Claim: Urban climate change means more rain

A UCSB geographer collaborates to model the impact of changing precipitation patterns in northern European and North American cities


Southern cities such as Houston and Tampa — which faced the wrath of hurricanes Harvey and Irma, respectively — may not be the only urban environments vulnerable to extreme weather. Northern cities also face the potential for flooding as global temperatures continue to warm.

In fact, higher temperatures have been found to disproportionately affect northern land areas, particularly the Arctic, which has already experienced fallout from climate change.

A new study by a group of international researchers, including UC Santa Barbara’s Joe McFadden, combines observations and modeling to assess the impact of climate and urbanization on the hydrological cycle across the distinct seasons in four cold climate cities in Europe and North America. Their findings appear in the journal Scientific Reports.

“In general, the amount of precipitation is increasing but also the kind of precipitation is changing,” said McFadden, an associate professor in UCSB’s Department of Geography. “While more precipitation may fall in a year, it arrives as rain rather than snow because temperatures are rising. A shorter period covered by snow, more spring rain and faster snow melt can combine to release large amounts of runoff that have the potential to stress urban hydrologic systems and cause flooding in urban areas.”

The scientists used measurements taken in Minneapolis-St.Paul, Minnesota; Montreal, Canada; Basel, Switzerland; and Helsinki, Finland. Lead author Leena Järvi of the University of Helsinki coupled those with an urban hydrological model — the Surface Urban Energy and Water balance Scheme (SUEWS) — to perform a multiyear analysis. The investigators found that after snow melt, urban runoff returns to being strongly controlled by the proportion of built-up versus vegetated surfaces, which can absorb water. However in winter, the presence of snow masks this influence.

Basel had more than 80 percent impermeable surfaces, whereas the American site — a first ring suburb in Minneapolis-St.Paul — had the lowest amount of impermeable surface, about 10 percent.

“Combining measurements and modeling in this way is very valuable because it gives us a starting point to compare different cities, gradations between the city and the suburbs or changes in the city as it grows over time,” McFadden said. “Once we understand how that works, that knowledge is portable and can be used to understand other problems.”

According to McFadden, not only does this analysis demonstrate that wintertime climate can be important for northern cities, it also shows the effects in terms of flood risks. However, he noted, how this plays out within each city is a complex interaction.

“We showed that the model accurately represents what we measured in cities, so now we can use it to conduct sensitivity studies, where only a single variable — the percentage of the city covered by impervious versus pervious materials –changes,” he said. “Then we can examine how the melt of the snow and the runoff changes in light of the percentage of each city’s impervious surface. This is really important because it helps us understand how the built environment of the city modifies the effects of global climate factors.”


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September 12, 2017 9:27 am

I’ve always wondered how many angels could dance on the point of a pin. Now I know.

Reply to  jorgekafkazar
September 12, 2017 9:36 am

42 right?

Reply to  Mark S Johnson
September 12, 2017 9:39 am

Yes!! The Answer to the ultimate question. Finally.

Reply to  Mark S Johnson
September 12, 2017 10:33 am

Wait, what was the question? I forgot.

Reply to  Mark S Johnson
September 12, 2017 11:40 am

The answer to Life, The Universe, and Everything!!!!

Dr. S. Jeevananda Reddy
Reply to  jorgekafkazar
September 12, 2017 8:57 pm

Let me present few cases in this context:
1. My state [undivided Andhra Pradesh] in India took up cloud seeding operations to augment precipitation in the state. For this US agency was given contract. The government appointed a technical committee to evaluate the results – I was one of them. We recommended not to “seed” intensive cyclonic system as we found such a seeding operation reduced the precipitation in downwind direction. The operator rarely seeded local clouds. The operator argued that the agreement has no such clause. Then I sent a mail to Chief Minister of the State on the dangers of this operation. He forwarded my letter to the officer in-charge of such operation. He discussed with me and stopped further extension to cloud seeding operation – though the minister wanted further extension for five more years. In China during Olympics the seeded clouds to stop rains in the games arena. On this farmers fought with the government in the downstream of winds of operation.
2. Mumbai Santacruz Airport – for expanding runoff for international flights they removed a hillock in the runway line. This gradually reduced precipitation by around 300 mm – compared Santacruz and Alibag/Colaba precipitation time series. After building the new terminal for international flights, large buildings have come up around the Airport. Again, this slowly reached original level of precipitation.
3. Indian rainfall is Topographic in nature. For example, the Western Ghats and Himalayan mountains [act as box] controlled the rainfall in the respective regions. On the windward direction [west of Western Ghats] high rainfall and on the leeward [east of Western Ghats] poor rains have been receiving in the southwest monsoon season and exactly opposite during the northeast monsoon season. The box effect of Himalayan Mountains created Chirapunji as the wettest place in the world.
4. The city of Hyderabad, where I live, with one-thirds of the state population was devastated by floods in Musi River that passes through the city in 1907 September. The then Navab to contain flood effect built two reservoirs across Musi and its tributary Easa. These two reservoirs to date providing drinking water to the city. In this catchment area there is no trend in rainfall time series except year to year fluctuations. However, the inflows to the reservoirs reduced drastically with construction activities in catchment area including Shamshab International Airport and outer ring roads. Within the city Musi River turned into a cesspool of poison with encroachments reducing by more than 50% of the area. Even the chained lakes built by past rulers that join Musi were encroached by more than 70% and rain water channels by more than 80%. In 2000 September flooding affected the city.
That means, there are several localized factors define the increase or decrease of rainfall — generally not influenced the precipitation associated with general circulation system –. It may influence localized thunderstorm activity that give local rains not widespread rains.
Dr. S. Jeevananda Reddy

paul courtney
Reply to  jorgekafkazar
September 13, 2017 10:13 am

97% of angels is the consensus science.

September 12, 2017 9:38 am

Models…. Ha!
NOAA can’t even figure out where Irma’s heavy rainfall remnants are headed. Last night they were still showing it headed to Tennessee. Rightnow, radar shows the heavy rainfall with remnant Low Pressure is over Southeast Arkansas headed into Louisiana.
Now this UCSB toady is trying to make me believe his models about future warming and urban precipitation show him anything but noise and tuned outputs? And they seem to believe they have the single variables mapped out and are separable, as if they know there is a linear response and the parameter coefficient associated with that assumption.
And I love this statement from the presser.

“not only does this analysis demonstrate that wintertime climate can be important for northern cities, it also shows the effects in terms of flood risks. However, he noted, how this plays out within each city is a complex interaction.

So the strategy seems to be: throw in two trivially true statements (wintertime climate is important to Northern cities, and floods have risks), and end on waffling disclaimer. Send more money.

Dave Fair
Reply to  joelobryan
September 12, 2017 11:48 am

Joel, they have done essentially the same thing as global climate models: Develop a model for particular data (tune), then extrapolate to unvalidated areas. Pseudoscience!

Bryan A
Reply to  Dave Fair
September 12, 2017 12:24 pm

This could make it possible to eliminate much runoff in city areas

Though it would also allow Saltwater intrusion from storm surges and create a greater potential for Sink Holes beneth the hardened surface

Tom Halla
September 12, 2017 9:41 am

So cities create their own weather? AFAIK, most weather patterns move in from outside the urban areas. Flooding is more of a truly local phenomenon, where land use might have an effect.

Reply to  Tom Halla
September 12, 2017 10:03 am

Cities have sometimes created their own weather. Their heat increases formation of convective showers and thunderstorms, which then cause extra rain – usually shortly downwind of the cities. This is not new.

Clyde Spencer
Reply to  Donald L. Klipstein
September 12, 2017 11:09 am
Mark Luhman
Reply to  Tom Halla
September 12, 2017 10:12 am

I live in the Phoenix are more correctly Mesa, yes the city does affect weather it take a very large thunderstorm to make it across out 100 mile wide city, most are deplete by the updraft that city creates often they will split rather than enter the city. Highway 60 through mesa it in most place sixteen lanes wide (it still a parking lot during the afternoon and morning depending what way you are going at those times.) Will stop a thunder storm in it tracks. it the storm is not large enough to overcome the updraft it will stall on one side or the other depend which direction the storm comes from,(down here they can come from all directions, it strange watching storm come from the east,living in the Minnesota ans North Dakota and storms out of the east only meant it was backing up, since they normal travel west to east.) When the sixty stops a storm the side it stops it on get drenched. So yes cites can change weather patterns just like mountains and valleys. even some not so noticeable geography.

Pop Piasa
Reply to  Mark Luhman
September 12, 2017 3:23 pm

UHI effect has a very observable effect in areas of low TPW.

September 12, 2017 9:49 am

It would seem to me that the local geography where the urban setting was located would be a larger contributor to water management than strictly impervious/penetrable surface area. Where the melt water runoff can escapes or is channeled will also contribute. There are huge topographical differences between Basel and Minneapolis.

September 12, 2017 9:53 am
September 12, 2017 10:06 am

So is snow cover supposed to melt faster than before, or slower than before despite melting earlier? I remember a study saying slower, because earlier in the year means less sunlight reaching the ground so fewer W/m^2 of solar power is available to melt the snow.

Mark Luhman
Reply to  Donald L. Klipstein
September 12, 2017 10:22 am

Humans can change the rate the snow melts, agriculture has been doing that all my life and it has nothing to do with CO2, a field left black in the fall will add dirt to the snow allowing sunlight to melt that snow faster. If the dirt of the field pokes through and the sunlight can get to, the snow will melt very fast, the native prairie right next to the plowed field will have snow cover over it for a few more weeks, a forest area with have snow up to a couple of months longer, add in that were mankind farms he eliminates both native prairie and forest areas to create the fields in the norther latitude such activity can have a enormous affect on the local climate. Yet since the human race only occupies the world 3% of the earth surface. the affect is small, yet in our temperature record the affect is large since that were most of out thermometers are were we are.

Tom in Denver
September 12, 2017 10:12 am

OK I get it, AGW will only cause bad things to happen, nothing good. If there is more rain it is the ‘bad’ more rain with flooding. if it is less rain it’s ‘Flash droughts’ (whatever that means).
There is simply no scenario where AGW could possibly cause higher crop yields, or cause me not to have to run my sprinklers as much in the summer.
As Stephen Schneider put it in a sudden moment of honesty: “So we have to offer up some scary scenarios, make simplified dramatic statements and make little mention of any doubts we may have…each of us has to decide what the right balance is between being effective, and being honest “

Reply to  Tom in Denver
September 12, 2017 10:19 am

Yes, the ‘more rain’ in summer is the bad kind…. surface flooding from summer storms is on the increase in UK cities – and not just cities… this sort of thing happens more often too:

Reply to  Griff
September 12, 2017 11:37 am

More rain in summer is the good kind. It means better harvests. That you can no longer manage your rivers in UK is not a climate problem. It is partly due to local incompetence and partly to silly EU rules.

Reply to  Griff
September 12, 2017 12:27 pm

Griff don’t be a pratt…again
The increased flooding in cities is entirely man made… inadequate drainage & too much concrete; nothing to do with climate
England Wales Precipitation for the last 250 yrs shows a steady linear trend of just +1.8mm/dec
your example –
Coverack 2017 – no injuries have been reported.
Boscastle 2004 – one broken thumb
Lynmouth Flood 1952 – deaths = 34
(Floods also in 1607 and 1796)
now go & look at the geography & hydrology of those areas

Reply to  Griff
September 12, 2017 6:41 pm

Griff, weren’t you whining about the drought in Montana in an earlier post?

Reply to  Griff
September 13, 2017 1:14 am

“In general, the amount of precipitation is increasing but also the kind of precipitation is changing,” said McFadden”
Not what this graph from Science of Doom sayscomment image

Reply to  Griff
September 13, 2017 7:11 am

More rain in the summer is a negative feedback that eliminates most if not all of the extra heat.

Reply to  Tom in Denver
September 12, 2017 10:29 am

Effective for what cause? I would think honesty would be the best course of action unless your cause is less than honest.

Leonard Lane
Reply to  rocketscientist
September 12, 2017 11:45 am

Tom. The very fact that they discuss the balance between lying and being honest tells us what we need to know about their constant blabbering about climate change (really global warming). We know enough to dismiss most of what they say and suspect the remainder.

September 12, 2017 10:48 am

Which could mean drought depending on the blame game in play.

September 12, 2017 10:50 am

“but also the kind of precipitation is changing”
So it’s the wrong type of rain is it?
We got the wrong type of snow in the UK several years ago, which made the trains late because it only fell on the railway tracks.
They never used that daft excuse again.

September 12, 2017 10:59 am

This appears to be a study of the effects of urban development on drainage systems and had little or nothing to do with “Climate Change”, which is code for AGW.
I suppose adding the key words in the paper’s title may have influenced availability of funding for the investigators. It would be more informative if articles like this listed the title of the grant proposal rather than the title of the paper.
If the grant proposal offered to perform an investigation of the effects of the hypothesized AGW on urban environments, it was very obviously not satisfied in any way by these results, which simply point to the effects of impervious surfaces on waste water removal (storm drains) in urban environments. If that’s truly the case, it’s an example of fraud and should be prosecuted by the US attorney general and the Reagents of the UC.

Tim Ball
September 12, 2017 11:08 am

As usual nothing new here. My doctoral thesis supervisor Bruce Atkinson did his doctoral thesis on the changed precipitation pattern in London England caused by the Urban Heat Island Effect (UHIE) over 40 years ago. He was building on the work done by Chandler 50 years ago. Every time one these people say or write anything they prove how little they know about climate and climate research. As I said many times, the IPCC effectively stopped any advance in climate research after 1990.

Rhoda R
Reply to  Tim Ball
September 12, 2017 11:25 am

I sort of remember, from my schooling back in the dark ages, that research of work already done was one of the prerequisites to designing a scientific study. Just so that you don’t inadvertently reinvent the light bulb, as it were.

NW sage
Reply to  Rhoda R
September 12, 2017 5:16 pm

That is true – except in climate ‘science’. In the climate world if there are three identical studies on the same thing (published separately of course) the results count triple the weight in convincing the deplorables. Obviously 3 times as many studies are WAY better than just one!

September 12, 2017 11:13 am

So I looked at the climate-at-a-glance precipitation data for Minneapolis-St. Paul and divided it into a 7 month period starting in April (during which most precipitation falls as rain) and the 5 months starting in November (mostly snow). In the mostly rain months it was very dry in the 1920s and 1930s and has been trending rainier ever since. The snow months don’t show much of a trend. Not much sign of the drought of the 20s-30s. Both the rainy and the snowy periods show an overall rising trend of precipitation since 1895.

September 12, 2017 11:16 am

In winter, air circulation depends on the pattern of the stratospheric polar vortex. This pattern arises over long periods of time.

Bill Illis
Reply to  ren
September 12, 2017 5:57 pm

Funny there is this “hole” that is supposed to start up about right now but at 60S, there is all-time world-record high Ozone levels.
Doesn’t that image just make it clear that all that happens is that the polar vortex sweeps the Ozone to 60S and 50S during the hole periods and then it moves back in by December.

Richard Bell
September 12, 2017 11:23 am

No one ever talks about all of the good effects of climate change. I saw a video which explained that Atlantic hurricanes spawn off the coast of Africa where hot dry air from over the Sahara meets cooler moist air from further south over warm water.
As vegetation reconquers the Sahara desert, the Saharan air stream will be both less dry and cooler and global warming will mean that moist air from further south will be warmer. Both of these conditions will weaken the storms resulting from the convergence.
A warmer globe leads to more clement weather.

Peta of Newark
September 12, 2017 11:24 am

It is really really worrying that people actually have become as moribund and dumb as these folks seem to think. And obviously program into their computers.
As an example I give you this:
(it contains video from the beeb – may not show everywhere but how the fook do they manage to let grow 250 tonnes of blubber in the drains under London?)
That thing did not just ‘appear overnight’
Has buck passing and sheer laziness got sooo bad.
In Victorian times, entrepreneurs went down there, gathered that stuff and cleaned it up a bit then sold it back to the consumers/people that sent it there in the first place.
It did them no harm at all, in fact they managed to bring up families of a dozen+ children at a time.
Nowadays it has most of the properties of Plutonium and as such vast, expenditure of time and money will be needed/used to clean it up.
Crazy crazy crazy

Joe Crawford
Reply to  Peta of Newark
September 13, 2017 10:17 am

“… that people actually have become as moribund and dumb as these folks seem to think.” I’m afraid they are at the least partially correct. From my experience most of the practitioners in the high tech arena are rather ‘idiot savant’ in that they spend an inordinate amount of time buried in the details of their specialty and either don’t have the time or the inclination to familiarize themselves with much of the outside world. I guess you could also include a rather large portion of academia in that as well.

September 12, 2017 11:28 am

Maybe we have too many people in the Cities and need to leave our little towns and rural communities thrive. In fact we should be helping them – not deterring them like socialist Govt. have been doing.

September 12, 2017 12:27 pm

The urban jungle has diverse faces not limited to color. Also, left-wing politics favors sardine populations, that combined with progressive diversity politics (e.g. racism, sexism, political congruences), is a first-order forcing of the “crab in a bucket” effect that has, among other outcomes, produced highly dysfunctional black families and communities, and, now, local and perhaps regional climate change.

Reply to  nn
September 12, 2017 1:49 pm

No, blame it all on Trump. Proof: (I have none)

Reply to  Curious George
September 12, 2017 2:08 pm

Assertions will get you a slice of a multi-trillion dollar economy and millions in speaking fees.

Tim Ball
Reply to  Curious George
September 12, 2017 5:39 pm

I had proof but I live in the city and the rain ruined it.

September 12, 2017 2:26 pm

They may have to file urban floods under the shit happens category rather than make such a desperate attempt to tie all bad possibilities to fossil fuel emissions.

Pop Piasa
September 12, 2017 5:57 pm

Yes, we are in a wetter and warmer period than previously, which is exacerbated in urban concentrations of human constructed infrastructure. How can we correctly design our cities? That is the challenge of the next century, rather than appeasing the gods of atmospheric balances.

September 12, 2017 6:04 pm

“In fact, higher temperatures have been found to disproportionately affect northern land areas, particularly the Arctic, which has already experienced fallout from climate change”
They forgot yo mention it’s because they altered the data…
Warm is cold and cold is warm – to paraphrase Orwell

Pop Piasa
Reply to  Scott
September 12, 2017 6:21 pm

“Warm is cold and cold is warm – to paraphrase Orwell”
It’s all-inclusive when you say “climate change”.
The masses are left to make sense of it individually.

Caligula Jones
September 13, 2017 7:22 am

This year, Lake Ontario had a very high water level due.
This was, of course, climate change, and The Usual Suspects rolled out the inevitable “science” in the form of a model that said that more precipitation was the “new normal”.
A few years ago, Lake Ontario had a very low water level.
This was, of course, climate change, and The Usual Suspects rolled out the inevitable “science” in the form of a model that said that less precipitation was the “new normal”.
Next year (I fearlessly forecast*, with a 33.333% chance of being correct): Lake Ontario will have a very normal water level that won’t make the news. Nobody will notice, and The Usual Suspects will have to go further afield for their fix of climate horror porn (probably Bangladesh, which had the doubly-poor luck of having its typical flooding at the same time as Houston this year).
* If I’m wrong, see sentence 1 or sentence 3 as required.
That was easy. Where’s my grant?

September 13, 2017 12:20 pm

ren, september 12, 2017, 11:16 am———- Great map of an ozone croissant! Did you notice that it is centered above the South Magnetic Pole? What’s up with that? I mean, ozone is diamagnetic.
Oxygen is paramagnetic, increasing with colder temperatures. I’ll bet that ozone croissant is emanting from an oxygen croissant. What do you think? Check out my paper.

September 13, 2017 1:45 pm

Could use some more rain here in the city as I look at my dried up lawn. Oh wait, next article they will blame climate change for my dried up lawn……

Reply to  Davies
September 13, 2017 3:17 pm

Where the sun shines on the lawn it is dry and brown, where the lawn is in the shade is lush green, but strangely, they are at the same “climate” as each other.

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