Posted by: ericgrimsrud | March 25, 2019

Underappreciated point made by Greta

Concerning her scientific knowledge, Greta Thunberg appears to know a lot more than most. For example, at about 3.4 minutes into her speech, Greta made a very important comment that I believe is not generally understood by many. Therefore, I will take this opportunity to explain it further.

While addressing the paucity of media coverage concerning global warming, one of her examples was “nor does anyone in the press mention that existing air pollution is hiding a warming effect – which when we stop burning fossil fuels, will add an additional increment of warming, perhaps as high as 0.5 to 1.1 degrees Celsius”. Wow! Think about that for a moment. If true, and there is no reason to think it is not true, even if we stopped all fossil fuel combustion today, we would then immediately add the amount she states to the 1.0 degrees C of warming we have already caused. That would mean that the new global temperature average would immediately be between 1.5 and 2.1 degrees C of warming! Wow again!

So, what exactly was she scientifically referring to by that profound statement? It is this. In addition to the greenhouse gases, our lower atmosphere today also contains pollutants in the form of particulate matter. They have been formed primarily by the oxidation and then condensation of the sulfur dioxide that is emitted from fossil-fuel-burning power plants. Ironically, these sulfate particulates actually have a beneficial cooling effect. They increase the reflection of incoming solar radiation, thereby cancelling out roughly one-third of the heating caused by our excess greenhouse gases. Therefore, as we manage to reduce and then eliminate fossil fuel use, we must also realize that we will be progressively losing that cooling effect – resulting in an increase in temperature on top of that produced by the greenhouse gases.

In addition, increased particulate matter also affects our clouds, causing them to also reflect more incoming solar radiation back into outer space. The effect of these clouds on heating constitutes one of the least well understood aspects of global warming. This fact leads to the large uncertainly of expected additional heat stated by Greta, from 0.5 to 1.1 degrees C. In any case, that is a lot of additional expected heating – as a consequence of stopping fossil fuel use – something we must nevertheless do in order to prevent increased levels of CO2.  Oh what a web we have woven!  No wonder Greta is so concerned – she knows the science involved.

My point in this post is to compliment Greta on her consideration of even the scientifically complex aspects of climate change.  Hopefully, discussions such as this one of Greta’s comments will increase the public’s knowledge of the global warming problem.  Perhaps even the media is now aware of the very important point Greta made’.


  1. I love Greta’s comment that some people (who discuss climate issues) “don’t even know the Keeling curve”. After all, some of her genes come from Svante Arrhenius!

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