rise on the central east and southern coasts of the continent are mostly similar to the global average.
    These variations are at least [partly due to] natural variability …
    (p 6)


    GREENHOUSE GASES


    Carbon dioxide emissions


    Australia [which represents 0.3% of global population] contributes about 1.3% of the global CO2 emissions.
    Energy generation continues to climb and is dominated by fossil fuels …

    The amount of … long-lived greenhouse gases [C02, Ch4 and N20] in the atmosphere reached a new high in 2011.
    The concentration of CO2 … was 390 parts per million (ppm) - much higher than the natural range of 170 to 300 ppm during the past 800,000 years. …

    The relative contributions to the enhanced greenhouse effect from pre-industrial times to 2011 … are:
    • CO2 (64%),
    • CH4 (18%),
    • synthetics (12%) and
    • N2O (6%).
    Observations of total CO2 emissions … are tracking along the higher end of expected emissions.
    (p 8)


    Sources of carbon dioxide


    About 50% of the amount of CO2 emitted from fossil fuels, industry, and changes in land-use, stays in the atmosphere.
    The remainder is taken up by the ocean and land vegetation, in roughly equal parts.
    The extra carbon dioxide absorbed by the oceans is estimated to have caused about a 30% increase in the level of ocean acidity …

    The observed trends in the isotopic (13C, 14C) composition of CO2 in the atmosphere and the decrease in the concentration of atmospheric O2 confirm that the dominant cause of the observed CO2 increase is the combustion of fossil fuels.
    (p 9)


    UNDERSTANDING GLOBAL WARMING


    Australia in the context of global warming


    Global-average surface temperatures were the warmest on record in 2010 …
    2011 was the world’s … warmest year on record during a La Niña event. …

    [There is at least a 90% likelihood] that most of the observed global warming since the mid-20th century is due to increases in greenhouse gases from human activities [and a less than 10% likelihood] that [it is due to] natural variability alone.


    Changes in extreme weather events


    Extreme events are relatively rare and identifying changes in intensity or frequency is more difficult than for changes in averages. …

    Weather associated with high fire danger has shown a rapid increase in the late 1990s to early 2000s at many locations in south-eastern Australia. …

    No significant trends in the total numbers of tropical cyclones or in the occurrence of the most intense tropical cyclones have been found in the Australian region.
    (p 10)


    FUTURE CHANGES


    Future Australian temperature, rainfall and extreme weather events


    Australian average temperatures are projected to rise by [a further] 0.6 to 1.5 °C by 2030 when compared with the climate of 1980 to 1999.
    The warming is projected to be in the range of 1.0 to 5.0 °C by 2070 …

    For Australia as a whole, an increase in the number of dry days is expected, but it is also likely that rainfall will be heavier during wet periods.
    {Droughts are expected to become more frequent in southern Australia …
    [The] direction of projected changes to average rainfall over northern Australia is unclear as there is a lack of consensus among the models.}

    [There is a more than 66% probability] that there will be [on average] fewer tropical cyclones in the Australian region … but [that] the proportion of intense cyclones [will] increase.
    (p 11)


    Climate change is continuing


    Multiple lines of evidence show that global warming continues and that human activities are mainly responsible.

    The fundamental physical and chemical processes leading to climate change are well understood. …

    Uncertainties remain regarding
    • future levels of greenhouse gas concentrations …
    • the precise timing and magnitude of changes, particularly at regional scales [and]
    • tipping points in the climate system, such as the break-up of ice-sheets, which [could] lead to rapid climate change.

    Unless greenhouse gas emissions decrease, we expect to see the temperature of the atmosphere and the oceans continue to warm and sea levels continue to rise at current or even higher rates than reported here.
    (p 12)

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