A new analysis led by researchers at International Institute for Applied Systems Analysis (IIASA) have for the first time assessed the economy-wide effects of coastal flooding.
Rising sea levels are one of the most dramatic effects of climate change, posing a dangerous threat to coastal communities, infrastructure and agriculture.
A team at IIASA evaluated the economy-wide effects of sea level rise in G20 countries whilst jointly considering the different climate mitigation and adaptation assumptions. They compared two different climate policy scenarios; meeting the aims of the 2015 Paris Agreement (keeping warming below 2 °C); and overshooting this target. In the overshooting case, two adaptation scenarios were assessed ‑ no adaptation and full adaptation to sea level rise.
Lead author and IIASA Risk and Resilience Deputy Program Director, Thomas Schinko, said, ‘We 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. However, 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%.’
The results show that if adaptation measures are put into place, the residual economy-wide effects could drop below 1% of GDP for individual G20 countries. This would also reduce impacts on coastal countries and communities vulnerable to tropical storms. With stronger mitigation measures, the model results reveal that GDP loss could even be reduced to 0.5%, despite adaptation costs.
An increase in sea level rise will negatively impact macroeconomics up to and beyond 2050. The results prove it is critical to coordinate mitigation strategies and to develop climate-resilient infrastructure to lessen the negative impact on global economies.
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