City Risk vs. Readiness
Overall risk and readiness scores measure 
how well cities perform on all of the 
indicators, irrespective of the type of 
environmental hazard.
Ideally, we would want to observe a positive 
correlation between these measures: If a 
city is highly vulnerable, being prepared 
would help the city adapt to a climate-related 
hazard. Unfortunately, we found a significant 
negative correlation of -0.29 between risk 
and readiness scores, meaning as risk scores 
increased, readiness scores decreased.
In other words, the cities that are most 
vulnerable are also the ones that will be 
the least prepared for a climate-related disaster. 
We identified cities with the biggest difference between risk rating and readiness: This metric helps us 
identify which cities are more vulnerable and less ready to adapt to climate-related events. When we 
rank the cities based on difference scores, Santa Ana again ranked as the top, followed by Hialeah, 
Anaheim, Miami, and Newark. 
We also compared coastal cities and inland cities in terms of their risk and readiness scores. On average, 
coastal cities have statistically higher risk scores (49.4) than inland cities (40), meaning that coastal cities 
are more vulnerable to climate change. However, coastal and inland cities did not differ in their 
readiness scores. 
This means coastal cities are more vulnerable and sensitive to climate change-related events than inland 
cities, but they show similar levels of preparedness.
Note: High risk does not mean that a climate change event will happen in these cities; rather, these results 
suggest that if any of them experience an extreme climate event, they will likely be impacted worse than 
others. To measure the overall impact of climate change, we incorporated ND-GAIN's probability metric 
to assess the likelihood of a climate disaster occurring.
Defining Our “High-Impact” Metric
For each extreme climate event, we developed a Climate Change Impact Metric to rank cities (i.e., “highest impact”). 
We first ranked the 100 most populated cities on the three previously introduced metrics: probability of the 
extreme event, risk, and readiness. We then weighted the “probability of the extreme event” .6 and “risk score” 
and “readiness score” .2 each and added those measures together to calculate our Climate Change Impact Metric. 
The probability of the extreme event is weighted more because we wanted to prioritize the possibility of the hazard 
occurring in a particular location. Vulnerability to and preparedness for disasters are important metrics, but the 
probability of an extreme event should take precedence when assessing the overall impact of climate change to 
a particular city. 
Higher scores on this metric indicate higher impact (e.g., a score of 100 would mean the highest ranking on 
probability, the highest ranking on risk, the lowest raking on readiness). 
Here are the results, where a higher score indicates the greater impact of a particular hazardous weather event 
on a city.