Computer simulations, the aim of which is to estimate the climate of the planet’s cities by the end of this century, bring news that is not very encouraging for regions like the Mediterranean Sea, the North American interior, and, in Brazil, parts of the Midwest and the Amazon. The urban areas of these locations may get 5 degrees warmer by 2100 or even exceed this mark.
Such estimates, which vary depending on possible scenarios for greenhouse gas emissions (which store heat near the surface of the earth), have just been published in the journal Nature Climate Change. The team led by the Chinese researcher Lei Zhao from the University of Illinois in Urbana-Champaign (USA) estimates that the average for district heating at the end of the century will be 1.9 degrees Celsius despite a trajectory to reduce these emissions. 21; Without greenhouse gas savings, the average temperature increase is 4.4 degrees.
Zhao and colleagues explain that most of the computer models used to predict the future of global climate neglect the specifics of the urban environment. “Essentially, they are projections of a non-urban climate,” the scientists write. To avoid this limitation, they used as a basis the only model that takes into account certain parameters of energy flows, surface temperature and air that have already been tested in urban climate analyzes.
The methodology used by the team starts in 2006 (which makes it possible to use available data on recent climatic conditions to “feed” the calculations) and lasts until 2100, making forecasts at different times of the year and at the average temperature, the maximum are during the day and at most at night.
Both at night and during the day, the predicted situation will be particularly hot in North America, much of Europe, the Middle East, Central Asia, and northwest China. Central South America – with a focus on areas corresponding to states like Mato Grosso do Sul, Mato Grosso, and Rondônia – are at greater risk of suffering from high temperatures at night.
Relative humidity is also expected to be lower in almost all urban areas of the world over the course of the century. And the feeling of warmth, measured using two different methods, is likely to be even greater than that suggested by the direct rise in temperature, say the researchers.
“The predicted situation for the Midwest and the Amazon is undoubtedly worrying. This is probably related not only to the rise in global temperature, but also to the effects of continentality, ”says climatologist Alexandre Araújo Costa, professor at the State University of Ceará, referring to the fact that due to the distance from the ocean, areas in the interior of the continents tend to have more extreme climatic zones.
“What now seemed heavier than anything else was the Mediterranean stew we see in the projections,” he says. “It’s a densely populated region and the European summer is already complicated under normal conditions. A heat wave in such a scenario is a disaster. The 2003 tragedy [onda de calor que matou 70 mil pessoas na Europa, em especial na França] it becomes a small thing. “