Marcel Leroux

Marcel Leroux (1938 - 12 August 2008) was a French climatologist, a former Professor of Climatology at Jean Moulin University in Lyon, France, and director of the Laboratory of Climatology, Risk, and Environment. Leroux defended his PhD on climatology entitled "The Climate of Tropical Africa" in 1980. His thesis was published in 1983 by the World Meteorological Organization and distributed within all members states.
Leroux argues in his book "Global Warming: Myth or Reality? The Erring Ways of Climatology" that the case for global warming is based on models which, with their insufficiencies in the understanding and explanation of weather phenomena, are not reliable to support this prediction. He also poses the question if warming may be considered a benefit in some regions.
On the causes of climate change, he writes in a section entitled "Conclusion: The greenhouse effect is not the cause of climate change": "The possible causes, then, of climate change are: well-established orbital parameters on the palaeoclimatic scale, with climatic consequences slowed by the inertial effect of glacial accumulations; solar activity, thought by some to be responsible for half of the 0.6°C rise in temperature, and by others to be responsible for all of it, which situation certainly calls for further analysis; volcanism and its associated aerosols (and especially sulphates), whose (short-term) effects are indubitable; and far at the rear, the greenhouse effect, and in particular that caused by water vapor, the extent of its influence being unknown. "
Scientific Contribution
Leroux' work is intended to demonstrate through the analysis of synoptic maps, satellite imagery, meteorological and palaeoenvironmental data over Tropical Africa, that the seasonal and palaeoclimatic migration of the Meteorological Equator represents a reliable proxy of the Earth’s climate evolution.
In his theory, this migration and the extent of the Meteorological Equator are the consequence of continuous meridional exchanges in the denser, lower layers of the atmosphere, which circulation is governed by the incessant ballet of the Mobile Polar Highs or Anticyclone Mobile Polaire, 1.5 km high, 3,000 km diameter discoid, lenticular cold air-masses anticyclones originating from the poles, whose strength and frequency depends directly on the thermal polar deficit. Cooling spurns an accelerated circulation while warming will slow the general circulation and exchanges.
His argument is that the aerological spaces of circulation, zones of continuous circulation from the pole to the equator are bound by relief over 2,000m and the present position of continents. In light of direct observations , Leroux’s reconstruction, if correct, would show the inconsistencies of previous general circulation models, of oscillation indexes and of frontological, dynamical, reductionist and diagnostic schools of meteorology. This made him a controversial figure.
In doing so, Leroux work has been considered to refute the artificial separation between Meteorology and Climatology and through the MPH concept, redefines both disciplines in a similar way Plate Tectonics revolutionized Earth Sciences in the 1960s. He reconstructed the geometry of the troposphere general circulation<ref name="high"/> and demonstrated that very little is owed to hazard or chaos: there is no ‘unruly climate’ but intensity shifts of the sum of weather processes that constitute the climate. This research would indicate that the climatic shift observed since the 1970s corresponds to the setting of an accelerated mode of circulation, always associated with cooling during the late Quaternary palaeoclimatic evolution, and its meteorological consequences: contrasted weather, stronger mid-latitude storms, increase water vapour in the troposphere and impermanent anticyclonic stability over continents leading to vigorous cold snaps in winter and heatwaves in summer.<ref name="dynamic"/>
In consequence, his views refute the validity of a Global Mean Temperature curve as a major climatic proxy and contradict the assumption that weather changes observed in the second half of the 20th century were the consequence of an Anthropogenic Global Warming climatic change brought by the release of greenhouse gases due to industrial and human activities.<ref name="GW"/>
In general, his hypotheses provide the meteorological mechanism for past glaciations and de-glaciations, improves meteorological prediction models and climate simulation accuracy in constraining them through the real geometry of atmospheric circulation, its discontinuities, energy exchanges and their associated clouds.<ref name="dynamic"/>
The English 2nd edition of “Dynamic Analysis of Weather and Climate, Atmospheric Circulation, Perturbations, Climatic Evolution” was completed in 2008 two months before his death and published in January 2010.<ref name="dynamic"/>

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