A monitoring station in South Africa, founded by a team of Finnish scientists, has proved invaluable in churning out data related to climate change. Although precise measurements of the atmosphere have been taken across the globe for years, those from the African continent have been lacking – so far.
The station, founded in 2006, is intended to provide information on the composition of particles in the planet's atmosphere, or aerosols.
"These results represent the first continuous long-term monitoring of atmosphere aerosols in Africa," says Petri Tiitta from the University of Eastern Finland, who joined the project four years ago. "The measurements provide real-time information on the size and composition of the particles."
The most significant conclusions drawn from the project conducted by the University of Helsinki, the Finnish Meteorological Institute (FMI) and the local North-West University related to the dry season, the period from May to September. The biggest cause of aerosol emissions at the time were the savannah fires typical to the season.
Tiitta says that during that time, some part of South Africa is always on fire.
"The measurements showed that the particles caused by savannah fires actually had an overall cooling effect on the atmosphere. Roughly 90 percent of the aerosols were cooling, and the rest warming," Tiitta says.
In practice the fire-born particles help constitute denser cloud masses, which reflect and scatter solar radiation back into space, cooling the climate.
Emissions could halt global warming, momentarily
No direct inferences can yet be made based on the results, because the overall effect of the savannah fires must include figures for other factors such as carbon dioxide, which the study did not measure.
"In terms of climatic effects, particles are one thing and gases are another," Tiitta says. "When the global climate heats up, savannah fires are likely to become more frequent and this might work as atmospheric feedback in the same way as forests do in Northern Europe."
Similar climate change feedback phenomena include dramatic events such as volcanic eruptions. The eruption of the Pinatubo volcano in the Philippines in 1991, the most powerful eruption in recent decades, halted climate change globally for several years. A similar particle-induced cool-down effect is born when a meteorite collides with the Earth.
Measurements indicate that during the rainy season – from November to February – the highest proportion of particles came primarily from coal-burning industries.
A majority of South Africa's energy is coal-based and only a few facilities have proper filtration systems. This means that the levels of sulphate in the air can rise to dangerous levels quickly. Coal is also used for fuel manufacturing in South Africa.
Emissions requirements tightened
The results of Africa's first atmospheric measurements are considered a global breakthrough. The savannah plains of Africa are one of the most remarkable ecosystems in the world, says group leader Lauri Laakso from the FMI.
"The world population is centred in cities and especially in developing countries we see these so-called megacities," he says. "We can study the effects of urbanisation on surrounding ecosystems and the global climate."
The Finnish measurements were a factor in changing local air pollution control legislation. The Rustenburg mining area in South Africa was declared a high security zone after the results were in.
"That means that the largest gold mine in the world tightened its emissions protocols, thanks to the study," Laakso explains.
The nearly decade-old research continues with local help in South Africa.
"The project was begun with development funding from the Ministry of Foreign Affairs, but now it is dependent on the local university's research grants," Laakso says. "The situation looks good right now, and I hope we can keep it up."
The effects of aerosols on global warming have not yet been widely researched.