Cycles; of Ice and Warm Ages lasting tens of millions of years each; of Glacials and Interglacials in Ice Ages lasting tens of thousands of years each; of cooling and warming Periods lasting hundreds of years each; and of cooling and warming Phases lasting decades each have characterized global climate for more than two billion years.
Since the most recent “Little Ice Age” cooling Period ended about 1850, the average global temperature had increased by only 0.9 degrees Celsius by 2000 and was still 1 degree lower than in the year 1000..
Another short term cooling Phase began in 2002 and the average global temperature had cooled by 0.12 degrees Celsius by 2011.
In the last ten thousand years, the average global temperature has varied by only three degrees Celsius. The midpoint of the range is 15 degrees Celsius. In 2011, the global average temperature was 14.9 degrees Celsius – about the middle of the ten thousand year range.
The sun is the driver of temperature on earth. When solar activity increases, the earth warms; when it decreases. the earth cools.
The only reason the earth doesn’t alternately boil and freeze like the moon does as it rotates is because it is blanketed by a 30-mile thick protective atmosphere that acts exactly the same way that a greenhouse does. Actually, 90% of the greenhouse effect occurs in the troposphere which is only 9 miles thick at sea level and less than 4 miles thick above Mt. Everest. Virtually all weather occurs within 5 miles of sea level.
Between 95% and 97% of the greenhouse effect is caused by the water vapour in the troposphere – clouds, mists, fogs, etc.
Only 3% to 5% of the greenhouse effect is caused by four dry gases – carbon dioxide, methane, nitrous oxide and fluorcarbons. The last two occur in only trace amounts and there are less than two molecules of methane in a million molecules of atmosphere.
Carbon dioxide is the major dry gas. Currently there are 395 molecules of carbon dioxide in a million molecules of atmosphere. The level of carbon dioxide in the atmosphere has risen from 291 molecules in a million molecules of atmosphere since 1870. This increase is perfectly coincident with the current global warming Period which began in 1850.
The oceans contain more than 100 times more concentration of carbon dioxide than the atmosphere does. When the earth is warming, the oceans release carbon dioxide into the atmosphere. When the earth is cooling, the oceans take some carbon dioxide from the atmosphere. To rephrase – more carbon dioxide in the atmosphere does not cause global warming. Global warming causes more carbon dioxide in the atmosphere.
Carbon dioxide is critical to life on this planet because it is what vegetation breathes. Without Carbon dioxide there would be no trees, plants, grasses, vegetables or people! More carbon dioxide means more plant life means a greener planet. Warming Periods have coincided with advances in the human condition for thousands of years. In just the current warming Period, the greening of the planet has been spreading to dry and cold regions of the earth, biodiversity and plant growth rates have greatly increased and the human population has increased from just over one billion in 1850 to over seven billion today.
Commercial greenhouse operators pump carbon dioxide into their facilities to a level of 1200 molecules of carbon dioxide per million molecules of air in them. They do so to promote the growth of their flowers or vegetables.
The oceans are by far the main source of atmospheric carbon dioxide. Volcanoes and animal exhalations also release carbon dioxide into the atmosphere. Combined, these three sources contribute 95% of the carbon dioxide in the atmosphere. Human activity contributes only 5%, therefore, the contribution of human activity – the burning of fossil fuels – to the greenhouse effect is miniscule – 5% of 3% to 5% or less than a quarter of 1%! If there had been no people on earth, global warming and cooling cycles would still have occurred as they are doing on other planets in the solar system on which, so far as we know, no one is burning fossil fuels!
It is truly amazing that such a small component of the atmosphere, and such a tiny absolute increase in its amount, should have such a huge impact on life on our planet. In fact, be it it ever so small a contribution, the activity of taking carbon fixed in coal, oil and gas, and fusing it with oxygen in the combustion process to make carbon dioxide, is a positive contribution to life on this planet. We should do more!
And we certainly should immediately stop the folly that is wrecking our western civilizations’ economies.