The amount of sunlight that reaches the Earth’s surface has been fluctuating for decades, and a new study supports the idea that human activity is to blame.
In the late 1980s, researchers first observed a steady decrease or “decrease” in the Earth’s brightness in various parts of the world, including a nearly 30% decrease in sunlight since the 1950s in a particular region of the Soviet Union. .
Only a few decades later, after the most harmful aerosols were banned and the Soviet Union dissolved, the trend suddenly shifted from a “global fading” to an illuminating effect.
Fine particles, such as sulfate aerosols, have long been suspected of creating a fog in the atmosphere that blocks the sun’s penetration. Evidence has shown that this type of pollution reflects almost all the radiation it encounters in the atmosphere, reflecting at the same time or absorbing light.
Whether or not these particles are responsible for decades of global blurring remains controversial, and some argue that natural variability, such as the absorption of clouds by sunlight, is a greater factor than polluting the amount of light that reaches Earth.
This new study aimed to take into account variations in sunlight in clear and cloudy conditions and found that man-made pollution is, in fact, a major culprit for fading.
Wild and colleagues used historical data collected between 1947 and 2017 by the Potsdam Solar Radiation Recorder. The Potsdam recording is considered one of the longest and best maintained continuous measurements of solar radiation in the world on the Earth’s surface.
Even when the sky is clear of clouds, the analysis shows that there can be strong tendencies of blurring and lightening, similar to the cloudy sky.
“Our analysis shows that strong decadal variations (fading and brightness) not only occur when clouds are considered, but remain evident in cloudless conditions when the effects of clouds are removed,” the authors write in their published paper.
With the clouds excluded, the authors argue that aerosol variations must be a substantial modifier of overall dimming and brightness.
“Although we’ve already assumed just as much, so far we haven’t been able to prove this directly,” says climate researcher and lead author Martin Wild.
It would be nice to believe that global blurring is no longer a problem, but just because the world is getting brighter, doesn’t mean our future is.
Recently, some internationally banned aerosols have begun to grow mysteriously, and even as we control scientists, scientists are concerned that the historic decline has already helped mask some of the effects of global warming.
Be warned that more sunlight pouring on the planet is not necessarily a good thing. it could make the future “Earth greenhouse” even hotter.
Therefore, some experts are looking for ways to induce global decline through solar geo-engineering, although others consider it far too risky.
Recently, for example, a study in the Arctic linked heavy mining practices to regional fading, which has shown that it has been reducing tree growth since the 1970s.
Forests are one of the most important carbon sinks on Earth, and if the growth of trees slows down with less sunlight to such an extent, we could seriously shoot ourselves in the foot.
Clearly, there is no easy solution, but this new research suggests that we have brought the problem to us.
The study was published in Geophysical research letters.