A new study led by a Spanish researcher from the University of Bristol has revealed the importance of the El Niño meteorological phenomenon for the evaporation of water on the continents.
The water cycle begins in the oceans, where it evaporates and moves in the form of clouds to the continents, where it finally precipitates. Part of this rain recharges our aquifers and is used by animals and plants, while the remaining part returns to the sea through rivers. That’s how they explained it to us in a simple way at school. However, multiple scientific investigations over the years have underlined the importance of an essential factor in this cycle: evapotranspiration . Basically it is the evaporation of water on the continents, mostly through vegetation, in the process known as transpiration.
A priori, evapotranspiration can be used as a measure of global warming, since with increasing temperatures it is expected that evapotranspiration will be more intense. Now, thanks to data provided by satellites over the past three decades, new research has proven the role of this process. As Diego G. Miralles, lead author of the research, explains, “only in northern latitudes has evaporation increased at the expected speed. In the rest of the continental areas, the effect of the natural climatic oscillations of El Niño and La Niña (almost periodic cycles of oceanic temperature that cause torrential rains and droughts in the tropics) have been a much more determining factor for evapotranspiration than warming. global ”.
In El Niño seasons, the rains in South Africa and Australia are drastically reduced, which in turn causes a reduction in the transpiration of the plants, which also slow down their photosynthetic activity to avoid drying out. As the principal investigator of the article published in Nature Climate Change points out, “these regional reductions in perspiration are so intense that the total volume of water vapor from the continents to the atmosphere is severely diminished on a global scale.” And he adds, “ the future of the terrestrial water cycle depends largely on how the El Niño and La Niña cycles react to climate change . Therefore, we should pay attention to ocean phenomena in our studies of the future availability of water on the continents ”.
Thousands of researchers around the world analyze data from climate models and satellites to anticipate the fate of the climate. This study takes a further step in understanding the water cycle and global climatology through a phenomenon as important as the El Niño and La Niña cycles.
