Climate-induced storminess forces major increases in future storm surge hazard in the South China Sea region

It is vital to robustly estimate the risks posed by extreme sea levels, especially in tropical regions where cyclones can generate large storm surges and observations are too limited in time and space to deliver reliable analyses. To address this limitation for the South China Sea region, we force a hydrodynamic model with a new synthetic database representing 10,000 years of past/present and future tropical cyclone activity, to investigate climate change impacts on extreme sea levels forced by storm surges (± tides). We show that, as stronger and more numerous tropical cyclones likely pass through this region over the next 30 years, both the spatial extent and severity of storm surge hazard increases. While extreme storm surge events in this location become generally a more frequent occurrence in the future, larger storm surges around Vietnam and China coastlines are projected to regionally amplify this hazard. This threatens low-lying, densely-populated areas such as the Red and Mekong River deltas, while sections of the Cambodian and Thai coastline face previously unseen storm surge hazards. These future hazards strongly signal that coastal flood management and adaptation in these areas should be reviewed for their resilience against future extreme sea levels.

The Effect of Wind Stress on Seasonal Sea-Level Change on the Northwestern European Shelf

Projections of relative sea-level change (RSLC) are commonly reported at an annual mean basis. The seasonality of RSLC is often not considered, even though it may modulate the impacts of annual mean RSLC. Here, we study seasonal differences in 21st-century ocean dynamic sea-level change (DSLC, 2081-2100 minus 1995-2014) on the Northwestern European Shelf (NWES) and their drivers, using an ensemble of 33 CMIP6 models complemented with experiments performed with a regional ocean model. For the high-end emissions scenario SSP5-8.5, we find substantial seasonal differences in ensemble mean DSLC, especially in the southeastern North Sea. For example, at Esbjerg (Denmark), winter mean DSLC is on average 8.4 cm higher than summer mean DSLC. Along all coasts on the NWES, DSLC is higher in winter and spring than in summer and autumn. For the low-end emissions scenario SSP1-2.6, these seasonal differences are smaller. Our experiments indicate that the changes in winter and summer sea-level anomalies are mainly driven by regional changes in wind-stress anomalies, which are generally southwesterly and east-northeasterly over the NWES, respectively. In spring and autumn, regional wind-stress changes play a smaller role. We also show that CMIP6 models not resolving currents through the English Channel cannot accurately simulate the effect of seasonal wind-stress changes on he NWES. Our results imply that using projections of annual mean RSLC may underestimate the projected changes in extreme coastal sea levels in spring and winter. Additionally, changes in the seasonal sea-level cycle may affect groundwater dynamics and the inundation characteristics of intertidal ecosystems.

Human Resilience in the Face of Mid-Holocene Climate Change on the Central West Coast of South Africa

After the Last Glacial Maximum, important yet milder climatic trends continued to characterise the Holocene. None of them was more challenging to forager groups in the central west coast of South Africa than the mid-Holocene Altithermal (8200–4200 cal BP). Hot and dry weather and 1–3 m higher sea levels were thought once to have barred local foragers from this region because of a lack of sites dating to this period. Instead, this initial scenario reflected largely a sampling problem. Steenbokfontein Cave is one of a few sites with some of the largest mid-Holocene deposits, allowing insights into forager adaptations during this period. Results show high mobility over large distances and a terrestrial diet mostly dependant on small bovids, complemented with fewer coastal resources. Stone tool kits and lithic raw materials among various sites suggest that much evidence for mid-Holocene occupation is actually found near the local riparian systems.

Climate change is raising sea levels in the oceans

Climate change is a global challenge, directly affecting ecosystems, environmental resources, and human life. One of its consequences is the problem of sea and ocean surface area, sea level is increasing day by day. In the long term, global mean sea level will continue to change continuously. The birth of the industrial revolution has made the Earth warmer and warmer, followed by many different causes leading to the rapid increase of global sea level: melting ice, expansion of the sea. water and changes in the Earth's climate system, costing the global economy trillions of dollars with many development consequences.

Incorporating historical information to improve extreme sea level estimates

Extreme value analysis seeks to assign probabilities to events which deviate significantly from the mean and is thus widely employed in disciplines dealing with natural hazards. In terms of extreme sea levels (ESLs), these probabilities help to define coastal flood risk which guides the design of coastal protection measures. While tide gauge and other systematic records are typically used to estimate ESLs, combining systematic data with historical information has been shown to reduce uncertainties and better represent statistical outliers. This paper introduces a new method for the incorporation of historical information in extreme value analysis which outperforms other commonly used approaches. Monte-Carlo Simulations are used to evaluate a posterior distribution of historical and systematic ESLs based on the prior distribution of systematic data. This approach is applied at the German town of Travemünde, providing larger ESL estimates compared to those determined using systematic data only. We highlight a potential to underestimate ESLs at Travemünde when historical information is disregarded, due to a period of relatively low ESL activity for the duration of the systematic record.

Factors Controlling the Extreme Storm Surge Flooding - Insights From Coastal Sedimentary Record of the Southern Baltic Sea

Climate change and related sea-level rise pose significant threats to sandy lowland coasts, which account for approximately 30% of the global coastline. However, the role of key controlling factors responsible for the frequency and extent of extreme storm surge of inundation regime is not yet fully understood. Here, we present the longest to date, high-resolution sedimentary record of extreme storm surge flooding from the microtidal southern Baltic Sea, spanning two periods: 3.6-2.9 ka BP and 0.7 ka BP until present. Wetland sediments, including sandy event layers, were analyzed by sedimentological (grain size, loss-on-ignition, micromorphology), geochronological (14C, 210Pb, 137Cs), geochemical (XRF), mineralogical (heavy minerals) and micropaleontological (diatoms) methods. Our results revealed that both periods are characterized by high-frequency storm surge flooding in order of 1.3 – 4.2 events per century. They are correlated to widely recognized enhanced storminess periods in NW Europe and took place during both rising and fluctuating sea levels. The presented results show that the storm surge driven coastal inundation frequency and extent largely depend on the development of coastal barriers (e.g., beach ridges). Thus, in the context of the future coastal storm surge hazard, the protection of existing coastal barriers is essential.

Clapping From the Arena

Climate change is a serious global issue and concern that is attributed to change. A change of climate that is directly or indirectly related to human activity, that which alters the composition of the global atmosphere and which in addition to natural climate variability observed over comparable time periods. There is therefore no doubt that the earth is warming, and the climate changing. Despotism and the rule of despots as agents of democracy has created a rift in the issue of climate change on its citizenry in the southern zone of Plateau State in the area of health, water shortages, cutting meals due to the economic recession in Nigeria. Research has shown that climate change can create a conflict, and it does have a direct effect on scarce resources required to sustain life. Water is at the heart of human existence. Global warming has a major impact on global water cycle, hence on rainfall, soil moisture, rivers, and sea levels. If climate change is not tackled urgently, the calamity will be enormous.

Great egret (Ardea alba) habitat selection and foraging behavior in a temperate estuary: Comparing natural wetlands to areas with shellfish aquaculture

Movement by animals to obtain resources and avoid predation often depends on natural cycles, and human alteration of the landscape may disrupt or enhance the utility of different habitats or resources to animals through the phases of these cycles. We studied habitat selection by GPS/accelerometer-tagged great egrets (Ardea alba) foraging in areas with shellfish aquaculture infrastructure and adjacent natural wetlands, while accounting for tide-based changes in water depth. We used integrated step selection analysis to test the prediction that egrets would express stronger selection for natural wetlands (eelgrass, tidal marsh, and other tidal wetlands) than for shellfish aquaculture areas. We also evaluated differences in foraging behavior among shellfish aquaculture areas and natural wetlands by comparing speed travelled (estimated from distance between GPS locations) and energy expended (Overall Dynamic Body Acceleration) while foraging. We found evidence for stronger overall habitat selection for eelgrass than for shellfish aquaculture areas, with results conditional on water depth: egrets used shellfish aquaculture areas, but only within a much narrower range of water depths than they used eelgrass and other natural wetlands. We found only slight differences in our metrics of foraging behavior among shellfish aquaculture areas and natural wetlands. Our results suggest that although great egrets appear to perceive or experience shellfish aquaculture areas as suitable foraging habitat during some conditions, those areas provide less foraging opportunity throughout tidal cycles than natural wetlands. Thus, expanding the footprint of shellfish aquaculture into additional intertidal areas may reduce foraging opportunities for great egrets across the range of tidal cycles. Over longer time scales, the ways in which natural wetlands and shellfish aquaculture areas adapt to rising sea levels (either through passive processes or active management) may change the ratios of these wetland types and consequently change the overall value of Tomales Bay to foraging great egrets.