Nature Climate Change asks this:
How does snow affect the amount of water in rivers?
New research has shown for the first time that the amount of water flowing through rivers in snow-affected regions depends significantly on how much of the precipitation falls as snowfall. This means in a warming climate, if less of the precipitation falls as snow, rivers will discharge less water than they currently do.
From the University of Bristol and the department of obvious science.
How does snow affect the amount of water in rivers?
New research has shown for the first time that the amount of water flowing through rivers in snow-affected regions depends significantly on how much of the precipitation falls as snowfall. This means in a warming climate, if less of the precipitation falls as snow, rivers will discharge less water than they currently do.
The study by PhD student Wouter Berghuijs and Dr Ross Woods, Senior Lecturer in Water and Environmental Engineering in the Department of Civil Engineering at the University of Bristol together with a colleague from Delft University of Technology is published online in Nature Climate Change.
The researchers, using historical data from several hundred river basins located across the United States, investigated the effect of snow on the amount of water that rivers discharge.
How river flow is generated in snowy areas is poorly understood due to the difficulty in getting appropriate measurements. Previous studies have mostly focused on the role of snowfall for the within-year distribution of streamflow – how much water is there in the river during a particular period of the year – and assumed that there was no important effect of snow on the average streamflow. This study is the first to focus on the role of snow for how much water is on average available in rivers.
With data from 420 catchments located throughout the United States the researchers show that snowiness is an important factor for the average river discharge.
Global warming is very likely to reduce the amount of snow significantly in snow-affected catchments, even if temperatures rise only two degrees Celsius. The new research suggests that the amount of water in rivers will be reduced as a result of the decrease in snow.
The authors of the study said: “With more than one-sixth of the Earth’s population depending on meltwater for their water supply, and ecosystems that can be sensitive to streamflow alterations, the socio-economic consequences of a reduction in streamflow can be substantial.
“Our finding is particularly relevant to regions where societally important functions, such ecosystem stability, hydropower, irrigation, and industrial or domestic water supply are derived from snowmelt.”
Given this importance of streamflow for society, the researchers propose that further studies are required to respond to the consequences of a temperature-induced precipitation shift from snow to rain.
Paper: A precipitation shift from snow towards rain leads to a decrease in streamflow, W. R. Berghuijs, R. A.Woods and M. Hrachowitz, Nature Climate Change, Vol 4, June 2014.
PR Source: Eurekalert http://www.eurekalert.org/pub_releases/2014-05/uob-hds051614.php
So if snow affects the amount of water in rivers, what’s in store for us folks in Texas?
Mike in Houston
Nick Stokes states, “It’s not obvious science. It asks the relevant question, how does the amount of river runoff vary depending on whether a given amount of precipitation falls as rain or snow? Is that something you all knew?”
Sir – every rancher/farmer in the area I was raised who possessed only a sixth-grade education have known for generations exactly what the fall/winter/spring snowfall/rainfall amounts and the differences thereof meant to irrigation for the spring/summer/fall planting/growing/harvesting season.
You should have expressed surprise, instead, that city slickers (to whom the science was not obvious) should have taken so long to discover those facts.
Nick Stokes: Your point is well taken. The study focuses on the average streamflow, not the transient flow. They find that this depends more on average snowfall than rainfall. As you say, it is worth finding out. If anyone commenting has actually read the paper, maybe they could provide more insight.
“Given this importance of streamflow for society, the researchers propose that further studies are required to respond to the consequences of a temperature-induced precipitation shift from snow to rain.”
The bottom line. Give us more money please.
If one expects less flow it follows that the capture of more water is necessary. The logical solution is more dams and increased capture of the water available for storage. Do you think the green pay masters would agree?
This paper marries perfectly with my theory that snow is made entirely of water.
Before any carbonazis who lurk here and wish to pick on me and totally refute it, it’s only a personal theory derived from models.
So there will be less runoff according to this warmist but more floods according to others. And the media will report AGW caused water shortages and AGW caused floods. It’s cool how that works.
My wife and I take twice daily readings every day of the year (as do many volunteers every day across North America) re, rain fall, snow depth, snow on ground and dew . The only thing this article reminds me of it is a….
SNOWJOB!
Is this new? Really? Cause I thought papers weren’t supposed to be published if they didn’t cover new ground? Or is that only when they don’t support an alarming idea?
I’ve been at the base of m/any “glaciers” in the Canadian Rocky Mountains. I’ve read good travel stories of others following drainages that start as glaciers in the Andes. The situation is the same: the direct amount of melt is small coming from the ice masses, but the rives downstream are full and raging. Why? Because rainfall and snowmelt (going into the water table) are the dominant sources of water in all rivers.
Look at the waterflow in all signficant rivers that are sourced in glaciers (except, of course, Greenland or Antarctica) and you’ll find the same. It is general precipitation that counts. The world experiences roughly 1000 mm of rainfall/precipitation per m2 per year. The direct portion that is glacial fed is small, obviously, when the oceans are rising at about 2 mm/yr.
Pretty much, yes. You didn’t?
There are these things called hydrologists that study and understand river flows. I am one of them. Snowmelt is well understood and there aew several well established snow melt models so what exactly new or novel are these fools doing? Plus they are totally wrong! When snow accumulates low flow is reduced and theb in melt season elevated. If less snow there will be reduced annual varriation in low flow but the mean flow does not change. It only changes if net precipitation changes and that varies massively from year to year.
“Well, then I guess it’s a good thing that the trend for fall and winter snowfall in the Northern Hemisphere winter is up!”
Winter snowfall plots better as a shift in mean snow extent starting 2007..
https://www.flickr.com/photos/122205302@N02/13602645375/
Exhibits as 7 points above the long term mean, with an average extent about 1,5 km2 greater.
Another “Given global warming, . . . .” study.
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Bill Illis says:
May 18, 2014 at 5:27 pm
Every news release start with “New research shows for the very first time …”
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Not only that, they have to trash previous studies by saying how deeply flawed they were.
I am not a hydrologist, but I have watched my local river (the Missouri) for over 24 years now. I can say the river flow is probably way more complicated, as well as better known by practicing hydrologists, than these authors suggest.
tumpy said it best, and, as usual, Stokes is spouting nonsense. It requires little, if any, intelligence to realize that precipitation is precipitation (i.e. water is water) and whether it appears out of the sky as snow or rain has nothing to do with the total amount of water we receive, and which will eventually end up in the rivers. So, in effect, these morons are actually claiming is that a
warmer Earth is a drier Earth, which is not true if you believe either the other global warming alarmists or the skeptics. Or you possess a brain. This study is so dumb I wonder whether even alarmists, other than deadenders like Stokes, will buy into this nonsense.
The main takeaway is that global warming causes publications to happen.
Not going to pretend I read the paper. I am going to have to ask how did they come up with their comparative answer, though, by parallel worlds where they could see what happened in a given river when the climate provided the precipitation in the form of snow in one and rain in the other, or did they use (I hate to use this phrase) computer simulation to create their data? I can’t see how you could actually claim to know as a truth that precipitation falling as snow causes greater average stream flow any other way.
Since parallel worlds are probably not available to the researchers, then the computer simulation has to be the route they used, and when you are coding in your belief set, oddly enough, the program outputs proof of your beliefs. Why is it that the climate change people can’t understand that a computer simulation can only output according to the sum total of the variables they choose, and if they don’t choose ALL of the variables, they can NOT get an accurate output from the simulation? But of course, they already know that, just as do the politicians that use these simulations to scare people, do as well. It’s only the under educated population that doesn’t.
This almost surely has to do more with increased evaporation in a warmer world than precipitation.
Nick Stokes says:
Rather, it is obviously not science.
That is not the relevant question.
Given that “global warming” theory also asserts that overall precipitation over land will increase in response to the same mechanism that is situationally asserted to cause both more snowfall and less snowfall, the relevant question is – What is the net effect?
That is not the question asked by this “science”, but it is the question being “answered” by this “science”. Completely unscientific bullshit.
If (as “global warming” theory asserts) more precipitation will fall on land
and if (as “global warming” theory now also asserts) less precipitation will be discharged by rivers
then where the F@ur momisugly#$ is all that water going?
corollary conclusion If more precipitation falls on land, but less is discharged from rivers into the sea … then “global warming” will cause sea level to decline!
Woo hoo! Turns out that the cure for “global warming” is … “global warming”.
What we all know is that there is no coherent theory of climate. All there is are a bunch of disconnected and frequently contradictory assertions about how little pieces of a massively multivariate and recursive system might work.
Well, there is that plus a bunch of political actors pretending to be scientists spinning each of those disconnected factoids into a wholly inconsistent narrative of original sin and retribution with a conveniently left wing political “solution”. That is the current state of “climate science”, and that is why the models don’t work. And why the more the models fail the more that confidence in them is more loudly asserted.
Utter bullshit.
When precipitation falls as rain, it could evaporate and fall again before it gets to a river. So there might be some double counting. It is important to look at the overall effect.
Several points not mentioned in this study at this point : if snow precip gets to the river but rain precip not as much, where did the missing rain precip go? Also,why the implied claim that precip going into the river is preferable to precip going elsewhere? What do they consider a “significant missing amount” to be, and why? Until there are satisfactory answers to these questions, I will :
1) not believe their data and 2) until that data is enumerated, not believe it makes any meaningful difference whether the precip went where they think it should have gone, without some logical arguments that make sense (not holding my breath). I also don’t believe they have any clear and irrefutable correlations beween avg temps and snowfall amounts. And I KNOW they have no knowledge of future temps. They also have failed to show that less river flow and more precip NOT going into the rivers is not beneficial. They have chosen to adopt but one view of the effects, which means they haven’t done their job as investigators. We all know that precip runoffs do no good for the flora and crops, etc.
their next paper will be on the unexpected rise in temperature with the sunrise and the unexpected fall in temperature with the sunset …
Eli Rabett says (May 19, 2014 at 8:03 am): “This almost surely has to do more with increased evaporation in a warmer world than precipitation.”‘
According to the abstract, they applied “the Budyko water balance framework to catchments located throughout the contiguous United States.”
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2246.html
A quick Google search and… “The Budyko hypothesis describes the annual water balance as a function of available water and energy. Mean annual actual evapotranspiration approaches mean annual precipitation as the climate becomes drier, assuming the long-term change in basin water storage is negligible.”
http://adsabs.harvard.edu/abs/2010AGUFM.H23D1231W
Intuitively, this makes sense. Snow is cold, and when it melts it’s still cold, so less evaporates while running off than warmer rain would. River catchments where snow falls are presumably colder than warmer areas where it rains, so there is slower–and later–plant growth and so less water is lost via transpiration. Result: more runoff for the river.
So if I’m interpreting this paper correctly, the authors are making the rather banal prediction that–all else being equal–a river with a cooler catchment area will lose less water to “evapotranspiration” than the same river with a warmer catchment area. Seems reasonable as far as it goes, but of course as we all know, “all else” is never equal.
‘jorgekafkazar says: May 18, 2014 at 8:49 pm
Jason H says: “Global warming causes less snow, except when it causes more snow…”
No, no, Jason. Global warming causes less snow AND more snow AT THE SAME TIME.’
NO..NO..NO
You both got it wrong. Global warming causes more snow AND less snow AT THE SAME TIME.
or “Global warming causes more snow, except when it causes less snow…”
And I got a computer to prove it.