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The Contender
Con (against)
7 Points

Global Warming has not accelerated the Water Cycle in the last 115 years

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Voting Style: Open Point System: Select Winner
Started: 7/28/2015 Category: Science
Updated: 2 years ago Status: Post Voting Period
Viewed: 1,565 times Debate No: 78131
Debate Rounds (4)
Comments (7)
Votes (1)




Global Warming has not accelerated the Water Cycle in the last 115 years.

Global Warming - A process of climate change frequently associated with the warming of the environment due to man made pollution.

115 Years - For statistical limitations to be 1900 to 2014 and early 2015

Accelerating the water cycle - A sustained increase in water evaporation, or precipitation beyond the first 30 years of the 115 year range, or 1900 to 1930.

Round 1: Acceptance, and Definitions. Con will decide if R2 will have an Argument or Rebuttal in R1
Round 2: Presenting all arguments (no rebuttals if con presents an argument otherwise con may rebut)
Round 3: Refutation of opponent's arguments (no new arguments)
Round 4: Defending your original arguments and conclusion (no new arguments)

BOP: Pro unless Con presents an argument then Shared


I accept. Thank you for challenging me to this debate. I look forward to a lively discussion.
Debate Round No. 1


I would like to thank my opponent for accepting this challenge.

I will be presenting a controversial view that Global Warming has not accelerated the water cycle. This will have actual analysis of weather station data from NOAA. It is a large dataset, and I am willing to show anyone who asks how to begin analysing it. The Evaporation data is small enough to analyse in excel, but precipitation data would require a database or custom tools to work with.

Analysis Method:

In order to estimate precipitation, and evaporation levels I will be utilizing the NOAA GHCND weather station dataset. If you wish to download and verify the dataset can be found here:

1) To process this data the first step is to convert each stations monthly 31 day values into a single monthly median value for each station.
2) Then each stations monthly median values are averages to create the average median for the life of the station.
3) The station average median is then subtracted from the station median to create a delta that represents that stations change away from the average median.
4) Stations are then selected based on the date of operation. For analysis starting in 1900 all weather stations that were operational in 1900 and operational at the end of the analysis must be used. Weather stations that were not operational at the start of the analysis cannot be used because they will induce an unknown bias that cannot be accounted for.
5) From there the data can be graphed, or each months delta for the year can be averaged to create a yearly change for a simpler graph.

1900 to Present Precipitation

The Figure 1 below shows the change in precipitation from 1900 to 2015. As shown the precipitation for 1900 to 1930 stays consistently above the average median by about 1mm. The graph of SO2 emissions is there to demonstrate the correlation found in Global Dimming is present in this data. SO2 impedes precipitation by blocking the amount of light that reaches ocean organisms like Phytoplankton that create critical rain cloud compounds[1]. It also cutbacks on plant life by reducing light which also means less water in the air from plant transpiration which is what 90% of the water a plant gets is used for[5].

As SO2 emissions were successfully cut back in 1990 there is a clear indication of an increase in precipitation. At most it increased to similar levels in the 40’s and 50’s up until around 2005. It is my burden to prove that the radical increase post 2005 in precipitation is clearly caused by factors not created by man.

Figure 1:

1971 to Present Pan Evaporation Rate:

Fortunately, NOAA’s dataset does provide additional detail to see what may have changed in Figure 2. If evaporation increased due to additional heat it should appear in the Pan Evaporation rate. Regretfully there is an insufficient number of stations with pan evaporation rate data going back to 1900 so to increase the number of stations to a sufficient number for analysis the start date has been moved to 1971 allowing us to use 124 stations.

Rather than show a gradual increase evaporation from gradual warming the pan evaporation stays constant from 1971 until about 2010-2011 where it then makes a radical change which correlates to the radical change in precipitation.

Figure 2:

1980 to Present Precipitation and Evaporation

In order to get a better idea of what is happening the date range will need to be compressed further to allow the number of stations to be increased for further analysis. This way we will have 10,209 stations for precipitation, and 156 stations for evaporation for monthly analysis. We can see in Figure 3 better detail what a 20% decrease in SO2 pollution did to the precipitation rate. Unfortunately the increase in 2005, and later, was due to China, and India having increased SO2 pollution[7].

Now we can see a mild increase in evaporation starting in 2005, and the shift in 2010 can be isolated to October 2010 using a box and whiskers analysis on the dataset to flag outliers.

Figure 3:

Solar Forcing of Evaporation:

October 2010 is a very important time period. It marks a violent beginning of the Sun’s solar cycle 24 approach to solar maximum[8]. By graphing the Sun’s Sunspots it is possible to see if cycle 24 had an actual influence on the evaporation rate. Clearly the increase in evaporation has many of the same features as cycle 24 in Figure 4. However, none of the prior cycles appear to have any significant influence. However, in 2008 NASA announced that they had discovered the Earth's Electromagnetic Field was weakening[2]. This weakening most likely began before it was detected leading one to believe that higher than normal levels of light, and radiation began to leak in explaining the small increase during the previous solar minimum. As the field began weakening further evaporation accelerated. This also feed more plants, and phytoplankton allowing for more rapid development of rain clouds post 2005.

Now that the Earth's field is weakening 10 times faster[3] than before explaining the continued increase even thow sunspots are on the decline. None of the increases above 1900 to 1930 norms can be attributed to any man made causes, and is entirely separate from any global warming claims. The accelerated water cycle is caused by the complex machinations of the Sun, and Earth's Magnetic Field.

Figure 4:




I would like to thank medv4380 for presenting his arguments.

The Water Cycle

I want to start by providing a brief description of the water cycle, and what it means to accelerate the water cycle. At the most basic level, the water cycle is the explanation of why precipitation occurs. Water evaporates from the oceans as a result of solar heat input, rises into the atmosphere, condenses as the air gets cooler (forming clouds), moves on land, releases its water, which heads back circuitously into the ocean. Here is a picture showing the many intricacies of the water cycle:


The acceleration of the water cycle would mean that the cycle is becoming stronger - more water evaporates, implying that more precipitation occurs. It is my burden, then, to show that more precipitation is occurring now compared to 115 years ago.

Global Warming and the Water Cycle

At the most basic level, a warmer climate would mean that there would be more precipitation, because more water would evaporate from the oceans, due to the fact that the chance of a water molecule in the oceans breaking free of its bonds with other water molecules would be more likely to escape, and given enougn kinetic energy (and it's moving in the right direction), the water would do so. While the climate does work like this, the climate is a bit more complicated than that. Some places will get dryer because warmer climates dry the soil out faster, and regions that don't typically get a lot of rain can suffer as a result.

There are many ways one can observe an acceleration of the climate cycle. One obvious way would be to find that the amount of precipitation falling around the Earth is increasing. This is indeed the case. "An advanced statistical analysis of rainfall data from the years 1901 to 2010 derived from thousands of weather stations around the globe shows that over 1980-2010 there were 12 percent more of these events than expected in a stationary climate, a scenario without global warming." This seems to show that global warming is accelerating the water cycle. However, there are many other indicators that this is so.[2]

One could look at how much water is being evaporated from the oceans and how much water is running off in rivers, for example (we'd expect an increase in both of these indicators). A measure of how much water is being evaporated is humidity - a measure of the "saturation" of the atmosphere (the atmosphere can only hold so much water vapor; humidity measures the percentage of this amount). The greater the evaporation, the greater the global humidity, because there's more water vapor in the atmosphere. "
All five reanalyses produce similar relations, with increasing surface temperature being associated with increasing atmospheric specific humidity. These results agree with previous analyses that the water vapor feedback in response to shortR08; term variations is strongly positive. This is also consistent with P09, who looked at the seasonal cycle in the extratropics in the NCEP/NCAR reanalysis and found that it showed a positive correlation between surface temperature and 500 hPa specific humidity."[3]

How much water is being run off in rivers? "For the relatively short 13-year period studied here, global discharge increased by 540 km^3W25;y^2 [this is a rate of approximately 1.5 percent a year], which was largely attributed to an increase of globalocean evaporation (768 km^3W25;y^2). Sustained growth of these flux rates into long-term trends would provide evidence for increasing intensity of the hydrologic cycle." A graph of this increase can be seen below[4][5]:

The data that clouds give us is more difficult to understand. You'd think that more evaporation would entail there being more clouds, but this isn't necessarily true. The way clouds work is much more complicated than that. In addition, you have to contend with the feedbacks that clouds cause.

What is the evidence that the acceleration of the water cycle is due to global warming? Well, warmer air holds more moisture. We'd expect precipitation increases to follow the change in the temperature of the atmosphere. "While a statistical analysis of course cannot provide direct physical cause-effect relations, the scientists compared their findings to existing knowledge about how much more water can be stored in the atmosphere when temperatures rise, as given by the well-known Clausius-Clapeyron equation. This additional moisture can be released during short-term heavy rainfall events. The scientists show that the observed increase in unprecedented heavy rainfall events generally fits with this thermodynamically expected increase under global warming."[2]

Overall, the significant acceleration of the water cycle is unlikely to be due to any natural variation of the climate, nor is it likely to just be a statistical anomoly. The theory behind anthropogenic global warming clearly explains why the water cycle is accelerating, as a warmer atmosphere would evaporate water faster and would be able to hold more of that water vapor.


Overall, the water cycle involves evaporation, condensation, precipitation, and runoff. I've shown that evaporation (in the form of humidity), precipitation, and runoff have all increased, and this is most likely due to global warming, due to the connection between warming and the acceleration of the water cycle.


Debate Round No. 2


Dam Rivers:

I like that river in Egypt - De Nile. Fun fact, since 1970 the Nile in Egypt hasn’t done it’s annual floods. Amazing isn’t it? A river iconified in myth, and legend representing the cycles of death and rebirth though its life giving floods depositing fertile silt hasn’t flooded in almost 4 and a half decades. It’s amazing what changes the Aswan Dam has done to the Nile for Egypt.

My opponent brings up an important point about the freshwater river mouth surge data, and that it is of a very limited time frame of 1994 to 2006. That wouldn’t actually contradict my data since from 1990 there was in an increasing trend in precipitation due to a reduction in SO2 pollution. However, it has an even bigger flaw. Even if there was an increase in precipitation there is very little reason it would actually increase the outflow of water at a river mouth. Perhaps two centuries ago it would have, but over the last 200 years we have left very few rivers free of hydro engineering[9].

Any excess water has a much better chance of being banked into the world's reservoir system then it has of just being flushed downstream. It’s not like we don’t have irrigation networks built to divert overflow in one reservoir into other depleted reservoirs[11][12].

"Our reservoir system is built so that as one reservoir fills that water spills over into another reservoir," Libby Pischel[13]

So why would we have any increase in river water at the mouth of a river unless we did it deliberately? If the last reservoir on a river overflows then it would have no where to go, but the last reservoir only represents a small fraction of the dammed water. A more likely cause is increased electrical demand. If we want to utilize the water for electricity we have to send it down to the next dam so it can use it for electricity[14]. Then there is fish and wildlife maintenance were we deliberately maintain a higher rate of speed to keep the fish healthy[15]. One may be able to argue that the over dammed waterways are a detriment, or a boom. However, there is hardly a single cubic foot of water that leave waterways that we didn’t intend on it leaving. Had my opponent's source been able to tap into a larger samples with with less of a limited sampling bias by having river data from prior to the rise of dams they may have come to a different conclusion.

Global Historical Climatology Network:

The advantage to the GHCN data that I’ve processed is that is that is contains all of the world's weather station data. It makes it possible to attempt to verify what is, or is not wrong with my opponent's source that claims that there has been a 12% increase in weather ‘events’. Unfortunately, the actual study is hidden behind a nice pay wall, but the abstract can be read here.
It is also cross references another study at the American Meteorological Society[17], and the PDF can be viewed here.
The first problem with all studies of extreme precipitation events can be summarized by quoting a part of the 2nd page on the study above.

These and other studies, which all differ in their methods of analysis, definition of extreme precipitation indices, and/or the observational datasets used, consistently report increases in extreme precipitation in more land locations globally than locations with decreases.

In other words the definition of ‘extreme precipitation’ is a cherry picked definition, and all of these are only of ‘extreme’ events, and not a sum, average, or median of the precipitation. The reason they don’t use the far more direct argument is that would be Figure 1, and it disagrees with their world view.

Further analysis of my opponents source reveals a claim that shows that their results are nothing more than an anomaly caused by their statistical methodology. To quote his source

The average increase is 12 percent globally – but 56 percent in South East Asia

56% is an outlier nearly 4 and a half times away from the average, and should have flagged the results for closer scrutiny. A closer examination of the South East Asia, SEA, precipitation data in GHCN data shows the cause as limited sampling bias. In other words, SEA has about 369 weather stations reporting precipitation data. However, the earliest weather stations started reporting in 1943: SONGKHLA, DON MUANG, CHIANG MAI, and UDON THANI. A statistically viable sample doesn’t even exist until 1950 when about 30 to 100 stations are reporting. That puts the majority of SEA’s measurements after Global Dimming had reduced the precipitation rate so it stands to reason that they’d see an increase in ‘extreme’ precipitation when rain started to return to normal in 1990.

By including weather station with varying limited sampling bias like SEA they induced a non response bias into their 12% figure. This kind of bias is actually addressed in my analysis in step 4. By restricting the analysis to only include those that existed at the start, and at the end non response bias is mitigated only to events that may have shut a station down for a period of time. Limited sampling bias is also addressed by using the largest date range, and maintain a suitably large sample size.


As for my opponents 3rd source that attempts to prove that humidity has escalated due to global warming it suffers from the same deficiencies as his other sources. Namely limited sampling bias. The study uses only time period of 1973 to 2007 which means that it falls completely under the Clean Air Act of 1970 where SO2 emissions were held back and then reduced in the 90’s. Because of their samples limited score they’d be unable to determine if the cause was out of line with an atmosphere returning more to a 1930’s era, or if it was global warming.




I would like to thank medv4380 for presenting his rebuttals.

If I'm reading my opponent's argument correctly, he seems to be arguing that solar activity is the cause of the evaporation increase, saying that the reduction in solar activity causes the Earth's magnetic field to weaken, causing more radiation to reach Earth. However, if this is indeed his case, it has two problems. One, it posits that the strength of the Earth's magnetic field is determined by solar activity, and that there is a correlation between magnetic field strength and water cycle strength.

Earth's magnetic field originates from moving charged particles at its core. "Magnetic fields are produced by the motion of electrical charges. For example, the magnetic field of a bar magnet results from the motion of negatively charged electrons in the magnet. The origin of the Earth's magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel. This mechanism is termed the dynamo effect." Thus, it seems that solar activity has nothing to do with the strength of the Earth's magnetic field. A decline in solar activity then would not cause the water cycle to accelerate. But there's still the problem of whether magnetic field strength has any effect on the temperature. Below are three graphs - one of the Earth's magnetic dipole moment (a measure of how strong the Earth's magnetic field is), one of solar irradiance (a measure of solar activity), and one of a measure of precipitation levels.

total solar irradiance

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As you can see, it doesn't appear that Eaerth's magnetic field strength correlates with solar activity. In fact, just purely looking at the data, it appears that the opposite is true - increased solar irradiance decreases Earth's magnetic field strength, not decreased solar irradiance. As for the magnetic field strength/precipitation correlation, the question is a bit more complicated. Unfortunately, we don't have (or at least I can't find) global precipitation anomalies for more than 100 years. However, there's two things I'd like to note. One, if precipitation was really affected by magnetic field strength due to the amount of solar radiation Earth absorbs, then, since the decrease in magnetic field strength is linearly downwards, we'd expect precipitation levels to follow solar irradiance, because that also determines how much radiation the Earth receives. However, precipitation trends do not seem to follow solar irradiance (if they did, you'd expect 11-year cycles in precipitation levels). And two, you'd think that, since solar activity has been decreasing a lot lately, that precipitation levels would trend down. If the amount of radiation reaching Earth is the key here, then you'd need to consider solar irradiance and magnetic field strength together. The most you have is a 5-year trend. In the grand scheme of the 115 years this debate considers, that's a statistically insignificant trend, especially since the magnetic field strength has been declining for at least 400 years, and there don't seem to be any other precipitation/solar irradiance links for any of the other solar cycles.


I apologize if this was a bit choppy - I've had a lot do the past few days. However, I feel like I've covered the gist of it. The solar irradiance/magnetic field strength and magnetic field strength/water cycle rate correlations do not seem to exist, save for the past five years, which is statistically insignificant on climatological time scales.


Debate Round No. 3


I’d like to thank my opponent for his response.

Unfortunately my opponent hasn’t fully grasped my main argument. It’s understandable if you haven't been following the news generated from my second citation. I can only assume that the news involving a possible polar flip in our life times isn’t as interesting to most people, or at least it doesn’t generate enough of a news bite to say in the news for long.

I’m not actually referencing the continual weakening of the Earth’s magnetic field. Rather it’s in reference to a rapid, and unexpected weakening that is believed to be leading to a polar flip. The THEMIS satellites that are responsible for this discovery were launched around 2007 in response to increasing atmospheric anomalies that started to draw concern around 2005. The big issue THEMIS found which was what was reported in 2008 was that the Earth’s EMF northerly aligned fields when hit by northerly aligned Coronal Mass Ejections, CME, was ripping open rather than deflecting them. As it was put by the scientists involved.

"To the lay person, this may sound like a quibble, but to a space physicist, it is almost seismic. When I tell my colleagues, most react with skepticism, as if I'm trying to convince them that the sun rises in the west."[2]

So according to the scientists would this do anything for Solar Cycle 24?

"We're entering Solar Cycle 24. For reasons not fully understood, CMEs in even-numbered solar cycles (like 24) tend to hit Earth with a leading edge that is magnetized north. Such a CME should open a breach and load the magnetosphere with plasma just before the storm gets underway. It's the perfect sequence for a really big event."[2]

In other words, it’s loading the Earth's Atmosphere with an unusually large load of heat, and solar energy. My claim is this excess energy gets expressed as evaporation which is why figure 4 evaporation rates correlate to to cycles 24, but not any other cycle.

So is this unusual?

"We've seen things like this before, but never on such a large scale. The entire day-side of the magnetosphere was open to the solar wind."[2]

So yes, but never on this scale, and it’s this scale that makes it visible in the current cycle, but not any of the data my opponent brought up. His data all ends at 2000, and doesn’t go back far enough to see what the prior flip had. Not surprising since that would be 780,000 years ago for the last major flip, or about 40,000 years for the last minor flip that lasted only a few hundred years.

I can understand my opponent not understanding my claim, but I did cite it so he could, if he had more time, read the source.

I’m under no illusions about this argument ether. Many people will want to vote against me based on a belief that the claims of Global Warming must be true. For those I ask that you take the time to examine the data I’ve linked too. My methodology is sound for the generating of the graphs I have personally rendered, and the raw data is from a reliable source, NOAA.

If you’ve verified data, and the methodology then you are left with only one question. Why does the evaporation rate so clearly correlate to cycle 24, and not any other cycle? Surely if it was Global Warming caused by man it should have started moving up long before 2005, but from a statistical standpoint it is flat throughout the entire period prior. This can only mean that the heat from global warming responsible for evaporation is either nonexistent, or so minor that it cannot be seen with a sample of the given size, but that cycle 24 is.

Keep in mind that if you side with my opponent that his evidence for precipitation is deficient for the time period that this debate covers, and is heavily biased by our water management of the rivers via dams. His humidity data is also deficient for the time period, and is explained by Global Dimming caused by SO2. The data the he has that does cover the time period is cluttered with weather stations with an incomplete coverage of the time period resulting in a biased that favored the cherry picked statistic of “extreme” weather events. Had he picked a study that used a sum, or average precipitation, and accounted for nonresponse bias that the result with be similar, or identical, to my Figure 1 graph.

I realize that it is difficult for many voters to vote against global warming. However, I have presented a sound case against the claim that global warming is accelerating the water cycle.



I would like to thank medv4380 for this debate.

Dam Rivers

There are three responses to this. One, human impacts only account for about half of the observed increase in river runoff. "On average, land-use change has increased global runoff by 0.08 mm/year^2 and accounts for ~50% of the reconstructed global runoff trend over the last century." There's still the other half that needs to be accounted for.[1]

Two, CO2 also has a negative effect on river runoff. "When allowing for the increase in foliage area that results from increasing atmospheric CO2 levels in a global vegetation model, we find a decrease in global runoff from 1901 to 1999." This seems a bit counterintuitive. However, the increased precipitation that CO2 induced warming has caused has still had an effect on the rivers. The effect is just masked by the land-use changes and negative feedback related to plant growth. This is entirely separate from the water cycle.[1]

And three, this topic has been very controversial, namely owing to different collections of data and statistical methods used with that data. However, this science is solid.


Actually, decreased SO2 levels would cause humidity levels to reduce. "Trajectory studies and model simulations suggest that the SO2increase results in the formation of more sulfuric acid aerosol particles in the upper tropical troposphere. As a consequence, more ice crystals of smaller size are formed in the tropical tropopause, which are lifted into the stratosphere more readily. Our model calculations suggest that such a mechanism could increase the amount of water that entered the stratosphere in the condensed phase by up to 0.5 ppmv from 1950–2000." While the decrease in SO2 emissions has slowed the rise in humidity levels a little, CO2 levels are still rising exponentially.[2]


Overall, this is basic physics. A warmer climate, caused by rising greenhouse gas emissions, causes more water to evaporate from the oceans, which causes more rain to fall, which causes the river runoff to increase. While we have been affecting river runoff in other ways, the underlying data is still there. My opponent has also failed to adequately refute my humidity (related to the amount of water in the atmosphere), and he has completely dropped my precipitation point. My opponent has provided a confusing, uncertain, and misguided argument himself. The evidence supports the conclusion that human induced global warming is the cause of the acceleration of the water cycle.


Debate Round No. 4
7 comments have been posted on this debate. Showing 1 through 7 records.
Posted by 16kadams 2 years ago
if someone PM's this to me tomorrow I'll vote.
Posted by whiteflame 2 years ago
>Reported vote: dan40000000// Mod action: Removed<

7 points to Pro. Reasons for voting decision: I thought the debate was very interesting. My original opinion is I am on the fence currently and I am looking to be swayed. And Medv4380 had the better argument because he used raw data that is hard to beat. The raw data clearly supports his decision. Subutai had a strong argument but I personally feel that it wasn't as strong. Great debate you both were very solid.

[*Reason for removal*] (1) This vote is extremely vague. It doesn't point to any specific "raw data" presented by Pro that swayed this voter's decision, instead stating that the usage of this "raw data" somehow outstrips all of Con's arguments. The voter also needs to do more than just say that he doesn't "personally feel that [Con's argument] wasn't as Pro's", requiring that he directly assess points made by Con, which he failed to do. (2) The voter includes too many statements that make it appear biased. What the voter "personally feel[s]" shouldn't be a part of the decision, nor should he be coming into making the decision solely on the basis of which side swayed him personally. While the voter can certainly seek to learn from the experience of reading this debate, the voter's view following the debate should not affect its outcome.
Posted by Subutai 2 years ago
So apparently my third picture decided not to show up. I'm not sure why that happened. Just look at the third chart of source four. Apologies.
Posted by medv4380 2 years ago
Remember the first round isn't intended to be actual debate, but I'm fine if you're using it to research.
Posted by Subutai 2 years ago
Thank you. I'll accept.
Posted by medv4380 2 years ago
Updated to 10k
Posted by Subutai 2 years ago
Make the debate 10,000 characters, or let me post sources in the comments.
1 votes has been placed for this debate.
Vote Placed by roguetech 2 years ago
Who won the debate:-Vote Checkmark
Reasons for voting decision: Pro's stance is that "global warming" is not causing an "accelerated Water Cycle", however, they then establish in Round 2, that global warming HAS caused an accelerated water cycle, which somehow demonstrates global warming is due to solar forcing. The title and Round 1 claim is extremely disengenous, by shifting the focus away from causation for global warming (e.g. anthropogenic or solar activity) to causation for an *implied* lack of increase in "the Water Cycle". Given the shift in focus, there's no possible way I could give the win to Pro, since they did not address AGW. They simply claimed SOME of global warming is caused by solar forcing. Even if I were either ignorant of that dishonest bait-and-switch, Pro did not support that global warming is due to solar forcing (despite the pretty graphs), and provided no sources for the supposed correlation. Con also successfully rebutted the points, despite also apparently being confused as to the subject of debate.