Climate Change has Decimated Societies Around the World – Watts Up With That?

By Jim Steele

The Great Famine of the 1870s resulted in 50 million deaths from drought-induced mass starvation across South America, Africa, and Asia. It was an all-natural climate event during colder times with lower CO2 concentrations and those drought-causing climate dynamics are still in play today. To understand if the world could again suffer such a drought, it helps to view climate change from a 10,000-year perspective starting with the African Humid Period. During the Holocene Optimum the Sahara was covered with lakes and rivers and abundant wildlife as depicted by the rock art of the many African societies that thrived in the Sahara (graphics B & C). Then around 6,000 years ago it turned to desert.

In the tropics, rainy and dry seasons alternate depending on the position of the Intertropical Convergence Zone (ITCZ- graphic D). The ITCZ is seen in satellites as a narrow band of clouds where world’s greatest amounts of precipitation fall. The ITCZ is very sensitive to solar heating. During the northern hemisphere’s summer when the sun’s strongest rays move northward, so does the ITCZ. As the sun migrates southward, so does the ITCZ and its band of rains.

A 40,000+ year cycle of the changing tilt of the earth’s axis, referred to as obliquity, also determines how far north and south the suns strongest rays will migrate. Ten thousand years ago the tilt was at a maximum and the ITCZ migrated further north than today, bringing more moisture to the Sahara (graphic F; ITCZ average northern location=yellow dashed line). As the tilt decreases to its minimum, the ITCZ moves southward (graphic G). Thus, as the ITCZ migrated southward, the rains decreased enough over the Humid Sahara to turn it to a desert.  The axis tilt will continue to decline for another 10,000 years. Another orbital cycle, precession, contributed to the ITCZ southward migration by causing the southern hemisphere to slightly warm while the northern hemisphere slightly cooled.

Research has also found that as the ITCZ moved southward over the past 6000 years, El Nino activity has increased. El Nino events caused extreme drought in southeast Asia in 1998, as well as in southern Africa such as was recently experienced in 2023-2024. Likewise, the Great Famine of the 1870s coincided with the strong El Nino of 1877-1878, while the ITCZ was at its most southward location (graphic E).

The Little Ice Age from 1300 to 1900 AD coincided with sunspot minimums. The reduced solar heating caused the ITCZ to contract further towards the equator. That altered atmospheric circulation to bring drought to the tropics and the Great Famine of 1870 as well as colder temperatures to North America and Eurasia. It also brought the northern rain-belts further south, bringing heavy snowfall and growing glaciers. Manchuria suffered famines not from drought but from cold winters. Growing glaciers in the Swiss Alps destroyed farmland and towns.

The last 150 years has witnessed the ITCZ migrating northward as sunspots exhibited a maximum, bringing a warm rebound from the LIA (graphic E). Small changes in solar irradiance are not enough to warm the climate directly. However small changes in solar irradiance affects the ITCZ which then has global impacts that can have bigger warming effects.

Small changes in solar irradiance are not enough to warm the climate directly. However small changes in solar irradiance affects the ITCZ which then has global impacts that can have bigger warming effects. The ITCZ is the driver of the Hadley circulation that drives circulation changes from the equator to the poles (graphic H). A southward migration of the ITCZ causes a weakening of the polar vortex and the polar jet stream. In turn that allows cold air that is normally contained in the Arctic to flow southward and cool North America and Eurasia. A strong polar vortex that constrains cold air transport causes a warming global temperature. The decrease in sunspots during the Little Ice Age, as well as since 1990s coincides with a weaker vortex and winter cooling across sub-polar regions.

The Hadley circulation, driven by the ITCZ strength and location, creates a tropical rain-belt, a mid-latitude dry belt or the desert-latitude belt, and a sub-polar rain-belt. (graphic I; blue more precipitation vs red more evaporation). As the ITCZ moves southward so does the regions of dryness and rainfall. Accordingly, as the ITCZ brought drought to tropical regions, it simultaneously brought heavy snow fall and devastating glaciers to the sub-polar rain-belts.

People must understand, anomalous droughts and floods, anomalous cold and heat, are the natural consequence of the earth’s natural circulation patterns and solar variations. Similar to El Nino effects, weather changes can bring both floods and droughts. Likewise, the ITCZ migration brings warmer tropics and colder sub-polar regions. These natural dynamics do not claim that there is no greenhouse effect. However, those dynamics simply reveal how much natural climate dynamics affect our lives, global temperatures, and weather extremes. Anyone arguing CO2 is driving all the climate changes and all the extreme weather events are either very ignorant of these weather dynamics, or dishonest grifters trying to manipulate your support for their political agenda!  The greatest Climate Injustice of all will happen if the world’s under-served people are denied the inexpensive energy from fossil fuels that best allows them to deal with natural climate extremes!