A favorite argument of the typical ClimateDenierTroll® is the “cycles” gambit. The planet is constantly changing they say. There are natural cycles that the Earth is always going through and climate change is a normal part of that process. Usually accompanied by abuse and invective, this information is presented as if they personally discovered it, and thousands of climate scientists had somehow missed it.
As is the case with most spurious dialectic, they are right to a point. But in the context that they intend, they could not be more wrong.
The point at which they are not right is right now, as atmospheric CO2 levels have cycled past 410PPM for the first time.* We passed upward through the 400PPM threshold in 2016. Do the math.
Atmospheric CO2 has not been at these concentrations for millions of years.** How’s that for cyclical?
CO2 levels have risen alarmingly since the beginning of the Industrial Age, shooting from 280 to the present 400+PPM average. Scientists are virtually unanimous in their belief that this rapid increase has raised the average global temperature about 2F degrees. 2016 was the warmest year on record, beating 2015, which beat 2014…etc.
The second chart here really puts things in perspective, but not in a happy way. Derived from ice core samples, this data shows carbon cycles for the past 800,000 years. As you can see, nowhere on this chart does CO2 exceed 300 PPM at any time. Levels have increased so rapidly from the fluctuations of the past geologic ages as to be unprecedented.***
The natural cycles referenced by the CDTs are called Milankovitch Cycles, and they are an uber force in terms of affecting global warming and cooling over the course of eons. The Milankovich Cycles run about 100,000 years and are controlled by the Earth’s orbital and axial variations.
This is as far as CDT’s get in their education, primarily because they are being taught at the ExxonKoch University of fossil fuel bullshit.
The fact is that the current data on CO2, atmospheric and ocean temperatures shows clearly that our situation is far outside of any fluctuation that could be accounted for by Milankovich Cycles.
We are no longer in a natural cycle. We are far outside the parameters constrained by the Milankovich Cycles.
We are now in the Anthropocene Epoch, and the Anthropocene Epoch is going to be very interesting indeed.
* Measurements at Mona Loa began in 1958. Prior to that, measurements are obtained via ice core samples.
** The increases in methane releases from melting permafrost and fossil fuel emissions are not included in these results. Methane is a far more potent greenhouse gas than CO2, but does not remain in the atmosphere are long.
***Natural carbon sinks have taken up about half of human CO2 emissions, or the situation would be worse.