Some people accept that the world's climate systems are changing, but try to argue that humans are too puny to be any part of the cause.

The reason for putting forward such an argument in the face of a wealth of historical and scientific data seems to be a matter of political agenda: if humans are too puny to cause climate change then they must surely be too puny to put matters right.  It follows that 'right thinking people' should oppose any attempt to 'do something' about climate change - especially at the taxpayers expense.

Concern for the environment is not a ploy recently invented by politicians to raise taxes or to impose a new world order.  From the earliest days of humanity our ancestors observed that depletion of resources can be fatal to the group.  With the dawn of agriculture came the simple observation that if you eat all the seed, you can't sow for next year: if you eat all the livestock there is nothing left to breed.  Before economics there was husbandry: the art of making best use of all natural resources.

Prior to the industrial revolution fuels were burned for heating, cooking and small-scale metalworking.  The major sources of power for industry were wind and water mills.  The advent of the steam engine gave civilization a self-amplifying power source.  You can't burn wood to make forests and you can't use windmills to make wind.  But you can burn coal to make steam to power the engines to extract coal.  The ensuing rise in coal consumption was rapid.  As was the ensuing rise in pollution.

As new coal fields were discovered across the planet, pit exhaustion was not considered to be a problem.  Long before the coal started to run out, science would undoubtedly have solved the problem of energy efficiency.  With each passing year we would use less and less coal, not more and more.
Referring to your timely leader on the probable exhaustion of the English coal-fields, production can  never keep pace with the present wasteful use of coal. Science will yet come to the rescue, enabling us to utilise 100 per cent, of the energy stored up in the coal, instead of 15 per cent, in the steam engine mid 11 per cent, in the steam dynamos now gained. Electrical energy can be obtained direct from coal without the aid of steam or the ordinary combustion of that fuel.
Reader's letter,
The Mercury, Hobart Tasmania, May 1st 1901
http://trove.nla.gov.au/ndp/del/article/12838744
The best coal in the world for steam engines was Welsh steam coal.  It was exported all over the world at its peak.  It is now exhausted.

Since the industrial era we humans have been extracting resources from the ground as if there is no tomorrow.  The effects of this are visibly damaging our environment.  In 1868, George P. Marsh wrote his book '
The Earth as Modified by Human Action'.  Over 140 years later his writings on anthropogenic environmental changes remain largely ignored.

    The object of the present volume is: to indicate the character and, approximately, the extent of the changes produced by human action in the physical conditions of the globe we inhabit; to point out the dangers of imprudence and the necessity of caution in all operations which, on a large scale, interfere with the spontaneous arrangements of the organic or the inorganic world; to suggest the possibility and the importance of the restoration of disturbed harmonies and the material improvement of waste and exhausted regions; and, incidentally, to illustrate the doctrine that man is, in both kind and degree, a power of a higher order than any of the other forms of animated life, which, like him, are nourished at the table of bounteous nature.

The Earth as Modified by Human Action
George P. Marsh
http://www.gutenberg.org/etext/6019


The atmospheric blanket

Since the time of George P. Marsh we have much more evidence of the environmental impacts of industrial scale activities.  We have also come to know that treating the atmosphere as a dumping ground for our waste gases is a very bad idea.

Seeing snow on a mountain top was a puzzle to the ancients.  They knew that as you get closer to the equator it gets hotter, and as you move north it gets colder.  The Ancient Greeks even figured out that the far north should spend half the year in sunshine and half in darkness.  Some observers put the differences in temperature down to the curvature of the Earth which causes the equator to be nearer the sun than the poles.  If true, that would mean there should be no snow on mountain tops because they are nearer the sun, as noted by George Best.

In the 1800s, Horace de Saussure's experiments with hot boxes showed that mountain tops get far less benefit from the blanketing effect of the atmosphere than regions lower down.  Temperature is a matter of balance between heat inputs and heat outputs.  With a thermal blanket you can get a higher temperature from the same heat input or the same temperature from less heat input.  That's why we lag boilers and insulate houses.

De Saussure’s hot box served as a model for nineteenth-century scientists demonstrating the relationship of the sun to the earth and its atmosphere. Like the glass covers of the hot box, our atmosphere allows most sunlight to strike the earth. About three quarters of the sun’s radiation reaches the earth’s surface when the sky is clear. The earth, like the bottom of the hot box, absorbs sunlight and releases heat. But this heat cannot readily escape through the atmospheric blanket—just as solar heat is trapped by the panes of glass in a hot box.
http://solarcooking.org/saussure.htm

Saussure statue at Chamonix - courtesy Wikimedia Commons.

Water vapor is a 'greenhouse gas': it is a form of atmospheric 'lagging' which helps maintain temperatures within broad limits.  The amount of vapor in the atmosphere can vary substantially and rapidly at different locations depending on various factors.  Carbon dioxide - CO2 - is also a greenhouse gas.  The amount of CO2 in the atmosphere can vary with location but it does not vary rapidly.  Unlike H2O, CO2 can't precipitate out of the atmosphere.  It can only be absorbed by biological and geological processes, and that takes time.

If CO2 goes into the atmosphere faster than it is taken out, then there will be a trend towards a planet which is ever warmer on average. Global warming doesn't mean that every single bit of the planet gets warmer.  It means that the globe, taken as a whole, is warming.  It means that the bits which are getting warmer are doing so faster than any other bits might be cooling.

People have been putting CO2 into the atmosphere since the discovery of fire.  Following the invention of the steam engine, people burned the same fuels as previously but then burned coal additionally - mostly for industrial and transport purposes.

With the invention of the electric motor and generator there was a further rise in industrial output.  A small scale enterprise which could not be run using a steam engine could be run using electric motors.  The spread of electrical power into every workshop and then every home in industrialized countries led to further demand for coal.

We are now so used to having electrical power in the home that we take it very much for granted.  There is a basic fact that the ordinary consumer of electricity does not realize.  Burning coal to make electricity is very inefficient.  In effect, for every kilowatt you use, you throw away about four kilowatts.  Apply that economic model to buying a bag of potatoes, flour or rice.  You are required to buy five bags of food.  You are required to throw four bags on a bonfire before you are allowed to take the one bag home.  If anyone tried to run a store that way they would certainly get some interesting feedback from their customers.  But that is how coal-fired power stations work: we use roughly one bag of coal to get electricity and throw four away.  Oil and gas-fired power stations are also extremely inefficient.


The subtlety of change

It has often been remarked that we humans are not adapted to notice slow change.  Also, many people quite simply refuse to believe that the living things around us - and we humans as well - have evolved due to environmental pressures.  It seems hard for some people to imagine that micro-changes in environment can lead to micro-changes in living things and ultimately: new species.  Small wonder that people who won't acknowledge what we have changed on the human scale will not accept our ability to make changes on a global scale.

Charles Darwin pointed out that our domesticated animals are a result of selective breeding - the selection of stock for breeding based on minor deviations from the average stock.  This is also true of our domesticated plants.  Domesticated plants and animals have been evolving over millenia through human influences, but often in a manner unremarked and hence unrecorded.
As soon as the points of value are once acknowledged, the principle, as I have called it, of unconscious selection will always tend,—perhaps more at one period than at another, as the breed rises or falls in fashion,—perhaps more in one district than in another, according to the state of civilisation of the inhabitants,—slowly to add to the characteristic features of the breed, whatever they may be. But the chance will be infinitely small of any record having been preserved of such slow, varying, and insensible changes.

Charles Robert Darwin (1809-1882)
Origin of Species. Chapter I.  Variation under Domestication

http://www.bartleby.com/11/0106.html
Many people simply cannot - or will not - see that our domesticated breeds are descendants of wild ancestors and that they constitute an example of how subtle changes can produce something seemingly quite different to the previous norm.

The process of evolution doesn't just apply to our stock, but to our urban environments.  Most people will know of local buildings demolished and new ones built; roads widened or newly built; rivers dammed; harbors enlarged; open land swallowed by new housing or industrial complexes - the list is endless.  This is evolution.  This is your local environment changing before your very eyes: your town - even your country - is likely to have changed greatly since your childhood.

Change surrounds us in our daily lives, but the atmosphere appears constant and unchanging.  That is because the changes are small, subtle and long-term.  Also, the many gases we dump in our atmosphere are invisible.

The globe's local climates have always changed, and always will for as long as our planet retains its oceans and atmosphere.  Our current problem lies not in change as such, but in a general blindness to such change and its potential consequences for the whole human race. 

If people will open their eyes and see scientific and historical proofs that we humans have changed local climates in the pre-industrial past, then perhaps they will concede the virtual certainty that we industrial era humans are changing our whole planet-wide climate system.

We are not too feeble to change the planet, so let us not be too feeble to undo any harm we may have done to formerly predictable natural cycles.