Exploring the EPA and CEQ Environmental Justice Maps: The Dangers of Mapping and Policy Snowballs

All of the maps in this post can be clicked on to see more clearly.

This is the second in two posts about the Justice 40 Initiative and the EPA and CEQ maps.  The CEQ map is called the “Climate and Economic Justice Screening Tool” while the EPA map is called the Environmental Justice Screening and Mapping Tool.  That’s why I first became curious about these efforts… something like “how many agencies does it take to map screwing in a light bulb?”

For those of you concerned about government duplication and inefficiency, it appears that both maps use the same Front Street data. I’ll talk some more about that data source in another post.

I’d like to call your attention to a couple of things, though.

(1) According to the EPA map, all these topics are “climate change”.  Drought, coastal flood hazard, 100 year floodplain, sea level rise (NOAA), wildfire risk, and flood risk. So it appears that risks may already have climate change already modeled into them.  Fortunately for wildfire we can look at the Front Street results and find they used a reasonable 4.5 scenario. But it’s not particularly clear that all these estimates used the same one, or that they modeled climate the same way. Perhaps it doesn’t matter as EPA says

Screening tools should be used for a “screening-level” look. Screening is a useful first step in understanding or highlighting locations that may be candidates for further review. However, it is essential to remember that screening-level results:

  • do not, by themselves, determine the existence or absence of environmental justice concerns in a given location
  • they do not provide a risk assessment and
  • have other significant limitations.

So they are saying, we mapped risks but .. they may not be accurate? It seems to me that non-ground-truthed maps can lead to a kind of bad mapping snowball, where more and more policies are based on maps which were never intended for that purpose and are.. well.. wrong for what the policy is intended to do.  We have seen that before with scientific papers in which authors use others’ data inappropriately (according to the people who collected it). Mapping also can obscure the differences between measurements and models.  Like is PM 2.5 measured or modeled? You have to look at the fine print to figure that out.

(2) But let’s go back and look at downtown Boulder. The EPA map simply says that it has a 95-100% wildfire risk in case you can’t read the numbers in the graph above.  Below is the CEQ version, which explains the numbers a little better.

So the good news is that both agencies seem to be using the same data, and based on my sample size of one, come up with the same numbers for the same area.  But let’s see what CEQ tells us that the 99 (!!!) percent number means.

Projected wildfire risk

Projected risk to properties from wildfire from fire fuels, weather, humans, and fire movement in 30 years.
Note: the next census tract east is in the 78th percentile for wildfire risk.
So let’s go back to what EPA says “they do not provide a risk assessment”, so what does that actually mean? I don’t believe that there is any probability that fire suppression folks in Boulder County will let a fire run through downtown Boulder in the next 30 years.  So is this risk as if suppression didn’t exist (because it’s hard to model, I grant you that?). Or is  it 99% of something else?
What is the argument for mapping and amplifying (what appear to be) bogus numbers? Why put risk numbers on the map if they are not appropriate for assessing risks?  I think part of this could be a language problem.


Below are some non-wildfire maps I thought were interesting. Asthma, below.

Population over age 64- red is 95-100%. So maybe that actually means 95-100% of the highest number in the US somewhere.. but if so why not use the numbers themselves? Very puzzling.


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