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Cheers, Gavin! - Josh 349

Here's an odd thing.

Replying to Tweeter 'Hot Topic', who was highlighting this article in the Guardian, Gavin Schmidt said that there are "More than 10x number of English vineyards now than in medieval times." with a link to a 2006 Real Climate article.

Gavin implies that this comparison trumps the argument about English vineyards being proof that Medieval Warm Period was hotter.

However, one can conclude that those who are using the medieval English vineyards as a ‘counter-proof’ to the idea of present day global warming are just blowing smoke (or possibly drinking too much Californian).

Hang on a sec! Surely you would not compare the two without mentioning the population size -  the number of people buying and drinking the stuff - I mean that would be unscientific, wouldn't it?

A quick bit of research and doing some sums, admittedly by a cartoonist, gave me approximate ratios of 15 Vineyards per million in medieval times compared to 7.5 Vineyards per million today. That means that if you want to use Vineyards as a proxy for temperature (I wouldn't) the MWP was twice as hot as it it today!

I think we can conclude that this is simply Vintage Gavin (pronounced Ga-Vin) and we should all be enormously cheered up by the logic of climate science - what they can brew up with numbers is very entertaining.

Please embibe responsibly. No more that two units of Climate Science per day.


P.S. I didn't see it at the time but William Briggs also noted Gavin's omission.

Cartoons by Josh

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Reader Comments (63)

Seems to me that Gavin admits that grapes WERE being grown in midieval times. And that was the point, not the quantity being grown. Grapes do not like cold weather.

Oct 28, 2015 at 3:02 PM | Unregistered CommenterJimB

0% proof.


Oct 28, 2015 at 3:03 PM | Unregistered CommenterCheshireRed

Spooky - my neighbour is harvesting the grapes in his two vineyards as I type.

But they're both tiny - corners of fields that were proving a flipping nuisance to modern wheat-growing kit. Surely the important stat is not how many vineyards, but what total acreage?

Oct 28, 2015 at 3:13 PM | Unregistered CommenterCharlie Flindt

Do I assume correctly that the 70C was to the recent news of the "future un-livability" study in the Persian Gulf region?

Oct 28, 2015 at 3:14 PM | Unregistered CommenterOldUnixHead

The underlying thrust of Gavin's 2006 RealClimate article that he referred to is that the number of English vineyards is not a good proxy for temperature. The fact that there are 10x the number now than in the MWP is just an aside to point out that even if it were a good proxy, the evidence for comparing MWP and modern temperatures is not clear, countering Hubert Lamb's earlier remarks that English climate is now too cold for wine production.

The various reasons why this isn't a good proxy for temperature include those given in Gavin's 2006 article as well as changing population. Even if these other factors weren't relevant, you still wouldn't divide number of vineyards by population without also considering (it it were known) the size of the vineyards and the size of their production.

Number of vineyards isn't a good temperature proxy, number of vineyards per capita isn't a good temperature proxy, number of bottles produced per capita isn't a good temperature proxy. Maybe the location of them could tell us something if we know the variety. Maybe the changing grape harvesting dates could tell us something if most other things haven't changed.

But the basic thrust of Gavin's earlier article is that it isn't a good proxy and by ignoring this point, the current post comes across simply as point-scoring rather than informative or useful for furthering discussion.


[Tim, many thanks. The cartoon is in response to Gavin's point scoring Tweet ;-) I agree with you, as I mentioned above, I don't think Vineyards are a good proxy either. J]

Oct 28, 2015 at 3:17 PM | Unregistered CommenterTim Osborn

We're probably using types that are better able to resist cold. Also, the market for wine is bigger as there are more people, so driving a market. There's land available as forests and woods have been cleared for agriculture and we can afford to devote some of it for luxuries rather than for food production.

It's just a really dumb argument, the existence of vineyards are proof of nothing, what would be more interesting would be their locations in the UK during the MWP compared with now.

Oct 28, 2015 at 3:17 PM | Unregistered CommenterSteve Crook

Beer and wine were not actually luxuries, but staples as most water was undrinkable. The Haymakers in Somerset did not take flagons of water with them but cider, for the very good reason it was likely "less" bad for you.

Oct 28, 2015 at 3:30 PM | Unregistered CommenterRockySpears

Correct me if I'm wrong, but vinyards are not a good proxy here because they will also not respond well to particularly hot climates - the grapes all shrivel up and fall off - so if Britain is getting warmer (which I am happy to agree with Tim is not what was claimed in the original article, but seems to be the logical assertion of the tweet) then at a certain point would not the viability of vinyards start to fail (it being expensive to replace vines), causing reduced numbers.

If we were to take the number of vinyards as an indicator of anything (whether per capita, as a ratio of GDP or just on their own) it would surely be of a climate suitable to the growth of vines. And that opens up a whole raft of other questions.

Oct 28, 2015 at 3:33 PM | Unregistered CommenterWatchman

Steve Crook,

I am not sure location of vinyards works as a marker either - they are generally found south-east of the highland/lowland division (Severn-Tees line if you like) in Britain both now and medievally. This is probably an effect of geology, geography and hydrology as much as temperature. Without studying landscape in this sort of question, you gain nothing.

Indeed, if you were going to analyse this properly, you would have to see what else the land might be used for as well - because in medieval times (at least pre-1348) people tended to farm extensively, so a vinyard was cutting down on potential cereal or arable land. Nowadays we trade a lot more, and the land may be otherwise unused.

Oct 28, 2015 at 3:38 PM | Unregistered CommenterWatchman

Never mind the content, enjoy the brilliant cartoon.

Oct 28, 2015 at 3:44 PM | Registered CommenterPhillip Bratby

Nothing is said about microclimates either. During Roman times there were forests everywhere which could protect vines from cold East winds. Variations in both aspect and elevation can have a larger effect than most global temperature changes. The largest problem for vines is damp summers giving mildew on the leaves and fruit. Perhaps the vines were treated with copper sulphate then, but I doubt it.

Oct 28, 2015 at 3:51 PM | Unregistered Commentersrga

Not to mention all the technologies to mitigate frost damage available to modern vintners, including weather forecasts.

Oct 28, 2015 at 3:59 PM | Unregistered CommenterJeff Norman

I don't know if the UK is the same situation as Canada, but here (South Ontario, British Columbia) the vineyards were created by tearing up the stone-fruit orchards. Wine from local grapes has increased because of the "buy local" fad.

Oct 28, 2015 at 4:14 PM | Unregistered CommenterEric Gisin

GaVin Ordinaire. Best drunk young. Does not mature well, or improve with age, as it becomes inconsistent, bitter, unpalatable and toxic to many. Similar to Climate Science in many ways.

The EU was not around during the Medieval Warm Period to subsidise loss leading wine or climate scientists. Much of the wine production was linked to self interested monks, who found it helpful in administering their lifestyle and religious beliefs, though not necessarily to everyone's benefit. Whining climate scientists fulfil these roles today

Has anyone ever tried to match weather patterns and climate to great French Vintages, Chateau Lafite or others? Tree rings produce a record of good growing seasons for trees. Do Vintages Years of wine produce a record of good growing seasons for grapes, or are shortages and/or surpluses involved? Whinochronology

Oct 28, 2015 at 4:14 PM | Unregistered Commentergolf charlie

Has anybody here attempted drinking English wine?
Any I have tried was thin,sour and expensive.
I wouldn't put it on my chips.
Best laid down and forgotten.

Oct 28, 2015 at 4:17 PM | Unregistered CommenterRoger Tolson

One thing Gavin hasn't considered is part played by hundreds of years of selectively breeding different varieties of grapes.

The Momentum Vineyard in Scotland for example grows the following grape varieties:

Rondo - created in 1964 by Professor V. Kraus
Solaris - created in 1975 by Norbert Becker
Siegerrebe - created in 1929 by Dr. Georg Scheu

Technology, selective breeding and the availability of over 10,000 varieties of wine grapes makes a significant difference.

I wonder how many grape varieties there were in medieval times?

Oct 28, 2015 at 4:35 PM | Unregistered CommenterTerryS

The number of Vineyards in the UK is completely misleading.....

As always to borrow a phrase its the dancing on the head of a thimble quote.

Its the extent outside of the UK's south that it becomes interesting.......

Oct 28, 2015 at 4:39 PM | Unregistered CommenterJustAnotherPoster

8 bottles of this stuff and you're REALLY finished. haha


Oct 28, 2015 at 4:43 PM | Unregistered CommenterBad Andrew

Gavin, gavage. Whatever. The drink remains the same.

Oct 28, 2015 at 4:50 PM | Unregistered Commentermichael hart

Has anybody here attempted drinking English wine?

I think it's time you tried again. Sharpham vinyard in devon produces white wines that easily challenge their French equivalents. English wine used to be a joke but not anymore

Oct 28, 2015 at 4:52 PM | Unregistered CommenterArthur Dent

"We're probably using types that are better able to resist cold"

The UK is DEFINITELY using cold-resistent types of vine.

Gavin is just plain ignorant of modern viniculture.

Selective plant breeding has moved on in the last millennium, along with everything else.

Oct 28, 2015 at 4:58 PM | Unregistered Commentermarchesarosa

[snip: language]

Oct 28, 2015 at 5:05 PM | Unregistered CommenterRussell

Temperature proxies are only valid when Real Climate Scientists say they are, or until they decide they were a fogment of over their imagination.

I wonder what else GaVin will find as he scrapes through the dregs of desperation at the bottom of the barrel marked Climate Science. With Paris a month away, it is going to be like an Advent calendar, with each new day revealing fresh nuggets of unpalatable junk.

Oct 28, 2015 at 5:13 PM | Unregistered Commentergolf charlie

Gav's feet were never made for dancing.

Oct 28, 2015 at 5:21 PM | Unregistered CommenterMartyn

Doh. Grapes - including red grapes - were grown as far North as York way back. Not so now. Never mind, Gavin.

Oct 28, 2015 at 6:15 PM | Unregistered CommenterJeremy Poynton

For his next trick, GaVin is going to produce news of Greenlands 2015 record producing wheat harvest, to match records long buried by climate science in impenetrable permafrost.

Have they started producing the unprecedented weather records for 2016 yet? Obviously they completed the full set for 2015 ages ago. Similarities with FIFA choosing World Cup venues are only due to money.

Oct 28, 2015 at 6:53 PM | Unregistered Commentergolf charlie

The history of wine is quite interesting, but has little to do with climate. The Normans preferred wine, but as the Roman amphora was lost, they had to grow it locally. As soon as the barrel was invented, domestic wine was replaced by wine imported from France.

Oct 28, 2015 at 7:24 PM | Unregistered CommenterRichard Tol

Minnesota has at least 65 commecial vineyards. Beyond that there are hundreds or thousands of hobby growers (one of my neighbors just picked 140 lbs from his very small plot in the backyard). Why? People like wine, and the U of M has created a bunch of cold-hardy grapes: -- so not sure that varietals today are a good proxy for those available 7-800 years ago, regardless of population...

Oct 28, 2015 at 7:57 PM | Unregistered Commenterterrymn

Sorry if I am repeating what has already been said:

The point of the medieval claims was that vineyards were further north then. No one is claiming there are no vineyards in the British Isles now as opposed to then, only that there were better growing conditions then meaning they could be successfully grown for commerce further north. Notice the RealClimate paper does not go into detail as to how far north the successful vineyards are currently or were then.

I would point out that the higher CO2 levels and modern farming techniques now would give the current vineyards an edge even if temps aren't as high as then. (unless RealScience wants to give up on the idea that CO2 levels were at 280 back the. Snicker)

Oct 28, 2015 at 8:42 PM | Unregistered Commenterkuhnkat

Oh yeah, the Schmidt probably got his info from here:

"There are nearly 400 commercial vineyards in England and Wales covering approximately 2000 acres of land in total. Nearly all are in the southern half of England and Wales. Most English and Welsh vineyards are small (less than 5 acres), many very small (less than 1 acre). Only a small number exceed 25 acres and just a handful 50 acres. The largest (Denbies, Dorking, Surrey) has around 200 acres of vines under cultivation. "

Oct 28, 2015 at 8:51 PM | Unregistered Commenterkuhnkat

How does Gavin's claims fit in with the twice repeated complaints by French wine shippers that the Bishop of Durham's wine sold for 3 times their wine, while enjoying tax exemption?

Chaucer's father was a wine merchant so presumably Geoffrey wasn't just shooting his mouth when he claimed that there was a vineyard in Scotland.

At the height of the Medieval Warming Period, which Gavin now admits existed, grapes were grown way up north in Germany - "on the shores of the Baltic" - while the grape varieties available, Gouais, Rauchling, Elbling? were all one that required warmth to ripen. (Australia's only planting of gouais is in Rutherglen, not noted as a cold climate). As for the reds argant was grown in middle Germany, and possibly further north, with pinot noir, yet now is a lesser know variety in the south of France (and I believe Spain).

Add one more to the list of those sceptical of Gavin's claims.

Oct 28, 2015 at 9:12 PM | Unregistered CommenterGraeme No.3

Oct 28, 2015 at 3:13 PM | Unregistered Commenter Charlie Flindt
I believe you are a farmer Charlie but even if not you will know that weight / acre, sugar content, time of harvest are all better indicators of weather that Gavin's stupidity.
He best stay quiet rather than confirming he is a halfwit.

Oct 28, 2015 at 9:14 PM | Unregistered CommenterStephen Richards

Ah, the feckless do love scurrilous embroider, any sort of liquid conjecture - will do.

What say ye, Schmidt?

Hooray, and of success for the English vine,
but allusions and rumour of man made warming, he should not intertwine,
hearken Schmidt - correlation is not causation!
we are after all, merely talking of, satisfactory potation.

Oct 28, 2015 at 9:31 PM | Unregistered CommenterAthelstan.

"More than 10x number of English vineyards now than in medieval times."

Ah, a benefit of increasing plant food?

Oct 28, 2015 at 9:40 PM | Registered CommenterGreen Sand

Crikey, its a funny aud world - and when human beings who spend too much time in each other's company, empathize then begin to mirror each other, they're either long time married or something else is happening...........did anyone ever notice how those loons who were in regular contact with MacRuin began to act and talk like him? A similar thing with Ed the Red Miliband - may God help them.

Now then Josh, throw up the wiki page of Michael Mann, after, then do the same for Gavin Schmidt....................weird, very weird, I wonder, what does Richard Betts look like? And has........ Joolya Slingshot receded AND grown a goatee?


Oct 28, 2015 at 9:46 PM | Unregistered CommenterAthelstan.

This may be a bit tangential, but - being a fan of wines from the Chateauneuf-du-pape AOC - who have been growing grapes and making their heavenly juice since before 1300 - I've long known they had (and continue to employ) a genius bit of (micro) geo-engineering for the last 800 years: The small appellation is on top of a post-glacial morraine, and they spread the galets roulés deposited by the glaciers in the vineyards to capture heat from the sun during the day and then keep the soil warmer at night - to extend the growing season and/or make the fruit ripen faster. Depending on the characteristics of the annual weather, one or the other are usually desireable.

It would be interesting to know if - in our current "the planet has a fever" climate - any of the vintners have removed the galets roulés to ease the stress on their over-heated vines. Has anyone heard of this happening? Wiki pic of the rocks keeping the vines warm:âteauneuf-du-Pape_AOC#/media/File%3A140614_Chateauneuf-du-pape-02.jpg

Oct 28, 2015 at 10:33 PM | Unregistered Commenterterrymn

"Number of vineyards isn't a good temperature proxy, number of vineyards per capita isn't a good temperature proxy, number of bottles produced per capita isn't a good temperature proxy..." --Tim Osborn

It's a tradition in climate "science" to create correlations based on mediocre, meaningless, or even inverted proxies...and then omit or fabricate the error bars.

Oct 28, 2015 at 11:11 PM | Unregistered Commenterjorgekafkazar

Since warmth generally diminishes with latitude, viticultures northward spread evidences a warming climate.

British winemaking's Northward march through Yorkshire, Northumbria , and Scotland reflects a growing season gain of hundreds of degree-days in the last hundred years.

Oct 29, 2015 at 12:02 AM | Unregistered CommenterRussell

Gavin is using the Domesday Book (1085) as the reference point for the Medieval Warm Period data giving 42 vineyards. He discounts reports of vineyards elsewhere sorry RealClimate link As the climate improved for the next 250-300 years then that number must be the minimum for the MWP. There are records of 20,000 vines being planted in the 17th century on Lord Salisbury’s estate in Hertfordshire. History of English Wine production can be found here

Oct 29, 2015 at 12:17 AM | Unregistered CommenterSandyS

"During Roman times there were forests everywhere": no - about the same as in the 19th century. See Oliver Rackham's books.

Oct 29, 2015 at 12:20 AM | Unregistered Commenterdearieme

Where vines can flourish is surely the issue, not how many are planted.

Scotland's flourishing vines are out in the weather, not sitting behind glass .

Oct 29, 2015 at 12:26 AM | Unregistered CommenterRussell

So did the Vikings drink scrumpy (or just act like they had)?

Oct 29, 2015 at 12:29 AM | Unregistered Commentermichael hart

The UK's Medieval Grape Growing Period is now an established fact in Climate Science, because GaVin Schmidt said so at Real Climate.

Historians have known this since the Medieval Warm Period, which by an amazing coincidence, was happening at the same time, but Real Climate Scientists have always ignored historical evidence, favouring stuff they made up as evidence, like the Hockey Stick, which proved there could not have been a Medieval Grape Growing Period in the UK.

Oct 29, 2015 at 1:03 AM | Unregistered Commentergolf charlie

Rocky Spears: "Beer and wine were not actually luxuries, but staples as most water was undrinkable."

And yet water was drunk. We know that because of the cholera epidemics of the nineteenth century. When Dr Snow was identifying the cause of cholera in Soho, he recognised the significance of the absence of deaths at a brewery, contrasted with the high mortality in the percussion-cap factory across the street. The brewers, for obvious reasons, drank beer, while the factory-workers, for similarly understandable reasons, didn't. Enough people must have been water-drinkers for those cholera outbreaks to be very lethal. One of my ancestors died of "old age" during an epidemic in Edinburgh. Of the twenty-four other souls named on the same page of the parish register, twelve had "cholera" as the cause of death.

Oct 29, 2015 at 1:30 AM | Unregistered CommenterOwen Morgan

michael hart, I think the Vikings drank English wine mixed with zumerset scrumpy, and thus fortified, set off for home and accidently found Greenland, as the Navigator was trying to navigate by the stars, whilst face down in the bilges. None of his crewmates was in any state of mind to notice, until they realised that the warm embrace and welcome they received from polar bears, did not match their expectations of a grateful homecoming meal.

Oct 29, 2015 at 1:35 AM | Unregistered Commentergolf charlie

And how did Lief The Lucky get his name?

By being the Viking to survive a Davis Strait voyage at the height of the Medieval Cooler Than Now period.

Dead men earn no epithets

Oct 29, 2015 at 2:26 AM | Unregistered CommenterRussell

English vineyards now are <2000 acres and nearly all are very small businesses run by retirees of less than an acre.

Oct 29, 2015 at 3:19 AM | Unregistered CommenterTony

What a great cartoon! -- Eugene WR Gallun

Oct 29, 2015 at 3:23 AM | Unregistered CommenterEugene WR Gallun

“... the Viking to survive a Davis Strait voyage at the height of the Medieval Cooler Than Now period …”.
Tree line studies show that the during the MWP the NH was warmer than now : “… conifers have not yet recolonized many areas where trees were present during the Medieval Warm period (ca AD 800–1300) or the Holocene Thermal Maximum (HTM; ca 10 000–3000 years ago) …”.

Oct 29, 2015 at 5:53 AM | Unregistered CommenterChristopher Hanley

0% proof......


Oct 29, 2015 at 8:31 AM | Unregistered Commenterjones

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