Negative economy-wide effects of coastal flooding have already been predicted up to 2050 but could increase considerably towards the end of the century without further measures to mitigate climate change, according to a new analysis published on 14 January in Environmental Research Communications (1). The exact speed of future sea level rise is difficult for scientists to predict. Nonetheless, beyond 2050 the economic impacts will be severe and increasing if swift action is not taken.
Sea level rise is one of the most dramatic effects of climate change. Rising water levels amplify coastal floods, which pose a serious threat to coastal communities, infrastructure, and agriculture. Despite commitments made by 175 nations to the 2015 Paris Agreement, the years between 2010 to 2020 were the hottest on record.
No scenario will stop sea level rises this century, warned a stark landmark report released by the Intergovernmental Panel on Climate Change (IPCC) in September 2019. Therefore, serious impacts including intense storms and drastic reductions in marine life are already inevitable.
Now, a team of researchers, led by the International Institute for Applied Systems Analysis (IIASA) near Vienna, Austria, take a closer look at one of the key economic damages associated with climate change: coastal impacts due to sea level rise. The analysis assessed economic impacts of coastal flooding due to sea level rise under different climate mitigation and adaptation assumptions on a global level, as well as on individual G20 countries.
More specifically, the authors considered two scenarios: (1) meeting the aims of the 2015 Paris Agreement, i.e. the long-term goals to limit global warming to below 2 degrees Celcius compared to pre-industrial levels; or (2) overshooting the target. In addition, they examined two different adaptation scenarios in the overshooting case, no adaptation and full adaptation to sea level rise.
The study is unique because it provides a detailed look at G20 countries – some of the big emitters also being affected by climate change. Within the G20, the countries most affected will be China, India, and Canada. Macroeconomic impacts are analogous to the direct damages of sea level rise, but this could change if more powerful mitigation actions and sea level rise adaptation efforts are taken.
With appropriate adaptation measures, the authors suggest that individual G20 countries could limit residual economy-wide impacts to below one per cent of GDP. Furthermore, this would reduce impacts on the most vulnerable coastal countries around the world, for example, small island nations close to the equator that are particularly vulnerable to tropical storms and coastal flooding.
The authors found that “up to 2050 the global GDP losses in both climate futures are significant and similar given the effects of climate change that we are already experiencing.”
“By 2100, without further mitigation and adaptation and assuming continued sea level rise, projected annual global economy-wide losses can amount to more than 4 per cent”, lead author and director of the IIASA Risk and Resilience Deputy Program Thomas Schinko explained in a statement.
However, Shinko also added: “With ambitious mitigation and adaptation, the model results show that this number can be reduced to below 0.5% of global GDP loss, despite the associated costs for adaptation measures and residual impacts.”
“This confirms the importance and economic efficiency of adaptation in the long term: Making sure that coastal communities and their infrastructure are climate-resilient will affect economies across the globe much less than persistent climate impacts in the absence of climate action.”
The findings highlight the need for both mitigation and adaptation strategies to prevent further impacts of global warming while managing the already inevitable effects of climate change. “We need to think long term while acting swiftly” and “as a global society, need to further coordinate mitigation, adaptation, and climate-resilient development”, says Schinko.
(1) Schinko, T. et al. Economy-wide effects of coastal flooding due to sea level rise: a multi-model simultaneous treatment of mitigation, adaptation, and residual impacts. Environmental Research Communications (2020). DOI: 10.1088/2515-7620/ab6368