Methodology

Our weather patterns are already shifting, and the occurrence, frequency and intensity of extreme events are likely to change further over time. Therefore, it’s critical that states begin preparing now. States at Risk: America’s Preparedness Report Card is the first-ever quantitative assessment that summarizes the changing nature of weather threats linked to climate change and the corresponding levels of preparedness for related risks in each of the 50 states.

The Report Card’s goal is to spur action by states to recognize risks from the threats they face, to build an action plan, and to implement this plan in order to improve their level of preparedness.  This whole process takes time, but early action will pay off in the future.

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Our Research Approach

This Report Card first identifies a set of threats that are linked to climate change. Then, it identifies the priority threats for each state by assessing the relevance, level and significance of those threats, and defines a core set of actions that states must take to protect people and infrastructure from those risks in each priority threat area. Ultimately, the Report Card assigns grades to each state based on what it has already done as compared to its threat levels and to other states. The climate threat analysis and grading methodology for Alaska and Hawaii differ from those for the lower 48 states due to the use of a different climate dataset. The Report Card leaves the decisions about which actions make the most sense for each state to those officials who know their own state the best.

The Report Card considers five threats: extreme heat, drought, wildfire, inland flooding, and coastal flooding

Examples of the types of risks related to each threat are:

  • Extreme heat — sickness or premature deaths
  • Drought —economic slowdown due to lack of freshwater supply
  • Wildfire — burning structures in the wildland-urban interface
  • Inland or coastal flooding — property damage due to flooding

The core set of actions is divided into four categories: taking action to reduce current risks, and raising awareness of, planning for, and implementing actions to reduce future risks. State actions are evaluated in five sectors critical to modern society, including: Transportation, Energy, Water, Human Health, and Communities, as well as states as a whole.

The reality is that no one can be completely prepared for every contingency that might arise in the future. And a state need only prepare to the level of seriousness of which threats apply to it. But a state cannot be prepared unless it is aware of its threats and related risks; is planning to address them; and is taking action. That is what this Report Card is measuring.

It’s a lot like getting a child ready for a new school year.  Children who know who their teacher is, have a copy of their schedule, bring a backpack, and do the math review over the summer are not guaranteed to ace all their classes. But, they are more prepared for the new school year than children who do not take these actions.

States at Risk: America’s Preparedness Report Card uses a similar approach. It identifies threats that relate to climate change and associated risks, then evaluates whether states are taking a core set of actions to protect people and infrastructure from those risks. The Report Card leaves the decisions about which actions make the most sense for each state to those officials who know their own state the best. Instead, the Report Card is focused on spurring action by states to improve their level of preparedness. This whole process takes time, but early action will pay off in the future.

 

Overview of Climate Threat Analysis Methodology

The Report Card assesses the changing characteristics of five threats related to climate change for the baseline period (around year 2000) through the year 2050 across all 50 states. To analyze climate threats at spatial scales that are more relevant for decision-making, we’re using the latest fine scale climate and hydrology projections based on the high emission scenario (RCP8.5) for up to 29 global climate models derived from the Coupled Model Intercomparison Project 5 (CMIP5) that was referenced in the IPCC Fifth Assessment Report (AR5), plus localized sea level projections based off of AR5’s global simulation. We compute the results separately for each global climate model, and only report the central tendency (median) values.

 

Climate Threat Indicators

We have developed the following indicators to represent each of the five climate threats:

  • Extreme heat — average annual number of heatwave days
  • Drought — severity of widespread summer drought
  • Wildfire — average annual number of days with high wildfire potential
  • Inland flooding — average annual severity of high flow events
  • Coastal flooding — number of people at risk of a 100-year flood

 

Spatial Aggregation

With the exception of coastal flooding, the values for each threat are calculated separately at each grid cell before aggregating to a state-level value. In the aggregation process for extreme heat, wildfire and inland flooding, the sub-state results are weighted according to the sub-state distribution of the state’s vulnerable population. For instance, instead of simply averaging all the inland flooding values across all the grid cells within a given state, the weights applied to average high flow values from each major watershed are proportional to the population living in the FEMA 100-year floodplain in that watershed. Similarly, more weights are given to the extreme heat indicator values in locations with a higher concentration of population under the age of 5 and aged 65 or over living below the poverty line according to 2010 census. For coastal flooding, the population living on land within the baseline or projected 100-year coastal floodplain is totaled. In all cases we use 2010 Census data, and assume that populations remain unchanged. 

With the exception of drought, two state values – an “absolute” and a “relative” measure – are derived for each climate indicator. The former uses the number of vulnerable people as the weighting factor, and the latter uses vulnerable population as a percentage of total state population. It is necessary to account for both of these situations: for instance, vulnerable population may represent 1% of State A’s population and 8% of State B’s population; however, this could mean that State A has 45,000 vulnerable people and State B has 5,000 vulnerable people.

 

Priority Climate Threats Analyzed for Each State

It is particularly important for states to prepare for climate threats that have a certain level of seriousness and are projected to get worse in a changing climate. The emphasis of this Report Card is on climate threats determined to be of considerable magnitude and significantly increasing in the future due to climate change, thus the level of climate preparedness is only assessed for the qualified state climate threats. In the case of coastal flooding, all the coastal states are projected to experience sea level rise, thus are all assessed for their state climate preparedness. For the other climate threats, the number of states assessed for their climate preparedness are:

  • Extreme Heat: 48 states

  • Drought: 36 states

  • Wildfire: 24 states

  • Inland Flooding: 32 states

A climate threat is deemed a priority for the state if either the “absolute” or “relative” measure of the state’s indicator value exceeds a threshold value in either the baseline period or in the future period, and the threat is getting significantly worse in the future.

 

Overview of Climate Preparedness Analysis Methodology

Conceptual Approach

We know that a state’s preparedness relies on whether it is aware of the risks it faces; planning to address them; and taking action.  This premise is the foundation of the Report Card.

We developed the scoring methodology presented below in consultation with an Expert Panel of 5 leading experts in the areas of climate change indicator development, assessment techniques, and state approaches to preparedness.  This group reviewed and refined the methodology prior to launch of the study.  Expert Panel members include:  Dr. Virginia Burkett, U.S. Geological Survey, Dr. Melissa Kenney, University of Maryland, Dr. Thomas Wilbanks, Oak Ridge National Labs, Dr. LaDon Swann, Mississippi-Alabama Sea Grant Consortium, and Ms. Susan Love, Delaware Department of Natural Resources.

States are evaluated against a core set of actions that they must take to be prepared in each threat area, in 5 sectors, including Health, Communities, Transportation, Energy, and Water as well as the state as a whole. Each sector was selected based on the critical role it plays in modern society.

The core set of actions is divided into the following four categories:

1) Is the state taking action to address its current risks from the climate threat?
2) Has the state has undertaken activities to understand its future changes in vulnerabilities and risks from each climate threat?
3) Has the state planned for adaptation to the future changes in risks from each climate threat?
4) Is the state implementing specific actions to address future changes in risks to each climate threat?

Category 1 covers the actions that address climate risks in the present-day, and Categories 2 to 4 focus on those intended to address changes in risks under future climates.  Each category is made up of up to six indicators.  Performance against each of these indicators is assigned a score of 1- 4, designed to reflect the seriousness and rigor with which a state is addressing each of the categories for each of the climate threats and sectors.

For example, a state’s actions regarding awareness of climate threats and related risks are evaluated on the basis of the qualitative and/or quantitative nature of the assessment process employed by the state to understand the timing, magnitude, and geographic extent of the risks. This could range from a qualitative consideration of the information in known climate change assessments from the IPCC or USGCRP (which would receive few points) to a quantitative risk assessment of the climatic changes, and the impacts affecting different sectors of the state (which would receive maximum points).  

For more details on preparedness analysis, see Appendix 1 of the Technical Methodology. 

General Process

The research process behind the Report Card is evidence-based.  Each indicator is first evaluated through extensive web-based research, including reviewing publicly-available documents and state-published web content describing state actions that fall under the 4 categories.  To augment findings from the review of publicly-available documents, representatives from state agencies responsible for the sectors were then interviewed. These interviews filled any gaps in the online research and confirmed findings.

Each indicator is assigned a score based on the scoring rubric.