The climate change that the Earth is experiencing is causing the driest areas on the continents to become increasingly drier, while the humid regions become even wetter. The water cycle is redistributing on a global scale, but it is difficult to calculate the numerical values to appreciate this trend, the Australian researchers admit.
First of all, it is very difficult to install devices to measure precipitation on 70% of the planet’s surface because this part is covered with water. Furthermore, to assess long-term change, measurements going back decades are required, ecologists Taimoor Sohail and Jan Zika of the University of New South Wales said in a paper published by The Conversation on Wednesday.
However, the research team, of which both authors are part, found a way to calculate the rate of rainfall redistribution from an available parameter, which is the salinity of the water. Its value varies between different areas of the ocean and also in the same place on the sea surface, depending on how intense the precipitation and evaporation are.
The result of these calculations is that 46,000 to 77,000 cubic kilometers of fresh water moved from the tropics to colder areas between 1970 and 2014. The water cycle intensified by up to 7%, which means that in the end During this period, up to 7% more rain fell in the wetter areas and 7% less rain fell in the drier areas (or more water evaporated from them) than at the beginning.
These findings suggest that potentially disastrous changes in the water cycle may be closer than previously thought. The most dramatic estimates for the intensification of the water cycle offered by previous studies established the value of this parameter between 2 and 4%.
The new estimates align with others, from the Intergovernmental Panel on Climate Change, which predicted that even if the world’s governments meet their goal of reducing greenhouse gas emissions and keeping global warming to a ceiling of 2 ºC, extreme weather events on the planet will be on average 14% stronger compared to a reference period of 1850 to 1900.
In addition, the Australian researchers note, the changes in the water cycle that have been observed in recent decades are largely due to older emissions, from the mid-20th century and earlier. Since then, humanity has dramatically increased its emissions.
The researchers provide more details of their study in a scientific article published on February 23.
