Dr Anjani Ganase reports from the front lines of science looking for solutions to rapid ocean warming.
Coastal defences are better when nature is involved.
In Trinidad and Tobago, a common solution to any flooding or erosion event is to install a box drain or retention wall. Pouring concrete or straightening a riverbed ignores the downstream negative impacts, the loss of ecological systems and the prevention of any future adaptation. Box drains, concrete walls and such permanent constructs do not respond to climate impacts and require high-cost maintenance in the long run.
This is a common problem worldwide, with 40 per cent of Japan’s coastlines hardened by coastal defences. These engineered solutions are referred to as hard defences – directly referring to the hardening of the coastline or the riverbed.
In contrast, soft – also known as ecosystem-based – solutions aim to mimic natural ecosystem functions – mangroves, back beach habitats, coral reefs – to provide defensive services.
In some scenarios, hybrid defences were designed to combine the two (hard and soft) for the best of both worlds. Hybrids aim to provide immediate barrier to further erosion while maintaining the ecological form and adaptability of the area for any further changes especially climate change. While both soft and hybrid solutions are likely to be made more cost-effective and adaptable, they can be designed on par with the natural measures – namely existing coral reefs, mangroves, etc, that protected the coastline.
A review by the University of Tokyo based on 304 published articles for studies done in 55 countries around the world found hybrid solutions had the largest reduction in hazard and were cost-effective when compared to the hard solutions.
It must be noted that most of the observations were undertaken in conditions of low-level threats, as few studies investigated effectiveness during extreme storm events.
Jellification of the Arctic Ocean?
The first scenarios of climate change by researchers in the early 2000s anticipated an ocean dominated by jellyfish with expanded ranges across the world as warming extended the range of suitable habitats.
This is hastened by overfishing, which removes natural predators, and nutrient-polluted water, which encourages the blooming of some algae species.
However, while there are examples of jellyfish populations increasing in some places around the world, resulting in issues such as inundating fish nets, clogging intakes of power plants in coastal areas, there is no global consensus on jellyfish invasions or expanding their range.
A group of researchers from Bremen University, Germany, modelled the potential spread of jellyfish species into the Arctic with climate change. The results revealed that most species may be likely to occupy new spaces in the Arctic open ocean and coastal areas, which would have been limited by the presence of sea ice otherwise.
Sea ice is critical for the environmental condition and the food web of the Arctic, as it regulates light availability
