rare-earth and semiconductor pipelines could overwhelm the defenses, in which case water would mitigate impacts by holding higher inventory levels reach infrastructure that was previously safe. and by sourcing from different suppliers across multiple regions. This can be done efficiently. We estimate that a 200-year flood today (that is, a For buyers of semiconductors, for example, flood of 0.5 percent likelihood per year) in Bristol raising inventory to provide a meaningful buffer would cause infrastructure-asset damage totaling could be cost effective, with estimated costs for between $10 million and $25 million. This may rise warehousing and working capital increasing input to $180 million to $390 million by 2065. The costs costs by less than 1 percent. Nonetheless, the of knock-on effects would rise even more, from price of climate prudence will almost always be $20 million to $150 million today to as much as $2.8 some decrease in production efficiency—for billion by 2065, when an extreme flood might shut example, by creating limitations on lean or just-in- down businesses, destroy industrial stores, and halt time inventory. transportation. Can coastal cities turn the tide on rising We estimate that protecting the city from this 2065 flood risk? scenario would cost $250 million to $500 million Many coastal cities are economic centers that have today. However, the actual costs will largely depend already confronted flood risk. But the potential on the specific adaptation approach. direct and knock-on effects of flooding are likely to surge dangerously. Vietnam’s Ho Chi Minh City is prone to monsoonal and storm-surge flooding. Today, the direct Bristol is a port city in the west of England that has infrastructure-asset damage from a 100-year flood not experienced major flooding could be on the order of $200 million to $300 for decades. But without major investment in million, rising to $500 million to $1 billion in 2050. adaptation, extreme flood risk there could grow Here, too, the knock-on costs in disrupted economic from a problem potentially costing millions of dollars activity are expected to be more substantial, rising today to a crisis costing billions by 2065. During very from between $100 million and $400 million today high tides, the Avon River becomes “tide locked” to $2 billion to $8.5 billion in 2050. and limits land drainage in the lower reaches of the river-catchment area. As a result, Bristol is Many new infrastructure assets in the city, vulnerable to combined tidal and pluvial floods, particularly the local metro system, were designed which are sensitive to both sea-level rise to tolerate an increase in flooding. Yet the hazards and precipitation increase. The likelihood of both are to which these assets may be subjected could be expected to climb with climate change. greater than even the higher thresholds. In a worst- case scenario, of 180 centimeters of sea-level While Bristol is generally hilly and most of the urban rise, these thresholds could be breached in many area is far from the river, the most economically locations, and some assets might be damaged valuable areas of the city center and port regions beyond repair. are on comparatively low-lying land. More than 200 hectares (494 acres) of automotive storage near the Compared with Bristol, Ho Chi Minh City has many port (often harboring up to 600,000 vehicles) could more adaptation options, as less than half of the be vulnerable to even low levels of floodwater, and city’s major infrastructure needed for 2050 exists the main train station could become inaccessible. today. But adaptation may carry a hefty price Bristol has flood defenses that would prevent the tag. One potential comparison is Jakarta’s major vast majority of damage from an extreme flood event coastal-defense plans, which have a potential cost today. By 2065, however, more extreme floods could of roughly $40 billion. That is comparable to Ho Chi Minh City’s current GDP. 102 What now? Ten actions to emerge stronger in the next normal September 2020