Evaluating information – in this case, climate information

I’m kind of on a little project that entails exploring some ideas and approaches. One day I decided I would ask CoPilot sources of data on temperature. I wanted something on historical sources of data for heat indexes because it seemed that May was unusually warm. It seemed like Texas had heat waves a little too early. CoPilot replied back with some really interesting sites to explore.

I’ve done this before with the search engines and had never received interesting results before, so that is kind of one of the advantages of using one of these AI engines.

I went through some of the links to peruse the sites to see if I could use some of the data and I came across one site that sort of implied that there is no evidence that heat waves are becoming more frequent.

At least, that was how I read it upon first reading it. Here’s the specific wording that stuck out in my mind:

In recent decades in the United States, heat waves have been far less frequent and severe than they were in the 1930s.

Climate at a Glance, U.S. Heatwaves (climateataglance.com)

Technically, that sentence is correct because the 1930s had an extraordinary event leading the name of the Dust Bowl. But the bold face led my brain to interpret that to mean that the frequency of heat waves is not increasing. When I read that phrase, I thought, “Oh, that’s interesting. That’s different from what I have read elsewhere.”

So, I decided to investigate that site further to see what evidence they provide.

Source Data

After much perusal and digging, I find that the data the Climate at a Glance site was relying on was one that I had been pulling information from (the NOAA), which struck me as odd because when I pull temperature data from that site, I get indications that temperatures have been rising. I’ve been pulling temperatures though, not heat waves, which would necessitate a more complicated set of calculations. Heat waves have been roughly defined as a number of days – generally 4 or 5 days – where the temperature average of those days is higher than what would normally be for that time of year. Some definitions have 5% higher than normal, some have more or less days, but that is the general definition.

But I did think that if the temperatures have been rising, then it is possible that heat waves could become more frequent. I think it will depend on how you phrase your definition of heat wave, like what would be the normal temperature for that time period.

I went searching for other sites discussing heat waves and so far, they all point back to either the NOAA site with their database on temperature index, the same site that Climate at a Glance was pointing to OR the EPA site where they had requested research on heat waves: Climate Change Indicators: Heat Waves | US EPA. I believe this is the site that Climate at a Glance pulled one of their charts. And EPA’s data source? I think came from NOAA.

The NOAA appears to be the prime source of information for temperatures but discussion about heat waves came primarily from the EPA.

Temperature Anomaly NOAA Data Source

Climate at a Glance posted a chart that came directly from NOAA. Here’s the chart:

Looking at that chart, I can’t really see temperature increases. I was having that same problem earlier when I played around with the raw data from NOAA: I was having hard time clearly seeing temperature increases without fear of pushing what I was seeing. This graph kind of looked similar to what I was getting in the last month or so. But we are looking at a very constrained timeframe: Jan 2005 to August 2023. Climate change isn’t going to happen in twenty years.

The bitly provided by Climate at a Glance for that chart is if you want to investigate it: https://bit.ly/3JZfqzg

Or: National Temperature Index | National Centers for Environmental Information (NCEI) (noaa.gov)

If you want to play around at the NOAA site and try to obtain that chart or as close as you can, set up your parameters as:

Hit the Plot button and you should get something roughly like:

Timing is going to be different. There are these irritating markers, and the end date is April 2024 on my chart whereas the chart at Climate at a Glance ended in August 2023. At the bottom of the main chart, you will see a “slicer” where you can “slide” the date.

You can also toggle off the ClimDiv series by clicking on the blue legend. The chart below is starting to look very similar to the version shown at Climate at a Glance.

Comparing with my other NOAA source

Now that I’ve proven to myself that that is the data Climate at a Glance is using, I wanted to see how the temperature data that I had been pulling compared. They are also from NOAA but from somewhere else on the site. The information should be the same, but it is coming from the raw data rather than some prettified plotted version.

Here’s my graph.

Again, very similar charting results except I ended in December 2022 for reason that I couldn’t very easily make the pivot chart end in August 2023. I could end at the year end, not in the middle of the year, due to construction of data. But this suffices to show me that the chart looks very similar to the one Climate at a Glance had on their site.

Evidence of rising temperatures

So far, it’s hard to see evidence of rising temperatures. But we are only covering less than 20 years.

So, I did a version that covers all of the months/years of capturing temperature data, going all the way back to 1895.

It may be hard to see but if you squint closely, you can see temperatures rising at the end.

Sometimes looking at things at a daily basis can hide trends so stepping back at a higher level can help. Think of the stock market with the noise from the daily gyrations of stock prices often hiding trends. Same thing might apply here, so I did another version where I just graphed the average temperature for each year rather than plotting the average monthly.

Yeah, it gets dramatic. I had to check the numbers and it appears to be right – at least the calculations from the raw numbers. It’s highly suggestive of rising temperatures and a lot of my graphing (at state levels, at decade levels, etc.) show that upward trend in 21st century.

What EPA/NOAA says

Climate at a Glance said that heat waves are less frequent that the 1930s. When I investigated that site, I found that the “sponsor” is regarded as a climate denier, so that is the perspective of that site.

The EPA said:

Heat waves are occurring more often than they used to in major cities across the United States. Their frequency has increased steadily, from an average of two heat waves per year during the 1960s to six per year during the 2010s and 2020s (see Figure 1).

EPA, Climate Change Indicators: Heat Waves | US EPA

Very different conclusion.

The EPA did show a chart that clearly demonstrated that the 1930s was an outlier, far exceeding other decades. Climate at a Glance included that chart in their site.

The EPA had that same chart, and they were upfront about the fact that the 1930s were extreme.

Conclusion

Before absent-mindedly just accepting the conclusions, we need to do some deep research on the following:

• the known perspectives of the author (in this instance, Climate at a Glance is “sponsored” by an institute whose orientation is towards climate denial.)
• find the source of the data (here, the NOAA had the raw data, EPA had the research using NOAA data).
• maybe play with the data if you can
• dig deep into the sites.