Can’t see a problem in the middle of a greenhouse? CO2 clouds the mind – from 1000+ ppm

Hypercapnia it turns out, develops much more gradually than previously assumed. Apparently long before we pass thresholds that mean real medical trouble, our bodies – and our minds – can be disturbed by elevated CO2 levels in the air around us.

CO2 levels hypercapnia
Decision-making is impaired from 1000 ppm onwards [that’s only about 2.5x current atmospheric levels] and test subjects become ‘dysfunctional for taking initiative and strategic thinking’ at levels around 2500 parts per million CO2 per volume of air – Berkeley Lab researchers say.

We will not experience such concentrations in our planet’s atmosphere any time soon, but in poorly ventilated homes and office buildings that could be a different story. [Easiest remedy when you’re stuck to a totalitarian air conditioning protocol (‘cannot, may not & will not ever open a window’) is fire half the (breathing) staff to increase overall productivity].

CO2, perfectly harmless, you breath it!

You may have heard people ‘on the other side’ of the climate debate say something like ‘CO2 is a perfectly harmless gas’ – as if the biological property of toxicity was at question (in a climate debate) instead of the physical property of heat absorption [as we’ve known since quite some time it is a greenhouse gas – see this chronology of CO2 (as appendix at end of article)].

CO2 is indeed a totally harmless gas – in the sense that it is essential to life (the formation of biomass hydrocarbons and carbonates), and quite often even beneficial, meaning elevated CO2 concentration could promote (plant) life, through a route known as the CO2 fertilisation effect. Only in extremely high concentrations* is CO2 a poisonous gas to humans.

[*) These concentrations do occur, extremely rarely, at sites where underground CO2 stores suddenly leak to the atmosphere – with only two known cases in which such a phenomenon has resulted in human casualties, both in Cameroon, both originating from deep disturbances in a volcanic lake, in 1984 Lake Monoun (the CO2 leak killed 37 people) – and two years later around Lake Nyos. This was a true disaster, with an underwater eruption that created tsunami-like waves and that emitted large quantities of volcanic gases. CO2 poisoning may have killed (by suffocation) an estimated 1700 people at that event. Of course  almost classically, and largely ungrounded  such poisoning CO2 leaks are the popular CCS concern.]

So other than usually being off the point of any relevant debate – it’s a perfectly sensible remark to say CO2 is non-toxic.

Moderately elevated CO2 impairs range of cognitive abilities

But not today. Today we throw things around. Firstly it isn’t off the point, as CO2’s toxicity is for a change in fact exactly the subject – and secondly because it turns out that the gas may not be so harmless after all, even in very moderate air concentrations.

This we learn from researchers of the US Lawrence Berkeley National Laboratory who together with colleagues of the State University of New York have found CO2 exerts a physiological influence at levels that are 10 to 20 times lower than previously assumed – as we can deduce from their publication in Environmental Health Perspectives.

CO2 strategic thinkingIn their study the scientists had subjects tested on 9 scales of decision-making performance. At an elevated CO2 air level of 1000 ppm decision-making was significantly impaired at 6 of these. When CO2 levels were raised further to reach a concentration of 2500 ppm – decision-making ability was largely reduced on 7 of the scales. Both strategic thinking and cognitive initiative were in essence no longer possible – see also score difference in image to the right.

Dragging days in ill-equipped meeting rooms

Ironically, whereas normally in office buildings CO2 levels stay below 1,000 ppm, that value is most-often surpassed in meeting rooms, as these are often small, packed with people, and lacking (open) windows.

In classrooms, the researchers write, concentrations frequently exceed 1,000 ppm and occasionally exceed 3,000 ppm.

Atmospheric CO2 concentrations have risen by around 40 percent from about 280 ppm in preindustrial times, to on average some 390 ppm in 2012.

Our secret tip…!

When you’re having a hard day at the office and suddenly feel you’re losing out on those strategic thinking abilities your boss likes you for – if you can’t find a window, there is another quick fix: hyperventilating. Start breathing in and out – well, especially in, as fast and psyched as you can [and don't use a bag].

Hyperventilation normally leads to hypocapnia – decreased CO2 blood levels (and therefore increased pH, which feeds anxiety). Add your hypercapnic office state, and you’ll be just about fine and neutral for the day.

Don’t thank us. Just forward to friends and colleagues.

© Rolf Schuttenhelm |

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