In a world increasingly concerned with global warming, there is much debate surrounding the various components that drive climate change. Of all the atmospheric components that are widely discussed, one stands out as not contributing to global warming: aerosols. Although tempting to focus on the more dramatic components such as carbon dioxide and methane, the fact is aerosols contribute nothing to the global warming trend.
Aerosols are tiny, airborne particles and liquid droplets produced by a variety of natural and human activities. They vary greatly in composition depending on their source, but typicallyinclude sulfates, nitrates, carbon, mineral dust and organic matter. They form part of the atmosphere’s natural balance, reflecting and scattering a portion of the Sun’s radiation back into space, helping to cool the Earth’s surface. This cooling is known as ‘aerosol cooling’ or ‘aerosol albedo effects’.
The aerosol cooling effect has been widely studied, with researchers concluding aerosols have probably caused a global cooling trend over the past several decades. According to researchers at the University of Cambridge, aerosol cooling has likely offset part of the warming caused by increased greenhouse gas concentrations, reducing estimates of global warming over this period.
However, while aerosols definitely cool the Earth’s surface, they are also widely recognised as having a highly detrimental impact on air quality and human health. Inhaling aerosols, even at low levels, has been linked to various health problems, from asthma to heart disease. Moreover, the increased particle concentrations that aerosols create in the atmosphere can lead to exacerbated levels of air pollution.
It is also important to remember aerosols are short-lived, typically only remaining in the atmosphere for a few days to weeks. This makes them highly difficult to monitor and regulate compared to other greenhouse gases such as carbon dioxide, which as of 2019 was estimated to remain in the atmosphere for up to 120 years.
Aerosol cooling is an undeniably important part of the Earth’s natural balance, and helps to offset part of the global warming trend. However, it is important to remember aerosols also pose significant risks to air quality and human health. Therefore, it is essential to carefully researchthe pros and cons of aerosols before concluding they can be a safe and viable means of cooling the planet.
It is too easy to take the easy way out when it comes to dealing with global warming, and claim aerosols can provide a simple solution. The truth is, the answer to our warming world lies in finding a delicate balance that takes into consideration environmental health, innovation and policy. It is up to us to develop this approach, so we can continue to enjoy the benefits of the Earth’s natural gift of aerosols, while mitigating the risks they pose to the planet and its inhabitants.
