Rising sea-levels are likely to cause billions of dollars worth of damage during the 21st century, particularly after 2050, a new study led by Bournemouth University has found.
Using sea-level rise scenarios that align with strong climate change mitigation of 1.5 ºC or 2.0ºC, the team found that global damage costs due to sea floods could be up to $25,000 billion per year in 2100 if defences are not upgraded from today’s standards. Many of these costs will be incurred by upper middle income countries, where there is a growing amount of infrastructure in coastal zones, but presently limited protection. Those in high income countries were projected to have lower costs as there are already relatively high standards of defence, such as through sea walls. The scenario where only limited climate change mitigation was considered, and temperatures instead reach 4.0ºC by 2100, meaning global costs would be even higher – up to $31,000 billion per year in 2100.
Dr Sally Brown, Deputy Head of Department of Life and Environmental Sciences, who led the study, said: “Once again, this study demonstrates that rising sea-levels will cause damage to our coastline regardless of whether we mitigate for climate change or not. This does not mean to say that mitigation is not worth it, as the damages arising from coastal flooding are still reduced, but the residual damages are substantial. Of course, there are many other ways in which our planet would benefit from lower greenhouse gas emissions. However, it means that we have to be proactive in adapting to sea-level rise, through protection, changing the ways the coast is managed or ultimately retreating.”
Adaptation was found to greatly reduce damage costs, with damage reduced to $518 billion per year for a mitigation scenario and $673 billion per year for a non-mitigation scenario. Costs of adaptation are projected to be relatively higher for middle or lower income nations than high income nations compared with their gross domestic product as in many nations there is a limited protection in the present day. Dr Brown added: “Protection is not a magic answer, as sea-levels will keep on rising over the decades and centuries meaning that further adaptation and protection will be needed.”