Record Cold Cripples Food Crops: Future Food Security at Risk

Bellman,

Using mean temperature is one way of calculating degree-days. But it’s an older method. Following are excerpts from the degree-days.net web site on how they calculate degree-days.

———————————————————————-
On July 6th, colder weather started moving in: the temperature was 16C from 00:00 to 06:00, 15C from 06:00 to 12:00, 14C from 12:00 to 18:00, and 13C from 18:00 to 24:00. This gives the following:

(1 degree * 0.25 days) + (2 degrees * 0.25 days) + (3 degrees * 0.25 days) + (4 degrees * 0.25 days)
= 2.5 heating degree days on July 6th

Now, on July 7th, the temperature just kept changing… like it might on a real day… Between 00:00 and 00:30 it was 13C, between 00:30 and 01:00 it was 12.9C, between 01:00 and 01:30 it was 12.9C, between 01:30 and 02:00 it was 12.8C… it started getting warmer around 05:00, peaking at 17C between 14:00 and 14:30, and dropping again until it reached about 13.7C between 23:30 and 24:00. Complicated!

A proper calculation would not make for particularly interesting reading, so I’ll leave most of it out. But essentially you just have to add up the figures for each of the half-hour periods in the day (one half-hour period is 1/48 days):

(3 degrees * 1/48 days) + (3.1 degrees * 1/48 days) + ……. etc.
= 1.9 heating degree days on July 7th
———————————————————————-

——————————————————–
The problem with that approach is that, in the real world, outside air temperature doesn’t remain constant – in fact it changes pretty much all the time. Mathematically speaking you’d need an infinite number of temperature readings to calculate degree days properly.

Fortunately, “mathematically speaking” doesn’t really matter too much in this instance, and half-hourly or hourly temperature readings are plenty good enough to calculate degree days accurately using the method described above.
————————————————————-

This is how they do heating-days but doing the cooling-day calculations are the same. So the number of cooling-days (per day) does depend on how high the temperatures get. As maximum temperatures go up the more the contribution to the cooling-day count.

Bellman,

Europe *is* having a hot summer. I already pointed that out. But it is an indication of *weather*, not climate. If it was climate then the US and China, both in the northern hemisphere would be seeing the same phenomenon and they aren’t! They are seeing a cooler summer based on June results.

The claim was that June, 2019 was the hottest ever on Earth. I disagree with that claim. It is based on an *average* which can’t tell you whether maximums went up, minimums went up, or a combination of the two.

The cooling-day records from around the globe (admittedly a very small sample) that I looked at makes the claim about June, 2019 being the “hottest” ever dubious at best. June, 2019 may have had the hottest *average* temperature ever but we can’t tell if that is good or bad because we don’t know what actually happened to make the average go up!

Bellman,

“You haven’t really disagreed with this claim”

I totally disagree with the claim that the Earth is turning into a cinder which is what the AGW alarmists are preaching. The *average* temperature going up does nothing to validate that claim.

“The implication of this would be that minimums are rising more, which you consider a good thing and which would also counter the claim of the head post.”

If averages are going up it is obviously because minimum temperatures are going up. And that *is* a good thing. If is one of the contributing factors to four out of the past six years having consecutive record grain harvests on a global basis. It certainly isn’t because of maximum temperatures going up because high temperatures suppress grain production.

“but when I’ve given a couple of examples you say that doesn’t prove anything.”

DO NOT PUT WORDS IN MY MOUTH! I said that so much of the globe seeing lower cooling-days outweighs Europe having a heat wave. That’s two totally different things.

“I’d agree because I think it’s a silly metric to use and because you can tell little about global temperatures by looking at individual cities.”

The data I used was mostly from airports near the cities listed. Those sites provide consistent readings at the very least, even if their absolute values can be questioned. Cities *are* part of the global climate and, in my experience at least, if it not very often that the rural environment outside of the cities are warmer than the cities. Thus if the airports near cities are showing that June of this year was cooler than last year it is highly likely that the rural areas around those cities are also cooler this year than last.

“average maximum temperature over the last 20 years was 0.984°C above the 1951 – 1980 average”

And what about the 1920’s through 1940’s. When those temperatures are added to the mix, our maximum temperatures today are actually lower.

“he average maximum anomaly”

How many times do I have to repeat that averages tell you absolutely nothing about what is going on in the real world. If I tell you I have two sets of five numbers whose average is 6 and their average both go up to 6.2 can you tell me which values changed in each of the data sets?

If you can’t then of what use is the average value in determining what is happening?

“But it seems clear that both maximum and minimum temperatures have risen significantly over the 2st century.”

Cooling-day data disputes that claim.

For Dallas as an example, the only recent year to have five months with 100degF days was in 2006. No year since has had five months with 100degF days. The second most recent was 1998.

Let’s look at McAlester, OK.

The year with the most days of 100degF was 2011 with 28. The next highest was 2006 with 14. 2016, 2017, and 2018 had 1, 0, and 4 respectively. This data is from the National Weather Service in Tulsa, OK.

My own data from east central KS shows the same thing. And it *does* track with the cooling-day data. It only emphasizes how “average” temperatures truly tell you nothing. Assuming that average temperatures going up means the earth is going to turn into a cinder and we need to abandon all fossil fuels is the height of mathematical ignorance.

Bellman,

look here: wattsupwiththat.com/2019/04/30/analysis-of-new-nasa-airs-study-80-of-u-s-warming-has-been-at-night/

“Strawman much? Nobody in this thread has said anything other than last month was one of the warmest Junes on record, and that this put Vijay Jayaraj’s comments about no significant warming over the last two decades into perspective. ”

The post being replied to (Izaak) stated: “it is a good thing that June was the hottest June on record”, not the “warmest”. Most people reading “hottest” assume it is maximum temperature that is being addressed.

“You really seem to be disagreeing with the author of this post. He claims temperatures are not going up, and is very insistent that warmth is best for crops, with no exception made for maximum temperatures. “

You are lost in the thread forest. This is a sub-thread about the “hottest” June. It is not a thread directly related to the author.

“Not according to the BEST data. The 20 year average TMAX anomaly covering that period was around -0.04°C. “

Most of the record maximum temperatures, at least in the continental US, were set in the 30’s. Go here: stevengoddard.wordpress.com/2012/08/10/a-simple-proof-that-the-1930s-were-hotter/. Once again you have fallen into the trap of thinking that the average temperature is a proxy for maximum temperatures.

“You can repeat it as often as you like, it won’t make it true. Averages can tell you a lot about the real world, not everything but a lot. ”

What do averages tell you exactly?

“No, but I can tell you that some of the numbers must have changed, that some must have gone up,  ”

So what? Which numbers changed? The mnimum numbers One of the middle value numbers? Or the largest number? If you don’t know that then how do you make any judgment on what actually happened? If you don’t know what happened then how do you apply that to the real world?

“You realize cooling-day data is effectively an average? All you have is the sum of temperatures above an arbitrary value. ”

You didn’t actually work out the examples I gave you, did you? You know that when the cooling-day count goes up it was because the maximum temperature went up. You know that when the cooling-day count goes down that the maximum temperature went down. The use of the cooling-day count (or conversly the heating-day count) is used to size air-condition/furnace installations. That is highly dependent on what the maximum/minimum temperatures are.

“More importantly, you haven’t used the data to dispute the claim that maximum and minimum temperatures have risen over the 21st century. ”

I gave you a link to a post showing maximum temperatures from about 1900 to 2010. Can you legitimately contend that the cooling-day count in the late-30’s would not have been higher than in the 2000’s? Maximum temperatures have not risen in the 21st century, at least in the continental US.

“You don’t think averages can tell you anything, but counting months with a day above an arbitrary value in a single city does? ”

As I pointed out earlier, while the absolute temperature from a single site may be incorrect because of UHI the temperatures still serve as a proxy for the surrounding area. I haven’t given you data from just one city but from four or five from varying regions. There is no foundation that I can find for assuming that surrounding rural areas will be hotter than cities in the same region. It is obvious that you have still not grasped the concept of cooling-day. Perhaps I am being misleading using that old terminology. The term used today is “cooling degree days”. The definition is: “Cooling degree days”, or “CDD”, are a measure of how much (in degrees), and for how long (in days), outside air temperature was higher than a specific base temperature. They are used for calculations relating to the energy consumption required to cool buildings “

(note carefully the words “how much (in degrees)”

If the cooling-degree-day value for yesterday is higher than today then that indicates that the maximum temperature yesterday reached a higher value than it did today. Yesterday needed more energy to cool a building than was required today.

Bellman:

“I specifically quoted data for maximum temperatures.”

So did I. And you just used the argumentative fallacy of Argument by Dismissal to reject them.

“The problem with rejecting all averages is that you are then free to choose any specific value to prove your point.”

I don’t reject all averages but I certainly reject trying to make decisions for future actions based on a global average temperature which doesn’t tell you anything about what is happening in reality-world.

“And I’m not going to trust anything Steve Goddard says at face value.”

He didn’t post opinion. He posted data.

“As I said, an average does not tell you everything, but your claim is they tell you nothing.”

Global average climate data tells you nothing. It doesn’t tell whether grain harvests will be impacted by high temperatures. It doesn’t tell you anything about what regional impacts will be on growing seasons. All it does is provide fodder for the AGW alarmists.

“An average is really just a total, normalized to a more understandable value. ”

Adding up all months and dividing by 12 simply won’t tell you if your business is failing or not. You may think you are doing adequate business per month why the business is actual going under. If you aren’t looking at daily averages then you don’t know if you’d be better off shuttering the business on Sunday or not. A monthly average of all days won’t give you the granularity you need. And it’s the same for daily averages. If you aren’t looking at hourly averages then you don’t know if you need to be opening earlier or closing later to maximize net revenue.

“A CDD could be changed by a warmer minimum temperature, if it results in a longer portion of the day being above the base temperature.”

The minimum temperature is fixed for a cooling-degree-day measurement at 65degF. If the outside temperature stays higher than that for 24 hours then it will be picked up in the CDD value and be carried over into the next day.

“The daily CDD is an average – you cannot tell if a high value is because it reached a high maximum for a short period, or if it stayed flat for a longer period.”

You *still* don’t get how the cooling-degree-data works. Since you have fixed the minimum value usually the only way the total can go up is if the maximum value goes up. Take a period from 12pm to 4pm where the temperature goes up one deg per half hour (8 intervals). If the temperature starts at 65deg then it will go up to 73deg. Then assume it goes down at the same rate from 73deg to 65 deg. Add up each integer from 65 to 73 and double it. That’s your total. And divide by 16. Instead of going up to 73deg for the last three half-hours assume it stayed at 70deg. Will the total be greater or less than if it went up to 73deg? Since the sun is setting after 4pm you simply don’t usually get the heat input to keep temperatures up. You may get an odd day where the wind is blowing in warmer air at night on one day causing the temperature to stay up but that is why the CDD is calculated over a month.

Again the CDD and HDD measurements were developed to allow estimating cooling/heating load requirements for infrastructure. Maximum and minimum temperatures impact these load requirements significantly and it is why CCC/HDD are a direct indicator of how the minimum and maximum temperatures are behaving.

“deplorable climate science site, with some count of record days for the US. I cannot find a link to a post showing maximum temperatures since 1900.”

Record days *are* maximum temperatures! If you are setting records then the maximum temperatures have gone up!

“NOAA shows US maximum temperatures rising at about 1.6°C / century.”

The site you give using the following entries: Maximum Temperature, All Months, July, 1900-2019 shows 1901 and two years in the 30’s over 90. No other year is close. For the 2010’s no year appears to be over 98. Almost all of the 1930’s were. I simply don’t know what you are talking about unless it is the *mean*. The mean (i.e. average) is meaningless when it comes to refuting the AGW claims that the Earth is going to turn into a cinder. If you truly want to see why the mean is going up then change the Maximum Temperature parameter to the Minimum Temperature parameter. It is minimum temperatures that are going up, not maximums.

And higher minimums mean longer growing seasons and more food for the peasants. That’s a *good* thing. It’s why Freeman Dyson is critical of the the AGW alarmists and the climate modelers. They do not look at the overall picture of the Earth and its environment!

“I haven’t rejected any of your data. I’ve just questioned its usefulness in determining if maximum temperatures are warming.”

Of course you did, by saying you didn’t trust anything from the author.

“I’m not sure if you understand the meaning of the word “nothing”. Of course a global average doesn’t tell you everything about regional variations, but you can look at regional averages. What you cannot do is look at a single day in a single place and deduce what is happening everywhere.”

You are dissembling. This has nothing to do with regional averages vs global averages. All you can say is that global averages tell you something about global averages. That’s circular reasoning. You can’t state what is actually happening because global averages tell you nothing, not even about the globe.

“Really? If last year your average monthly profits were $100,000, and this year they are only $10,000, you cannot tell anything from that?”

I believe you said to get an average monthly revenue by adding up annual profits and dividing by 12. That will not tell you anything. It was *I* that said you needed to look at monthly averages generated from daily revenue totals per month.

“ou can look at that, but you still don’t want to be looking at individual hours – you want to see what the average hourly values. ”

You have to look at individual hours. If you are paying employees to open at 6am but from 6am to 8am you are making no revenue then it is costing you to open that early!

“Maybe not, but are you sure you understand them?”

Yes, I am sure I understand them.

“And there’s your problem, you don’t divide by 16,”

I was trying to set up an example you could understand. It actually doesn’t make any difference if you use 48 for each day because then it all comes out in the wash! Remember, for those hours in the day where the temperature is not above 65deg you get a zero in the nominator. Divide that by anything you want and you still get a zero contribution to the average!

“That depends on location and the base line – also on finding a place where the sun sets at 4pm in summer!”

It’s not a matter of the timing of sunset. It’s a matter of what the angle of incidence is between the sun and the Earth.As the sun starts to go down you get less energy input from the sun and the temperature begins to drop. The reason the temperature peaks later in the afternoon is purely time lag.

“In other words use a monthly average to smooth out outliers.”

Of course it is! But that has nothing to do with what the data shows for maximum temperatures!

“I’m not suggesting by the way that HDDs and CDDs are not useful. But if you are concerned about food, why not use GDDs?”

Do you have a global temperature gauge? I don’t. I don’t know anyone that does. Global averages simply won’t cut it!

“You specifically said that maximum temperatures had not increased in the 21st century in the US. I provided data that contradicts that claim.”

The site you gave shows otherwise. Did you bother to go back and look?

“No, I linked to a graph for US maximums.”

And that site shows that the maximums in the 30’s were greater than in the 21st century. So current maximums have gone down compared to the 30’s.

“Both are going up. Minimums, as expected, are going up faster than maximums, but maximums are still going up.”

No, minimums today are higher than in the 30’s. They are going up. Maximums today are lower than in the 30’s. The maximums have gone down since the 30’s. Whine about the Earth turning into a cinder when the 21st century maximums exceed those of the 30’s.

“Globally, as the BEST data suggests, maximums are warmer now than they were in the 30s.”

And the cooling-degree-day database from selected stations around the globe shows otherwise. Globablly maximums are going down. That data is used by people to make a living. If that data does not reflect reality then you would be hearing screaming from HVAC engineers around the world!

“I haven’t examined this particular claim in depth, but it isn’t showing data for maximum temperature, it’s showing daily records.”

It is showing how many record high temps are being set per year. If our maximum temperatures are really on the rise then we would be setting new record high temperatures every year. The fact is that we are not.

“but I think they are less useful than averaged data.”

Using averaged data to say that maximum temperatures are on the rise is wrong. You simply can’t tell from averaged data if maximum temperatures are going up.

“You still haven’t explained why you keep ignoring the BEST data and why selected CDDs or US only records trump them.”

Of course I have. The BEST data is AVERAGED data, either on a daily or monthly basis. Again, averaged data per day or month tells you nothing about what is happening to maximum or minimum temperatures.You can’t seem to get away from your belief that average temperatures tell you something about minimums and maximums. Why is that?

“Unless you specify which average you accept as useful”

Neither global, regional, or daily averages tell you nothing. They are, therefore, useless for telling you what is happening in reality. They can’t tell if grain harvests are going to go up because of stable or moderating maximum temperatures or if they are going to go down because of increasing maximum temperatures.

“It’s my contention that whether you look at an average monthly value or an annual total you can still see if business is growing or falling compared with last year.”

Which means it may take a whole year for you to see that your business is failing.

“Seeing that the average takings between these hours was to low to justify opening early would be a good example of how averages can tell you something.”

The point is that you have to go to the granularity for the average so that you get useful data. Average daily MAXIMUM temperature per month would tell you something useful about what is happening. Average daily minimum temperature per month would tell you something something useful about what is happening. The minute you combine the maximum and minimum temperature into a daily average you lose any ability to discern anything about what is actually happening. You lose your useful granularity.

“but that does not mean that the bigger picture tells you nothing.”

What does a global average temperature tell you? You’ve already admitted that you can’t tell if maximum temperatures are going up or of minimum temperatures are going up. The very site you provided shows that it is minimum temperatures going up that are the major impact on the average temperature. That is totally at odds with the AGW alarmists that keep saying the Earth is going to turn into a cinder.

“The more zeros there are the smaller the value.”

You are missing the point! The denominator only acts as a scaling factor! If it is hotter yesterday than today then the CDD for yesterday will be higher than the CDD for today! Which means the temperature went higher!

“Now suppose the next day you have the same maximum temperature of 73 degrees, but warmer nights”

And what causes the night tomorrow to be much warmer than today? You somehow believe that the temp will be above 65deg for only 8 hours today but for 16 hours tomorrow? Where do you live that such a thing happens?

“You need to spend twice as much cooling the building, despite the maximum staying the same.”

You just described what the CDD is good for! Remember, if yesterday the temperature was above 65deg for 16 hours then the temperature today will probably be above 65deg for 16 hours as well! And if the maximum temp yesterday was 75deg but it only reached 73deg today then the CDD for yesterday will be higher than it is for today!

“As far as I can see it’s calculated the same as for CDD but with a lower base level, and possibly not counting temperatures above a certain value.”

Then what good is GDD for determining maximum temps if high temps are not counted?

“You haven’t provided any examples of CDDs being higher in the 30s than today.”

Going back more than three years costs $50 per attempt. I don’t see any reason to spend that money when other data can be used to determine what is happening over the longer period.

“Incidentally, using the simplified version of CDDs, NOAA’s data shows CDDs in the US are quite a bit higher today then they where in the 30s.”

That’s because they use daily averages, i.e. (max + min)/2. And, once again, that doesn’t tell you anything. Are the values today higher because of higher maximums or because of higher minimums? You keep on making the same mistake the AGW alarmists make – that higher averages can only happen because maximum temperatures are going up and the Earth is going to become a cinder!

“You don’t seem to understand that when I refer to the BEST maximum temperatures, I mean their dataset that is averaging maximum temperatures

And what does the monthly average maximum temperature tell you? Can it tell you what the *maximum* temperatures were?

“How many times are you going to suggest I believe the Earth is about to turn into a cinder, before you accept I’m not arguing any thing of the sort?”

You are lost in the thread forest again.

“The fact that minimum temperatures are rising faster than maximums is what you would expect from warming caused by increasing CO2.”

Remember, CO2 provides the same “insulating” factor during the day that it does at night. So why wouldn’t CO2 drive maximum temperatures up as the AGW alarmists contend? If CO2 intercepts radiation from the Earth at night then it also intercepts it during the day. And the Earth *does* radiate during the day at an even faster rate than it does at night because daytime temperatures are higher.

“That only makes sense if you use the same denominator for each day. Is that what you meant when you divided 8 hours by 16? Why would you divide 48 half hours by 16? It doesn’t give you a degree day, it gives you a scaled degree day.”

I told you I was trying to set up an example you could understand! If you go back and look at my posts I gave you how the CDD site does it and it *is* by dividing by 48. Nor did I divide 48 half hours by 16! Why would you think scaling makes any difference at all? Fahrenheit and Celsius are two different temperature scales. Do that scaling make a difference?

“But as I tried to explain in my example it doesn’t necessarily mean that the maximum temperature went higher.”

Of course it does!

“It was an artificial example to illustrate a point. ”

Which has absolutely no relation to reality!

“It was no more realistic than assuming temperatures will increase or decrease in linear fashion.”

Temperatures increase and decrease in the same manner each day. That increase and decrease does not have to be linear, it only has to be similar. No one ever said it has to be linear. In fact it will probably never be linear because you get more heating from the sun when it is traversing from 80deg to 100deg than you do when it is traversing from 0deg to 20deg in its orbit!

“The point being illustrated is that you don’t need an increase in maximum temperatures to see an increase in cooling degree days.”

Of course you do. That’s what the whole exercise is for. If lower temperatures produced higher CDD values then how could engineers properly design cooling/heating units for maximum load?

“I didn’t say it was better for determining maximum temperatures. It’s better for deciding how temperature changes will impact food production. Which is what you claimed to be interested in.”

Really? At least for grains it would not be better for determining the impact on food production. Grains suffer when temperatures get above 90degF. If you throw out temperatures over 90degF then how do you estimate what will happen to food production?

“So you were wrong to claim that the cooling-degree-day database from selected stations showed that maximums were warmer in the 30s globally”

I didn’t use the CDD database for that. I gave you a site showing record high temperatures going back to 1900. And we simply aren’t setting new high temperature records at the same rate we have in the past. Meaning maximum temperatures are not increasing or we would still be setting new records at the same rate!

“I’ve not made that claim at all – I’ve only pointed out that both maximums and minimums are going up, but minimums faster than maximums. I don’t know why someone who thinks the warming has been caused by rising CO2 would claim otherwise, as it’s a testable prediction of the global warming hypothesis.”

But maximums are not going up. As I said, if CO2 was blocking the Earth from radiating heat then it would cause maximums to go up as well since it would block radiation during the day as well as at night. As Freeman Dyson pointed out, the climate models aren’t based on a holistic basis. The greening of the Earth, about 10% to 15%, since 1980 has to have had a distinct impact on temperatures. It would affect both albedo and evapotranspiration. Yet neither of the models apparently consider this at all.