Global Temperature Is It Rising Or Falling, Does It Even Exist?

Global temperatures are central to the alarm over climate change and global warming.

The entire issue is driven by global temperatures having risen about 0.5°C since 1980.

It is claimed by IPCC this rise has been caused by green house gases, with CO2 being responsible for about 1/2 this rise.

As CO2 emissions continue to raise the levels of CO2 in the atomosphere, then global temperatures will continue to rise possibly to dangerous levels.

So it seems reasonable to ask what is global temperature, how is it measured or calculated and does it even exist?

Ross McKitrick, Christopher Essex, and Bjarne Anderesen have written a paper
Does Global Temperature Exist?” which argues on the basis of mathematics, statistics and physics there can be no global temperature as it is possible to define any number of global temperatures.

This paper is quite complex. Here I aim to produce a simpler argument that the idea of a global temperature makes no sense and so does not exist in any useful sense.  After all if you calculate a number that has no meaning and no relation to the real world, how much use is it?

In addition I will give an indication of how the global temperatures are calculated which seem highly dubious.

Finally there is a practical problem. When people look at records from individual stations there is no sign of a major rise in temperature. This leads to the conclusion the rise is artificially produced when calculating the global temperature.

There are a many websites around the world showing work from people who have years of experience in researching temperatures, for most points I will give a brief overview and links to other websites.

As far as I know the only people who discuss if a global temperature exists are Ross McKitrick, Christopher Essex, and Bjarne Anderesen, and this is the main issue I am addressing.

What Is Temperature?

  • Is it a read out on a digital display
  • How far a red or silver liquid has advanced along a tube?
  • Something to do with thermodynamics and physics?

The part of science which talks about temperature is thermodynamics which is part of physics.  Temperature is an indication of how much energy (heat energy) stuff has.

Although IPCC present information to the public in terms of global temperature the scientific discussion is framed in terms of “energy inbalance” how much more energy is the earth absorbing versus how much it is losing. The favourite way of measuring this is in watts per square meter or wm-2.

We immediately hit a problem as different types of stuff require very different amounts of heat energy to produce a given change in temperature.

Energy is measured in joules and kilo joules

(Watts measure power or the rate energy is used, delivered or lost. 1 watt is 1 joule per second. You could argue energy balance should actually be called power balance as it would make more sense.

I’ll also pass over the idea that it makes any sense to average the sun’s energy that falls on the earth all over it’s surface when it is clearly very different at different places and different times of the year.

I’ll also gloss over the habit of treating the earth as a flat circular disc rather than some sort of sphere.)

latent heat of ice
energy required to melt ice
specific heat of water or ice
energy required to warm ice or water 1°C approx
specific heat of air
energy required to warm air 1°C approx

but density of air is much less than ice and water.

density of ice or water
kg m-3
density of air
kg m-3

So  a kilogram of ice takes 334 times as much energy to melt as it takes to raise a kilogram of air 1 °C. And whilst ice is melting it will not change temperature at all.

To put it another way the temperature of 1 kilogram air would  rise by 334°C if it absorbed the same amount of energy needed to melt 1 kilogram of water.

Moreover, air is about 1/1000 the density of water and ice, so to warm the same volume of water or ice by 1°C takes about 4000 times as much energy as it does to warm the same volume of air by 1°C.

For this reason, and the fact the oceans cover about 70% of earth,   almost all of the energy absorbed by the earth is actually absorbed by the oceans. Obviously most of the heat is absorbed in the warmer parts of the world.

The heat in the oceans is circulated around those oceans

  • some of it warms countries closer to the poles, e.g. UK is warmed by Gulf Stream.
  • some of it reaching the poles and will raise temperatures there, except when ice changes to water when it absorbs much more energy and doesn’t change temperature at all.
  • some of the energy in the oceans, particularly in the southern ocean, between the capes and antarctic, is radiated back into space.

I have lived by the sea for over 50  years and know that the sea tends to keep the temperature

  • higher than inland during winter
  • and cooler than inland in summer

The extra heat needed to warm the water in the sea acts as a brake which stops air temperatures rising or falling so fast or so far compared to inland. You only need to go about 5 or 10 miles inland from the coast to notice a difference.  Does this mean a different amount of solar energy is arriving, well may be if it suddenly gets cloudy otherwise probably not. So here is a practical everyday example of how temperature does not always directly indicate energy.

This effect is  magnified about 100 times  at the poles (or anywhere else there is ice) as ice absorbs nearly as much energy just to melt (where the temperature does not change at all)  as it does to take melted water to boiling point.

Thus temperature, especially when

  • measured in air
  • at a site on land

is a very poor indicator of how much energy the whole earth has gained or lost.

So it makes no sense to calculate an average global temperature and even use this global average to justify anything.

Note I am not claiming this mechanism will make reported global temperature too high, it might make it too low.

That is all I want to say at the moment concerning whether global (or regional) average temperature makes any sense as a meaningful guide to any power (or energy imbalance).  For the rest of this post I want to discuss how these averages are calculated.  It seems not only do global temperatures not mean anything useful, they way they are calculated (and later adjusted) doesn’t even approximately represent this thing that isn’t useful anyway.

[Update 25 June 2012]

Someone, I think it was Clive Best, made a similar but different argument.

Air may

  • Be dry
  • Contain water vapor
  • Contain water –  rain drops
  • Contain ice – hail or snow

and will consequently have a very different specific heat depending on the amount and state of water it contains. This will render the idea of global or even average temperatures meaningless as a guide to indicate any warming or cooling.

[End update]


How Are Average Temperatures Calculated Anyway?

Weather stations record maximum and minimum temperatures for each day. A daily average is calculated as the mean of these.
A monthly average is calculated from the daily averages
A grid is calculated around the earth, usually of 5 degree latitude and longitude cells. This means there are 2592 cells around the earth.  This post by Clive Best at WUWT shows that there is a very uneven distribution of weather stations around the world meaning many cells have no weather station.
A value is entered into each cell if one or more weather stations are located in that cell.
If there is on a single weather station, that stations value is taken
An average is used when there is more than one station.
An attempt to calculate the “temperature” of cells where there are no weather stations, probably by interpolating using adjacent or nearby cells with values.
Having ensured there is some sort of number in each cell, a global average is calculated somehow.

Immediately can see problems

  1. A daily maximum or minimum may have been reached for only 1 second but the daily average takes no account of this
  2. Some locations have very large temperature swings (e.g. deserts)
    others do not. But the daily average treats them all the same.
  3. Some cells will have a single weather station, others more than one
    this means the values from weather stations which are the only occupant of a cell are given more weight when calculating global average.
  4. It may be possible to estimate a temperature for a cell with no weather station, when the adjacent cells have one.  It may even be possible if there are a few adajacent cells with no weather stations.  Clive Best writing at Watts Up With That shows there are vast areas of the world, almost entire continents (e.g. Africa, South America, Australia) where there are either no weather stations or just a handful.  How can the “temperatures” in the grids on these continents be any more than a guess???  Will there be a significant difference between the values used and invoking =randbetween(0,50) in excel??

This makes any global mean temperature unreliable and not a basis to indicate anything.

But there are more problems here are some of them

  • The number of weather stations has changed over time.
  • The instruments in weather stations are changed from time to time.
  • Different weather stations have operated for different periods.  Ross McKitrick has notice a big change in mean temperature in 1990 when about 1/2  stations then in existing were decomissioned.

Here are just 3 of the many sites which explain temperatures in much more detail.

Temperature Graphs In Papers Are Not Graphs Of Temperature!

There is wide variation in temperatures around the world so it is difficult to make a literal average.

So what is done is for each location a temperature anomaly is calculated.

The long term average temperature is calculated (say from 1901 to 1960, or 1950 to 1990)
and the monthly means are converted to differences from the long term average.

The effect is to reduce the wide variation from all around the world to swings of a degree or so from the long term average.

An immediate consequence is to make the rise and fall look dramatic when it is only 1-3% change on actual average temperature as measure in °C. And if absolute temperatures (°K) are used temperature changes are only around 0.2% hardly enough to be called noise.  There is no logical reason at all to measure temperatures in °C for scientific purposes, unless you wish your random variations to appear larger than they really are.

Yet Another Problem With Global Temperatures

If the global average temperature is rising or falling you would expect to see this pattern when you look at the records of individual weather stations around the world.

But when people have looked at the long term temperature records at specific sites, eg

Michael Palmer, writing on Watts Up With That Blog
Roger Sowell writing at SowellsBlogSpot
This blog

there is no major rise in temperature.

It is hard to see how there can be a global increase in temperature
which is not seen when you look at specific sites. Surely a global increase
means an increase all around the world, or at least most of it, or even some of it?

And Another Problem The Temperature Records Are Changed?

The temperature records are adjusted from time to time, to remove spurious effects,such as towns being built near to a weather station which was previously out in the county
which would have the effect of increasing temperatures at the weather site.

There are people who keep a watch on changes to these datasets they claim
some of these changes are made without good reason,
so the changes are made just to artificially produce a temperature rise

There is another record of temperatures from around the world, from decades ago
newspapers. Google is making life easier by digitising them.
There have been extreme heatwaves in the past, which have been recorded in newspapers
but these heatwaves are not reflected in the global temperature datasets.

As the process of adjustment is not at all transparent this lends weight to the idea
that the adjustments are made just to show an increase in temperature. This suspicion is heightened as the datasets are maintained by proponents for warming.

scroll to Temperature Data Adjustment, then to Temperature Adjustment Examples
missing heatwave in Death Valley from 1912
cooling the past, warming the present
 warming New Zealand

What Does All This Mean For Global Temperature

Global temperature is not a reliable indicator of how much energy the earth has gained or lost and so a poor basis to decided if global warming or cooling has taken place.

Fortunately there are other methods which Peter Taylor discusses in his book

Peter  attributes all of the Global Warming/Climate Change saga to people not being able to tell the difference between

  • Trends
  • Cycles
  • Pulses

In this post I have written a review of Peter Taylor’s Chill.

Many of the points I have raised here were made by Chris de Freitas 10 years ago in his paper Are observed changes in the concentration of carbon dioxide in the atmosphere really dangerous?

There’s saying in advertising

  • You’ve got to tell people
  • Tell them again
  • And keep on telling them, till the message sinks in

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