A theory founded on three presumptions.
How solid is the theory that human-generated carbon dioxide is causing global warming?
Let us leave aside for the moment that the theory developed momentum becoming part of mainstream thinking because of the very persuasive 2006 documentary, An Inconvenient Truth that showed an apparently scientific temperature graph shaped like a hockey stick. The graph is not only misleading but subsequently it has been shown to be tantamount to fraud.
In simple terms the theory of global warming is based on three presumptions. Let’s take a look at them in turn.
1. Temperature measurements are true
The first presumption is that the measurements we have of temperature are scientifically objective and any of the increases observed are caused by the greenhouse effect.
The challenge is that many of the sensors that have been used to record temperatures over the last two hundred years are in or near cities. It is well established that the urban environment traps heat. This is known as the “urban heat island effect.”
One would expect that in Toronto, as the city has grown in every direction, temperatures would have been going up. However, if you download the data you find that the highest temperature recorded this decade was 38.2 °C, which is way lower than the 40.6 °C recorded in 1936.
The news stories we read every summer about temperature records being broken are because they report the average temperature recorded over 24 hours. And nighttime temperatures are higher due to heat being trapped by buildings and because the moisture from human activities and irrigation systems act as a blanket.
The fact that night time temperatures are milder than in earlier decades does not justify stories about global warming.
Humans change climate in many ways
There is another complicating factor; humans influence temperature in many ways other than by adding carbon dioxide to the atmosphere and it is impossible to reliably subtract all the different effects. For instance the condensation trails made by aircraft undoubtedly provide shade in the day and a blanket at night. They also are like tiny seeds helping clouds form.
In short, it is impossible to be certain about the effects of carbon dioxide on global temperatures.
Temperature records are "adjusted"
There is another issue with temperature measurements.
Temperatures measured at weather stations on the ground are affected by local factors, such as whether the sensors are close to roads, buildings or trees. To eliminate these local effects climate scientists “homogenize” the data. When they rework the temperatures the temptation is to make them fit the IPCC agenda and show that past temperatures were not as warm as now. And in some cases that is what they have done – see this 9 minute video from Tony Heller.
Tony Heller has made a retirement hobby out of investigating the claims of climate Alarmists and pointing out the tricks, exaggerations, contradictions and outright deceptions used when manipulating and presenting temperature data.
He is now pumping out these videos several times a week and his following is growing. If you look at these videos note the view count. More videos here…
Temperatures measured from balloons and satellites haven't warmed much
Satellites and weather balloons are used to measure atmospheric temperatures and they are less affected by local distortions.
They have been showing about a 0.3°C increase since 1980, which is less than that predicted by most IPCC models and well within normal statistical variability.
2. The Earth’s temperature has been relatively stable
Outside of man’s interference Alarmists presume that the climate has been slowly warming as we recover from the last ice age. However, there is ample evidence that the climate has never been stable. It is interrelated with other systems including cosmic events (solar irradiation, sunspots and cosmic rays to name a few), tectonic events (including eruptions, earthquakes and tsunamis), ecological events (infestations, plagues, die-offs) and oceanographic changes (including changes in currents).
Climate events of every timeframe and every size have happened through recorded and geological history. There have been at least five die-offs that are clearly demarcated in the geological record when most of the plants and animals were wiped out. The reasons are not completely clear, except for the last one that happened 65 million years ago when the 135 million year reign of the dinosaurs came to an abrupt end. There is a well-defined layer in rock strata, rich in otherwise rare minerals, called the K–Pg (previously K-T) boundary. It marks the point at which an asteroid struck the Yucatán Peninsula and within seconds triggered a die-off of 75% of the world’s animals and plants.
At the other end of the scale, every time you take a shovel full of soil, each particle tells the story of a series of climate events. The ground beneath our feet is there because of a stream of catastrophes from two kilometer thick ice sheets to floods, and catastrophes in micro-ecosystems, such as when a pond dries up.
3. The Earth’s climate can be forecast reliably
A question commonly posed by non climate scientists is: “If your computer models cannot forecast the weather accurately next season, what makes you so confident that they’ll be accurate for the world decades in the future?”
The response is that climate is an average of weather. The details are unpredictable but when they are aggregated they behave predictably.
This argument presupposes that the components of climate can be extrapolated from the basic laws of physics and chemistry and behave in linear, predictable ways, and that near-term randomness becomes smoothed out over the longer term.
The reality is that the components that make up climate including the turbulence of air masses and the ways water vapour condenses are chaotic, nonlinear systems. Irrespective of the completeness of the data that describes the starting point, the way things unfold, both in theory and in practice, are impossible to forecast reliably beyond the immediate future.
There are parallels with the stock market. It is tempting to presume that if someone is really, really clever it is possible for them to forecast movements in stock prices. But the stock market depends on the behavior of people, and with positive feedback loops something trivial can cause the herd to change their mood, either causing a bull run or a market crash. It is impossible to predict the direction people will go. They may calm down or they may panic.
A further issue are events that are impossible to anticipate. In economics they are known as “black swans.” Dislocations of all sorts far from being unusual, are normal.
At this point, no matter how much data they start with, how powerful the computers or how detailed the algorithms seem to be, no scientist knows enough about all the factors influencing climate to make forecasts that are reliable. Nor is it possible to quantify uncertainty – without guessing.
How are we doing so far?
Dr. John Robson of the Climate Discussion Nexus fact-checks the predictions in the Canadian government’s 2001 pamphlet warning of six consequences of global warming. Zero out of six forecasts are proving correct.
• We should not trust the accuracy of climate models that predict temperature changes of a few degrees ten or twenty years in the future.
• Our resources are more effective when they are utilized in protecting citizens from catastrophes and recovering from them, rather than attempting to anticipate the unpredictable and prevent the unpreventable.