Posted 22 September 2015
Are we to blame for climate change? I doubt it
On this subject I am a sceptic. And before you throw your toys out of the cot in disgust at my apparent sinfulness, please sit down, face the front and take a big, big relaxing breath.
Let's begin by clarifying the issue. I accept that the Earth's climate changes over time. There are natural cycles of warming and cooling. The important question to ask is: Do humans have an impact upon these cycles? It is on this point that I am sceptical, in the sense: I am not convinced, based on the evidence, that humans have a practical effect on the natural warming and cooling cycles.
What is it then that makes me a sceptic? Let us begin with the geological record. In the last 500 million years the Earth has gone through five major ice ages followed by warming interludes – interglacial periods. I wonder what caused these cycles to occur, long before humans, oil and industrialisation? The Earth emerged from the last ice age about 12,000 years ago. Since then there have been periods warmer than today (eg the Roman Warm Period when they grew grapes in northern England and Greenland was green) and cooler periods than today (eg the Little Ice Age when they skated and held ice fairs on the frozen Thames). I wonder what caused these changes, both up and down, in pre-industrial times?
I accept that the Earth's climate has warmed in about the last 150 years as it moved out of the Little Ice Age. I wonder what triggered this change? Taking a broad brush over this period, I accept that with the warming, ice has melted and sea levels have risen. But there is no convincing evidence that the rate of warming and rate of sea level rise have increased or are increasing over this time, especially in the last 50 years when CO2 concentrations have risen dramatically.
This warming trend stopped in 1998, according to the satellite data, despite a 10 per cent increase in CO2. There has been no significant warming for 18 years. So I am again left wondering what is going on. Is CO2 really the problem?
Further doubt arises. CO2 is a greenhouse gas. So too is methane and nitrous oxide. The science is settled. But then I learn that the most important greenhouse gas is water that makes up about 80-90 per cent of the greenhouse effect. The science is most definitely not settled on its effect — does water have a positive effect, enhancing the warming due to CO2, or a negative effect, cancelling out the effect of CO2? Seems obvious, does it not — cloudy days tend to be cooler.
But to my mind the ice-core data deals a fatal logical blow to the CO2-dangerous-human-warming theory. Drilling into ice sheets is like drilling into history from which a record of past temperatures and CO2 concentrations can be derived. The data show that when the Earth emerges from ice ages, temperature change precedes the increases in CO2 by about 700-800 years. CO2 does not drive temperature!
In fact it is not difficult to draw up a list of factors other than CO2 which can affect Earth's climate. The Earth's proximity and orientation to the sun is an obvious starter, giving rise to what are called the Milankovitch cycles. More recent theories include changes in the gamma radiation from the sun, which in turn affect cloud formation. It has now been shown that there are linkages between the Earth's temperature, the southern oscillations of the oceans, and the sun's activity as expressed by sunspot activity or its irradiance.
These alternative mechanisms seem to me to be more plausible explanations for the geological changes in the Earth's climate. I can see you scratching your brow. So where does all of this leave the polar bears, the receding polar caps, the white plumes gushing from industrial chimneys, the famous hockey-stick graph, Al Gore's film, Niwa's long-term temperature record, and the endless stream of dire predictions from the fourth estate? Therein lies the rub.
The endless flood of dire predictions, which the press dutifully prints, are based on mathematical climate models. None of these models correctly predicted the current 18-year nil-warming period. We normally set aside models that do not work. Polar bear numbers have increased since hunting controls were introduced.
The famous hockey stick showing alarming and dangerous late 20th century warming, which was used to great effect in Al Gore's film An Inconvenient Truth has been exposed as a scientific fraud. Those frequently "as seen on TV" white plumes of "pollution" are not CO2, which is a colourless, odourless gas and essential for life on Earth. The ice caps are growing again and, despite what Niwa continues to claim, New Zealand's long-term temperature record, when objectively analysed, shows no significant warming.
I accept that you think there is a consensus. That is of course what you are told day in, day out. That is how political and religious movements begin and are perpetuated — endless repetition of a mantra. And the climate change movement that theorises dangerous, human-made global warming shows all the appropriate hallmarks of such movements — no argument can be advanced sufficient to negate it and those who dare question it are vilified and branded as deniers and heretics — poor old Galileo!
But do not take my word for it. I am not a climate scientist. Mind you, neither is the Pope nor the Prime Minister's Science Adviser, both of whom regurgitate the mantra. They, of course, must be believed and obeyed.