The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - ocean acidification". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE The uptake of atmospheric CO2 by the ocean results in changes in seawater chemistry, including a decrease in pH and dissolved carbonate ion concentrations, know as ocean acidification. Since pre-industrial times the pH of waters around Australia are estimated to have decreased between 0.08 and 0.10, consistent with global estimates of pH change. Superimposed on the large-scale change is much more variability at seasonal and local scales where natural processes can amplify or offset ocean acidification in a range of environments (Mongin et al., 2016; Walbusser et al, 2014; Shaw et al., 2012). The detection of trends and state in most coastal, shelf and subsurface waters around Australia is limited by lack of data. The pH and dissolved carbonate ion concentration of ocean waters around Australia will continue to decrease at the ocean takes up atmospheric CO2 emissions. The rates of change are linked to different emission scenarios (Lenton et al., 2015). Ocean acidification will persist for many millennia, even if emissions are reduced (e.g. Frolicher and Joos, 2010). Seasonal undersaturation of aragonite in surface waters of the Southern Ocean is predicted to occur by 2030 with consequences for calcifying organisms like pteropods (McNeil and Matear, 2008; Hauri et al., 2015). Ocean acidification is expected to lead to widespread shifts in ecosystems and puts at risk regional economies reliant on healthy and sustainable marine ecosystems such as tourism and aquaculture. DATA STREAM(S) USED IN EXPERT ASSESSMENT Offshore data from around Australia as described in Lenton et al 2015. Details of the specific data sets used to generate this assessment have not been provided. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Very high impact Assessment trend: Deteriorating Confidence grade: Adequate high quality evidence and high level of consensus Confidence trend: Adequate high quality evidence and high level of consensus Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Deteriorating Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT More data are now available.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - sea surface temperature". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Sea-surface temperature (SST) is a vital component of the marine ecosystem system as it exerts a major influence on the structure and function of the marine and atmospheric environment. DATA STREAM(S) USED IN EXPERT ASSESSMENT The majority of the assessment is based on data and analyses published in peer review papers. Some analyses of SST observations and model output have been included in the assessment. Details of specific data sets used to generate the assessment have not been provided. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • Assessment grade: High impact. Sea surface temperature has continued to increase and extreme events have occurred in some regions. • Assessment trend: Deteriorating. Increasing sea surface temperature has significant impact on marine biodiversity and ocean health • Confidence grade: • Confidence trend: Adequate high-quality evidence or high level of consensus. Observations and models agree that sea surface temperature will continue to increase and extreme events may increase in frequency CHANGES SINCE 2011 SOE ASSESSMENT Grade and trends are somewhat comparable to the 2011 assessment.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - oceanic dissolved oxygen and oxygen minimum zones in shelf and offshore regions". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE The ocean is undergoing physical and chemical changes as carbon dioxide and other greenhouse gases in the atmosphere rise. These changes are warming the upper ocean, altering the upper ocean density structure and acidifying the oceans (see ocean sections). Oxygen is consumed in aerobic respiration and most marine ecosystems are composed of aerobic organisms that need oxygen to survive. Due to aerobic respiration, the dissolved oxygen concentrations in the ocean are lowest in the intermediate water (300 m to 1000 m). In coastal regions with limited circulation the biological consumption of oxygen can lower oxygen considerably. Global warming is projected to reduced the dissolved oxygen and lead to expansion of areas with low oxygen (Cocco et al., 2013). DATA STREAM(S) USED IN EXPERT ASSESSMENT Offshore data from around Australia from the latest CARS compilation (CARS2009a v1.1, as of 12 July 2010). See http://www.marine.csiro.au/atlas/ 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Evidence and consensus too low to make an assessment Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Unclear what data were used in the 2011 assessment; the 2016 assessment is based on the latest CARS compilations and so includes observations added to CARS 2011-2016.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate change - ocean currents and eddies". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE The dominant Australian boundary currents are the; East Australian Current (EAC), Indonesian Throughflow (ITF) and Leeuwin Current (LC). The EAC is the western boundary current system of the South Pacific. In the Australian region, it redistributes heat between ocean and atmosphere and the tropics and mid-latitudes. The ITF, a major component of the global ocean circulation, moves water between the Pacific and Indian Oceans. It strongly influences Australian climate and seas off Western Australia. The LC flows southwards off Western Australia redistributing Indian Ocean heat to the mid-latitudes. This differs from the cooler, equatorward flowing currents found along other eastern ocean boundaries. DATA STREAM(S) USED IN EXPERT ASSESSMENT The assessment is based on the results of analysis published in peer reviewed papers. Details of the specific data sets used to generate this assessment have not been provided. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • Assessment grade: High impact. Boundary current strength is strongly linked to major climate modes – ENSO, IOD and SAM- whose variability are predicted to increase with climate change. • Assessment trend: Deteriorating. Increasing variability of boundary current strength and heat, freshwater, and nutrient transport, will impact coastal circulation, extreme marine conditions, and the marine ecosystem. • Confidence grade: • Confidence trend: Adequate high-quality evidence or high level of consensus. Observations and models agree that modes of climate variability will be impacted by continued climate change. CHANGES SINCE 2011 SOE ASSESSMENT Grade and trends are somewhat comparable to the 2011 assessment.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with climate and system variability". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Climate and the marine environment varies on multiple temporal and spatial scales. This variability results in seasonal, inter-annual, decadal and longer changes to water temperature, rainfall patterns affecting ocean salinity, and surface winds, oceanic currents and tidal regimes which can influence the degree of vertical mixing through the water column. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports on climate variability. Details of the specific data sets used to generate this assessment have not been provided. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Not previously asssessed • 2011 • (Not previously assessed) CHANGES SINCE 2011 SOE ASSESSMENT Climate and system variability as a pressure on the marine environment was not assessed in 2011.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Effectiveness of marine management of climate variability and climate change". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE BEING MANAGED, AND ITS IMPACT Anthropogenic ocean warming, superimposed on natural climate variations – in particular El Niño–Southern Oscillation and decadal variability – and ocean acidification pose risks to Australia’s coral reef ecosystems, giant kelp and other habitats. In response, there have been significant shifts in the ranges of various invertebrates and fish. Recent reviews of climate change impacts and adaptation on Australia’s commercial marine fisheries and marine ecosystems discuss the implications for marine management. On the Great Barrier Reef, rising summer sea temperatures and steadily increasing ocean acidity increase the risk of mass coral bleaching. The cumulative impacts of economic activities – port dredging and runoff of sediment, nutrients and fertiliser from agriculture, for example – cause coral reefs to become stressed and more prone to the effects of climate change. More broadly around Australia, ocean warming and changes in currents are affecting fisheries and aquaculture. World-leading research on these risks is ongoing through Australian universities and research institutes and in consequence the understanding of physical processes is high. Understanding of the economic and cultural significance of the marine environment for Australia is lower, but considerable value is attributed to coastal regions in temperate and tropical Australia. Understanding of the management strategies required to combat the risks is lower still due at least in part to its complexity. Research is ongoing, but a greater investment in developing, implementing and monitoring strategies, monitoring and understanding change, and systematic acquisition and storage of data, is required. DATA STREAM(S) USED IN EXPERT ASSESSMENT The assessment is based on published literature – a list is provided in the attached Expert Assessment. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • Understanding of pressure: Understanding of climate variability and its management is reasonably high and improving with government funding for well-established and internationally-respected institutions. • Planning associated with management of pressure: In-depth planning for icons such as the Great Barrier Reef continues, and commercial fisheries are aware of the need to plan around climate variability. Elsewhere efforts are more patchy. • Input for informing management of pressure: Short-term funding cycles are a continuing threat to effective management for long-term goals and sustainability. • Processes associated with developing, monitoring, and updating management: Management tools and approaches exist and in some cases are applied; stronger regulation is required for long-term environmental health. • Outputs from management framework in place: Conflicting interests between economic development and the environment are leading to a gradual long-term environmental declines, which current management is not addressing. • Outcomes of management framework in place: Further policy and management controls are required to address declining environmental health and emerging risks of climate change. CHANGES SINCE 2011 SOE ASSESSMENT Not specified. Review of additional literature has been conducted since 2011 SoE Assessment.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressure of Climate and System Variability". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Pressure – Climate and System Variability" DESCRIPTION OF PRESSURE Climate and the marine environment vary on multiple temporal and spatial scales. This variability results in seasonal, inter-annual, decadal and longer changes to water temperature (e.g. Figure 1), rainfall patterns affecting ocean salinity, and surface winds, oceanic currents and tidal regimes which can influence the degree of vertical mixing through the water column. Collectively, these changes also propagate from the physical environment up the food chain. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports on climate variability. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: High impact Assessment trend: Deteriorating Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Comparable • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Not previously assessed • 2011 • N/A CHANGES SINCE 2016 SOE ASSESSMENT The assessed state and trend of this pressure has increased from low/stable in 2016 to high/increasing for 2021 based on research documenting a trend for overall higher extremes of impacts associated with climate variability over the reporting period that is expected to continue.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with marine renewable energy generation". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE Marine renewable energy generation is a fledgling industry in Australia. Presently, marine energy generator deployments are limited to two pre-commercial scale (small-scale, < 500kW) power stations, and a few experimental / prototype deployments. Any pressures on the marine environment associated with marine renewable energy generation are localised, and sparse. The marine renewable energy industry is an emerging industry globally. Numerous ocean energy technologies and devices are being developed around the world, and understanding of the environmental effects of these devices are dispersed among technology developers and countries. The environmental impacts of marine renewable energy are poorly known, and further research and understanding of the issue constitutes a major work programme of the International Energy Agency’s working group on Ocean Energy Systems (IEA-OES Annex IV – Assessment of Environmental Effects of and Monitoring Efforts for Ocean Wave, Tidal and Current Energy Systems) (NOTE: Australia has lapsed membership of IEA-OES). This task has focused on three interactions between marine energy devices and the marine environment: 1) The physical interactions between animals and tidal turbines; 2) The acoustic impact of marine energy devices on marine animals; and 3) the effects of energy removal on the physical environment. This task has identified and documented a growing database on the environmental effects of marine energy development. However, the working group summarise their Stage 1 final report by stating that ‘there continues to be a dearth of quantitative environmental information from tidal and wave devices that have been deployed in coastal waters’. Furthermore, they conclude ‘there are inadequate research and modelling data to adequately characterise the potential effects of marine energy devices, particularly at the large commercial scale’. The Australian marine renewable energy sector is predominantly focused on wave energy, with the focus being the large resource along the southern temperate coasts of Australia. There is a smaller tidal energy sector, where the predominant resource is located in tropical Northern waters (aside from localised areas adjacent to Bass Strait Islands). Through a number of commonwealth and industry funded activities, Australia is endeavouring to improve the knowledge base of the environmental effects of wave energy devices in these temperate environments. Whether these activities are applicable to large scale deployment (>100 MW capacity) is currently unclear. DATA STREAM(S) USED IN EXPERT ASSESSMENT Assessment of impacts of marine renewable energy is an emerging science. Few deployments are available in Australia, and assessment is largely derived from review of international scientific literature. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Very low Assessment trend: Unclear Confidence grade: Limited evidence or limited consensus Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend are comparable to the 2011 assessment • 2011 • Assessment grade: Very low Assessment trend: Unclear Confidence grade: Limited evidence or limited consensus Confidence trend: Evidence and consensus too low to make an assessment CHANGES SINCE 2011 SOE ASSESSMENT No change.

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with marine mining". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record. DESCRIPTION OF THE PRESSURE A wide variety of mineral resources exist within Australia’s maritime jurisdiction (see Table 1 in attached Expert Assessment). Mining of those resources however, remains an 'emerging industry'. DATA STREAM(S) USED IN EXPERT ASSESSMENT Published papers and reports. Assessment has been completed by literature review. 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Low impact Assessment trend: Unclear Confidence grade: Limited evidence or limited consensus Confidence trend: Evidence and consensus too low to make an assessment Comparability: Grade and trend are somewhat comparable to the 2011 assessment • 2011 • Assessment grade: Very good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus CHANGES SINCE 2011 SOE ASSESSMENT Climate and system variability as a pressure on the marine environment was not assessed in 2011.

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressure of Ocean nutrients and dissolved oxygen". A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Pressure – Ocean nutrients and dissolved oxygen" DESCRIPTION OF PRESSURE The vital physical processes supplying nutrients to the upper ocean (Figure 1) are the seasonal deepening of the surface ocean mixed layer, the upwelling and vertical mixing associated with ocean eddies, and wind-driven upwelling. In the Australian region, the first two processes dominate because wind-induced upwelling is confined to a few small areas (e.g. Bonnie Upwelling off South Australia). As the climate warms, the upper ocean will develop a stronger vertical gradient in temperature, becoming more stratified, reducing the vertical supply of nutrients to the surface ocean (Kwiatkowski et al., 2020). Climate change is also projected to modify winds, and strengthen boundary currents and increased eddy activity their vertical nutrient supply (e.g. the East Australia Current, Matear et al., 2013). Oxygen is essential to living aerobic organisms in the ocean. In the surface ocean, oxygen levels are high because air-sea exchange keeps oxygen near saturation levels. Due to aerobic respiration, the dissolved oxygen concentrations in the ocean interior decline and are lowest in the intermediate water (300 m to 1000 m) away from regions these waters exchange with the atmosphere (i.e. the Southern Ocean, Figure 2). High oxygen consumption in coastal regions can lower oxygen to a level where it can no longer support aerobic organisms leading to fish kills (Hobbs and McDonald, 2010). Solubility of oxygen is reduced in a warming ocean, and climate change is projected to lead to the expansion of areas with low oxygen (Kwiatkowski et al., 2020). With climate change warming of the ocean, marine heatwaves in Australian waters are projected to increase in frequency and intensity (Hayashida et al., 2020b). Additional pressures exist in coastal ocean regions, such as increased nutrient input (rives and estuary); which reduces oxygen with the potential for local anoxic events and increases nutrients with the increase phytoplankton blooms. DATA STREAM(S) USED IN EXPERT ASSESSMENT Data come from the CARS climatological atlas of nitrate, phosphate and oxygen (1996). Details can be found at http://www.globcolour.info/products_description.html. 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: High impact Assessment trend: Unclear Confidence grade: Low Confidence trend: Low Comparability: Somewhat comparable (oxygen and nutrients assessed separately in 2016 CHANGES SINCE 2016 SOE ASSESSMENT The seasonal climatologies are based on the latest version of CARS, which brings in additional observations collected since 2016. Additionally, dissolved oxygen and nutrient supply and cycling were previously assessed separately, but have been combined into a single ‘biogeochemistry’ assessment for 2021.