couple of people have asked me why “Paul Lentz” is commenting on and sometimes questioning blog posts by “Paul Lentz.” The Questioner (whose thoughts keep me honest, and which I appreciate) is my nephew. He’s about 50 years younger than I am, a graduate of the University of West Virginia, and is becoming an electronics technician in the Air Force. I want to say, again, that I appreciate his comments both on the blogs and in private email messages to me. He has caused me to do considerable research and to be more precise in my statements and more careful in my references.
Recently, he posted a comment to the blog on “Trump’s Cabinet” (2016-12-13). He posited two thoughts. First, that climate has gone through cycles in the past. Second, that the winter of 1777—1778 at Valley Forge was an indication of a climate anomaly.
He is absolutely correct that Earth has gone through climate cycles.
Just to clarify things, weather does seem to follow a seven-or-so-day cycle. If it’s rainy this weekend, it’s likely to be rainy next weekend. That, by the way, rather than the creation story in Genesis, is probably why we have a seven-day week… the ancients knew that weather tended to follow a seven-day cycle, and that cycle is probably the reason the Genesis story takes seven days.
On the other hand, climate change is defined in terms of decades, even centuries, while weather is defined in terms of “today,” “this week,” and “this month.”
Probably the most famous graphic showing climate change in terms of global temperature variation and global CO2 variation is from the Vostok Ice Cores (Antarctica) from about 450,000 years ago until today. The chart oddly enough runs time backward: the present day is on the left; the oldest data (about the end of the Ordovician Period) is on the right side.
One must therefore be very careful in reading this chart. Going from right to left, in most cases (it’s hard to see in the scale of the attached graphic), temperature changes lead CO2 changes by about 600 to 1000 years. Temperature falls before the concentration of CO2 falls; temperature rises before the concentration of CO2 rises. That does not seem to support the popular understanding of today’s scientists’ theories that rising CO2 causes rising temperatures. What’s going on?
The answer in part is that while CO2 did not cause the initial temperature changes, it amplified those changes.
The initial changes in temperature were caused by changes in Earth’s axial tilt and changes in the eccentricity of its orbit. (See my 2016-11-20 blog post [It’s All About… the Sun], in which I describe “Milancović Cycles.”)
In the case of warming, the biggest contribution of CO2 as an amplifier comes as a positive feedback phenomenon: as the ocean warms, it spews, releasing dissolved CO2. (Think of opening a warm can of soda… it spews because the warm liquid cannot hold as much carbonation—CO2—as cold liquid can.) This CO2 released into the atmosphere helps trap solar energy. The air gets warmer. The oceans get warmer and release more CO2. Other feedbacks include other sources of CO2 such as thawing permafrost and changes in snow and ice coverage, as well as changes in vegetation (which is pretty good at absorbing CO2).
There are many other things going on. For example, melting ice sheets (glaciers, sea ice) increase the amount of fresh water in the oceans, changing the huge oceanic circulation patterns that carry heat through the oceans. They also change the albedo (reflectivity) of Earth, affecting the amount of solar energy that is absorbed.
Another part of the answer is that the ice cores present (describe, show) CO2 at a global level. CO2 is easily mixed in the atmosphere and concentrations everywhere in the world are “about the same”) but temperature is presented only at Antarctica. There are better and worldwide records of the most recent glacial and post-glacial era that show this phenomenon in more detail.
In simple terms, these things “reverse” during the cooling phase.
(I realize that that’s a bit of a “trust me” answer. I plan to have more information for you in the future.)
Now, let us take a look at Valley Forge. While that particular winter was a hard time for the Continental Army, I’m not confident either that weather was extreme or that weather was responsible for most of the privations suffered by the Army. I’m going to quote from a National Park Service document. You can read the whole thing at
“… an early and romanticized version of the encampment story became a convenient parable to teach Americans about perseverance… The Valley Forge winter was not even a severe one. … Disease, not cold or starvation was the true scourge of the camp. Army returns reveal that two-thirds of the nearly 2,000 men who perished died during the warmer months of March, April, and May, when supplies were more abundant.”
What’s the lesson, here?
First, that what we are experiencing (the polar vortex, for example, as well as the El Niño Southern Oscillation (ENSO) are weather events.
Second, that climate change does seem to follow cycles. (That doesn’t mean that it’s completely natural or that there’s no human-caused component. More on that, later.)
Third, that the legends and stories we’ve grown up with aren’t necessarily true. They may teach a lesson (most parables do), but in the end, they are just stories.
Finally, that the words of Peter Abelard are important, perhaps more important then when he uttered them.
“Doubt; question everything. Doubt leads to questioning; questioning leads to truth. Distinguish rational proof from propaganda or persuasion. Be precise with words and demand precision of others. Be wary of error, even in the most sacred texts.”
I wonder. How many people, watching Fox News, watching CNN, linking to Breitbart or Huffington Post, even know those words, much less consider them.
On the other hand, I demand that you learn them and consider them. If you won’t, please find another web site to read.
Registered Curmudgeon, scientist, skeptic, humanist, and writer.