Greenhouse or fridge?
According to general opinion, the average temperature of the earth's atmosphere is increasing due to the anthropogenic greenhouse effect. However, this thesis is not entirely undisputed. An American scientist is of the opinion that the gases of civilizational origin tend to lead to cooling and that the measured temperature fluctuations have natural causes. Using computer models, University of Michigan professor Joyce Penner has calculated that carbon and sulfur emissions have a cooling effect on the Earth's atmosphere. According to their simulations, the greenhouse gases led to an energy consumption of 2.5 watts per square meter, but at the same time aerosols such as soot particles and sulphurous acid reflected twice as much energy back into space.
„This effect clouds our knowledge about the climate changes of the last 100 years. However, it cannot yet protect us from the increase in greenhouse gases that is expected in the future,” says Penner. "If further research confirms our initial findings, the warming we have recorded over the past 100 years would simply be the result of natural fluctuations." Penner presented her ideas at the fall conference of the American Geophysical Union.
Those carbon aerosols that are free in the air heat the air by 0.16 to 0.20 watts per square meter. According to simulations by Penner and her colleagues at the Lawrence Livermore National Laboratory in Livermore and the Center des Faibles Radioactivites in-g.webp
Bum, however, qualifies that these numbers are uncertain because little is known about natural aerosol sources. The reflection could also be as low as -2.4 watts per square meter. But even then, she says, the results are amazing. “I didn't expect to find such strong aerosol reflections in clouds. If these results are confirmed, we still have a lot of work to do before we understand how the climate will change in the future.”
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