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Richard Maltzman
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Stupid is as CO2 does

Categories: co2, cognition, forrestgump, stupid

First: an explainer of the title.  Many of you have seen the terrific film, Forrest Gump, and if you haven’t, consider that homework (not work, really!) from this blog post.  Watch it – or re-watch it if it’s been a while.   One of the most memorable lines from the film is, “momma always said, ‘stupid is as stupid does”, meaning that one should make judgements based on actions, not on appearance.

Well, CO2 is invisible, so we cannot judge it on appearance, but after reading this post, you will see that it does have an ability to act, and to act on humans – and unfortunately, that action is to make us stupider.

Some background first

It’s not really up for debate, or at least not the debate of this post – as to whether there is a significant rise in CO2 concentration in Earth’s atmosphere.  And, there’s no longer much debate about the fact that human activities are the cause (that is, that the CO2 rise is anthropogenic).

Figure 1 (above) shows the increase in CO2 in parts per million (PPM) from 800,000 years ago to today.  Of course, there are glacial cycles*, but what you see is a recent, sudden, and meteoric rise – an increase of 50% between 1813 and 2019.  The chart also projects what will happen depending on the mitigation strategies (called RCPs – Representative Concentration Pathways). 

On to the main topic

Even if you debate the causes of the rise shown in the figure, the numbers are there.  The CO2 is up.  What would it mean – or better yet, what DOES it mean – if our CO2 levels are increased.  What does it mean for humans, for projects, for work, if CO2 levels are elevated? 

In this post, I am NOT talking about the other effects of CO2 and Greenhouse Gasses, such as:

  • Ocean acidity
  • Ocean level rise and glacial decay
  • Species loss
  • Climate change

All of those things are, of course, horrific, but here I want to focus only on one aspect of CO2 concentration increase that I’d never before considered, and one that may be of particular interest to project managers, so pay attention!

As you read this, keep in the forefront of your mind that project managers and team members require strategic decision making and higher-level cognitive skills.

I’m talking about the findings from a recently-published article from the American Geophysical Union’s publication GeoHealth called, Fossil Fuel Combustion Is Driving Indoor CO2 toward Levels Harmful to Human Cognition”, by Karnauskas et al, which you will find posted on the US Government’s National  Institutes of Health website.

Here is the abstract of that article:

Human activities are elevating atmospheric carbon dioxide concentrations to levels unprecedented in human history. The majority of anticipated impacts of anthropogenic CO2 emissions are mediated by climate warming. Recent experimental studies in the fields of indoor air quality and cognitive psychology and neuroscience, however, have revealed significant direct effects of indoor CO2 levels on cognitive function. Here, we shed light on this connection and estimate the impact of continued fossil fuel emissions on human cognition. We conclude that indoor CO2 levels may indeed reach levels harmful to cognition by the end of this century, and the best way to prevent this hidden consequence of climate change is to reduce fossil fuel emissions. Finally, we offer recommendations for a broad, interdisciplinary approach to improving such understanding and prediction.


Testing for the effects of indoor CO2 concentration on cognition is nothing new.  As you would expect, military organizations are very interested to know how (for example) submarine crews are affected.  That’s why these studies date back to the 1960s, and indicate that there are significant impacts on cognition if the CO2 levels rise, mainly in the area of:

  • Responding to stimuli
  • Reasoning
  • Processing threats

From the article:

Early experimental studies testing for the influence of relatively high concentrations of CO2 (5–8%) that might be present in confined and enclosed  spaces like submarines found significant  impacts on ability to respond to a stimulus (Harter, 1967), reasoning (Sayers et al., 1987), and threat processing (Garner et al., 2011).

But submarine crews aren’t the only ones who have to respond to threats, use logic and reasoning, and make strategic decisions.  You’ll recognize this as the stuff you need to do each week, maybe every day as a project manager.

More recent studies have demonstrated a tens of percent decrease in cognitive function with increases of CO2 that would occur with double our current concentration of CO2.  That doubling is not too hard to imagine with the current unmitigated strategy with respect to limiting emissions.

Of even more concern is the fact that the effect is stronger for higher-level cognition.  From the article:

It may be that higher‐level, more cognitively demanding tasks are more likely to be sensitive to the effects of moderate levels of ambient CO2.

A study in juvenile rodents found that increased CO2 in the air reduced levels of a neuroprotective growth factor, severely harming brain development, increasing anxiety, and impairing learning and memory (Kiray et al., 2014).

I know that many of you will point out that your project team members are rarely juvenile rodents.  And I know that some of you will point out that you often think of your project team members as juvenile rodents.  Comedy aside, the point remains.

But these are all forecasts.  What about now?  We’re okay, right?


According to the article, which I remind you, is on the US Government’s own NIH site:

On the unmitigated CO2 emission pathway (RCP8.5), we may be in for a ~25% reduction in our indoor basic decision‐making ability and a ~50% reduction in more complex strategic thinking, by the year 2100 relative to today. These results are almost entirely avoidable by reducing global CO2 emissions according to RCP4.5, which is tantamount to achieving the broad goals set forth under the Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC).

...we estimate that our basic engagement and decision‐making ability should have (already) been reduced by about 8% (or 13%, if the urban CO2 dome effect is both entirely anthropogenic and developed over the same time period). It is important to note that this is an estimate of the influence specifically of the rise in CO2 concentration, all other factors being equal.


So our project teams are already likely affected by the increases in CO2. What can we do to prevent this from getting worse?

I’ll conclude the way the article concludes:

The best way to prevent indoor CO2 levels from reaching levels harmful to cognition is through reduced fossil fuel emissions.


*the CO2 level varies only between 172 and 300 in these cycles over hundreds of thousands of years.

Posted by Richard Maltzman on: July 20, 2020 02:00 PM | Permalink | Comments (3)

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