A new study used geologic data to reconstruct past climate changes to find out how the global water cycle was linked to temperature changes.
The study, published in Nature Geoscience, was carried out by Past Global Changes Iso2k, a multinational team led by Dr Bronwen Konecky from Washington University, in collaboration with Associate Professor Greg Skrzypek from The University of Western Australia's School of Biological Sciences.
"The research used geologic and biologic evidence preserved in natural archives, including 759 different paleoclimate records from globally distributed corals, trees, ice, cave formations and sediments to understand global water cycle changes," Associate Professor Skrzypek said.
In the global water cycle, water evaporates from the surface of the Earth, rises into the atmosphere, cools, and condenses into rain or snow in clouds before falling again to the surface as precipitation.
The water mass movement and changes between vapour-liquid-solid phases depend on temperature and at the same time influence global heat distribution.
"Each water molecule that is part of the cycle has a certain isotopic 'fingerprint', or composition, which reflects small variations in the atomic weight of the oxygen and hydrogen atoms that comprise the molecule," Associate Professor Skrzypek said.
The study provided the first evidence that on a global scale, temperature and the isotopic composition of environmental waters go hand-in-hand and have done for centuries.
When the global temperature is higher, rain and other environmental waters contain more heavy hydrogen and oxygen isotopes.
"Fluctuations in the global water cycle over the past 2,000 years closely tracked the cooling and warming of the planet", Associate Professor Skrzypek said.
The changes observed were driven by global ocean evaporation and condensation processes, with lower values during the period of time known as the Little Ice Age (1450-1850) and higher values after the onset of human-caused climate warming, starting around 1850.
The findings suggest that more water cycle changes are likely as global temperatures continue to increase.
