Is the World Going into a Cooling Period?

Over the past months I’ve posted numerous updates on cold weather around the world….such as this:

I share weather updates this because I think we are entering a period of global cooling, and this may have important impacts for crops, heating needs, etc. Several years back, I was teaching and economic modeling course to our graduate students. Some of the more sophisticated economic modelers sometimes link economic models to ecological models, climate models, etc. To prepare for the course, I spent a considerable amount of time reading the climate model literature…but I had trouble understanding them. Models can be “black boxes” in that one can’t really understand the what’s driving the outputs from the models. I tend to favor simpler models because then you have a better chance at understanding the underlying drivers of any output produced by the model. One thing I did understand was that climate models, like economic models, are dependent on the assumptions one makes when building models. And there are a lot of assumptions embedded in the climate models. That’s not necessarily a bad thing…we make all assumptions and lean on them…but we have to try our best to understand the implications of the assumptions we make.

As explored the issue, I ran across the work of astrophysicist Professor Zharkova who studies sun cycles…shorter-run cycles and longer-run cycles. Importantly, she made very clear connections over long periods of time between the different types of energy coming from the sun and changes in earth’s climate. You can read about her research via the links below.

Zharkova, 2020,

Zharkova, et al. 2015

Zharkova (2020) summarizes research on how the Sun has entered the modern Grand Solar Minimum (2020-2053), which will lead to a reduction in terrestrial temperature.  The Sun experiences a 11-year cyclic variation in the number of sunspots, which influences earth temperature. Overarching these shorter cycles are 350-400 year cycles as illustrated in Zharkova, et al. (2015).

Image Taken from Zharkova (2105)

The image demonstrates significant variation in solar activity modulating in 350-400 cycles.  As shown in the next image these cycles align closely with terrestrial temperature variation over time.  For example, the Maunder minimum correlates with the cool period from 1645-1710, wherein the average temperature in Northern Europe decreased by 1-1.5˚ C.  This change led to frozen rivers such as the Thames in England, long cold winters, and relatively cold summers.  During this period, sea ice expanded south from the arctic, alpine glaciers stretched into valley farmland. Even the canals in the Netherlands froze.

Image taken from Zharkova 2020.

Zharkova’s models show us that we have now entered another solar minimum period (2020-2053) in which she expects global temperatures to drop by at least 1˚ C.  Zharkova (2020) offers a warning:

“The reduction of a terrestrial temperature during the next 30 years can have important implications for different parts of the planet on growing vegetation, agriculture, food supplies, and heating needs in both Northern and Southern hemispheres. This global cooling during the upcoming grand solar minimum (2020–2053) can offset for three decades any signs of global warming and would require inter-government efforts to tackle problems with heat and food supplies for the whole population of the Earth.”

In my assessment, Zharkova and others have demonstrated that sun cycles and their impacts on earth’s climate can be forecasted.  Will we heed their warnings and make the needed adjustments as the Earth enters a cool period over the next 30 years?

Published by markskidmore

Mark Skidmore is Professor of Economics at Michigan State University where he holds the Morris Chair in State and Local Government Finance and Policy. His research focuses on topics in public finance, regional economics, and the economics of natural disasters. Mark created the Lighthouse Economics website and blog to share economic research and information relevant for navigating tumultuous times.

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