by Tom Harris and Dr. Jay Lehr, ©2020

(Nov, 7, 2020) —  Democratic presidential nominee Joe Biden tells us in his ten-thousand-word climate change plan that he “has long appreciated the enormity of climate change and has always believed that we have a moral and economic imperative to address it.”

That is an understatement. Climate change is, in fact, so enormous that we have no chance of significantly affecting it. And, yes, we do have a moral and economic imperative to address it. We do that by recognizing that the Sun, not human activity, is undoubtedly the main driver of climate change on Earth, and planning accordingly.

The former vice president tells us that, should he win the presidency, America will “re-enter the Paris Agreement on day one of the Biden Administration.” Before committing America to rejoining the useless and economically-devastating treaty, Biden has an ethical responsibility to learn far more about this complex issue.

That the Sun would have a major impact on climate should not surprise Joe. Compared to Earth, our home star is a behemoth and a huge source of energy whereby only a minuscule portion comes to the Earth. Yet that is enough to raise the temperature of our planet from near absolute zero (-273 degrees Celsius) to the relatively comfortable and stable 15 C (59 F) we enjoy today.  

Contrary to popular opinion, the Sun is always changing. The variations in its apparent luminosity (called Total Solar Irradiance (TSI), which is the amount of the Sun’s power density that reaches the Earth’s upper atmosphere in kilowatts per square meter) occur over periods ranging from the well-known 11-year sunspot cycle to longer cycles lasting decades or even centuries. We see evidence that Earthly temperatures vary on the same time scales.

For example, it was during a period of high solar activity around 1000 AD when we experience the Medieval Warm Period. And it was during a period of low solar activity that the Little Ice Age occurred between 1300–1850.

This led prominent solar physicists to suggest that variations in the output of the Sun could account for most of the slight warming since at least the end of the Little Ice Age.

The Friends of Science Society has an excellent web page showing the correlation between recent TSI and temperature at https://friendsofscience.org/index.php?id=707. The below graph is described on that page as follows:

“A paper by Soon et al 2015 finds a strong correlation between Northern Hemisphere (NH) exo-tropic temperatures and total solar irradiance (TSI). The NH temperatures were determined by using mostly rural stations to remove the effects of urban development that contaminates government datasets.”

Some of the direct causes of the changes in the Sun’s energy input to the Earth are obvious:

1.     Variations in TSI.

2.     Changes in the physical Sun/Earth relationship. These changes are generally known as the Milankovitch cycles and are as follows:

·       the Earth’s orbital path around the Sun varies its eccentricity every 100,000 years, changing its distance from the Sun from 83 to 120 million miles. 

·       the tilt of the Earth on its axis varies from 22.7 degrees to 24.5 degrees over 41,000 years, altering its seasonal climate. The inclination is now 23.7 degrees.

·       the Earth wobbles slightly upon its axis as it rotates, like a slightly off-center spinning top. This cycle is called axial precession and spans about 25,771.5 years.

​A visual representation of the changes in the Sun/Earth relationship is as follows:

However, neither of these kinds of changes appear to be the direct cause of the warming seen on the Earth since the end of the Little Ice Age.

·        The first factor, changes in TSI, is, according to the reports of Working Group I of the Intergovernmental Panel on Climate Change (IPCC), too small to account for the changes we have seen since 1750. The IPCC estimate the radiative forcing on climate from solar activity between 1750 and 2011 at around 0.05 watts per square meter (W/m2). This value is essentially negligible compared to changes in anthropogenic greenhouse gases whose forcing, the IPCC maintains, is around 2.3 W/m2.

·        The second factor, the Milankovitch cycles, operate over time frames much longer than the period of recent warming.

Yet, it has recently been found that, based on measurements of the rate of sea level change over an 11-year sunspot cycle, the change in the amount of energy that enters the oceans is almost ten times larger than that due to the corresponding TSI variation alone. Something is apparently magnifying the impact of changes in the output of the Sun on temperature.

For changes in the Sun’s output to be a significant driver of Earthly climate change over the past century, there would have to be a previously unknown natural factor amplifying the TSI changes. Such a potential amplifier has indeed been discovered and, if it is correct, much of the warming in recent centuries could vary well have been an indirect result of changes to TSI.

Evidence for the existence of such a driver is described well in the paper “FORCE MAJEURE: The Sun’s Role in Climate Change” by Dr. Henrik Svensmark, a physicist and a senior researcher in the Astrophysics and Atmospheric Physics Division of the National Space Institute in Denmark. What is boils down to is as follows:

·        when the Sun is highly active, it has a stronger magnetic field

·        this field blocks a significant fraction of the Galactic Cosmic Rays (GCR) entering our solar system from deep space

·        since GCRs are understood to encourage cloud nucleation, the reduction in GCR entering the Earth’s atmosphere leads to less cloud formation on our planet

·        since clouds are known to, generally speaking, cool the planet, less clouds means a warmer Earth.

The reverse is also believed to be the case: a weaker Sun produces a weaker magnetic field and so more GCRs are allowed to enter our atmosphere resulting in more clouds and hence a magnification of the slight cooling effect of a low TSI Sun.

Svensmark summarizes:

“the impact of solar activity on climate is much larger than the official consensus suggests. This is therefore an important scientific question that needs to be addressed by the scientific community.”

So, yes, Joe, climate change is enormous. And you therefore have an ethical responsibility to properly address it by focusing on adaptation to whatever nature throws at us next, not yielding to the ridiculous calls to ‘stop climate change’ from extremists in your party.

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Tom Harris is ICSC Executive Director of the Ottawa, Canada-based International Climate Science Coalition (ICSC). Dr. Jay Lehr is Senior Policy Analyst with ICSC.

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