Oceans Are Getting Hotter but Evaporating Less, Climatologists Say It Points to Something Unexpected
Earth's atmosphere has gone through a multitude of changes. For several millennia, the planet has witnessed many phenomena. Researchers have understood with their years of studies that a particular condition will produce certain effects. However, it becomes difficult to comprehend when conditions don't follow the expected consequences. A study published in Geophysical Research Letters describes one such fascinating occurrence on Earth.
Researchers in the study claim that despite oceans getting warmer, evaporation rates have been on a regular decline, stated IFL Science. For decades, the increasing surface temperature of water bodies meant that more water vapor would follow. However, the data acquired by experts associated with the study implied that since 2008, evaporation has been showcasing a downward trend despite surface sea temperature witnessing a steady rise.
Experts associated with the study made use of data collected from four satellites, HOAPS, IFREMER, SeaFlux, and J-OFURO3. The data indicated that before 2008, evaporation was steadily increasing with temperature; however, after that, the trend reversed. "Since then, two-thirds of the world's oceans have experienced a reduction in evaporation, resulting in a slight decline in global evaporation rates between 2008 and 2017. This contradicts what we would typically expect in a warming climate," Dr. Ma Ning of the Chinese Academy of Sciences said. The phenomenon was specifically observed in the Atlantic, Indian, and Pacific Oceans.
The decreasing trend was not observed in all water bodies in the world. It was most prominent in two-thirds of the oceans falling in the latitude range between 60°N and 60°S. Polar regions were not incorporated into the study. The findings align with reports that claim waves are getting bigger in Southern Oceans.
To ensure accuracy, the data derived from the satellites was matched with in-situ observations undertaken by the Global Tropical Moored Buoy Array (GTMBA) from 1988-2017. Both datasets showed the same findings. A group of experts felt that the unique phenomenon was an outcome of "global dimming." In this process, an increased concentration of cloud and haze prevents sunlight from impacting water bodies, therefore, decreasing evaporation despite increased temperatures.
Dr. Ma and her team do not consider global dimming as the primary reason behind this phenomenon. "Changes in wind speed may be associated with decadal variations in Earth's climate system," Ma said. "The recent decline in ocean evaporation should not necessarily be interpreted as evidence of a weakened hydrological cycle, as it may instead reflect natural climate oscillations." The change was not observed for a long time because the decrease was not substantial and nowhere near the increase in evaporation experienced from 1998 to 2007.
The finding challenges the views of individuals who claimed that increased temperatures were good for the world as it would lead to more rain. This belief had already been questioned previously, with environment conservationists claiming that in the longer run rains would happen in larger bursts leading to floods. This wasn't good for places where agriculture was not facilitated by irrigation dams. Dr. Ma's findings further put the nail in the coffin, claiming that those rains were also no longer a plausible future to depend on.