Utilizing situation primarily based stress testing to establish medium (2050) and long run (2100) sea stage rise dangers

This challenge makes use of a situation primarily based qualitative stress testing method to establish US coastal census tracts anticipated to adversely impacted by sea stage rise (SLR) within the medium (2050) and long run (2100). One Baseline and two ‘believable however extreme’ Adversarial eventualities have been designed overlaying 1–7ft of sea stage rise.

The important thing observations by way of this evaluation have been that that outdoors of present FEMA excessive danger areas, there are ~3500 different census tracts alongside the contiguous US shoreline which can be anticipated to expertise a mean SLR improve of 1ft within the medium time period (by 2050). Long term (by 2100) an extra ~1660 census tracts are in danger for two–7ft of SLR. The observations for the medium time period are notably essential provided that they’re anticipated to materialize irrespective of future emissions pathways or different local weather mitigation motion due the warming of the ocean that has already occurred as a consequence of local weather change³.

This challenge predominantly makes use of Python information evaluation libraries, e.g., pandas and geopandas in addition to some visualization libraries, e.g., matplotlib, seaborn. The code for this challenge will be discovered right here. The info for this challenge has predominantly been sourced from the US census bureau and from NOAA. Additional particulars will be present in Know-how and Information part under

Why Coastal Actual Property and Why Sea Degree Rise?

About 40% of the US inhabitants, or ~128 million individuals, reside in coastal counties¹. Whereas residential property normally have been battered by a slew of utmost climate occasions lately, e.g., hurricanes, wildfires and many others., for these coastal residents, one other important rising danger is flooding and property loss as a consequence of accelerated sea stage rise (SLR). Nonetheless, within the exploratory analysis for this challenge, it was discovered that there could not but be a deep understanding of the total prolong of potential SLR impacts. Subsequently, this challenge intends to deliver consciousness to areas anticipated to be impacted within the medium time period (2050) and long run (2100) in numerous eventualities of accelerated sea stage rise.

The Nationwide Oceanic and Atmospheric Administration (NOAA) is a number one US scientific company charged with monitoring oceanic and atmospheric situations². Per NOAA’s 2022 Sea Degree Rise Technical Report³, sea ranges are presently rising at a considerably accelerated tempo in comparison with beforehand noticed ranges within the twentieth century: sea ranges alongside the contiguous US shoreline are anticipated to rise, on common, as a lot over the subsequent 30 years (2020–2050) as they’ve over the past 100 years (1920–2020).

Over the long run (by 2100), SLR projections alongside the contiguous US shoreline fluctuate between 2–7ft on common in comparison with 2000 ranges. The variability in these projections is especially as a consequence of uncertainity about future inexperienced home gasoline emission charges and resultant international warming, which is the important thing driver for SLR. Over the medium time period (by 2050), given the warming of the ocean that has already occurred as a consequence of local weather change³, contiguous US shoreline sea ranges are anticipated to rise between 1.3–2ft on common, irrespective of future emissions pathways or different local weather mitigation motion. Moreover, these larger sea ranges are additionally anticipated to trigger extra disruptive excessive tide flooding (HTF) occasions than occuring at the moment: minor disruptive HTF occasions projected to extend from 3 occasions/12 months in 2020 to >10 occasions/12 months by 2050, and main harmful HTF occasions projected to extend from 0.04 occasions/12 months in 2020 to 0.2 occasions/12 months by 2050).

Challenge Objectives

In gentle of those projections for coastal sea stage rise for the contiguous US, the objectives of this challenge are twofold:

1. To present most people (potential house consumers, mortgage lenders, et al.) a device to visualise the regional impacts of SLR over the medium time period (2050) and long run (2100). Sea stage rise is studied at numerous severities starting from 1ft to 7ft.
2. To supply particular data (FIPS codes) on the census tracts that might be impacted in every SLR severity situation. Homebuyers and mortgage lenders can then issue on this census tract stage location data into their buy choices to entry how a lot of a haircut, if any, they want to apply to their evaluation of property worth.

State of affairs Primarily based Strategy to Assess Lengthy Time period SLR Impacts

Over the long run, given the potential variability in SLR projections, this challenge has been designed as a situation primarily based qualitative stress check. SLR eventualities have been designed primarily based on the ideas utilized within the Federal Reserve Capital Stress Testing train⁴; one baseline situation and two “believable however extreme” eventualities of SLR have been utilized to evaluate how the assorted coastal counties/census tracts throughout the contiguous US could also be impacted at numerous SLR ranges over the long term.

The particular ranges of SLR chosen for every of those eventualities have been primarily based on the 2022 NOAA SLR Technical Report³. Particularly, three NOAA SLR long run ranges are thought-about on this challenge: Low (0.6m or approxiamtely 2ft), Intermediate (1.2m or approxiamtely 4ft) and Excessive (2.2m or approxiamtely 7ft); these projected SLR ranges have been mapped to the qualitative stress testing eventualities as proven under:

• A Baseline State of affairs the place sea ranges are projected to rise 2 ft
• An Adversarial State of affairs the place sea ranges are projected to rise 4 ft
• A Severely Adversarial State of affairs the place sea ranges are projected to rise 7 ft

The Baseline situation is mapped to NOAA’s long run “Low” SLR projection of roughly 2ft. This low projection is predicted to materialize even at low emission ranges with >92% certainity in any respect ranges of world temperature rise3. The Adversarial and Severely Advserse Situations are supposed to be “believable however extreme”. NOAA’s low time period “Intermediate” SLR of roughly 4ft and “Excessive” SLR of roughly 7ft, have been thought-about for the Advserse and Severely Adversarial eventualities respectively. These excessive SLRs are related to larger inexperienced home gasoline emissions and corresponding bigger will increase in international temperatures in comparison with pre-industrial ranges. Excessive eventualities of SLR larger than 2.5m (roughly 8ft) are now not thought-about believable by 2100³ and so the utmost SLR stage thought-about on this challenge is the “believable however extreme” NOAA Excessive SLR of 7feet for the Severely Adversarial State of affairs.

Extra Evaluation for the Medium Time period

Along with long run SLR impacts, this challenge additionally analyzes census tracts anticipated to be impacted by SLR over the medium time period (2050). Over the medium time period, SLR is certain on the decrease finish by 1ft and on the upper finish by 2ft for the contiguous US. Current scientific developments have led to an improved understanding of the elements driving SLR and due to this fact, there’s much more confidence on this narrower vary (no matter the longer term course of emission pathways)³. Attributable to this improve confidence within the SLR predictions over the medium time period, this challenge doesn’t use a situation primarily based method for the medium time period. As a substitute, all contiguous US coastal census tracts in danger for SLR of 1ft by 2050 are thought-about in danger over the medium time period on this challenge.

Evaluation of Present Dangers vs Rising Dangers

This challenge analyzed 20 coastal states within the contiguous United States overlaying ~200 coastal counties and ~22K coastal census tracts inside them. Every census tract was analyzed by way of whether or not is it presently identified to be in danger, i.e., “Present Danger Areas”, vs. if it may very well be in danger sooner or later over the medium to long run, i.e., “Rising Danger Areas”.

The primary a part of the challenge concerned understanding present dangers. By way of sea stage rise, one of many easiest types through which it may present itself could be flooding. The Federal Emergency Administration Company (FEMA) has recognized areas which can be at excessive danger for flooding (FEMA floodplains)⁵ . This challenge used FEMA excessive danger floodplains as a proxy for areas which can be presently identified to be in danger for coastal flooding. On this challenge, these areas are thought-about “Present Danger Areas”.

The second a part of this challenge delved into figuring out census tracts which may be in danger over the medium or long run. This challenge leveraged sea stage rise data from NOAA to establish census tracts that might grow to be an rising danger over the medium time period (2050) or long run (2100), i.e., “Rising Danger Areas”. In an effort to higher perceive the severity of danger of rising sea leveles, rising danger was divided into 4 classes — one class overlaying the medium time period* and three situation primarily based long run categores:

• Rising Medium Time period Danger (1 ft SLR by 2050)
• Rising Lengthy Time period Danger in Baseline State of affairs (2ft SLR by 2100)
• Rising Lengthy Time period Danger in Adversarial State of affairs (4ft SLR by 2100)
• Rising Lengthy Time period Danger in Sev. Adversarial State of affairs (7ft SLR by 2100)

*as given there’s extra confidence within the SLR predictions, no situation primarily based method is required over the medium time period.

Key Observations

The important thing observations by way of this evaluation have been that that outdoors of present FEMA excessive danger areas, there are ~3500 different census tracts alongside the contiguous US shoreline which can be anticipated to expertise a mean SLR improve of 1ft within the medium time period (by 2050) and long run (by 2100) an extra ~1660 census tracts are in danger for two–7ft of SLR.