Air pollution has played a significant role in climate change. A type of particle called aerosol is part of that influence.
In the ever-changing world of environmental awareness, many things can have an impact on our climate and the changes. Many people are aware of pollution and its effects, including air pollution. This type of corruption results whenever gases, dust, smoke, and fumes enter the air in harmful quantities. One form is aerosol, and these tiny particles can have a vast impact on the overall climate.
What Are Aerosols?
An aerosol is a subset of air pollution that remains suspended in the atmosphere. Some can be liquids, while others are solids. For the most part, aerosols come from natural sources, which includes:
Erosion leading to dust
Salt spray from ocean waves
Atmospheric gas reactions
Out of these kinds, some of the most impactful include smoke from the volcanic injections, as well as dust clouds kicked up within deserts. In both these situations, large amounts of aerosols can enter the atmosphere and disperse, leading to the spread of aerosol around the globe.
There are also human-made aerosols that come from many different industries, such as industry, transport, agriculture, and construction. Depending on the origin of a specific aerosol, it will vary in composition. Many involve water, salts, minerals, and potentially organic materials.
Once aerosols enter the atmosphere, they can further grow by absorbing other gases and water vapor. When they encounter moist air, aerosols will form into clouds, ultimately resulting in rain or snow which deposits particles into the land or ocean.
Whenever aerosols enter the higher levels of the atmosphere (like the stratosphere), they can remain there for substantial amounts of time. Some volcanic eruptions can lead to chemical reactions that remain in the air for years and spread around the globe. However, aerosols that are in the troposphere often quickly cycle out as they absorb water and become precipitation.
How Aerosols Impact the Climate
While it can be clear to see how fumes and other dangerous chemical reactions create a negative impact on the environment, understanding how aerosols play a role is a little different. NASA and other organizations have researched aerosols to understand the extent of their impact better. Science has found two significant ways these particles contribute to environmental changes.
One of the areas of impact on how aerosols react when in clear air. While tiny, aerosol particles have enough mass to interact with solar beams. Any particle that contains minimal traces of carbon will be closer to white, reflecting solar radiation. This reaction leads to a reduction in heat, cooling the atmosphere and the earth below.
In contrast, high amounts of dark carbon lead to much darker colored aerosols. Unlike their lightly colored counterparts, these aerosols absorb solar radiation, warming the surroundings. However, it can prevent light from reaching the surface, causing those temperatures to drop slightly. Often, these dark particles come from soot because of burning fossil fuels, biofuels, and biomass.
Whenever aerosols absorb enough water vapor and other gases to form clouds, they can create cloud droplets when in the lower troposphere. Clouds can have both cooling and warming effects on an area, as white color can reflect light, but the water particles absorb heat. The result is due to the specific composition of the cloud or clouds in question, as well as other weather effects.
To What Extent Is Human-Caused Aerosol Changing the Climate?
Aerosol particles that are of human origin often come from burnings of fossil fuels, resulting in dark-colored particles that absorb heat while creating shade on the ground level. Due to high levels of human-produced aerosols in the past years may have lead to a so-called "solar dimming," which offset some of the impact of global warming due to heat-trapping gases.
Even as there are advances in environmental awareness, we still see the impact of these human-produced aerosols on the environment. Haze clouds over urban cities and the burning of fossil fuels in many parts of Asia have caused large clouds of pollution.
Still, we have seen many changes in legislation and technology that have worked to cut back on activities that leas to aerosol production. These changes also are working towards less overall pollutants and dangerous chemical reactions in the air, which have helped to lessen the impact on the environment.
With that in mind, fewer aerosols will also lessen the influence of "solar dimming," allowing for more solar rays to reach the earth's surface. As this happens, we'll likely see the more significant impact of global warming on areas that experienced reduced effects.
On the other hand, the massive emissions of carbon dioxide have had a much more significant impact on global warming than aerosols have. These heat-trapping gases emerge from many of the same emissions that lead to aerosols, but, instead, these gases remain in the atmosphere easily and build up over time.
Whatever aerosols form at the time of CO2 emissions will pass out of the atmosphere far quicker than heat-trapping gases will. These gases also spread throughout the atmosphere, while most aerosols remain near their point of origin and pass out of the troposphere quickly through the formation of clouds. As such, they cannot counter each other enough to reduce the impact of global warming.
Do Aerosols Have Potential as a Form of Climate Intervention?
While the current balance of human-made air pollution and aerosols, there is no way for these particles to counterbalance the negative impact on the climate fully. However, some scientists have proposed the idea of climate intervention. The goal is to slow down the effects of global warming to allow for more time to enhance technology and put countermeasures into place.
Specifically, this plan hopes to artificially increase the concentrations of white aerosol particles, placing them in the lower stratosphere and above ocean surface areas. When enacted, the white aerosols would contribute to reflecting solar waves, keeping them at bay from the earth and reducing the overall amount of heat in the atmosphere, prolonging the effects of solar dimming.
However, this strategy has many uncertain elements to it. While we have seen how aerosols can impact the client, we do not yet fully understand the role they play in the balance of the atmosphere. By putting large amounts of aerosols in the atmosphere, we don't know the full reaching effects it could have on ecosystems, agriculture, and human health.
With climate intervention in its infancy, we may not have the time to conduct the necessary research to ensure the effectiveness of such a strategy. Additionally, there would be hurdles regarding how to place these aerosols in the atmosphere without causing additional harmful emissions. And since the atmosphere is not static, we don't know how far-reaching the impacts could be.
Even if it were possible to put these particles into the atmosphere without any dramatic consequences, they still do not remain in the air for long. Even aerosols in the stratosphere last for a few years, while heat-absorbing gases can last for decades. The potential offset may not be worth the effort it would take to maintain such a strategy.
As things stand, only cutting back on carbon dioxide will produce the results we need to combat global warming properly. Aerosols may play a role in impacting the climate, but it is a smaller role that will only help to alleviate some of the current environmental issues, not provide the correct solution that we need.
Future Studies into the Impacts of Aerosols
If we are to try and implement aerosols into a form of climate intervention, then we need to understand better the way they interact with the atmosphere. Science has made a great deal of progress in studies of aerosols, such as tracking the dynamics in the atmosphere and how air exchanges between the stratosphere and troposphere.
NASA's ongoing Atmospheric Effects of Aviation Project has played a significant role in understanding much of how aerosols interact in these spaces. The project works to pay attention to emissions from both commercial and research aircraft. Jet engine emissions do affect aerosols and atmospheric water vapor, further impacting the formation of clouds, though there is some question to the full extent.
Similar studies have been happening to see how aerosols from such aircraft and other emissions impact the concentration of clouds. The goal of these and other reviews is to understand the interactions of aerosols within the complex system of the atmosphere.
Even if we don't use such information within the context of climate intervention, it still has an essential place in further understanding our environment. Both natural and human-made aerosols can have similar effects, which may help us repair the atmosphere once we cut back on carbon dioxide emissions. More comprehensive knowledge is the key to this role.
Moving forward, we will likely see a continuing decrease in human-made aerosols as we move more towards environmental friendliness. Thankfully, many of these changes in practices will lead to less carbon dioxide emissions, reducing the concentration within the atmosphere.