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The global carbon sequestration and avoided emissions potentially achieved via blue carbon is high (∼3% of annual global greenhouse gas emissions); however, it is limited by multidisciplinary and interacting uncertainties spanning the social, governance, financial, and technological dimensions. We compiled a transdisciplinary team of experts to elucidate these challenges and identify a way forward. Key actions to enhance blue carbon as a natural climate solution include improving policy and legal arrangements to ensure equitable sharing of benefits; improving stewardship by incorporating indigenous knowledge and values; clarifying property rights; improving financial approaches and accounting tools to incorporate co-benefits; developing technological solutions for measuring blue carbon sequestration at low cost; and resolving knowledge gaps regarding blue carbon cycles. Implementing these actions and operationalizing blue carbon will achieve measurable changes to atmospheric greenhouse gas concentrations, provide multiple co-benefits, and address national obligations associated with international agreements.

Nearly a billion people depend on tropical seascapes. The need to ensure sustainable use of these vital areas is recognised, as one of 17 policy commitments made by world leaders, in Sustainable Development Goal (SDG) 14 (‘Life below Water’) of the United Nations. SDG 14 seeks to secure marine sustainability by 2030. In a time of increasing social-ecological unpredictability and risk, scientists and policymakers working towards SDG 14 in the Asia–Pacific region need to know: (1) How are seascapes changing? (2) What can global society do about these changes? and (3) How can science and society together achieve sustainable seascape futures? Through a horizon scan, we identified nine emerging research priorities that clarify potential research contributions to marine sustainability in locations with high coral reef abundance. They include research on seascape geological and biological evolution and adaptation; elucidating drivers and mechanisms of change; understanding how seascape functions and services are produced, and how people depend on them; costs, benefits, and trade-offs to people in changing seascapes; improving seascape technologies and practices; learning to govern and manage seascapes for all; sustainable use, justice, and human well-being; bridging communities and epistemologies for innovative, equitable, and scale-crossing solutions; and informing resilient seascape futures through modelling and synthesis. Researchers can contribute to the sustainability of tropical seascapes by co-developing transdisciplinary understandings of people and ecosystems, emphasising the importance of equity and justice, and improving knowledge of key cross-scale and cross-level processes, feedbacks, and thresholds.

Water is a critical resource, but ensuring its availability faces challenges from climate extremes and human intervention. In this Review, we evaluate the current and historical evolution of water resources, considering surface water and groundwater as a single, interconnected resource. Total water storage trends have varied across regions over the past century. Satellite data from the Gravity Recovery and Climate Experiment (GRACE) show declining, stable and rising trends in total water storage over the past two decades in various regions globally. Groundwater monitoring provides longer-term context over the past century, showing rising water storage in northwest India, central Pakistan and the northwest United States, and declining water storage in the US High Plains and Central Valley. Climate variability causes some changes in water storage, but human intervention, particularly irrigation, is a major driver. Water-resource resilience can be increased by diversifying management strategies. These approaches include green solutions, such as forest and wetland preservation, and grey solutions, such as increasing supplies (desalination, wastewater reuse), enhancing storage in surface reservoirs and depleted aquifers, and transporting water. A diverse portfolio of these solutions, in tandem with managing groundwater and surface water as a single resource, can address human and ecosystem needs while building a resilient water system.

In the version of this article originally published, reference 9 was incorrectly cited in the last sentence of the second paragraph under ‘Introduction’ and in the first sentence of the second paragraph under the ‘Water scarcity’ subsection. Scanlon et al. (Environ. Res. Lett. https://doi.org/ 10.1088/1748-9326/ac3bfc, 2022) was incorrectly cited in the last sentence under ‘Drivers of water-resource variability’ but is now replaced with reference 38, and Figure 3 was wrongly stated to be adapted from reference 19 instead of reference 36. Reference 40 was mistakenly cited in the last sentence of the second paragraph under the ‘Increasing water access and supplies’ subsection, and reference 37 was inadvertently duplicated in the reference list. References 28 (now reading ‘Winter, T. C., Harvey, J. W., Franke, O. L. and Alley, W. M. Ground Water and Surface Water: A Single Resource. Circular 1139 (United States Geological Survey, 1998)’) and 94 (now reading ‘Scanlon, B. R., Reedy, R. C., Faunt, C. C., Pool, D. and Uhlman, K. Enhancing drought resilience with conjunctive use and managed aquifer recharge in California and Arizona. Environ. Res. Lett. 11, 035013 (2016)’) initially referred to incorrect sources. Lastly, the name of author Hannes Müller Schmied was incorrectly spelled Hannes Mueller Schmied, and an affiliation for him was missing: Senckenberg Leibniz Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany. The errors have been corrected in the HTML and PDF versions of the article.

We provide a three-step analysis of the effects and responses to COVID-19 in Nordic countries (Denmark, Finland, Norway and Sweden), large Western European countries (France, Germany, Italy, Spain and United Kingdom) and OECD Europe. First, we compare public health trends over 2020 in terms of per capita COVID-19 cases, fatalities, testing and the stringency of social distancing (SD) measures. Second, in a ‘like-with-like’ policy response model between Nordic countries, we test for the effects of air border closures on the growth in per capita COVID-19 cases while accounting for differences in stringency of social distancing and other measures. Third, using data from OECD European countries, we regress percentage change in GDP (2020–2019) on cumulative per capita national COVID-19 fatalities. We find that: (1) Sweden is an outlier, relative to its Nordic neighbours, in its COVID-19 public health outcomes; (2) Sweden would have had reduced cases and fatalities if it had adopted the air border closures implemented by its Nordic neighbours in the first half of 2020; and, (3) for OECD Europe, there is a statistically significant and negative association between per capita COVID-19 fatalities and economic performance.

We respond to the problem of declining streamflows in the northern Murray–Darling Basin, Australia, a region that suffers from hydrological droughts and a drying trend. We partitioned the effect of meteorological trends from anthropogenic drivers on annual streamflow, quantified the effect of annual streamflow decline on waterbird abundance, estimated the effects of streamflow change on a measure of ecosystem resilience, and calculated the net benefits of in-stream water reallocation. The anthropogenic drivers of hydrological droughts were assessed by comparing the Lower Darling (hereafter the Barka) River, which has large recorded water extractions, with the adjacent Paroo River, which has very little recorded water extractions. Findings include: (1) only about one-third of the recent reduced streamflow of the Barka River is due to a meteorological drying trend; (2) statistically significant declines in waterbird species richness and abundance have occurred on both rivers between 1983–2000 and 2001–2020; (3) declines in waterbird abundance have been much larger along the Barka River than the Paroo River; and (4) ecosystem resilience, as measured by waterbird abundance, wasgreater on the Paroo River. Our four-step framework is applicable in any catchment with adequate time-series data and supports adaptive responses to hydrological droughts. This article is part of the Royal Society Science+ meeting issue ‘Drought risk in the Anthropocene’.

Multipurpose hydropower reservoirs are regularly framed as water security and climate change solutions. Although multipurpose projects can and do deliver a range of water services, ‘win-win’ outcom...

Background We investigated the public health and economy outcomes of different levels of social distancing to control a ‘second wave’ outbreak in Australia and identify implications for public health management of COVID-19. Methods Individual-based and compartment models were used to simulate the effects of different social distancing and detection strategies on Australian COVID-19 infections and the economy from March to July 2020. These models were used to evaluate the effects of different social distancing levels and the early relaxation of suppression measures, in terms of public health and economy outcomes. Results The models, fitted to observations up to July 2020, yielded projections consistent with subsequent cases and showed that better public health outcomes and lower economy costs occur when social distancing measures are more stringent, implemented earlier and implemented for a sufficiently long duration. Early relaxation of suppression results in worse public health outcomes and higher economy costs. Conclusions Better public health outcomes (reduced COVID-19 fatalities) are positively associated with lower economy costs and higher levels of social distancing; achieving zero community transmission lowers both public health and economy costs compared to allowing community transmission to continue; and early relaxation of social distancing increases both public health and economy costs.

Many from outside of Australia may be puzzled as to why anyone would write ‘a very angry book’ about water reform in, of all places, Australia? A country that senior Australian public servants, sci...

Using a policy tracing approach, we analyse the legislating of the Strategic Aboriginal Water Reserve (SAWR) in the Northern Territory, Australia. The SAWR is a share of the consumptive pool alloca...

This paper proposes a ranking of the countries where forest carbon sequestration is the most cost-efficient among 166 countries for which data are available. Taking into account the main cost factors leads to a more nuanced ranking of the countries to be favoured for cost-efficient forest carbon sequestration compared to the assumption that these would always be in tropical areas with high rainfall. The ranking reflects the differences in the opportunity cost of land use and labour cost (production costs), the quality of the business environment (transaction costs), natural conditions (forest productivity), wildfire risk and the avoided GHG emissions from alternative land use. Cost-efficiency also depends on the type of forest project (afforestation, reforestation or forest conservation) and how private (wood harvest) and non-private (environmental and social) co-benefits are counted. A sensitivity analysis is undertaken to examine the robustness of the results with respect to uncertainties in values of the cost and quantity factors of forest carbon sequestration. The results support the view that forests can be a cost-efficient way to offset GHG emissions and that significant cost reductions are possible by targeting the country and sub-national regions in which to locate forest carbon sequestration projects. The report also reviews the literature on the significance and cost of forest carbon sequestration and provides an overview of forest carbon offset schemes.

Australia is a food-surplus country with much of its landmass located in arid or semi-arid areas subject to extreme variation in both precipitation and summer temperatures. The possible economic effects of climate change on water in relation to Australian agriculture are analysed by region and sector, including its possible impacts in Australia’s ‘food basket’, the Murray–Darling Basin, using precipitation and temperature data from 2011 to 2020. Three scenarios are evaluated that include: (1) the decade 2011–2020; (2) a ‘2030’ scenario in which farm productivity falls by 10% relative to the 2011–2020 scenario in five of the 10 growing seasons; and (3) a ‘2050’ scenario in which farm productivity falls by 20% relative to the 2011–2020 scenario in five of the 10 growing seasons. The welfare impacts, on a national basis, of the first scenario relative to a baseline without year-on-year seasonal variations is minus $35 billion in net present value terms. The welfare impact in the second scenario is minus $46 billion and minus $59 billion in the third scenario. The findings support the selection and implementation of particular adaptation pathways in response to climate change for Australian agriculture.

We deliver a public policy perspective on the dichotomies, dilemmas, and decisions of water pricing. First, the dichotomies between price and value, and costs, are defined to explain the paradox of water pricing: the price of water almost never equals its value and rarely covers its cost. Second, the dilemmas of water pricing are highlighted across efficiency and equity, objectives for water pricing, and the instruments available to decision-makers. Third, the challenges of decision-making are evaluated and illustrated in relation to water pricing. Fourth, an adaptive process is provided that includes participatory assessment of risks and options to guide water-pricing decision-making.

We examine water governance in the Murray-Darling Basin using the frameworks of rent-seeking and regulatory capture. These frameworks are used to evaluate two government programmes intended to ensu...

We use published water balance data from irrigated cropping to show that water entitlements acquired for environmental purposes through water infrastructure subsidies in the Murray–Darling Basin, A...

A key challenge in designing Payment for Environmental Services (PES) programs is to balance conservation efficiency with equity where, typically, decision makers do not have practical and quantitative tools to consider the possible trade-offs. Here, we propose a policy-relevant and implementable ‘win-settle’ model that allows PES decision makers to maximize efficiency while considering the distributive equity associated with beneficiary payments. To demonstrate our approach, we calibrate the model to a current PES program in Vietnam that has one of the world's most comprehensive and self-sustained payment schemes for forest conservation. The results indicate that our approach could generate a substantial improvement relative to current methods. In other words, for the same expenditure and identical horizontal equity in payments to beneficiaries, more forest could be conserved, and with a lower administrative burden.

We compare the health and economic costs of early and delayed mandated suppression and the unmitigated spread of ‘first-wave’ COVID-19 infections in Australia in 2020. Using a fit-for-purpose SIQRM-compartment model for susceptible, infected, quarantined, recovered and mortalities on active cases, that we fitted from recorded data, a value of a statistical life year (VSLY) and an age-adjusted value of statistical life (A-VSL), we find that the economic costs of unmitigated suppression are multiples more than for early mandated suppression. We also find that using an equivalent VSLY welfare loss from fatalities to estimated GDP losses, drawn from survey data and our own estimates of the impact of suppression measures on the economy, means that for early suppression not to be the preferred strategy requires that Australia would have to incur more than 12,500–30,000 deaths, depending on the fatality rate with unmitigated spread, to the economy costs of early mandated suppression. We also find that early rather than delayed mandated suppression imposes much lower economy and health costs and conclude that in high-income countries, like Australia, a ‘go early, go hard’ strategy to suppress COVID-19 results in the lowest estimated public health and economy costs.

We examine the relationship between socio-economic disadvantage and exposure to environmental hazard with data from the catastrophic 2019–2020 Australian wildfires (Black Summer) that burnt at least 19 million hectares, thousands of buildings and was responsible for the deaths of 34 people and more than one billion animals. Combining data from the National Indicative Aggregated Fire Extent (NIAFE) and 2016 Socio-Economic Indexes for Areas (SEIFA), we estimate the correlation between wildfire hazard exposure and an index of community-level socio-economic disadvantage. Wildfire hazard exposure is measured as the interaction between the percentage of area burnt and proximity of the fire to settlements. The results reveal a significant positive relationship between fire hazard exposure and socio-economic disadvantage, such that the most socio-economically disadvantaged communities bore a disproportionately higher hazard exposure in the Black Summer than relatively advantaged communities. Our spatial analysis shows that the socio-economic disadvantage and wildfire hazard exposure relationship exists in inner regional, outer regional and remote areas of New South Wales and Victoria, the two worst-hit states of the Black Summer catastrophe. Our spatial analysis also finds that wildfire hazard exposure, even within a small geographical area, can vary substantially depending on the socio-economic profiles of communities. A possible explanation for our findings is resource gaps for fire suppression and hazard reduction that favours communities with a greater level of socio-economic advantage.

The integrated management (IM) of coastal and marine environments is an enduring problem, particularly in multi-sectoral and jurisdictional systems, with coastal management of New South Wales (NSW), Australia being no exception. Historically, NSW coastal and marine management was dominated by ecological and economic approaches, implemented in parallel through multiple government agencies with overlapping jurisdictions. A review in 2012 of NSW marine park management recommended addressing the unintended consequences of this management approach, and the Marine Estate Management Act (2014), was established to integrate management of the whole of the NSW coast. This paper discusses the role that a deliberative democratic approach has played in the approach to IM undertaken by the NSW Marine Estate Management Authority (MEMA). The NSW MEMA case study provides a robust reflection of the challenges identified by the literature in implementing effective integrated management, being the alignment of values, visions and methods of assessment, across multiple resources, ecosystems, stakeholders and administrative jurisdictions. Deliberative democratic approaches were used in reviewing the MEMA case to analyse its ability to address some of the challenges and realise benefits of IM. However, despite benefits being identified, a key finding is that achieving integration across multiple agencies with varied disciplinary approaches and organisational cultures, takes a significant amount of time. Even after several years, challenges remain in embedding cultural shifts and resource commitment at all levels to ensure the ongoing successful implementation of IM.

We examine the impediments to scientific integrity with an analysis of the water science-policy interface for the Murray-Darling Basin (MDB), Australia. We highlight the dangers to the public interest of ���administrative capture��� of science, whereby scientists are incentivised to narrow or close down the scientific questions asked, the debates on evidence and the scientific dialogue so to support predetermined policy actions. Administrative capture of science is not intended to be objective or disinterested and contributes to a diminution of trust in science and scientists. Using an integrative theoretical framework for analysis of the different stances taken by scientists in science���policy interactions, we show how scientists as Issue Advocates have sought to limit debate and the options available in relation to water reform in the MDB. We provide six possible actions to reduce administrative capture that encourages scientists to become Issue Advocates. These actions include procedural, professional, evaluative, judicial, instrumental and external controls that support scientific integrity by individuals and agencies that use and/or undertake publicly funded research.

Objective(s)Australia requires high quality evidence to optimise likely health and economy outcomes to effectively manage the current resurgence of COVID-19. We hypothesise that the most stringent social distancing (SD) measures (100% of level in Australia in April 2020) deliver better public health and economy outcomes.Design‘Fit-for-purpose’ (individual-based and compartment) models were used to simulate the effects of different SD and detection strategies on Australian COVID-19 infections and the economy from March to July 2020. Public reported COVID-19 data were used to estimate model parameters.Main outcome measuresPublic health and economy outcomes for multiple social distancing levels were evaluated, assessing “hard” versus “soft” lockdowns, and for early versus later relaxation of social distancing. Outcomes included costs and the timing and magnitude of observed COVID-19 cases and cumulative deaths in Australia from March to June 2020.ResultsHigher levels of social distancing achieve zero community transmission with 100% probability and lower economy cost while low levels of social distancing result in uncontrolled outbreaks and higher economy costs. High social distancing total economy costs were $17.4B versus $41.2B for 0.7 social distancing. Early relaxation of suppression results in worse public health outcomes and higher economy costs.Conclusion(s)Better public health outcomes (reduced COVID-19 fatalities) are positively associated with lower economy costs and higher levels of social distancing; achieving zero community transmission lowers both public health and economy costs compared to allowing community transmission to continue; and early relaxation of social distancing increases both public health and economy costs.SignificanceThe known is that COVID-19 infections can be suppressed with social distancing (SD) measures of sufficient stringency and duration.The new is we find highest levels of SD (100% SD that prevailed in April 2020) generate much lower COVID-9 deaths; reduced SD days; increased economic activity; and much higher probability of elimination over a subsequent 12-month period than lower levels of SD.The implications are that greater levels of SD are preferred to lower SD because they deliver both better public health and lower economy costs.

Differences in COVID-19 testing and tracing across countries, as well as changes in testing within each country overtime, make it difficult to estimate the true (population) infection rate based on the confirmed number of cases obtained through RNA viral testing. We applied a backcasting approach, coupled with Monte Carlo methods, to estimate a distribution for the true (population) cumulative number of infections (infected and recovered) for 15 countries where reliable data are available. We find a positive relationship between the testing rate per 1,000 people and the implied true detection rate of COVID-19, and a negative relationship between the proportion who test positive and the implied true detection rate. Our estimates suggest that the true number of people infected across our sample of 15 developed countries is 18.2 (5-95% CI: 11.9-39.0) times greater than the reported number of cases. In individual countries, the true number of cases exceeds the reported figure by factors that range from 1.7 (5-95% CI: 1.1-3.6) for Australia to 35.6 (5-95% CI: 23.2-76.3) for Belgium.

The authors acknowledge the financial assistance of the UNESCO Chair in Water Economics and Transboundary Governance at the Australian National University and the support of the Institute for Water Policy at the National University of Singapore