Assessing climate change impacts, sea level rise and storm surge risk in port cities: a case study on Copenhagen

Abstract

This study illustrates a methodology to assess the economic impacts of climate change at a city scale and benefits of adaptation, taking the case of sea level rise and storm surge risk in the city of Copenhagen, capital of Denmark. The approach is a simplified catastrophe risk assessment, to calculate the direct costs of storm surges under scenarios of sea level rise, coupled to an economic input-output (IO) model. The output is a risk assessment of the direct and indirect economic impacts of storm surge under climate change, including, for example, production and job losses and reconstruction duration, and the benefits of investment in upgraded sea defences. The simplified catastrophe risk assessment entails a statistical analysis of storm surge characteristics, geographical-information analysis of population and asset exposure combined with aggregated vulnerability information. For the city of Copenhagen, it is found that in absence of adaptation, sea level rise would significantly increase flood risks. Results call for the introduction of adaptation in long-term urban planning, as one part of a comprehensive strategy to manage the implications of climate change in the city. Mitigation policies can also aid adaptation by limiting the pace of future sea level rise.

An assessment of the potential impact of climate change on flood risk in Mumbai

“…The commercial and industrial economic damages were derived from the total economic damage, using the proportions indicated by their affected exposures. The total direct economic losses at state level were obtained from the Dartmouth Flood Observatory (2008) and Swiss Re (2006); we assume that 50% of these damages occurred in the Greater Mumbai area 2 and that around 70% of these losses were related to residential, commercial and industrial damages (extracting infrastructure as given in Hallegatte et al (2011b), in this issue), giving total losses of 1.7 billion USD.…”

“…The ranges reflect the uncertainty in vulnerability. Table 6 gives an estimate of the total direct losses including infrastructure losses; where these losses are assumed to be around 40% of the total value of residential, commercial and industrial losses (see Hallegatte et al 2011b in this issue). The loss estimates for the July 2005 event ($690-$1910 million USD) are roughly in line with the $1.7 billion losses estimated above.…”

Flood Risks, Climate Change Impacts and Adaptation Benefits in Mumbai

“…Commercial and industrial economic damages were derived from the total economic damage, using the proportions indicated by their affected exposures. Total direct economic losses at state level were obtained from the Dartmouth Flood Observatory (2008) and Swiss Re (2006); we assume that 50% of these damages occurred in the Greater Mumbai area 4 and that around 70% of these losses were related to residential, commercial and industrial damages (extracting infrastructure as given in Hallegatte et al 2008b), giving total losses of 1.7 billion USD.…”

“…Section 3.2 provides a map of critical infrastructure exposure, but this is only a partial view of all public assets. To take into account all public assets, in absence of localized information on all assets, we make the simple assumption that these losses are around 40% of the total value of residential, commercial and industrial losses (see Hallegatte et al 2008b). Table 7 gives an estimate of the total direct losses including infrastructure losses.…”

“…For this study, we introduced three main modifications in the ARIO model initial setting, which is used in the Copenhagen case study in this project (Hallegatte et al, 2008b):…”