History of deforestation and climate-change and what we can learn from earlier Covid eras

History gives a clear correlation between population decline and growth, size of forests, the natural cooling capacity and subsequent temperature. Climate change is a repeating and measurable issue during the last 2.000 years in history of mankind. Until the beginning of the 20^th century rising and falling of temperature was dictated by effect of population growth coupled with deforestation and epidemics reducing population followed by regrowth of forests.

What’s new in recent history is the pace of deforestation, about 9 million square kilometres since the beginning of the 20th century causing malfunctioning of the natural air-conditioning by disabling the Green Water Cycle. New is the combination of rising CO2-emissions and disabling of the Green Water Cycle happening in the same era together making temperatures rise and keep rising in short time. A temperature rise of 1C is not exceptional in ‘recent societal history of 2000 years’ but the same temperature rise in 100 years is. 

As we take a closer look to the last 2000 years we can see already temperature rise in Roman times caused by changes in land use meaning changing forests in farmland followed by cooler periods after epidemics causing de population (because virus transmitting animals lose their habitat by deforestation and at the same time their predetors are decimated and contact with humans becomes more frequent) and subsequent regrowth of forests. Such natural re-greening induced cooling events happened after the Antonin Plaque AD 165 – AD 189 (Roman Empire) and the Justinian Plaque (Eastern Roman Empire) AD 541 – AD 700.

Intermittent plaque events in the Eastern Roman Empire, and warfare caused collapse of the European population combined with regrowth of forests and decline of temperature.

A relative peaceful period between AD 800 – AD 1100 and improved agricultural practices made European population grow, forest decline and temperatures rise until mass killing during the Mongol invasions reduced population levels in Eastern Europe again and deforestation halted giving forests opportunity to regrow partly restoring the natural air-conditioning function.

In Mid America we see the Maya culture flourish, forest area decline, temperature rise and subsequent population decrease caused by famines and epidemics. After the decline of the population temperatures decline.

It was not before 1750 that population levels recovered not only recovery was hampered by intermittent local plaque events but also by Mid European ware fare (30 Years War) killing approximately 30% of the Mid European Population. History repeats as forest regrow and the natural cooling capacity increases again a bit more.

After Columbus entered America and introduced influenza about 95 of native population perished during the 16th century. Former deforested area re-greened and temperatures dropped.

It is clear that forest regrowth between 14th and 18th century restored the natural air-conditioning function worldwide, so the Little Ice Age LIA was a re-forestation induced cooling period, repairing of the damage made by mankind which resulted in temperatures rising before mid 14th century during, what we now call The Medieval Warm Period (MWP).

Temperature rise during the MWP was one degree Celsius and temperature decline during the LIA was also roughly one degree but what about the impact of rising CO2 levels due to deforestation during the MWP and decreasing levels during the LIA. The answer is simple; the fact is that fluctuation of CO2 levels was no more than a rise to a maximum 10 PPM during the MWP, between the 9th and 14 th century, which can’t explain a temperature rise of 1C. During the LIA CO2 levels dropped with a maximum of 10 PPM which cannot explain a temperature drop of 1C.

History gives a clear correlation between population growth, deforestation damaging the natural cooling capacity and subsequent temperature rise versus population decrease followed by re-growth of forests ‘repairing’ the natural air-conditioning function and subsequent decrease of temperature. During the MWP in 5 centuries approximately an area of 10 million square kilometres was deforested worldwide while temperature rose one degree. Since the start of the second industrial revolution and now approximately an area of 9 million square kilometres is deforested while temperature has risen with one degree.

History shows the dominant role of the natural air conditioning but only recently a group of 30 fellow researchers including ‘ scientific hot shots’ as Lovejoy and Nobre stated that temperature rise caused by deforestation of the Amazon is only for 50% accountable to CO2; 50% is related to loss of forest induced cooling processes.