Using grape harvest dates to estimate summer temperature over 650 years
tamino.wordpress.com
tamino.wordpress.com
A friend said something to me a while ago that I cannot get out of my head when people are complaining about a heat wave again: Think not so much that this summer is one of the hottest in the last, but one of the coolest in the next hundred years.
I am tempted to replace 100 by 650 to match the article, or just talk about "the past" and "the future". But a hundred years makes it more tangible for me. My late grandparents were born just a little over 100 years ago, and my youngest niece and nephew may live to see the next 100 years.
One summer in around 2010, I drove up the pass to see the glacier in Switzerland that melts to become the Rhone river. The viewing spot is a stunning location on a bend in the road, and you can see both down the valley and up the glacier. When I got there, it looked like a frozen waterfall, ice "falling" over the side.
You could also see that the trees in the valley were young. Inside the tourist centre, there were drawings of how the place looked 100 years earlier. Back then the glacier filled the whole valley.
There was also a carved-out ice cave, in the solid part of the glacier visible from the tourist centre.
Each year I'd drive back to the glacier, and each year it would be smaller. The overhang at the cliff disappeared, and the ice cave was carved further and further up.
Just compare old photos[1] with a more recent one[2]. It’s quite easy to see how much bigger the glacier used to be.
[1] https://www.google.se/search?q=old+photos+furkapass
[2] https://www.google.com/maps/@46.5763411,8.3867043,3a,78.6892...
https://www.data.jma.go.jp/obd/stats/etrn/view/monthly_s3_en...
Please avoid any temptation to assume this comment is intended to buttress a 'climate denial' belief. It isn't.
I’d say that is more than ”no change at all”.
Edit: I looked at february. Seven times in the same period (1875-1926) the average temperature was >= 5. The last time it wasn’t? 1988, 33 years ago.
So this data actually pretty much exactly matches the French data.
Am I misinterpreting? What exactly did you mean with "no change"?
I'm curious to know what your comment is intended to do, given the bizarrely faulty interpretation you've supplied.
That's not what I read in those numbers. To me there is a clear increase trend of 3 or 4 degrees:
Year Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual
1876 1.6 | 3.4 | 8.1 | 12.2 | 17.0 | 18.5 | 24.3 | 26.6 | 22.6 | 14.8 | 9.1 | 4.8 | 13.6
2021 5.4 | 8.5 | 12.8 | 15.1 | 19.6 | 22.7 | 25.9 | 27.4 | 22.3 | 18.2 | 13.7 | 7.9 | 16.6
plot made from octave with:
T = [....];
X = 1:1915;
P = polyfit(X,T,1);
M = P(1); C = P(2);
Y = P(1)*X + C;
plot(X,T,X,Y)
ylim([-10,40])
The planet has been +- 10 degrees from here. There were millions of years without ice caps even
One difference is that the rate of warming is very high now, probably much higher than ever before. At least where I live, in Europe, the climate has changed dramatically in less than 1 human lifetime and now it is extremely different from how it was when I was young.
The second difference is that now all larger wild animals and wild plants will no longer be able to react to climate like they did before, when they migrated towards the south or towards the north, depending on the climate evolution.
Now the terrestrial part of the Earth is mostly occupied by humans, crops and domestic animals, while the remaining wild plants and animals are mainly in "islands" scattered over the lands. This will make impossible a gradual retreat of the wildlife towards some more appropriate climate and they cannot make plans like humans, e.g. that they should travel 100 km through some inhospitable land, because at the end there would be a suitable biotope.
Of course, among the terrestrial wildlife, the best chances for surviving a climate change will be for those who can reach far distances through the air, over the man-made obstacles, e.g. plants with airborne seeds, birds, bats, insects, spiders and other very small living beings that can be carried by the wind, or by birds or insects.
In any case, it is pretty certain that this warming will be much more destructive for the wildlife than any other before.
Can you provide this to back up your statement that land on earth is mostly occupied by humans, crops and domesticated animals?
https://www.pnas.org/doi/10.1073/pnas.1711842115
whose conclusions are that, by mass, the humans alone are many times more than all the wild terrestrial vertebrates together, while obviously the domesticated animals exceed a few times the humans, both in number and mass.
Of course the number and mass of animals are only partially correlated with the area occupied by them, because the larger some wild animals are, the less their surface density is, and except for animals as small as rodents or small birds their surface density is much less than that of humans in cities.
There are a few countries with a relatively low density of population, e.g. most of North America, Russia, Australia, the northern European countries (Finland, Sweden, Norway).
I am not familiar with the land status in these countries, but these are the only places on Earth where there is a chance for some areas occupied by wildlife to form a connected mesh, allowing slow migration, but even that must be sectioned by many roads and fences that may discourage the migration of animals from the places that they have inhabited from birth.
Other low human density areas on Earth, i.e. the tropical forests and the deserts, do not count, as they will not be destinations for animals or plants seeking lower temperatures. Of the other areas with low human density, only in the high mountains there would be possible migrations, when the animals and plants adapted to high altitudes and lower temperatures could die and be replaced by animals and plants coming from lower altitudes. Except that in many countries most of the wildlife is already in the mountains, so there might be very few wild animals and plants left at lower altitude, ready to replace the former inhabitants from high altitudes, which will never have any way out.
On the other hand I am more familiar with the status in Western and Eastern Europe and in some parts of Asia, where I have traveled frequently through several countries.
Here, it is enough to fly a plane over several European countries in a sunny day, and you will see only agricultural land, villages and cities, with only isolated and scattered remains of forests, lakes or uncultured land, or isolated parts of mountains that remain wild.
There already is a great difference between how some places were when I was young and I traveled to them and how they are now. Several decades ago, there were relatively large connected wild areas in some mountains, but meanwhile a lot of roads have fragmented the mountains, owners have built fences around land parcels, some forests have been cut and so on, so where there was a larger wild area now there are many disconnected smaller wild areas.
https://earth.org/half-of-earths-land-surface-remains-relati...
If we cause large changes to these patterns in a relatively short period of time that's bad. The long-term trends you are talking about happened very slowly - slowly enough in theory a city could move back from the shoreline without anyone noticing it was happening. Slowly enough that species can migrate or adapt to them - slow enough natural selection can produce individuals more heat or cold adapted.
Climate change isn't going to cause humans to go extinct or anything like that. But it is going to have large and sometimes unpredictable effects, most of which are not useful or helpful to us. Many of which are actively detrimental.
Since the oil/coal/natgas will eventually run out anyway and the world so depends on them that gives leverage to people who really really want to hurt us: we might as well just deal with it and move away from burning things as much as possible.
In case anyone was curious, this is a significant understatement. It is currently believed that the Earth had no ice caps for its first 2 billion years, before the Huronian glaciation, and then again no ice caps for another ~1.5 billion years.
https://www.smithsonianmag.com/science-nature/how-climate-ch...
https://www.sciencedaily.com/releases/2013/12/131204090958.h...
What's being described with global mean temperature is not the temperature of any region, weather event, etc. A 2C warming can be a +10C in one region and a -5C in another.
The magnitude global mean temperature rise does not imply anything in particular about "summers" or anything of the kind.
So there could be more compounding factors in grape picking dates. Though in general seeking out a darker and higher Brix product would mean later picking dates, not earlier.
But grape varieties planted have also changed somewhat overtime, too. Not so much in Burgundy where this article is talking about, though, so TFA's Beaune is actually a good choice as a point to compare.
Not that this disproves the data, or global warming, but climate isn't the only thing changing.
Claret is an anglicisation of the word and is based on it. Somehow the English eventually used that term to refer to all Bordeaux wine and not just Clairet.
But the wine itself didn't change, what changed is just foreigners inappropriately using words to describe one type of wine to describe others.
At the time the word "Clairet" (in English use) was adopted Aquitaine and Bordeaux were English possessions. The aristocracy of England spoke a lot of French. The wine they consumed was imported from Bordeaux and the volume of exports of wine drove the expansion of viticulture in Bordeaux, with the draining of marshes and the expansion of the ports, etc. They called the wine Clairet or Claret, because that's the colour the wine was at the time. The wine changed, but the word did not, because it came to mean "Bordeaux wine."
There's no patent, trademark or copyright that can make a word mean anything else. The French language and the French wine industry does not "own" the term, because the word is as legitimately English as any other imported French word in the language as it is several hundred years old. There are thousands of such words in large part due to the Norman invasion but also other reasons.
It's not "foreigners" inappropriately using a word. It's a historical use.
And yes, the wine changed. Bordeaux's exports in the 15th, 16th, 17th century were different. What it is known for now is not what it was known for then.
But you're lucky, there's relief for you. It's only really the British that use this term, and less so every generation. Most of us just say "Bordeaux."
My original point still stands: the predominant style of wine production of Bordeaux changed. From a light wine in the style of a rose to a more extractive, tannic, and higher alcohol wine. That production involves more skin exposure during primary, but it also often involves picking the grapes at higher phenolic ripeness.
(I have a vineyard and grow and make my own wine from it.)
Regardless, the TFA was about Burgundy, which as I pointed out is actually a more useful comparison point for harvest date since AFAIK there's been less change in the grapes grown or style of wine produced.
Sorry for the late reply, but you should check out the underlying paper if you haven't yet: https://www.frontiersin.org/articles/10.3389/fpls.2016.00069.... Their result crucially depends on assuming a 7 day adjustment in harvest date in the early years to compensate for the change in style of wine produced. Possibly necessary, but I think it greatly undermines the strength of their conclusions.
Have you written anywhere else about your grape growing experience? I've been trying to learn more about the recent short season northern grapes that have been coming out recently.
Over time the term broadened (in English usage) to mean Bordeaux wine in general, even as the wine produced in Bordeaux changed.
It's a bit of an anachronism now, but my point was that at the time this was the chief export out of Bordeaux. The darker rich wine which now predominates in Bordeaux was not as desired.
Aquitaine was, by marriage, property of the King of England for a three-hundred-years period. That territory was still however subject to feudal homage to the King of France, and not "part of the Kingdom of England".
We probably shouldn't inconvenience ourselves in the slightest amount to mitigate these coincidences.
Anything that might damage profits, impact billionaires, or hurt shareholders of our best gigantic businesses isn't something we should consider.
Hopefully my seething sarcasm came through all of that bullshit.
You’re unfairly omitting how fossil fuels have lifted billions out of poverty. Stopping climate change also lowers standards of living.
It isnt true. Feeding 7bn people today requires the energy density (etc.) of fossil fuels; let alone what the 20th C. required to bring people out of poverty.
The idea that you're going to bring 1bn people in the developing world out of poverty, in the manner of the late 20th C., by building "low carbon" sources of energy in the 60s,etc. in those very poor regions is ridiculous.
The only way to rapidly industrialize and lift people out of dire poverty was to burn fossil fuels at an unsustainable rate. Now that we have built up a sufficient economic surplus we can gradually transition to a more sustainable future.
Cheaper is no longer good justification.
Stopping climate change is strictly necessary if we want to keep our current standard of living.
Drive electric? Stopping climate change would require massive infrastructure changes at this point. How about no car at all? Creating and improving that infrastructure takes decades.
Same goes for other things. Imports vs eating seasonal and buying local. Frequent (transatlantic) flights vs staying at home. More frugality with what we have, less frequent changes in tech, clothing, household products, etc.
People try to hold onto the status quo for dear life, not realizing that's the very thing keeping us from solving the issue. Or any future issue we can't just get a few scientists to solve for the lazy masses.
You act like gas stations came before cars - they didn't.
As more electric cars enter the market demand for charging increases and the market responds. It won't take decades.
The world transformed itself so quickly the last 100 years it seems dubious to think with all of our advances we can't advance quickly now.
The reality of stopping the climate change and environmental concerns in general is expensive fuels, gas from Russia (+ Ukrainians getting shelled), and closing of nuclear power plants.
I.e. populations of any organism grow to consume the available resources unfortunately.
We're in one of those ice ages right now.
> An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation.
( https://en.wikipedia.org/wiki/Ice_age )
> geologists describe the entire time period [from 2.58 million years ago] up to the present as an "ice age"
> Since planet Earth still has ice sheets, geologists consider the Quaternary glaciation to be ongoing, with the Earth now experiencing an interglacial period.
( https://en.wikipedia.org/wiki/Quaternary_glaciation )
Until the polar ice caps have disappeared, we're in an ice age by definition.
There is of course an obvious implication that the naturally-changing climate periodically takes us out of ice ages, too.
In fact, Pinot Noir that is grown in Beaune (in Burgundy) talked about in this article is one of the oldest selections and might go back as far Roman times.
The Pinot Noir vines grown by the millions around the world are literally the same individual, cloned for probably 1200 years.
There are new grape varieties being bred all the time (including by myself), including ones with crosses with American Vitis species that are far better adapted for newer fungal pathogens and weather conditions. And not just bred, crosses (inter and intra specific) happen in the wild, too.
But in general they are not permitted in European viniculture, which is very conservative and has laws mandating specific varieties for specific regions, and even forbids genetics from "non-noble" species. In fact even when European breeding programs produce new varieties with inter-specific crosses, they still pretend to be "functionally" pure vinifera, just to get around laws written a century ago.
Growers will pick based on a whole number of parameters. Soil pH and moisture being two important ones. Also degree of phyloxxera threat, etc.
Given what's happening with climate, etc. I doubt growers would go for accelerating ripening. Pinot is actually already a fairly early ripening variety for vinifera, usually early October or even late September in my climate (southern Ontario).
Dunno, maybe it's the nuclear tests, but I'm a bit skeptical to that explanation.
For a striking example, look at the changes in chickens since the 1950s.
Or the chicken
https://www.vox.com/xpress/2014/10/2/6875031/chickens-breedi...
Ive seen a similar pattern before in a watermelon before too, and it was in a small home grown watermelon, the only one of many but all from the same seed pack. Although I don't remember the specific growing conditions to say what could have been the cause, it did certainly seem under developed compared to its peers. It got picked because it was obviously not growing any more and would have been at risk of rotting in the dirt if we just let it sit there forever doing nothing for another month.
Clock faces are always flat surfaces- wall clocks, wrist watches, sun dials, etc. The gears and hands require rigid, flat surfaces.
If you're going to put a normal item in a surrealist painting, and choose a clock, making it a melting clock is essentially an obvious choice.
Some people disagree with this, but for more information look at https://imgur.com/a/zN8Kv
On the other hand, new fruit varieties are bred all the time. Human breeding programs can produce huge variations in a few decades. I have pluot trees that are hybrid species developed very recently.
And think: 650 years ago, Europeans barely even heard of the tomato and potato!
Human pressure on agriculture can both speed things up and slow them waaay down.
Maybe this method is heavily biased by the outliers?
https://phys.org/news/2011-10-team-european-ice-age-due.html
Possible confound not discussed: Have there been any changes in market or transportation or harvesting-technology or labor factors which would affect decisions about "harvest date" ? Were any new varieties systematically planted with/after X apparent breakpoint? Have direct effects, if any, of increasing CO2 been removed?
For the people who like thinking/studying: hot weather does not invite you to stay at home and study/think, so you are forced to do something else.
I imagine that as summers get longer and hotter, we'll see a diminishing in new ideas and the like because the people who like to think will be forced to do something else (laying on the cold floor to pass by the day).
The Roman Empire, the Greek Empire, Babylon, the Egyptian empire, the Persian empire, all were in relatively hot weather.
Needless to say some of these empire are famous for studying and thinking (e.g. Ancient Greece?).
Don’t tell me you actually subscribe to the theory of undeveloped countries are so because of the heat, not colonialism or global exploitation. Your theory is beyond weak, its kindergarten level nonsense.
And the fact is that Europe (subjected to harsh winters, global empires and constant wars) had a much better technology. Period.
And that advances in war and travel, were based in lots and lots of solid science, created much before colonialism. You can't build a big ship or a bridge that stands 1000 years without solid math and skills.
Being subjected to a strong religion that is against science o pro-science also played a huge part.
The idea that when in danger of overheating or freeze our brain stop all machines and concentrates only in how to keep our body alive for one hour more is totally reasonable.
Anyway too few data points and too much speculation to be able to say that advancement of civilization is casually dependent on the climate.
We have agriculture/cities/empires/writing/some technology that developed independently in many parts of the world, and the rise of Europe from the Reinessance. Very few data point for "civilization advancement events"
The irony in this view is that almost everything tech and otherwise is manufactured by developing countries. And in places like Shenzhen, they innovate at an unimaginably rapid pace.
But sure, Europe has “world class” tech and Asia has “pretty good” tech…
Of course today Europe is not the central point for technology anymore. Still they have a legacy of good schools, accumulated wealth and a middle class, something that is less radicated (for now) in the East
Where do you get the notion that developing countries don’t have “good schools”? They’ve had formalised education for millennia.
Unless you are measuring wealth purely in post colonial USD/EUR, every single country (developing or developed) clearly has an accumulated wealth class, middle class, and poor class. It’s absurd that you think isn’t the case?
Regardless, I don’t have the energy to debate your random points and why there are issues with your understanding of them.
I’d like to end with the fact that “developed” countries don’t have the ability to actually manufacture most of their “genius” inventions, so…
It’s wild to me that the definition and your viewpoint presume that somehow non-European countries never considered making profit on investments? That’s… I don’t know what to say. Maybe read a book about history.
> You can't build a big ship or a bridge that stands 1000 years without solid math and skills.
I refuse to engage with someone so woefully misinformed about the non West world. I’ll leave it to you to read and learn more. Open your mind…
Perhaps the climates 2000 years ago were not as hot as we might think.
TL;DR - Warm weather good, cold weather bad. Plague much worse.
https://www.smithsonianmag.com/science-nature/how-climate-ch...
> the characteristic warm, wet and stable weather was conducive to economic productivity in an agrarian society
> violent sequence of eruptions triggered what is now called the ‘Late Antique Little Ice Age,’ when much colder temperatures endured for at least 150 years.
> This phase of climate deterioration had decisive effects in Rome’s unravelling. It was also intimately linked to a catastrophe of even greater moment: the outbreak of the first pandemic of bubonic plague.
Go the 5 whys route and you'll end up at the environment.
> This summer is what a 1.2°C-heated planet looks like. But in the future this won’t seem so bad — compared to the 1.5°C-heated planet. If we get to 2°C …
The suspension points are there because trying to put actual words won't be as scary. A literal option would be "... we'll have summers an average 0.8C hotter". Which somehow fails to make me tremble in my boots, especially since it also means we'll have winters 0.8C warmer, which is a very very good thing.
I live in Spain. This summer is being absolutely unbearable. We're constantly hovering around 40ºC. You can't open the windows to go to sleep because at 23:00 it's still 29-30º outside. We've been like this since the beginning of July. And I live in Madrid, which isn't even one of the hottest parts of the country.
And that's just now. I can't imagine how it's going to be in the future. It's going to make parts of the country completely unlivable in the summer. Insulating and protecting from extreme heat is far more difficult from extreme cold, at this point the only alternative we really have is AC, which makes things worse due to the energy usage, and there are zones that aren't equipped with it because they don't usually get a lot of heat. Quite a lot of people will die of heat stroke (those vulnerable to hypothermia in the winter are also vulnerable to heat stroke in the summer, it's not like warmer weather will save any lives). The effect on crops, vegetation and wildlife is going to be devastating. The desertification process of Spain will continue even faster.
So yeah, the prospect of 2ºC heating is really, really scary.
Same result.
In Greece, grapes are harvested normally before the feast of the transfiguration of Christ (6 August, tomorrow).
If you harvest earlier, they’re very Aesopian and sour, so farmers are really on the edge around these dates, constantly working to prepare the harvest.
But if they try leaving the grapes on the vines for a few more days, so they ripen more, you might lose the lot in the rain that usually follows a couple days later the feast.
There are few things more enjoyable these days here than taking random walks among the grape fields, chatting with the farmers, and leaving with a big smile and an even bigger bunch of grapes for the rest of your walk to the sea.
It's a pity it probably isn't going to be easy to communicate to laypeople because it is undoubtedly the correct way to talk about climate data.
The simplest model is that the underlying phenomenon has some constant value, and the variations in your observations are all just random noise. You can estimate the true value as just the average of all the data. Computing the variance (the average squared distance from the true value) gives you a sense of how much noise there is.
Now lets say that we make our model a little more complicated and allow that the temperature changes year-to-year. In fact, let's say that we know the true value for each year. Imagine overlaying this "true" plot on top of the noisy observations. We can re-compute the variance, but rather than looking at the error relative to the mean, we're looking at the error relative to this true value. This variance is likely to be lower than the first one we calculated, because some of that variance wasn't actually noise, it was changes in the true value. We've "explained" some of the variance.
Now, rather than having access to the true values, we have some other variable that we think may be a good proxy for the temperature. In this case it's the grape harvest date. The first step is to find some mapping of the proxy variable onto the one that we're interested in (the article doesn't explain what mapping they're using). We assume that explaining more variance means that the (mapped) proxy variable is higher-quality.
Note that the mapping function is essentially learned from the data. In a simple case it might be just finding a scale factor and offset using a linear regression, but it could be more complicated. You need to be a little bit careful that you're not overfitting. It's a good idea to use some of the data to fit the proxy variable, and then compute the explained variance on other data (train/test split).
Seems too risky to plant shit tons, then random (and increasingly common) bad weather fucks everything up. Also, because most people farm outside, when bad weather destroys crops, indoor farmers can hike up the price and make bank.
Here's a satellite photo of a cluster of smaller greenhouses in Spain: https://i.redd.it/5w3jvyq5nx811.png
What would it take to put a wheat field indoors?
Ive realized by experiencing this summer in France, which feels like the hottest conditions Ive ever lived in (and Ive lived in Thailand and Morocco) that things are actually dead simple. We've landed on the moon, we've invented vaccines and smartphones; now picture how dead simple this is for us to predict the consequences of injecting CO2 in a test tube.
You can train people "its complicated, so trust the experts" or to "its complicated, don't trust the experts"
See some of these ads from big oil:
https://www.theguardian.com/environment/2021/nov/18/the-forg...
Can I ask what is it that gives you this taste? What I see in the article is a graph, showing temperature clearly going up towards the end of the graph. I don't find this complicated to interpret.
But I agree with you that some people may find it complicated. I'd like to understand that better, because I'm having trouble putting my head in a space where seeing a temperature graph is complicated. Trying to understand the other perspective, but maybe you can explain what it is that gives you this distaste when you see a graph.
For example, if not a temperature graph, what way could this data be presented that would not leave an "after taste"? I'm trying to think of a simpler way.. to me this graph says, basically "before: straight line, now: going up." I can't think of a simpler way to state it that would be "less complicated" than that.
For the average Joe, a big explanation gives the impression you dont know.
The point I was making was we could explain it with one simple sentence and simple drawing: pour CO2 in a test tube, its hotter inside. "We've measured it".
That should be what people see because that gives the impression its sure. Short means "it's sure". Long means "you dont know". For most people; even at the top of a company.
Around the 25 of june 2022 near Bordeaux at 23:30 (you read it well, 11:30pm), it was 36°C.
The closest Ive experienced was in Las Vegas Nevada, which is in the middle of what qualifies as a desert.
[1] https://www.rigb.org/sites/default/files/styles/original/pub...
> While transparent to visible light, carbon dioxide is a greenhouse gas, absorbing and emitting infrared radiation ... Absorption of infrared light at the vibrational frequencies of atmospheric CO2 traps energy near the surface, warming the surface and the lower atmosphere. Less energy reaches the upper atmosphere, which is therefore cooler because of this absorption.
* https://en.wikipedia.org/wiki/Carbon_dioxide#In_Earth's_atmo...
Or if you would rather Futurama explain it https://www.youtube.com/watch?v=6cjx4gJFME0
It’s literally that easy to demonstrate.
As I understand it (and I applaud the authors for the clarity of their explanation) the original data from the 1600's shows a harvest date about 7 days earlier than the 1700 and 1800's. The decided that this didn't agree with records for neighboring regions where such records existed, so they "homogenized" the data by pretending the actual recorded harvest dates were 7 days later.
Their justification for this is a one-time change in winemaking practice in Burgundy. Oh, by the way, according to the original records the difference harvest between the 1600's and today would otherwise have been just over 7 days. Lest I seem that I exaggerate, here it is in their words (Section 2.6):
In the perspective of reconstructing past spring–summer temperatures, this bias must be taken into account. Otherwise it would have mean April-to-July GHD temperature-based reconstructions with maxima and minima ca. 1 ∘C warmer before 1718 than afterwards on the decadal scale, even though temperature measurements available in France since 1658 do not provide any evidence of such a warming during the period 1658–1718. To homogenise the Beaune GHD series we have then added 7 d to raw data prior to 1718. The Pearson correlation with April-to-July mean temperature in Paris for the period 1658–2018 is stronger with the homogenised Beaune GHD time series (r=0.76) than with the non-homogenised one (r=0.74).
Anthropogenic changes in winemaking are the most likely explanation.
They aren't necessarily wrong to make an adjustment here, but it completely undermines the causal argument they are making (or at least, that Tamino is making). While it is unlikely that there were no changes in winemaking in the last 650 year, assuming that there was one and only one major change and that it can be dealt with by uniform change to a single period of the data is fantasy. The raw data shows an early harvest, they change it to a later one, and then go on to argue that harvests are happening earlier than ever!
Again, I presume their general conclusions are correct: recent temperatures are warmer, and recent harvests are getting earlier. But this paper really doesn't do a good job of showing the extent to which this is true, and it makes almost no effort to convince the reader that other cultural changes (which are almost certain to have occurred) didn't have effects of similar magnitude in unknown directions.
Other than that, who cares. We've driven the diminishing returns on new evidence of climate change to zero. There is not a smoking gun that is suddenly going to change perception.
Stop using AGW as a political lever, and start looking for (implementing, because they exist) solutions, both in terms of carbon removal, and adaptation. The burden of proof has been met, we don't need more data. The only cause more data serves is preaching to the choir that wants to use AGW to implement large scale socialism. Stop doing that, and start solving the problem.
(I still think the analysis is neat)
I would argue the problem is the hyper-vigilant anti-socialists since they have sabotaged all proposals, including market-based ones.
Or instead I guess we can just keep congratulating ourselves on how airtight the case for AGW is and mocking "deniers", hoping one day we get the political tools to ignore their concerns.
Anyway, I'm happy to be reminded of why i stopped posting here.
Aren’t you tired of it? We’ve all seen it a thousand times.
Are you saying that is why it's been an overall failure?