Dr. Tim Ball's latest post On Pravda’s New Ice Age Story starts off by taking aim at the UN's Intergovernmental Panel on Climate Change (IPCC) and the premise of human induced (anthropogenic) global warming from the emissions of carbon dioxide:
I have said the IPCC focus on CO2 is akin to saying my car is not running well and I am going to determine the cause by ignoring the engine (sun), the transmission (water vapor), and most other mechanical parts and focus on one nut (CO2) on the right rear wheel. Worse, they only look at one thread of the nut, the human portion of CO2. The ease with which they have achieved this degree of focus is frightening, but understandable because it was premeditated.But that's just the prelude. The main focus of Dr. Ball's post is a recent article in the Russian newspaper Pravda titled Earth on the Brink of an Ice Age which states:
“The Earth is now on the brink of entering another Ice Age, according to a large and compelling body of evidence from within the field of climate science.”To put this into perspective and avoid confusion with the recent short term period of global cooling, Dr. Ball offers this explanation over a much larger time frame:
This is the fact that the Earth over the last 10,000 years has emerged from one segment of the most recent Ice Age (Pleistocene). We are currently in an interglacial (Holocene) and scientists anticipate it will end as we slide into another Ice Age. A diagram of global temperatures over the last 400,000 years derived from Antarctic ice cores shows the pattern during the Pleistocene.Read the full story at FCPP Publications. (h/t)
The blue line shows the temperature with current temperatures on the right. Notice there are four previous interglacials, two of them with higher temperatures than today. The intervening periods are the ice ages when massive glaciers formed on the land. Also note how the temperature declines after the interglacial peak; that is the cooling the Pravda article is discussing.
It is generally agreed that changes in the sun/earth relationship are the major mechanism driving long-term climate patterns. These are collectively known as the Milankovitch Effect and include; changes in the Earth’s orbit caused primarily by the gravitational pull of Jupiter with a 100,000-year cycle; changes in the tilt of the Earth of undetermined cause, with a 40,000- year cycle; and a shift in the date of equinox with a 19,000-year cycle. Although Milankovitch’s work was initially accepted it lost favor when his results conflicted with some radiocarbon data. I recall conferences in the 1980s when reference to Milankovitch brought vigorous protest. However, by the 1990s he was back in favor.
Another important point about the Pravda article is the observation that supporters of the human caused global warming (AGW) only consider a short time frame. “ The main flaw in the AGW theory is that its proponents focus on evidence from only the past 1,000 years at most, while ignoring the evidence from the past million years--evidence which is essential for a true understanding of climatology.” It is true that the now discredited “hockey stick” examined climate of the last thousand years, but this was only to try and eliminate the Medieval Warm Period. In fact, the focus is at most the temperature of the last 140 years.
Related: The IPCC under the Microscope. (h/t)