Carbon dixode in the atmosphere and its effects

Carbon dioxide has the greatest effect of all the greenhouse gases on climate change, simply because it is the most prevalent. Methane has a greater effect per volume, but there is simply so much carbon dioxide around that its effects overweighs all the other greenhouse gases combined.  That is why measurements of atmospheric carbon dioxide are probably the most significant indicator of the effect of human activity on climate change, because one way or another, humans cause the emissions of carbon dioxide more than any other climate effecting substance.

Some of the best work in measuring carbon dioxide is done by the United States Department of Commerce’s facility at Mauna Loa on the Big Island of Hawaii. There they measure CO2 molecules in the atmosphere in dry air and calculate the concentration as part per million.

There are fluctuations in their readings which are caused by anomalies of weather systems around Mauna Loa but these can be understood by looking at averages and mean readings and by understand the trends that the data reveals.

The Mauna Loa readings are taken at a height of 3,400 metres. Readings taken at the surface or at much higher altitudes will differ. In 2008 concentrations varied between 389ppm and 385 ppm and there is a possible error factor of plus or minus 0 .11pmm. 250 years ago the concentration was thought o be around 280pmm. Since 1966 the growth rate has been more than 1% per annum except for two years, but every single year since 1959 has recorded a growth in CO2 concentrations.2007 recorded a mean growth of 2.14%.

Most climate models assume that the forests, oceans and soils of the earth will absorb about half of the carbon dioxide that is emitted but the latest trends are throwing some doubt on those assumptions because it seems that more carbon is staying in the atmosphere and less is being reabsorbed. That may well make the carbon emission targets beloved of Kyoto, the UN World Climate Change Conference and major world governments fall very short of the mark.

Now if you were to round up 389 to 400 pmm and then reduce it you will find that the carbon part of the atmosphere is only 40 parts per 100,000 or 4 parts per 10,000 or 1 part per 2500. Put that way the concentrations sound much less frightening

Should we be concerned? Are we simply measuring something that we now have the science to measure and thereby giving cause for needless alarm?
I do not think so. Most scientists think that carbon concentrations have not been at these levels for 650,000. That in itself is not cause for concern. These seem to be small concentrations, why a concert hall full of people will have more that 400 ppm of carbon in the air without it causing anyone any damage.

Think of it in a different way; imagine that you are in bed keeping your body perfectly warm with three thin woolly blankets. Your body temperature is fine. Without any blankets you would be unbearably cold.

If someone adds another blanket to your bed your body temperature will rise. It may still be perfectly comfortable – perhaps you might get a little sweaty but you can cope with that. Imagine another blanket being added and then another. The cumulative effect of these thin blankets is what causes problems, by changing the stability of what you have enjoyed. You may adapt to the higher temperature but how many blankets need to be added before the heat becomes unbearable to you?

So it is with climate change. We might not know exactly how many blankets but we do know if we keep piling them on the bed eventually something will go wrong.

Do not be fooled by small numbers – they are significant. If you were exposed to 800 parts per million of carbon monoxide for four hours you would die. If you breathe a similar quantity of cyanide you would die. Dangerous things are around us every day in every aspect of our lives. They do not usually harm us because they are in small quantities. But if you make some of those small quantities a little bit larger they become life threatening.

If we can find ways to stabilise the volume of carbon dioxide in the atmosphere we should do so.

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