Dedicate 5 minutes today to read from the National Aeronautics and Space Administration (NASA) about the Milankovitch Orbital Cycles.
Above all, this theory is the most accepted explanation regarding variations in Earth’s Climate and the glacial-interglacial cycles.
What are the Milankovitch Cycles?
Milutin Milankovitch identified a century ago how variations in Earth orbital movements affect how much solar radiation reaches the top of Earth’s atmosphere.
Certainly, these changes in solar radiation are a strong driver of Earth’s long-term climate, triggering the beginning and end of glaciation periods (Ice Ages).
There are three Milankovitch Orbital Cycles which include:
1️⃣ The shape of Earth’s orbit: Eccentricity with 100,000-year cycles.
2️⃣ The tilt angle of Earth’s axis: Obliquity with 26,000-year cycles.
3️⃣ The direction Earth’s axis of rotation: Axial precession with 41,000-year cycles.
Credit: NASA/JPL-Caltech
The Causes of Climate Change
Milankovitch’s published its calculations and charts in 1920. They describe three positional cycles that influence the climate on Earth. The three cycles are the eccentricity of Earth’s orbit, the planet’s axial tilt and the wobble of its axis.
These cycles cause variations of up to 25 per cent in the amount of incoming insolation at Earth’s mid-latitudes. Most importantly, its long cycle length does not explain the rapid warming/climate change that we perceive these last decades.
Moreover, recent research supports Milankovitch’s work and the theory that Earth Orbital Cycles drive the timing of glacial-interglacial cycles.
In addition, experts consider the model a sort of a climate time machine. The model can be run backwards and forward to examine past and future climate conditions.
According to a recent publication by NASA, the solar energy received by the Earth had no net increase since the 1950s while global temperature has risen markedly.
It is therefore unlikely that the Sun caused the global warming trend and thus the change of climate over the past half-century.
Climate Change Anomalies
Another great visualization that shows the effects of climate change in the past years is the increasing number of Temperature Anomalies by Country from 1900 to 2016.
Data and definitions from NASA.
Conclusions
In short, next time somebody mentions natural variations of the Earth as the cause of climate change, you can refer to them to the Milankovitch Cycles and its thousands of year-cycle variations.
For more information, read NASA global climate change site or my article about CO2 emissions in the world: World Carbon Dioxide Emissions per Capita.
