Every breath you take: Population growth v CO2

The link between climate change and CO2 might not be as simple as people think. Has anyone taken into account human population, respiration and CO2 concentrations?

Every breath you take: Population growth v CO2

First off, this is not a 'climate-sceptic', 'climate change denier' or any other kind of anti-climate-change piece.

I do admit that I am not totally convinced of the science being “absolutely” proven - there are simply too many variables in the atmosphere to model it accurately in a human lifespan - but I do agree there is something weird going on with our weather. Especially sat here in Scotland in January with bugger all snow on the hills and temperatures recently being up into double-digit centigrade (10C in Stornoway, for instance).

One of my problems with the whole “climate change” thing is quite simple really. Global climate has been changing constantly since the first atmosphere condensed from the ball of molten rock and gas that Earth formed from four and a half billion years ago. Concentrations of all of the various gases that make up that incredibly thin layer we call the atmosphere have been constantly varying and it wasn't until around two billion years ago that Oxygen appeared as a free gas in the atmosphere. Add to that the fact that mankind has been altering the global climate for the last 7,000 years through permanent agriculture and you get a very different picture to the idea that the past 50 years are the be-all-and-end-all of climate change.

Then there is the total politicalisation of the entire subject. People go on about how “big oil” funds anti-climate change research but no one actually mentions the amount of money that green groups pump into research. I am now at the point of thinking that there is no such thing as truly 'independent research', as someone is funding it and if you (the scientist) want to continue getting funding, you have to 'toe the line' expected by the funders. Adding politicians to the mix only makes it worse, so now we have a situation where a single gas is being totally blamed fro everything that is going wrong in the world. Particularly because it is relatively easy to tax.

There is a gas I hasten to add that every living thing on this planet exhales all day, every day. It is NOT a pollutant, it is a naturally-occurring gas produced by a 100% organic process. Sat reading this, dear reader, you are exhaling 0.24litres of CO2 per minute (on average), so every four minutes you have added one litre of CO2 to the atmosphere. Now, think on this: there are seven billion people currently living on the planet. That's a lot of CO2 being exhaled.

This leads me nicely into my discussion today: has anyone actually taken account of how much CO2 has been added to the atmosphere by human respiration in the past 200 years? If we think that, in the year 1800, human population hit one billion; had doubled to two billion by 1930 then doubled again by 1974; currently stands at approximately seven billion in 2016 and will only take 13 years to get to eight billion - it is fair to say that there are a lot of humans that have lived and are living on the planet, which equals a lot of respiration and a lot of CO2 being exhaled.

If you look at the graphs in the image alongside this blog post, even a layman will see that there is an almost identical trend between population growth in the lower two graphs and the concentration of CO2 in ppm in the atmosphere in the top 2 graphs. If you could superimpose one on the other, I think they would match perfectly.

Now, I agree that the increase in CO2 concentration in the atmosphere is not just due to the explosive growth in human population. As population has grown, we have demanded more and more energy. As technology has developed and changed, even more energy has been demanded and as countries develop energy demand grows even more. In our technological, industrial, advanced society, the average person demands between 180 to 300kWh (a 'unit' of electricity on your domestic energy bill) of energy per day.

The UK, on average, has a constant demand for electricity between 30 to 50GW - that's 50,000,000,000 watts (thanks to Richard for pointing out this glaring error). To put that into context, that is 25 million kettles boiling water for a cup of tea ALL THE TIME. As much of this energy has been obtained by burning of hydrocarbons, it is fair to say that a significant proportion of the CO2 increase is due to this. But in all the climate change hysteria, has anyone calculated how much CO2 is from increased agriculture to feed the constantly-growing population? Remembering that livestock and crops all respire and exhale CO2 - how much of the CO2 is due to land use change, in particular, cutting down trees? And how much is from every breath we take?

The graph in the middle of the image shows the 400,000-year profile for CO2 concentrations. Four times in the past 400,000 years, CO2 concentrations have crashed. If you saw a crash like that in the stock markets... hang on, we HAVE seen crashes like this, twice in the past 16 years. Twice, CO2 concentrations returned to around 300ppm and, since the last crash (around 150,000 years ago), CO2 returned to about 280ppm and levelled off. It plateaued until 1769 when James Watt patented his “separate condenser to improve steam-engine efficiency” thereby stimulating the Industrial Revolution. Thirty-one years later, we see the start of the explosive growth in human population and the start of the exponential rise in CO2 concentration which appears as the runaway curve in the middle graph.

So the increase in CO2 concentration can be inherently linked to human population growth. Therefore, if we can somehow find a way to manage human population and stabilise it at 10 billion (for the sake of argument, as it is a round number and likely to be achieved before 2100 at the current rate), will we see the concentration of CO2 stabilise again but at a significantly increased amount? Given that we are already reducing our reliance on hydrocarbons for energy and if we plant more trees (not just as forests but also in our towns and cities) as well as preserving the forests we still have; is it inconceivable that CO2 concentrations might actually show a slower increase before stabilising as population stabilises then slowly decreases? Might we see another CO2 crash as has happened previously? If so, what then? The next ice age?

If the Industrial Revolution had not happened, would population have grown so fast? If it had, would CO2 concentrations have risen as fast or to as high a level? Without the Industrial Revolution, I doubt we would be seeing 400ppm, but I do think that we'd see higher than 320ppm as seen in previous highs in the past 400,000 years. Humanity would still have burnt hydrocarbons after all, but maybe not in as high a quantity that we do today; coal fires to keep warm, oil lanterns to read by, for instance.

Finally, after all this talk of CO2 and “every breath you take”; is it possible that we have been demonising the wrong gas? Could it be methane that is the real culprit? Could that juicy steak really be to blame? Does anyone have a graph measuring CH4 vs cows?


Topics: Climate change
Tags: agriculture | CO2 | coal | energy bill | gas | population | Scotland | technology | water | weather
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