IHCantabria research staff participate in a study on the vulnerability of coastal areas to sea level rise.

Itxaso Odériz Martínez, a researcher at the Institute of Environmental Hydraulics of the Universidad de Cantabria (IHCantabria) within the Climate and Climate Change group, is one of the primary authors, together with various specialists in the climate sector, of the article Dissemination for Transitional Wave Climate Regions on Continental and Polar Coasts in a Warming World, published in the journal Nature Climate Change.

The article highlights the vulnerability of coastal areas to the current climate emergency due to their high sensitivity to weather events and climate disruptions on multiple time scales (from storms to variations lasting more than years or decades).

In addition to sea level rise, climate change affects the mean wave characteristics, modifying the frequency of occurrence of global wave climates (east, south and west). In this study, coastal areas where waves change in frequency and inherently in direction and energy are referred to as wave climate transition regions (WCRTs). This work identifies them and demonstrates that most are found in the southwest coasts, eastern ocean basins and polar regions.

Studies show that 1) the global swell climate is composed of three main atmospheric circulation-driven climates that affect coasts around the world: south swells (generated by subpolar and subtropical winds), east swells (generated by trade winds and polar winds) and west swells (generated in the extra-tropical and monsoon region). For this purpose, an analysis of the spatial and temporal variations of these wave climates in global warming scenarios proposed by the IPCC at the end of the 21st century was carried out, and, 2) the large increase in wave energy is concentrated in high latitudes of the Southern Ocean induced by a poleward intensification of the extra-tropical atmospheric circulation.

On the one hand, the results showed that the regions of south swell climate transition (coasts with an increase in the frequency of south swells) are located in the eastern Pacific, the southeast Atlantic and the eastern Indian Ocean. To this swell climate belong the most intense swells affecting the Pacific coast of the Americas during the last decade.

On the other hand, easterly swell weather is expected to be more frequent along the southeast coast of Africa, and the northwest and southwest Atlantic. Westerly swell weather is expected to be more frequent in the northwest Pacific Ocean and New Zealand due to the poleward shift of extra-tropical winds.

In addition, in some coastal regions, the difference in the frequency of occurrence of wave weather between seasons will be more noticeable, altering the natural balance in coastal environments.

About the polar regions and the importance of ice melt in wave generation, areas of the polar coasts were identified that would be exposed to wave climates that were not present in the last century. Changes in melt patterns will affect waves and vice versa. For example, sea ice melt results in new regions of open ocean where the likelihood of storm development increases, which may lead to increased erosion of permafrost and ice in the polar regions. In addition, waves in new the open ocean regions may allow for the transport of species and pollution. The results are most critical in the Arctic Ocean, however, changes in waves in the Southern Ocean may affect continental coasts due to the propagation capacity of these waves travelling from high to low latitudes.

Finally, we must consider the implications for coastal risk and coastal adaptation, as projected changes in directional wave energy, combined with sea level rise and extreme events, may modify the spatial and temporal patterns of wave climates and severely alter coastal risk (erosion and inundation).

Finally, within the wave transition climate regions, the polar regions are particularly complex because melting ice can open up new wave generation zones, which are critical for the future of the coasts. Currently, the approach to this issue is still developing, highlighting the study of these as potential risk zones where changes in the variability of wave climates may alter long-term coastal processes.