The Earth is losing balance/ How the Northern Hemisphere is getting darker

2025-10-01 08:38:00, Blog CNA

NASA has discovered that since 2020 there has been an asymmetry between the two hemispheres, between the solar radiation they receive and the one they reflect.

From data collected over the past 24 years, NASA satellites have revealed that Earth is getting darker. For a variety of reasons, all of them human-caused, the planet is reflecting less solar radiation than it did in the past. But they have also noticed that the Northern Hemisphere is getting darker more than the one south of the equator.

The Earth is losing balance/ How the Northern Hemisphere is getting darker

The symmetry that existed between the two hemispheres is now breaking down. This will have far-reaching consequences for the Earth's climate system, which relies on the redistribution of changes in heat or energy that fuel atmospheric and ocean circulation.

The upper atmosphere in each hemisphere receives the same average annual amount of sunlight. In 1971, using data from the first generation of satellites, it was found that one-third of this incident radiation is reflected by clouds, aerosols, and the surface itself (more by ice than by water and land).

This process is known as the albedo effect, and the glow of freshly fallen snow is a good example of what it is. Half of it is absorbed by the same surface, especially the oceans, while the rest is blocked by the atmosphere. It was also found that both hemispheres have the same albedo. This surprised scientists: there is more continental land mass in the north than in the south, where water predominates, so the latter should block more radiation.

So other factors, such as clouds, greater air pollution, and a possible difference in water vapor, would equalize the north and south. But this balance is being disrupted, and the northern hemisphere has been darkening for some time.

The Earth is losing balance/ How the Northern Hemisphere is getting darker

Another change is the increase in snow and ice melting, which was faster in the Northern Hemisphere than in the Southern Hemisphere. This is most pronounced in the Arctic. Melting sea ice loses a double albedo: it stops reflecting solar radiation, which its substitute, seawater, captures. Antarctica is also losing ice, but at a much slower rate, and the large frozen continent maintains the same albedo.

Until the beginning of the CERES era, the southern hemisphere gained energy in the upper atmosphere, while a net loss occurred in the north. But since 2020 this balance has been reversed. So the warming, although global, is greater in the north.

The Earth is losing balance/ How the Northern Hemisphere is getting darker

It will take years, perhaps decades, to see if the system is able to readjust and regain hemispheric albedo balance. Changes in precipitation, a slowdown in the main ocean current and even a northward shift of the so-called Intertropical Convergence Zone, a belt around the equator where the trade winds of the two hemispheres converge, have already been confirmed by scientists./ CNA