I might regret this but I have decided to pen a piece on “global warming”; or to be technical Anthropogenic Global Warming (AGW) or to be melodramatic Catastrophic Anthropogenic Global Warming (CAGW).
Why do it? Because I fed up with the rubbish being peddled by the media.
For those who don’t know I was first and foremost a scientist (a chemist in fact) and whilst I’m now retired science is still a subject close to my heart. Science is about collecting data, developing theories from those observations, making predictions based on those theories and seeing whether the theory is correct ( ie the predictions come true) – and when things don’t work out as expected refine the theory until it does work or drop the idea and look at something else. Whilst many scientists still adhere to this tried and tested method of establishing what is going on in the natural world some seem more interested in headlines – either for fame and fortune or simply to keep the research funds rolling in. Whatever; it is the headline seekers that seem to get the attention of the news media and politicians and their views and predictions, however flawed, can become “fact” in the public eye.
Around 30 years ago I was convinced by the claims by scientists that increases in carbon dioxide would warm our planet, the ice would melt, sea levels would rise and we needed to grow fins and gills……. or move to higher ground. The would be a local upside as Deal became Mediterranean in its climate and if sea levels rose enough the water would flow into the valleys around Kingsdown giving them a fjord like feel; I was looking forward to opening a marina at the bottom of my garden (though for that to happen sea levels would have to rise 60 feet or so).
The threat of rising sea levels was a factor as to why my wife and I didn’t buy a house in the Sandwich area (that and the house we were looking at not having a mains sewage system) and why I wouldn’t consider living in North Deal (having seen it flood in 1978). Needless to say the house in Sandwich is still there and hasn’t been flooded once in the following 27 years, and neither has North Deal. I can’t say what happened to the sewage system.
So why was I a believer back then? Simple, I knew carbon dioxide was a greenhouse gas, coal and oil was being consumed at ever increasing rates and when men of science said something I listened and believed. Seems naive now.
Now roll the clocks forward 30 years to the present.
I started to get really interested in global warming when I started bird watching. Was global warming affecting our bird population or not. Listen to the BBC and the RSPB and the answer would come across loud and clear - it was the reason for any and every decline in bird numbers being seen (and anything else going on in the world for that matter). However the more I read the more convinced I became that there was not a lot of truth in what was being claimed and it became clear that those predicting our future climate were, to say the least, prone to exaggeration and hype.
My first study was when British (mainly Scottish) seabird colonies had a string of terrible breeding seasons and a warming sea around our coast was cited as the cause (a local manifestation of global watering). But I knew no such problem was occurring in the warmest seas around these islands (West Wales) so I had a look at the data. My conclusion? Yes the sea have warmed a little but it was over fishing that decimated the North Sea sand eel population and caused the poor breeding success of the sea birds; it was nothing at all to do with global warming. (I posted a blog on this a few months ago).
Some of our common birds, especially farm birds, are also suffering a marked decline in numbers. Reason given? Global warming. Again I couldn’t understand why birds that live and breed successfully from the Mediterranean to Scandinavia would be affected by a degree or so of temperature change. For those birds on the limit of their range a small change in temperature may well cause a rise or fall in population (eg Dartford warbler; a couple of cold winters and their population plunges) but it just didn’t make sense for those that live across wide temperature zones.
So I started looking at the data and the more I looked the less convincing the arguments looked.
And so to the point of this little essay - what is happening to global temperatures?
Oh such a simple question but one where the more you think and read about it the more difficult and confusing the picture becomes.
Firstly it is remarkably difficult to determine what the actual global temperature is. A lot of the planet is uninhabited, a lot covered by sea, or ice, or deserts, etc consequently huge gaps exist in temperature data. These gaps have to be filled with estimated values to build up the global picture - not exactly black and white. A lot of weather monitoring stations are also in towns or airports and these areas exhibit increases in temperature over the surrounding countryside due to human activities (the “heat island effect”) so again adjustments have to be made. All in all an estimate of the global temperature involves a lot of estimates and adjustments.
In these days of satellites it should be easier to get an overall global picture of what is happening but I don’t know enough about what it is they are measuring from up there – the temperature at ground level being much higher than those a few thousand feet up and above 10-12,000 feet it is bloody cold all the time. Also the data doesn’t go back very far.
So with all these caveats here’s what’s going on with the temperatures.
The above chart shows what is believed to be the global temperature variation over the last 450,000 years and was cribbed from “Watts Up With That” http://wattsupwiththat.com/2014/01/25/when-did-global-warming-begin/#more-102114 who cribbed it from somewhere else (see the Watts Up With That ref). I say believed because it is estimated from materials trapped in ice cores. Anyway let’s just assume these are correct because if we don’t there’s nothing to discuss!
In these charts temperature has been plotted against the “normal temperature” so warmer than “normal” are positive numbers and cooler than normal have negative numbers. I have no idea how this normal temperature was chosen (or what it is for that matter) but what is indisputable is that the temperature has fluctuated widely from ice ages (below the zero line) to interglacial periods (like now) where the temperature is above the line (well sort of). So temperature goes up and down without our influence and warm periods, like the one we are enjoying, are actually rather unusual; most of the time it is considerably colder than it is now………… we call these cooler periods “ice ages”.
If we look at the latest warm period in a bit more detail we see:
This chart begins at 11,000 years ago where the global temperature increased as we came out of the last ice age. The temperature then bounced around the norm (0.0 on right hand scale of top graph) with it being about 1 degree warmer around 3250, 6900 and 7800 years ago (the highest 3 peaks), about 0.75 degrees colder around 8200 years ago and about 0.5 degrees colder around 70 years ago when the planet started warming (and where the blue line flicks up on the extreme right hand side of the graph). So far it looks like we are in a very normal period of temperature fluctuation.
The red graph is interesting in that it shows carbon dioxide levels for the same period. From 11,000 to 7500 years ago these were dropping slowly and since then these have been rising. I have no idea why but it certainly wasn’t us and our consumption of oil and coal causing it.
From these charts there is no compelling evidence that carbon dioxide causes global temperatures to increase. In fact you could say the data seems to suggest the opposite – the last 3000 years show a temperature declining (albeit erratically) whilst carbon dioxide levels have been increasing.
I have one more chart to show you. This concentrates on the temperatures of the last 160 years and so should be the most accurate (with all the caveats outlined earlier). It also encompasses the temperature kick up seen in the extreme right of the previous chart.
This chart shows the temperature bouncing around 0.4 to 0.5C below “normal” from 1850 to 1910, it then rises rapidly from 1910 to 1942 (ish) to our “normal” temperature where it holds steady till 1980. From 1980 till 2000 it rose rapidly getting to 0.5C above the arbitrary “normal” and since then there has been NO increase. I repeat there has been NO increase in global temperature since 2000.
And what was been happening to carbon dioxide levels during this 160 year period?
Atmospheric carbon dioxide concentrations
and global annual average temperatures
over the years 1880 to 2009
This graph covers the same time period as the previous one but with atmospheric carbon dioxide levels on it (from Facts and Details.com http://factsanddetails.com/world/cat52/sub328/item2106.html)).
This is the plot that has got the global warming believers hot under the collar. On this time scale overall there has been an increase in carbon dioxide level and there has been an increase in temperature. However this observation does not prove one was caused by the other. The British Empire has been in decline over the same period of time so was that the cause? Carl Benz patented the first motor car in 1885 so are cars the cause?
If the cause of global warming was truly carbon dioxide it should stand up to examination. It doesn’t. Note the time period between 1880 and 1910 – the temperature was falling but carbon dioxide was rising – no evidence there that carbon dioxide was causing global warming. Between 1940 and 1980 the temperature was steady but carbon dioxide levels were rising. And from around 2000 to present the temperature has been steady again yet carbon dioxide levels have been rising more strongly than ever. So would you say carbon dioxide was the cause of the temperature changes seen? I wouldn’t and I hope anyone with an open mind wouldn’t either
From what I have read it is generally believed that carbon dioxide emissions before 1950 were regarded as too low to have an effect on temperature. That being the case what caused the 1910 to 1942 warming. Why did warming stall between 1942 and 1980 just as global emissions took off and finally why has warming stalled since 2000 – this latest stall being when carbon dioxide emissions are increasing faster than ever and are at at an all-time high.
So where are we with my original question – what is going with global warming?
Compared to the ice ages the planet is significantly warmer but it’s no warmer than it has been on several occasions over the last 500,000 years.
Since 1910 the planet has warmed by around 1C with the rise coming in 2 bursts one between 1910 and 1942 and the other between 1980 and 2000 and it has been stable since.
Carbon dioxide is a greenhouse gas and so could play a role in global temperatures modulation but from the evidence presented above the link is not very strong (being kind) or not there at all (being objective).
So why all the fuss.
As I suggested at the beginning science was once conducted in dark corners of laboratories and the exponents only came out into the daylight when they had something to say to like-minded soles. These like-minded soles would evaluate the claims (face to face or via the learned journals) and the findings become the new truth…………………. or the theory got kicked into touch. Now we have the media machine where the prime objective seems to be to sensationalise - remember measles mumps and rubella vaccine?
Are we and our consumption of fossil fuels the cause of the recent temperature rise?
I see nothing compelling in the evidence to say we are despite carbon dioxide levels rising recently and despite my belief that carbon dioxide is a greenhouse gas.
I do believe (very strongly) that the global population is too large and in the long run unsustainable and I do believe that our generation is consuming too many of the planet’s resources (especially oil and gas) too quickly.
But there’s little evidence that our consumption of fossil fuels is driving an increase in global warming.
The planet has gone through a couple of periods of warming recently but carbon dioxide does not seem to be the cause. To find the real reason we need the scientists to get back to the old way of working develop theories that fit the facts. NOT develop theories then refuse to move from those theories when the data says they are incorrect.
There’s a lot more that could be said about this subject; our poor knowledge of what really drives climate, the shortcomings in the computer models, the industries that have grown up around the fear of climate change (wind farms), the billions being shelled out to fund research into climate change and its impact……………… but I won’t. I don’t know enough about many of the subjects and there would be no point because global warming has acquired all the characteristics of a religion. You either believe or you are a heretic. And when has logical argument and common sense prevailed in a religious war?