The magnetosphere is the immense magnetic field that surrounds our planet and protects us from the solar wind, radiation and cosmic rays from deep space. The forces that generate our magnetic field are constantly changing , and therefore the Earth’s magnetic north and south poles also gradually vary in location, even reversing every 300,000 years or so.
Some people rely on these facts to claim that the magnetosphere contributes to global warming, but science does not support these arguments. On the NASA climate change blog, Jet Propulsion Laboratory journalist Alan Buis examines and refutes some of these wild hypotheses:
Magnetic movement and inversions
As we have already mentioned, the Earth’s magnetic field does not remain static, but rather shifts, and its intensity increases and decreases. However, there is little scientific evidence of significant links between Earth’s drifting magnetic poles and climate . In the case of the reversals of the magnetic poles, the fossils of animals and plants that lived on our planet during the last great inversion (which lasted thousands of years) do not show great changes, and the samples of deep oceanic sediments from that time indicate that glacial activity remained stable. In fact, the geological and fossil records of earlier reversals show nothing extraordinary, such as apocalyptic events or major extinctions.
The same is true of so-called geomagnetic excursions: short-lived but significant changes in the intensity of the magnetic field, lasting from a few centuries to a few tens of thousands of years. While there is some evidence of regional climate changes during the Laschamps event time period (the last geomagnetic excursion), the Antarctic and Greenland ice cores show no major change. Bottom line: There is no evidence that Earth’s climate has been significantly affected by the last three excursions of the magnetic field, nor by any excursion events in at least the last 2.8 million years.
Physical principles that show that there is no relationship between magnetosphere and climate change
Although it is true that electromagnetic currents exist within the Earth’s upper atmosphere, the energy that drives the climate system in the upper atmosphere is, on global average, a tiny fraction of all the energy that drives the climate system on the surface of Earth. the earth. There is simply not enough energy in the air to influence the planet’s climate.
And, much more important: while iron from volcanic ash is transported in the atmosphere, and the small amounts of iron and iron compounds generated by human activities are a source of air pollution in some urban areas, it is not a source of air pollution. significant component of our atmosphere. There is no known physical mechanism capable of connecting weather conditions on the Earth’s surface with electromagnetic currents in space.
On the other hand, solar storms and their electromagnetic interactions only impact the Earth’s ionosphere, which stretches from the lower edge of the mesosphere into space. They have no impact on the Earth’s troposphere or the lower stratosphere, where the Earth’s surface climate originates.
In short, when we talk about climate change, we must stop throwing balls away: variations in the Earth’s magnetic field are not a cause for concern, but the tons of greenhouse gases that we emit as a result of our activities are.
Texto: Global Climate Change, NASA.