Climate Change Accounted for $8 billion of Hurricane Sandy Losses: Study

Sea level rise caused by carbon emissions accounted for approximately 13% ($8.1 billion) of the $62.7 billion in losses incurred by New York, New Jersey and Connecticut from Hurricane Sandy, according to a study published by Nature Communications.

The study’s authors, led by researchers from Princeton, NJ-based Climate Central, Stevens Institute of Technology, and Rutgers University used historical and alternative sea level reconstructions, plus flood simulations to determine how much climate change contributed to damage inflicted by the 2012 storm. They found that human-caused warming had raised New York-area sea levels roughly four inches over the century preceding the storm—enough to extend coastal flooding further inland and deepen flood waters everywhere, increasing damage to submerged structures. The heightened water levels allowed Hurricane Sandy’s storm surge to reach 36,000 more homes and affect 71,000 more people, according to the study.

The $8.1 billion estimate represents the midpoint (50th percentile) in the range of losses attributable to human-caused climate change. The study found that no less than $4.7 billion (5th percentile) in losses—and as much as $14.0 billion (95th percentile)—were caused by sea level rise linkable to greenhouse gas emissions.

The study, Economic Damages from Hurricane Sandy Attributable to Sea Level Rise Caused by Anthropogenic Climate Change, Nature Communications (18 May, 2021) is available here: https://www.nature.com/articles/s41467-021-22838-1

Author Quotes

Benjamin Strauss, Ph.D., Chief Scientist and CEO, Climate Central
To request comment, please contact Peter Girard (Climate Central): pgirard@climatecentral.org (609-986-1999)

Just a hands-width of sea level rise from climate change caused more than 10 percent of the damage from Sandy’s towering floodwaters. The implications are enormous. For any lesser ocean flood, the percentage must be higher. Human-caused sea level rise is already making every coastal flood more destructive and costly. Our approach can be applied to other past or future storms or even just the high tide flooding that’s becoming so common around the world. The costs of climate change are likely much greater than we appreciate today.

Daniel Gilford, Ph.D., Postdoctoral Associate, Rutgers University and Climate Scientist, Climate Central
To request comment, please contact Peter Girard (Climate Central): pgirard@climatecentral.org (609-986-1999)

The human impact of climate change is clear and costly. Emissions of greenhouse gases have warmed our atmosphere and oceans, melting ice and expanding water, resulting in increasing sea levels over the past 100 years. This human-caused sea level rise drove higher flood levels during Hurricane Sandy, increasing the costs of damages by about thirteen percent in New York, New Jersey, and Connecticut. As the effects of climate change grow more frequent and more severe, documenting human impact (as we have done here) is critical to understanding and reducing our adverse contributions to the climate system.

Philip Orton, Ph.D., research associate professor, Stevens Institute of Technology
To request comment, please contact Thania Benios (Stevens Institute of Technology): tbenios@stevens.edu, (917-930-5988)

This study is the first to isolate the sea level rise effects attributable to human activities and put a dollar sign to the additional coastal flooding damage they cause. If we were to calculate the costs of all coastal flooding damage they cause, it would provide clarity on the severe damage we are inflicting on ourselves and our planet and hopefully add urgency to doing more to prevent it.

Table: Hurricane Sandy Losses Attributable to Human-Caused Sea Level Rise

Key Points

  • Hurricane Sandy struck the northeast U.S. coast in 2012, causing widespread damage estimated at $62.7 billion. The key finding of this study is that about $8.1 billion of this damage (~13% of the total) resulted from the increased flood heights reached due to human-caused sea level rise. 
  • About 71,000 more people experienced flooding during Hurricane Sandy than they would have in the absence of human-caused sea level rise; and about 36,000 more houses were exposed to flooding.
  • In the case of Hurricane Sandy, the higher sea levels in New York, New Jersey, and Connecticut meant that the storm surge could penetrate further inland than it otherwise would have been able to, and was deeper throughout the affected area, causing more damage than would have been expected in a world without sea level rise.
  • Estimates of economic damages due to climate change for individual extreme weather events are exceedingly rare. This paper may be the first instance of such an analysis based on human-caused sea level rise.
  • It is notoriously challenging to attribute human influences on single weather events. In this study, researchers used two independent modeling and budget-based approaches—which produced similar findings—to estimate human-caused sea level rise in the New York area, then performed flood/damage modeling to produce a range of estimates of how much more damage from Sandy in the area resulted from sea-level rise since 1900.
  • The researchers can say with confidence that human-caused sea level rise in the New York area over the past 100 years amounts to roughly four inches, or about 55% of all sea level rise observed in the area since 1900.  
  • Attributable damages could have been as high as $14.0 billion or as low as $4.7 billion, but we know with high confidence that the figure is far more than zero.

Context

  • Human emissions of greenhouse gases have warmed both the atmosphere and ocean over the past 100-plus years. As the ocean has warmed, the water has expanded and sea levels have risen. Simultaneously, a hotter atmosphere has caused ice sheets and glaciers around the world to melt, dumping more water into the ocean and driving sea level rise.
  • As environmental disasters mount in the face of climate change, understanding the extent of human influence can be important for a number of reasons, not the least of which is that it could inform future policy.
  • New York, New Jersey and Connecticut collectively reported a total of $62.7 billion in repair, response, and restoration costs from Hurricane Sandy; respectively $32.8 billion (New York), $29.4 billion (New Jersey), and $360 million (Connecticut).
  • Researchers restricted this study to impacts from human-caused sea level rise. If climate change strengthened Sandy or influenced its track, climate change’s total effect on damage inflicted would likely have been greater, but this analysis confines its scope to a controlled, isolated picture of what we can say with high confidence based on attributable sea level rise alone. FEMA models indicate that wind during Hurricane Sandy caused less than 0.01% of damage in these states, so nearly all costs can be attributed to coastal flood damages (Federal Emergency Management Agency, 2013).
  • Sandy disrupted tens of thousands of lives across the New York and New Jersey region. Scores of public housing units in Queens and Brooklyn remained without light and heat for days. Hundreds of disabled and elderly nursing home residents were evacuated to emergency shelters, with some families searching for them for weeks.
  • According to the Hurricane Sandy Rebuilding Strategy report (2013):
  • 650,000 homes were damaged or destroyed
  • 6,477 storm survivors were in shelters at the peak of the disaster
  • 43% of those registered for FEMA assistance were renters:
  • 64% of renter registrants from New York were considered low-income
  • 67% of renter registrants from New Jersey were considered low-income
  • 200,000 small business closures were due to damage or power outages 
  • 2 million working days were lost
  • $58 million in damages were related to the recreational fishing sector
  • There is no conclusive evidence that Sandy’s intensity, size, or unusual storm track were made more likely by climate change. 

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