Facilitating student understanding about climate science: El Niño as an online case study

El Niño – Southern Oscillation (ENSO) has been shown to be the dominant factor affecting year-to-year climate changes globally, and may dramatically affect rainfall patterns around the world. In the education of climate scientists, it is critical that they comprehend the complex concepts that underpin ENSO. This paper discusses an online practical (tool) developed to teach undergraduate students the fundamental principles that underpin not only the average state of the ocean, but also ocean variability associated with ENSO. Results from two formal student evaluations of this practical, one by third year physical geography students and the other by second year physics students, will be presented and discussed

A stakeholder-guided marine heatwave hazard index for fisheries and aquaculture

Marine heatwaves pose an increasing threat to fisheries and aquaculture around the world under climate change. However, the threat has not been estimated for the coming decades in a form that meets the needs of these industries. Tasmanian fisheries and aquaculture in southeast Australia have been severely impacted by marine heatwaves in recent years, especially the oyster, abalone, and salmon industries. In a series of semi-structured interviews with key Tasmanian fishery and aquaculture stakeholders, information was gathered about the following: (i) the impacts they have experienced to date from marine heatwaves, (ii) their planning for future marine heatwaves, and (iii) the information that would be most useful to aid planning. Using CMIP6 historical and future simulations of sea surface temperatures around Tasmania, we developed a marine heatwave hazard index guided by these stakeholder conversations. The region experienced a severe marine heatwave during the austral summer of 2015/16, which has been used here as a reference point to define the index. Our marine heatwave hazard index shows that conditions like those experienced in 2015/16 are projected to occur approximately 1-in-5 years by the 2050s under a low emissions scenario (SSP1-2.6) or 1-in-2 years under a high emissions scenario (SSP5-8.5). Increased frequency of marine heatwaves will likely reduce productivity by both direct (mortality) and in-direct (ecosystem change, greater incidence of disease) impacts on target species. The illustrative hazard index is one step towards a marine heatwave risk index, which would also need to consider aspects of exposure and vulnerability to be of greater utility to stakeholders

Natural hazards in Australia : sea level and coastal extremes

The Australian coastal zone encompasses tropical, sub- and extra-tropical climates and accommodates about 80 % of Australia’s population. Sea level extremes and their physical impacts in the coastal zone arise from a complex set of atmospheric, oceanic and terrestrial processes that interact on a range of spatial and temporal scales and will be modified by a changing climate, including sea level rise. This review details significant progress over recent years in understanding the causes of past and projections of future changes in sea level and coastal extremes, yet a number of research questions, knowledge gaps and challenges remain. These include efforts to improve knowledge on past sea level extremes, integrate a wider range of processes in projections of future changes to sea level extremes, and focus efforts on understanding long-term coastline response from the combination of contributing factors

Global Water Governance and Climate Change: Identifying Innovative Arrangements for Adaptive Transformation

A convoluted network of different water governance systems exists around the world. Collectively, these systems provide insight into how to build sustainable regimes of water use and management. We argue that the challenge is not tomake the systemless convoluted, but rather to support positive and promising trends in governance, creating a vision for future environmental outcomes. In this paper, we analyse nine water case studies from around the world to help identify potential ‘innovative arrangements’ for addressing existing dilemmas. We argue that such arrangements can be used as a catalyst for crafting new global water governance futures. The nine case studies were selected for their diversity in terms of location, scale and water dilemma, and through an examination of their contexts, structures and processes we identify key themes to consider in the milieu of adaptive transformation. These themes include the importance of acknowledging socio-ecological entanglements, understanding the political dimensions of environmental dilemmas, the recognition of different constructions of the dillema, and the importance of democratized processes.The research for this paper is a part of the “CADWAGO: Climate change adaptation and water governance—reconciling food security, renewable energy and the provision of multiple ecosystem services” project funded as part of the “Europe and Global Challenges programme” by Compagnia di San Paolo, VolkswagenStiftung and Riksbankens Jubileumsfond.https://www.mdpi.com/2073-4441/10/1/2

Projected marine heatwaves in the 21st century and the potential for ecological impact

Marine heatwaves (MHWs) are extreme climatic events in oceanic systems that can have devastating impacts on ecosystems, causing abrupt ecological changes and socioeconomic consequences. Several prominent MHWs have attracted scientific and public interest, and recent assessments have documented global and regional increases in their frequency. However, for proactive marine management, it is critical to understand how patterns might change in the future. Here, we estimate future changes in MHWs to the end of the 21st century, as simulated by the CMIP5 global climate model projections. Significant increases in MHW intensity and count of annual MHW days are projected to accelerate, with many parts of the ocean reaching a near-permanent MHW state by the late 21st century. The two greenhouse gas (GHG) emission scenarios considered (Representative Concentration Pathway 4.5 and 8.5) strongly affect the projected intensity of MHW events, the proportion of the globe exposed to permanent MHW states, and the occurrence of the most extreme MHW events. Comparison with simulations of a natural world, without anthropogenic forcing, indicate that these trends have emerged from the expected range of natural variability within the first half of the 21st century. This discrepancy implies a degree of “anthropogenic emergence,” with a departure from the natural MHW conditions that have previously shaped marine ecosystems for centuries or even millennia. Based on these projections we expect impacts on marine ecosystems to be widespread, significant and persistent through the 21st century.This research was supported by the Australian Research Council grants CE170100023 and FT170100106, Natural Environment Research Council International Opportunity Fund NE/N00678X/1, National Sciences and Engineering Research Council of Canada Discovery Grant RGPIN-2018-05255, and Brian Mason (Impacts of an unprecedented marine heatwave). This project was partially supported through funding from the Earth Systems and Climate Change Hub of the Australian Government’s National Environmental Science Program.Peer ReviewedPostprint (published version

A hierarchical approach to defining marine heatwaves

Marine heatwaves (MHWs) have been observed around the world and are expected to increase in intensity and frequency under anthropogenic climate change. A variety of impacts have been associated with these anomalous events, including shifts in species ranges, local extinctions and economic impacts on seafood industries through declines in important fishery species and impacts on aquaculture. Extreme temperatures are increasingly seen as important influences on biological systems, yet a consistent definition of MHWs does not exist. A clear definition will facilitate retrospective comparisons between MHWs, enabling the synthesis and a mechanistic understanding of the role of MHWs in marine ecosystems. Building on research into atmospheric heatwaves, we propose both a general and specific definition for MHWs, based on a hierarchy of metrics that allow for different data sets to be used in identifying MHWs. We generally define a MHW as a prolonged discrete anomalously warm water event that can be described by its duration, intensity, rate of evolution, and spatial extent. Specifically, we consider an anomalously warm event to be a MHW if it lasts for five or more days, with temperatures warmer than the 90th percentile based on a 30-year historical baseline period. This structure provides flexibility with regard to the description of MHWs and transparency in communicating MHWs to a general audience. The use of these metrics is illustrated for three 21st century MHWs; the northern Mediterranean event in 2003, the Western Australia ‘Ningaloo Niño’ in 2011, and the northwest Atlantic event in 2012. We recommend a specific quantitative definition for MHWs to facilitate global comparisons and to advance our understanding of these phenomena

A global assessment of marine heatwaves and their drivers

Marine heatwaves (MHWs) can cause devastating impacts to marine life. Despite the serious consequences of MHWs, our understanding of their drivers is largely based on isolated case studies rather than any systematic unifying assessment. Here we provide the first global assessment under a consistent framework by combining a confidence assessment of the historical refereed literature from 1950 to February 2016, together with the analysis of MHWs determined from daily satellite sea surface temperatures from 1982–2016, to identify the important local processes, large-scale climate modes and teleconnections that are associated with MHWs regionally. Clear patterns emerge, including coherent relationships between enhanced or suppressed MHW occurrences with the dominant climate modes across most regions of the globe – an important exception being western boundary current regions where reports of MHW events are few and ocean-climate relationships are complex. These results provide a global baseline for future MHW process and prediction studies

Longer and more frequent marine heatwaves over the past century

Heatwaves are important climatic extremes in atmospheric and oceanic systems that can have devastating and long-term impacts on ecosystems, with subsequent socioeconomic consequences. Recent prominent marine heatwaves have attracted considerable scientific and public interest. Despite this, a comprehensive assessment of how these ocean temperature extremes have been changing globally is missing. Using a range of ocean temperature data including global records of daily satellite observations, daily in situ measurements and gridded monthly in situ-based data sets, we identify significant increases in marine heatwaves over the past century. We find that from 1925 to 2016, global average marine heatwave frequency and duration increased by 34% and 17%, respectively, resulting in a 54% increase in annual marine heatwave days globally. Importantly, these trends can largely be explained by increases in mean ocean temperatures, suggesting that we can expect further increases in marine heatwave days under continued global warming

Marine heatwaves threaten global biodiversity and the provision of ecosystem services

The global ocean has warmed substantially over the past century, with far-reaching implications for marine ecosystems 1 . Concurrent with long-term persistent warming, discrete periods of extreme regional ocean warming (marine heatwaves, MHWs) have increased in frequency 2 . Here we quantify trends and attributes of MHWs across all ocean basins and examine their biological impacts from species to ecosystems. Multiple regions in the Pacific, Atlantic and Indian Oceans are particularly vulnerable to MHW intensification, due to the co-existence of high levels of biodiversity, a prevalence of species found at their warm range edges or concurrent non-climatic human impacts. The physical attributes of prominent MHWs varied considerably, but all had deleterious impacts across a range of biological processes and taxa, including critical foundation species (corals, seagrasses and kelps). MHWs, which will probably intensify with anthropogenic climate change 3 , are rapidly emerging as forceful agents of disturbance with the capacity to restructure entire ecosystems and disrupt the provision of ecological goods and services in coming decades. © 2019, The Author(s), under exclusive licence to Springer Nature Limited

Interrogating resilience: toward a typology to improve its operationalization

In the context of accelerated global change, the concept of resilience, with its roots in ecological theory and complex adaptive systems, has emerged as the favored framework for understanding and responding to the dynamics of change. Its transfer from ecological to social contexts, however, has led to the concept being interpreted in multiple ways across numerous disciplines causing significant challenges for its practical application. The aim of this paper is to improve conceptual clarity within resilience thinking so that resilience can be interpreted and articulated in ways that enhance its utility and explanatory power, not only theoretically but also operationally. We argue that the current confusion and ambiguity within resilience thinking is problematic for operationalizing the concept within policy making. To achieve our aim, we interrogate resilience interpretations used within a number of academic and practice domains in the forefront of contending with the disruptive and sometimes catastrophic effects of global change (primarily due to climate change) on ecological and human-nature systems. We demonstrate evolution and convergence among disciplines in the interpretations and theoretical underpinnings of resilience and in engagement with cross-scale considerations. From our analysis, we identify core conceptual elements to be considered in policy responses if resilience is to fulfill its potential in improving decision making for change. We offer an original classification of resilience definitions in current use and a typology of resilience interpretations. We conclude that resilience thinking must be open to alternative traditions and interpretations if it is to become a theoretically and operationally powerful paradigm