There was a recent letter to the editor published in the Pittsburgh Post Gazette making the claim that the climate change we are currently experiencing is natural and is caused by the natural wobble in the earth’s axis of rotation. Rod Elder, who volunteers on the 350Pittsburgh speakers bureau,  wrote a letter to the PG in response, Reduce Carbon Fuels, published Dec. 29, and set that mental wobble straight:

The Dec. 15 letter “Gyroscopic Precession” correctly stated that climate change is caused by the Earth’s changing axis of rotation, called gyroscopic precession. It is also caused by variations in the Earth’s orbit around the sun. The orbit is elliptical and becomes more circular in a 100,000-year cycle. The ice samples noted in the letter show that the Earth’s carbon dioxide levels vary from lows of about 150 parts per million (ice ages) to an upper limit less than 300 ppm (warming periods). This cycle takes about 100,000 years.
The problem is that the current global warming is happening in hundreds of years and is caused by human burning of carbon fuels. If we look at the factors described above, we should be starting a cooling period. But in fact, we are warming at an alarming rate.
By burning carbon fuels, the Earth’s CO2 level is now 413 ppm. This level of atmospheric CO2 has not been seen for millions of years and is clearly not natural. Since CO2 is a greenhouse gas, this abnormally high level is the primary cause of the heating we are experiencing.
It is critically important that we reduce our use of carbon fuels. The plan that seems most likely to be effective is the one supported by the Citizens’ Climate Lobby. This plan would place a fee on all carbon fuels at the well, mine or port of entry. All money collected would be returned to the citizens of the U.S. This plan is now in Congress as H.R. 763. It has 84 co-sponsors and hopefully will be enacted into law under the Biden administration.
                                                                                                                                    Rod Elder,  South Park

Image courtesy of NASA. Read their explanation of various planetary wobbles and climate change in: Why Milankovitch (Orbital) Cycles Can’t Explain Earth’s Current Warming by Alan Buis, Feb. 2020.