Study finds water cycle accelerating with warming
Wet gets wetter, dry gets drier
Climate models are inaccurate, but not in a comforting way: that’s the conclusion of an ocean salinity study conducted by CSIRO and the Lawrence Livermore National Laboratory, which indicates that changes in the water cycle are running faster than models predicted.
Based on the relationship between salinity, evaporation and rainfall, the scientists have concluded that the water cycle strengthened by four percent between 1950 and 2000 – which is double the rate predicted in current climate models.
The scientists, led by Dr Paul Durack at LLNL, also supports the idea that with a warming climate, wet regions are likely to get wetter, with a corresponding drying trend in already dry regions.
Durack says the study found “robust evidence of an intensified global water cycle at a rate of about eight percent per degree of surface warming”.
An enhancement of the water cycle, he said, is driven by the ability of warmer air to hold and redistribute more moisture.
The study, published in Science (abstract here), was designed to overcome the ambiguity of land-based observations of the water cycle. Salinity provides a good proxy for both rainfall and evaporation, and with a fleet of 3,500 profilers now in the field, the researchers are able to work with a global data set.
Moreover, as Durack points out, oceans receive 80 percent of the world’s rainfall, and have absorbed about 90 percent of the heat added to the Earth due to atmospheric warming.
While the error margin in Durack’s prediction is high (water cycle accelerating 8 percent plus-or-minus 5 percent per degree of atmospheric warming), even at the low end, he says, acceleration of the water cycle would have serious implications for freshwater availability. ®
Salinity provides a good proxy for both rainfall and evaporation,
Herein lies many of the problems of particular areas of science.
Measuring the actual item to be studied is too hard, so we measure something else. While that may be accurate and convenient, it may not be, or it maybe in some areas but not in others - the added indirection makes the science less certain. At least, the data might be certain, but it relates less to what we were trying to study. We end up with lots of interpretation based on very little direct evidence.
Not a global effect...
This research applies to everywhere except the UK...
'cos it doesn't allow for droughts, hosepipe bans, and flood warnings in the same week.;)
Re: Salinity provides a good proxy for both rainfall and evaporation,
"We end up with lots of interpretation based on very little direct evidence"
Welcome to experimental physics! I know it seems like "bad science" when scientists rely on proxies, primarily because it can be hard to understand why and how proxies are used, but all of the things we can "see" directly have been observed already, so the newer things we look at have to be viewed indirectly. Ergo proxies, whether that be new particle discoveries, galactic interactions, climate, or something else.
I find it odd that if ppl who have a political view on climate modelling/change read a story based on proxy measurements they decry them as inaccurate, but then "ooh" and "ahhh" over a new particle discovery which has been discovered by measuring proxies (not referring to the OP, just in general).
Salinity isn't a bad proxy btw - the salts have a tendancy to stay where they are, there's a finite amount of water in the water cycle which has a finite number of states, so measuring the salinity gives you a decent picture of where the water is at any given time.