Superfact 122: We know that the current global warming, or if you call it Climate Change, or Climate Disruption, is caused by us primarily because of our burning of fossil fuels. It is not “natural causes”, and it is not orbital cycles, so called Milankovitch cycles. These orbital cycles include changes in orbital eccentricity, axial tilt, and axial precession.
The evidence that the current rapid global warming is chiefly caused by our burning of fossil fuels is extensive and for all practical purposes conclusive. One of the steps towards understanding this evidence is understanding why no known natural cause of climate change can explain the current warming, and that includes orbital cycles. Therefore, this post is just one small step towards preparing you for the evidence that the current rapid global warming is chiefly caused by us. However, there is a lot of disinformation around this specific topic.
Very briefly; Earth’s orbital cycles, called the Milankovitch cycles are largely responsible for the ice ages, but they are not responsible for the current warming because the current warming is too rapid for the orbital cycles to be the cause, and the way the warming is happening is incompatible with how a warming caused by Milankovitch cycles would have happened. In addition, according to the Milankovitch cycles we should be cooling, not warming.
I am considering this a super fact because a lot of people have been fooled by the disinformation on this topic, and there is also a lot of gaslighting from less than reputable organizations and from politicians. They have bamboozled a lot of people. About 15 years ago, I was bamboozled by the disinformation myself. That was before I took the time to try to understand the topic. Understanding a topic, and understanding the evidence makes all the difference, and that is why climate scientists are near unanimous the world over that climate change / global warming is both real and caused by us.
Ask yourself, why would the climate scientists and the atmospheric physicists around the world, including scientists at NASA and NOAA, not investigate orbital cycles and other natural causes for climate change as a possible cause for our current warming? They are the experts on orbital cycles and past climate after all. We know that orbital cycles are not the cause of the current global warming, and this is important to know. Therefore, I think it is a super fact.
What Are Orbital Cycles?
One type of important type of climate forcing that’s been the cause behind the multiple ice ages that we’ve had over the last two million years are earth’s orbital cycles, or the Milankovitch cycles. There are primarily three orbital cycles, orbital eccentricity, change in axial tilt, and axial precession. Could they explain the current warming? No, they can’t because they are too slow, we are currently in a cycle that should be cooling the planet, and the way orbital cycles would warm the planet if they were responsible for the warming is very different from what we are witnessing.
Changes in Eccentricity
Earth’s orbit is not a perfect circle. Earth’s orbit varies from nearly circular to slightly elliptical and this change can cause climate change. This shift in Earth’s orbit takes place over periods of about 100,000 and 400,000 years. Click on the video from NASA below for an illustration of Earth’s eccentricity.
Changes in Obliquity (Tilt)
The angle Earth’s axis of rotation is tilted as it travels around the Sun is known as obliquity. Obliquity is why Earth has seasons. Over the last million years, it has varied between 22.1 and 24.5 degrees with respect to Earth’s orbital plane. The greater Earth’s axial tilt angle, the more extreme our seasons are. In addition, a larger tilt angle favor periods of deglaciation. The changes of Earth’s obliquity have a period of 41,000 years. Click on the video from NASA below for an illustration of the changes in obliquity.
Axial Precession (Wobble)
Earth wobbles slightly as it rotates, like a slightly off-center spinning top. The axis of Earth’s wobble changes slowly and is called axial precession. The corresponding cycle spans 25,771.5 years, or approximately 26,000 years. Click on the video from NASA below for an illustration of the changes in axial precession.
Video Explaining Earth’s Orbital Cycles
The video below from PBS gives an explanation and overview of earth’s three orbital cycles.
Orbital cycles are far too Slow to Cause the Rapid Global Warming Happening Today
The changes in Earth’s orbit and tilt operate over 20,000+ to 100,000-year periods, making Orbital Cycles unable to drive the sharp temperature spikes seen in a single century.
Orbital Cycles Predict Slow Cooling, not Rapid Heating
About 6,000 years ago Earth’s temperature was a bit warmer than it is today largely due to the climate fluctuations caused by orbital cycles. The warm period in the beginning of the Holocene epoch is referred to as the Holocene climatic optimum. Natural causes for climate change caused Earth’s temperature to slowly cool off until the recent very sudden uptick in average global temperatures.
Below is a video that explains in greater detail why orbital cycles cannot explain the current warming. You can also read more about it here.
The Cooling of the Upper Atmosphere Tells Us the Current Warming is not Caused by Orbital Cycles or the Sun
Yes, the cooling of the upper atmosphere (specifically the stratosphere above the troposphere) is a key sign that current global warming is not caused by Milankovitch cycles or changes in the sun. Instead, observations show a warming lower layer (troposphere) and a cooling upper layer, which is the exact “fingerprint” of human-caused greenhouse gases. Other evidence that the warming is caused by greenhouse gases and not orbital cycles or the sun is the distribution of the warming across the globe and over time.
A Couple of Videos
The video below is a short one-minute overview of the causes behind global warming.
The video below from NASA is a bit longer, 13 minutes, but it gives a more detailed overview. Click here to see the page from where this is coming from.
Conclusion
We know that Orbital Cycles are not responsible for the current rapid global warming because Orbital Cycles operate on tens of thousands of years or hundreds of thousands of years, not a couple of centuries.
We know that Orbital Cycles are not responsible for the current rapid global warming because the effects of Orbital Cycles are slowly cooling Earth, not warming it.
We know that Orbital Cycles are not responsible for the current rapid global warming because if it was orbital cycles (or the sun) the upper atmosphere would not be cooling and the temperature increases would be distributed differently across Earth and distributed differently with respect to time.
Other super facts related to global warming
- Global Warming is Happening and is Caused by us
- The Hockey Stick Graph is not Wrong
- Scientists Agree that Global Warming is happening and that we are the Cause
- Climate change worsens wildfires in the US
- Without carbon dioxide the Earth would freeze
- IPCC Did Not Backtrack on Global Warming Being Human Caused
Super Facts 