El Global Dimming is due to a reduction in solar radiation reaching the earth's surface, caused by fine particle pollution in the atmosphere, which reflects the sun's radiation back into outer space, especially when water vapor condenses around the particles. Learn more about this topic here.
Background
Global dimming, changing the climate of our planet since the 1950s, was first revealed by Gerald Stanhill, an Israeli biologist, is the reduction in the intensity of light that reaches the Earth's day.
Also known as dimming, it creates a cooling effect that counteracts greenhouse warming in our climate, this effect is likely to be partly masked by the magnitude of global warming.
From the year 1950 to 1985, the solar radiation on the earth's surface has decreased from 8% to 30% taking into account regional and seasonal fluctuations.
While, on the African and American continents, the researchers measured a 15% decrease in sunlight, the lowest dimming was measured in northern Europe and Australia and the strongest dimming (30%) in Russia. The main cause of this "global dimming" it is the activity of rich countries that continuously emit microparticles into the air.
These microparticles from our factories and the burning of oil in our vehicles, carry water droplets of Clouds, turning them into real mirrors.
What is Global Dimming?
Global dimming is defined as the decrease in the amount of solar radiation reaching the Earth's area, the product of flammables are small crumbs or pollutants that dampen solar energy and reflect sunlight back into space.
This phenomenon was first recognized in the year 1950, scientists believe that, since that year, the sun's energy reaching Earth has decreased by 9% in Antarctica, by 10% in the US, by 16% in parts of Europe and by 30% in Russia. With an average drop of 22%, this causes a high risk for our environment.
Many of the regions in much of the world observe varying elevations of global dimming, it can be said that, so far, the southern hemisphere has examined very small sets of global dimming, while the northern hemisphere has reported more revealing decreases, of the order of 4-8%.
Regions such as parts of Europe and North America have seen a partial recovery in dimming, while parts of China and India have seen an increase in global dimming.
Causes
Changes in the sun's luminosity were initially thought to produce global dimming, but it was later concluded that this was too small to state the extent of global dimming.
It has been shown that aerosols are the main cause of global dimming, both the ignition of archaeological fuels by manufacturing and internal combustion engines, which have other values such as sulfur dioxide, soot and ash, all of these constitute a particulate pollution, which are known as aerosols.
Aerosols act as precursors to global dimming in the following two ways:
- These particles enter the atmosphere and directly absorb solar energy and reflect radiation back into space before it reaches the planet's surface.
- Water droplets containing these particles in the air form polluted clouds. These polluted clouds have a higher and larger number of droplets, these modified properties of the cloud, such clouds are called "brown clouds", make them more reflective.
The vapors that are the product of smoke from planes flying high in the sky, better known as contrails, are also the ones that cause the reflection of heat and in turn the related global dimming.
Both global dimming and global warming have been happening around the world and together they have caused drastic changes in rainfall patterns, just as it is understood that it was the global dimming after the 1984 drought that killed many of people in Africa.
Scientists say that, despite the cooling effect created by global dimming, the earth's temperature has risen by more than 1 degree in the last century.
If global dimming had not happened, the temperature of this planet would be much higher and could have had a serious effect on the life of humans, plants and animals.
Evaporimetry data
La evaporimetry is an essential variable in water management and irrigation planning, hence the importance of quantifying and analyzing the methods that most satisfactorily estimate the evaporimetry at the local and basin level. Therefore, the aim of this study was to estimate the evaporimetry reference, based on meteorological data.
Throughout history, about fifty years evaporimetry records have been carefully collected, scientists pointed out something that at the time was appreciated as a rather rare fact, it is the fact that the rate of evaporation was increasing. collapsing, however, it was expected to progress due to global dimming.
Effects
While we cannot rule out the possibility that natural variations in Earth's climate (via naturally occurring cloud diversity) may have contributed to the global dimming, the effects are so closely related to trends in air pollution that there is strong evidence that human activity is an important and determining factor.
For example, European and North American clean air legislation in the 1990s corresponded to an increase in brightness in these regions. By contrast, China and India have seen further dimming, matching pollution increases from rapid industrialization.
Global dimming is believed to have had several substantial impacts. For example, there is evidence to suggest that it has masked some of the historical warming caused by greenhouse gases—in fact, the areas that have been illuminated have experienced rapid warming.
Future global dimming changes can be expected to be closely related to air pollution emissions. This would be an element that historically has not played a significant role, but that may become more revealing in the future, is the mark of warming greenhouse gases in global dimming.
If future global warming proves to be substantial, widespread damping by water vapor could be a consequence, although the cooling effect of this is unlikely to significantly reduce the overall warming trend.
rapid climate change
The soon climate change does not have much to do with a simple increase in temperatures. The reasons are many and complicated, the most extraordinary being that autonomous studies are part of a phenomenon that is linked to global warming, as well as global dimming.
This effect, which is found in any part of the planet, is a consequence of the increase in the average rate of aerosols in the air after the manifestation of various particles related to forest burning, motorized transport, the activity of our manufactures and the combustion of flammables. fossils.
Gerald Stanhill, in his action on sunlight in Israel for an irrigation project, “I was surprised to see a very substantial reduction in sunlight in Israel. When we compare these measurements in the 22s to today's measurements, we see that there was an astronomical XNUMX% decrease, and it's incredible."
We see all this dark fog hanging in the atmosphere of our cities. Beate Liepert, a German graduate researcher in climatology, conducted an independent study on the subject and found similar results.
El global dimming is no longer a doubt, also confirmed by two Australian biologists, Graham Farquhar and Michael Roderick, both from the Australian National University.
They found a global decrease in the rate of evaporation and think about the question. It seems that the key factors for evaporation are sunlight, humidity and wind. But sunlight is really the dominant factor, if the rate of evaporation slows down, it may be because the sun is setting.
The impact of this global dimming can significantly alter the rate of precipitation and decrease in other monsoon regions like Asia, eventually leading to famine in Africa first, then Asia.
Dr Leon Rotstayn, a climatologist working on atmospheric research, said: "These droughts in the XNUMXs and XNUMXs may have been caused by pollution from Europe and North America, which affects cloud properties and cools the world's oceans. North Hemisphere".
Relationship between Global Warming and Global Dimming
Speculation about the impact of variations in surface solar radiation on global warming ranges from concerns that solar dimming has largely masked the full magnitude of greenhouse warming, to claims that the recent reversal of the Solar dimming over brightness rather than the greenhouse effect was responsible for what was observed.
To disentangle solar surface and greenhouse influences on global warming, trends in the diurnal temperature range are analyzed. They suggest that solar dimming was effective in masking greenhouse heating, but only until the 1980s, when dimming gradually changed to brightening.
Since then, the discovered greenhouse effect has revealed its full dimension, as manifested in a rapid rise in temperature (+0,38 degrees C/above earth since the mid-XNUMXs).
Global dimming is a phenomenon that is produced by Fundamental Forces of Nature that act in the opposite way to global warming. Global dimming reduces the amount of the sun's rays reaching Earth's atmosphere, causing temperatures to drop around the world.
Furthermore, global dimming interferes with hydrological cycles in the biosphere and reduces the rate of evaporation, a study of global warming would not be complete without mentioning global dimming.
Global dimming is caused by an increase in particles such as sulfate aerosols in the atmosphere, the pollutants that lead to global dimming also lead to various environmental problems, such as phytochemical smog, respiratory problems, and acid rain.
Scientist Research
According to experts, the only means by which humans can avoid a climate catastrophe is to make a significant reduction in industrial activity and greenhouse gases, for example carbon dioxide (CO2). This would simultaneously reduce the dispersion of aerosols, eg sulfur dioxide (SO2) which impacts cloud nucleation and formation.
In short, less cloud cover means less cooling, that is, less dimming, in a world with this environmental impact, what generates a lot of fear and fear around because of this issue.
The effect was first discovered by Gerry Stanhill, an English scientist working in Israel. Comparing Israeli sunlight records from the 1950s with today's, Stanhill was surprised to find a large drop in solar radiation. "There was a staggering 22% drop in sunlight and it's really amazing."
Intrigued, he searched records from all over the world and found the same story almost everywhere, with sunlight dropping by 10%, nearly 30% in parts of the former Soviet Union, and even 16% in some parts of the islands. British. Although the effect varied widely from place to place, overall the decline amounted to 1-2% globally per decade between the XNUMXs and XNUMXs.
Gerry called the phenomenon global dimming, but his research, published in 2001, was met with a skeptical response from other scientists. It was only recently, when his conclusions were confirmed by Australian scientists using an entirely different method of estimating solar radiation, that climate scientists finally realized the reality of global dimming.
The dimming appears to be caused by air pollution, the burning of coal, oil and wood, whether in cars, power plants or kitchen fires, creates not only invisible carbon dioxide (the primary greenhouse gas responsible for global warming ) but also small airborne particles of soot, ash, sulfur compounds and other pollutants.
Scientists are now concerned that dimming, by shielding the oceans from the full power of the Sun, may be altering the world's rainfall pattern. There are suggestions that the dimming was behind the droughts in Africa that claimed hundreds of thousands of lives in the XNUMXs and XNUMXs.
There are disturbing signs that the same thing may be happening today in Asia, home to half the world's population. Says Professor Veerhabhadran Ramanathan, one of the world's leading climate scientists:
“My main concern is that global dimming will also have a detrimental impact on the Asian monsoon. We are talking about billions of people.
This has led many scientists to conclude that today's climate is less sensitive to the effects of carbon dioxide than it was, for example, during the ice age, when a similar increase in CO2 caused a temperature rise in 6°C
But now it appears that the warming from greenhouse gases has been offset by a strong cooling effect from dimming; in effect, two of our contaminants have canceled each other out. This means that the climate may be more sensitive to the greenhouse effect than previously thought.
Global Dimming and the Hydrological Cycle
The fundamental role of the hydrological cycle in relation to global global dimming motivates a comprehensive evaluation of its responses to climate change and mitigation. It is a coordinated international effort to assess the climate impacts of solar geoengineering, a proposal to counteract global dimming with a reduction in polluting effects.
We evaluate the mechanisms underlying the rainfall response to a simplified simulation of such solar obscuration, across the model ensemble to identify robust features.
While solar geoengineering nearly restores pre-industrial temperatures, global hydrology is altered and changes in tropical precipitation dominate the response across the entire model suite and these are primarily driven by Hadley circulation cell changes. .
Dynamic changes explain different tropical rainfall anomalies between models better than changes in relative humidity or the scale of precipitation minus evaporation (P–E), given that the temperature and relative humidity responses are robust across the suite. .
The sharp reductions in Temperature and Humidity over vegetated terrestrial regions are likely related to the physiological response to CO2 in plants and in turn contribute to global dimming.
Natural and man-made hazards of Global Dimming
Aerosols include sulfate from the burning of fossil fuels such as coal, soot from factories or firewood, road dust, and land degradation. Anthropogenic aerosols such as those from factories, exhaust pipes and fires are known to negatively impact the environment and can cause everything from darkening to warming, air pollution and accelerated glacial melting. all over the world, which have a great impact on the environment.
Generally, discussions about global dimming they focus too much on artificial sources, while neglecting natural ones. Natural aerosols include deserts, trees, sea salt, dust, and volcanoes. Volcanoes have long been known to produce a cooling effect on the atmosphere.
Volcanoes emit sulfur dioxide (SO2) into the upper atmosphere, known as the stratosphere, this is above the troposphere where weather actually happens. This impact can last for several years, unlike industrial aerosol sources that enter the troposphere and typically rain in less than a week. Natural aerosols can offset warming greenhouse gases and have the potential to cool the Earth.