Few know the father of the 'Enhanced Greenhouse Gas Hypothesis,' the 1903 Nobel Laureate Svante Arrhenius, was optimistic humanities’ growing use of hydrocarbons in the 19th-century could give rise to an improvement in the Earth's climate..In his book Worlds in the Making, Arrhenius said: "By the influence of the increasing percentage of CO2 in the atmosphere, we may hope to enjoy ages with more equable and better climates.".As with many scientists of that era, Arrhenius was acutely aware of the extreme winters during the Little Ice Ages. Likewise, geologists of the 19th century were discovering extensive evidence showing the Earth experienced numerous global ice ages over the previous million years. It was widely accepted climate change was cyclical and largely natural in origin..It was awareness of the fact glaciers were advancing across the Earth for the previous few centuries, together with the knowledge things could get much worse for humanity, gave occasion for Arrhenius to be optimistic about the rise of modern industry and the use of coal.. Glacial advance .Olga Solomina et al's 2016 study effectively captures the frequency and geographic distribution of glacial advances between the Medieval Warm Period (1000 AD) and the early 1900s. The accumulation of glacial ice during this period was so extensive and rapid that NASA's surveillance of Greenland's ice fields using airborne ice penetrating radar measurements have shown 50 to 75% of the current ice present in this region formed during this period..The abrupt transition from glacial advance to glacial retreat towards the end of the 19th century is not unique to the Current Warm Period. In fact, palaeoclimatological records of the last eight global ice ages over the past million years show the gradual transition from an interglacial thermal maximum into an extended period of cooling and glacial growth is routinely interrupted by rapid and extensive warming events that can last centuries before returning to the longer-term cooling trend..Javier Vinos effectively captures this dynamic climate evolution in his book Climate of the Past, Present and Future. The peak of this plot is often called the Holocene Thermal Maximum or Holocene Climate Optimum. During the Holocene Thermal Maximum, the Sahara Desert was covered by lush grasslands, lakes and rivers and the Arctic Ocean's icecap was almost entirely seasonal..The Neoglacial Phase in climatology, is specific to the state of climate that follows the Thermal Maximum and is defined by short periods of rapid cooling and warming, which occur on top of a lower frequency or more gradual long term cooling trend taking the Earth into its next global glacial maximum. It is believed that the Earth will be entering its next glacial maximum around 12,000AD..These higher frequency climate transitions in neoglacial phases, are referred to as stadials (cooling) and interstadials (warming). Using these definitions, it can be said the Little Ice Age was a stadial event, while the Medieval Warm Period and the Current Warm Period are interstadials. Of course, to some I'm a climate heretic for suggesting the Current Warm Period is of natural origin..The lower frequency, larger amplitude trend in Javier Vinos's illustration is the 41,000-year cycle associated with the famous change in the Earth's obliquity as part of the complex Milankovitch Cycle. Obliquity is the tilt of the Earth's axis of rotation relative to the orbital plane, which markedly changes the relative amount of solar radiation absorbed in either hemisphere..There are numerous other orbital features of planet Earth, such as precession of the axis of rotation and changes in the eccentricity of its orbital path, just to name a few, which cyclically evolve over tens of thousands of years. No one knows what causes the complex array of orbital changes that are part of the Milankovitch Cycles.. Interglacial .The Earth is not unique in this regard within the Solar System..For example, Jupiter`s 11-year orbital period and its path is moderately eccentric. As with the Earth, Jupiter`s orbital eccentricity evolves over time. The gravitational tug-of-war (i.e., tidal forces), caused by Jupiter's periodic alignment or conjunction with Saturn, it’s the causative agent in its eccentricity exhibiting 60- and 950-year cycles..The eccentricity of Jupiter`s orbit likewise cause gravitational tidal forces in the Sun, like our Lunar tides, which initiates the 11-year solar cycle of the Sun. It's believed Jupiter`s tidal forces, together with minor contributions from Earth and Venus, triggers the 11-year reversal in the Sun's magnetic field..As Jupiter's mass is greater than twice that of all the other planets, its evolving orbital eccentricity causes the Sun to wobble as the center of gravity oscillates between itself and Jupiter according to the 11-, 60- and 950-year cycles..During these cycles, the Sun goes through a whole plethora of physical changes, some of which include changes in its radiant intensity, magnetic field strength, sunspot numbers and coronal mass ejections (i.e., solar storms.) In other words, changes in the gravitational field between the planets, gives rise to an effective change in the climate within the Solar System..No surprise, the ripple effect of these processes can be measured within the Earth's climate system..The larger the gravitational perturbation, the greater the tug-of-war on the Sun and the resulting oscillation in climate, both within the Solar System and on planet Earth..Coincidentally, the 11-, 60- and 950-year cycles are dominant modes measured across many Earth based climate indexes..For example, the 60-year cycle shows up in a myriad of global records, such as sea level, air temperatures, equatorial monsoonal precipitation and atmospheric circulation patterns. Recent studies have shown even the rotation rate of the Earth's Core and the planetary length of day exhibits a 60-year cycle..Additionally, the 950-year astronomical cycle is believed by an increasing number of physicists to be responsible for the transition from the Medieval Warm Period to the Little Ice Age and onto the Current Warm Period..Nicola Scafetta developed a mathematical model based on these astronomical cycles and effectively reproduced the last 1,000 years of changes in the deviation from average global air temperature. This model agrees with empirical data showing the Medieval Warm Period ended around 1,070 AD, but it also predicts the Current Warm Period will peak around 2,060 AD..Time will tell..This review of the literature reminds me of the simple yet unfortunate fact simple lies are often easier to accept than are complex truths.
