• Energy Research

Increasing sea surface temperature and extreme heat events pose the greatest threat to coral reefs globally, with trends exceeding previous norms. The resultant mass bleaching events, such as those evidenced on the Great Barrier Reef in 2016, 2017, and 2020 have substantial ecological costs in addition to economic and social costs. Advancing remote (nanosatellites, rapid revisit traditional satellites) and in-field (drones) technological capabilities, cloud data processing, and analysis, coupled with existing infrastructure and in-field monitoring programs, have the potential to provide cost-effective and timely information to managers allowing them to better understand changes on reefs and apply effective remediation. Within a risk management framework for monitoring coral bleaching, we present an overview of how remote sensing can be used throughout the whole risk management cycle and highlight the role technological advancement has in earth observations of coral reefs for bleaching events.

AbstractSeagrass meadows store globally significant organic carbon (Corg) stocks which, if disturbed, can lead to CO2 emissions, contributing to climate change. Eutrophication and thermal stress continue to be a major cause of seagrass decline worldwide, but the associated CO2 emissions remain poorly understood. This study presents comprehensive estimates of seagrass soil Corg erosion following eutrophication‐driven seagrass loss in Cockburn Sound (23 km2 between 1960s and 1990s) and identifies the main drivers. We estimate that shallow seagrass meadows (<5 m depth) had significantly higher Corg stocks in 50 cm thick soils (4.5 ± 0.7 kg Corg/m2) than previously vegetated counterparts (0.5 ± 0.1 kg Corg/m2). In deeper areas (>5 m), however, soil Corg stocks in seagrass and bare but previously vegetated areas were not significantly different (2.6 ± 0.3 and 3.0 ± 0.6 kg Corg/m2, respectively). The soil Corg sequestration capacity prevailed in shallow and deep vegetated areas (55 ± 11 and 21 ± 7 g Corg m−2 year−1, respectively), but was lost in bare areas. We identified that seagrass canopy loss alone does not necessarily drive changes in soil Corg but, when combined with high hydrodynamic energy, significant erosion occurred. Our estimates point at ~0.20 m/s as the critical shear velocity threshold causing soil Corg erosion. We estimate, from field studies and satellite imagery, that soil Corg erosion (within the top 50 cm) following seagrass loss likely resulted in cumulative emissions of 0.06–0.14 Tg CO2‐eq over the last 40 years in Cockburn Sound. We estimated that indirect impacts (i.e. eutrophication, thermal stress and light stress) causing the loss of ~161,150 ha of seagrasses in Australia, likely resulted in the release of 11–21 Tg CO2‐eq since the 1950s, increasing cumulative CO2 emissions from land‐use change in Australia by 1.1%–2.3% per annum. The patterns described serve as a baseline to estimate potential CO2 emissions following disturbance of seagrass meadows.

Forests and coral reefs are structurally complex ecosystems threatened by climate change. In situ 3D imaging measurements provide unprecedented, quantitative, and detailed structural information that allows testing of hypotheses relating form to function. This affords new insights into both individual organisms and their relationship to their surroundings and neighbours.

Coastal communities in the Coral Triangle are increasingly threatened by climate change. Sea-level rise (SLR) will result in biophysical and socioeconomic impacts that could increase the loss of livelihoods, cultural heritage and infrastructure. Effective adaptation requires a holistic approach that incorporates scientific knowledge together with local and traditional knowledge. Community-based adaptation built on local knowledge is of great value for environmental management, particularly when scientific data are lacking. This article reports a case study that integrated traditional and scientific knowledge using participatory three-dimensional modeling (P3DM) in BoeBoe village, Solomon Islands. P3DM is a process by which members of the local community build a physical terrain model and overlay it with the location of important resources such as protected areas or harvesting sites. Additionally, SLR inundation scenarios based on surveyed elevations were incorporated into a geographic information system (GIS), allowing for a real-time integration of science with local knowledge. Despite discrepancies in scales and accuracy, information from both the P3DM and GIS were complementary. The process, itself, provided a forum for discussion between many members of the village who would normally not be involved and highlighted the importance of community engagement when building capacity for adaptation to climate change.

AbstractThe distribution and abundance of seagrass ecosystems could change significantly over the coming century due to sea level rise (SLR). Coastal managers require mechanistic understanding of the processes affecting seagrass response to SLR to maximize their conservation and associated provision of ecosystem services. In Moreton Bay, Queensland, Australia, vast seagrass meadows supporting populations of sea turtles and dugongs are juxtaposed with the multiple stressors associated with a large and rapidly expanding human population. Here, the interactive effects of predicted SLR, changes in water clarity, and land use on future distributions of seagrass in Moreton Bay were quantified. A habitat distribution model of present day seagrass in relation to benthic irradiance and wave height was developed which correctly classified habitats in 83% of cases. Spatial predictions of seagrass and presence derived from the model and bathymetric data were used to initiate a SLR inundation model. Bathymetry was iteratively modified based on SLR and sedimentary accretion in seagrass to simulate potential seagrass habitat at 10 year time steps until 2100. The area of seagrass habitat was predicted to decline by 17% by 2100 under a scenario of SLR of 1.1 m. A scenario including the removal of impervious surfaces, such as roads and houses, from newly inundated regions, demonstrated that managed retreat of the shoreline could potentially reduce the overall decline in seagrass habitat to just 5%. The predicted reduction in area of seagrass habitat could be offset by an improvement in water clarity of 30%. Greater improvements in water clarity would be necessary for larger magnitudes of SLR. Management to improve water quality will provide present and future benefits to seagrasses under climate change and should be a priority for managers seeking to compensate for the effects of global change on these valuable habitats.

AbstractAmong the biggest global challenges for policymakers is the development of land use policies robust to climate change impacts. While diverse fields can inform adaptation, integrated social‐ecological assessment of the multiple adaptation options are rare and cannot be easily applied. Here, we build on past studies by undertaking an integrated fine scale and strategic allocation of sea level rise (SLR) adaptation options that can direct policy making. We use models of probabilistic SLR inundation, urban growth, and sub‐ and intertidal ecosystem migration, to investigate the impacts of different SLR adaptation strategies, and how these can be allocated to best achieve both development and conservation goals. Coastal adaptation will involve trade‐offs among development and conservation objectives and these will vary based on the extent to which sea levels rise. There will be trade‐offs between conservation objectives regardless of the adaptation options chosen, however, retreat does provide opportunities for enabling the expansion of coastal ecosystems inland. Local governments can save billions of dollars and minimize political conflict between conservation and development goals through integrated strategic spatial planning. Our planning approach both informs policy and is transferable to other coastal regions faced with a rising sea.

Island societies are being disproportionately affected by climate change, a situation likely to continue for some decades. Using an example of an island affected by multiple climate-linked stressors, a situation likely to become more common in the future, this paper examines the nature of these, the ways they are perceived and responded to by local residents, and how these people believe environmental changes might unfold in the future. Yadua Island has one settlement (Denimanu), where most of the 170 residents sustain themselves largely by fishing and farming. Like most Pacific Island settlements, Denimanu is coastal and has experienced progressive shoreline erosion that, a decade ago, washed away a row of houses. In 2012, a storm surge (during Tropical Cyclone Evan) demolished most of the remaining bure (traditional dwellings) in the village. The Fiji Government relocated the affected families to a new upslope location (Korovou), 80–230 m from the beach, and up to 20 m above mean sea level. In March 2017, heavy rain caused a landslide at the back of Denimanu that endangered the primary school, forcing its abandonment. Some questionnaires were given to representative members of the community in an attempt to understand and quantify the pressures that Yadua Island people are subject to, and how they plan to manage them. All respondents believed that climate change has affected their livelihoods and will continue to do so in the future. Clear majorities stated that climate change – especially higher temperatures and increased frequency/magnitudes of heavy-rain events – had negatively affected the supply of marine and terrestrial foods. Most respondents noted increased temperature and decreased precipitation. Clear majorities stated they would eventually relocate their homes further inland, and would consider planting mangroves. Most participants were contemplating the effects of climate change (especially sea-level rise) on food supply, prompting them to consider relocating lowland crop production further inland and planting crops that are more tolerant of saline groundwater and/or periodic wave over-wash. The people of Denimanu recognise how the environment has been changing but debate the ultimate cause of this and therefore how best to respond. It is likely that Yadua will become impacted more by tropical cyclones and sea-level rise (in particular) in the future. To be effective and sustainable, adaptation strategies should acknowledge residents’ worldviews and beliefs rather than try to uncritically substitute them. Keywords: Small Island Developing States, Fiji, Sea-level rise, Climate change, Environmental risk, Landslides