,Neil Santillan, Macquarie University,
Sydney. Most of the world’s natural coastlines are protected by living habitats, particularly mangroves in warm waters and tidal marshes near the poles. These ecosystems support fisheries and wildlife, absorb the impact of crashing waves and clean up pollutants. But, these vital services are threatened by the continued rise in global temperatures and rising sea levels.
Recent research has shown that wetlands can help mitigate rising sea levels by building their root systems, pulling carbon dioxide from the atmosphere in the process. A growing recognition of the potential of this ‘blue’ carbon sequestration is underpinning mangrove and tidal marsh restoration projects.
While the resilience of these ecosystems is impressive, there is no limit. Defining the upper limits of resilience of mangroves and marshes under rapid sea-level rise is a topic of great interest and considerable debate. Our new research, published in the British scientific journal Nature, analyzes the vulnerability and vulnerability of mangroves, marshes and atolls to sea level rise. The results underscore the critical aspect of keeping global temperature increases within two degrees Celsius of pre-industrial baselines.
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what we did
We gathered all available evidence on how mangroves, tidal marshes and atolls respond to sea level rise. This includes studying how coastal systems have responded to past sea-level rise in the geologic record. Analysis of satellite images for changes in the extent of wetlands and atolls at different rates of sea level rise – using a global network of survey measurements in mangroves and tidal marshes – after the last ice age.
In total, our international team assessed 190 mangroves, 477 tidal flats and 872 atolls around the world. We then used computer modeling to explore how these coastal ecosystems would be affected by rapid sea level rise under projected temperature increase scenarios.
What we got
Mangroves, tidal marshes, and atolls may face lower rates of sea level rise. They remain stable and healthy. We found that most tidal wetlands and mangroves are keeping pace with the current rate of sea-level rise, about 2-4 mm per year. In these conditions, even coral islands appear frozen.
In some places, the land is sinking, so the relative rate of sea level rise is higher. This figure of 2-4 mm could be twice or more the rate expected under future climate change. Under these circumstances, we find that wetlands are failing to keep pace with sea level rise. They are slowly sinking and in some cases even breaking. Moreover, this is the same rate of sea-level rise at which swamps and mangroves are submerged in the geologic record. These cases give us a glimpse of the future in a warming world. (conversation)
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Tags: coastal areas, Journal Nature, Research, Sydney, temperature
First published: August 31, 2023, 14:53 IST