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« A Rose on winter | Main | All models are wrong »

Wheat in India

New Scientist has a very strange report about an article published in Nature Reports Climate Change. It's about what it calls "premature ageing" in wheat in India.

Satellite images of northern India have revealed that extreme temperatures are cutting wheat yields. What's more, models used to predict the effects of global warming on food supply may have underestimated the problem by a third.

Golly. Sounds serious, doesn't it?

But wait a moment. A satellite image is bit of an odd way to measure grain yields, isn't it? I had always thought dear old-fashioned scales and weighbridges were quite an acceptable way of doing this kind of thing. Let's take a look at how this tech-based approach to measuring grain yields works:

David Lobell of Stanford University in California used nine years of images from the MODIS Earth-observation satellite to track when wheat in this region turned from green to brown, a sign that the grain is no longer growing.

He found that the wheat turned brown earlier when average temperatures were higher, with spells over 34 ºC having a particularly strong effect. He then inferred yield loss, using previous field studies as a guide.

I'm not quite sure how you tell a crop that has yield problems from one that is merely ripening a bit earlier - I'm also not sure about the distinction between "premature ageing" and early ripening. 

Another question that occurs is whether Prof Lobell has sense-checked his findings. I mean, how about this headline from the Times of India?

Highest-ever wheat yield may rot away

The reason it's going to rot away is lack of storage. Now there are all sorts of other factor that might affect the size of the harvest - the acreage given over to wheat being an obvious one. Another possibility is the introduction of new varieties and  I wonder if he has controlled for this.

Without access to the paper it's hard to say more, but the idea that the warming of recent decades has affected yields seems on the face of it somewhat implausible.

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Reader Comments (78)

"What's more, models used to predict the effects of global warming on food supply may have underestimated the problem by a third."


"Highest-ever wheat yield may rot away"


Jan 29, 2012 at 8:07 PM | Unregistered Commenternot banned yet

new scientist. It's where you either start your career as a 22 year old fresh out of a 'science communication' course that, of course, is absolutely useless, or it's where you end your career, after you have 'retired.'

Jan 29, 2012 at 8:12 PM | Unregistered Commenterxc


You're right to be cautious about this until you've read the actual paper. I'll download a copy when I'm at work, and email it to you. (I've not seen it yet either)

BTW I guess you meant to say "Without free access to the paper...." You could buy it if you really wanted - but I am on your side when it comes to free public access to journals, particularly because without it, people can only get their opinions second-hand. (Indeed I had this exact debate with one of the editors of Nature Climate Change when it started last year!)

Jan 29, 2012 at 8:34 PM | Unregistered CommenterRichard Betts

New Scientist & Nature - why believe anything in them.
I haven't seen any evidence of scientific journalism in the last decade from either publication.

Jan 29, 2012 at 8:36 PM | Unregistered CommenterCinbadtheSailor

He then inferred yield loss, using previous field studies as a guide.

Let me guess, he ran a model on a computer !!!!

Jan 29, 2012 at 8:39 PM | Unregistered Commenterbreath of fresh air

Any worse-than-we-thought-paper should be taken with a grain of salt.

Jan 29, 2012 at 8:48 PM | Unregistered CommenterHans Erren

This has all the hallmarks of a "Climate Change Problem":

1. The science is settled; it's worse than we thought. (You must not point out the contradiction.)
2. Let's not bother with an experiment - it is much easier to get some stuff off the internet and make some wild guesses.

Jan 29, 2012 at 8:58 PM | Unregistered Commentergraphicconception

Any Worse than We Thought paper should be considered a work of fiction.

Jan 29, 2012 at 9:03 PM | Unregistered CommenterEd Caryl

If there isn't any indication they have gone further to check if the yields actually have been seen to drop in real life reports on the ground then you can bet they either haven't looked, or they have and found nothing to confirm the modelled results. This is the thing about these studies they seemed designed to give the desired result and no more. I'd guess the study came to a joyous halt the moment they saw a colour drop below a modelled limit - that was enough to say their new models are better than the old models, being more pessimistic they change in the right direction and hence follow the litany. This is the crappy essence about climate science that I think any layman can spot, the lack of real language that denotes a real attempt to cover all possible confounding issues.

Jan 29, 2012 at 9:38 PM | Unregistered CommenterThe Leopard In The Basement

Maybe the problem is the publish-or-perish type: guy does a study, reports more "brown" wheat or more brown wheat, earlier. Hypothesises crop yield. Gets a paper published. Three months later, takes his study and compares it to crop planting, and gets another paper published. Third paper, comparison of plantings and yields over time. One subject, 3 papers. University/funders pleased. Then comes ....

Fourth paper but not by him: WHERE the plantings occur, and what the historical yield efficiency are compared. Conclusion: more dry areas planted now, so increased total proportional loss, but due to new methods, lower local loss.

Technology saves! for now .... but what of water, fertilizer use in these formerly unfarmable areas? Guy does study, publishes paper ...

Everybody right, nobody upset, everybody gets more time at the trough.

Jan 29, 2012 at 9:49 PM | Unregistered CommenterDoug Proctor

Re: Hans Erren

> Any worse-than-we-thought-paper should be taken with a grain of salt.

Sorry Hans, but the consensus is that salt is bad for you, hold on it's changed the consensus says it is now good for you, wait a minute it has changed again...

Jan 29, 2012 at 9:51 PM | Unregistered CommenterTerryS

the only think that matter here, is the real world evidence,which would appear to be wheat yields have gone up..
In a business section I read that infrastructure s a huge problem, in India, something like 30% of food rots in the ground, because of inefficiences of storage, etc and getting it to market..

Extract: "India's $400 billion retail market is the nation's second-largest employer, after agriculture, according to consulting firm Deloitte.

Advocates see the move as a way to strengthen India's almost absent food supply chain — which is so beset by spoilage, poor infrastructure, hoarding and middlemen that the government estimates some 30 percent of produce rots in a nation with soaring food costs and tens of millions who go to bed hungry each night.

If companies like Wal-Mart and Tesco are allowed to open shops of their own, they may invest billions in improving farming techniques and getting produce into stores more efficiently, bringing down food inflation — which has averaged 10.5 percent over the last year — and possibly improving rural incomes.

The Ministry of Commerce says it will cost 76.9 billion rupees ($1.7 billion) to build the additional 35 million metric tons of food storage India needs.

In a July paper, it suggested that loosening restrictions on foreign investment in India's retail sector could be the best way to get more storage space built.

Yet the country has struggled to find consensus because of concerns about what it would mean millions of small shopkeepers as well as the poor. "

Jan 29, 2012 at 9:55 PM | Unregistered CommenterBarry Woods

I looked into the question of wheat production in India and climate change a while back.

As we can see, across India as a whole, wheat yield has increased nearly fourfold since 1961. If the region which produces half of that wheat has been falling because of the ‘ecological consequences of intensive monoculture systems’, it would surely be visible. But instead we can see that the area used for wheat production remained relatively static, and production suffered a slight dip in the early 2000s, but recovered through the remaining part of the decade — the opposite picture to the one presented by Christian Aid. It is possible, nonetheless, that the loss in Punjab were absorbed by production increases elsewhere, but the point remains that the increase in yield and production across the country has been sustained, for half a century, thanks substantially to agricultural chemicals.

Jan 29, 2012 at 9:58 PM | Unregistered CommenterBen Pile

Our planet earth rests on a giant turtle, which is supported by a giant turtle.... in fact it is giant turtles all the way down.

CAGW theory rests on giant computer models which are based on giant computer models.... it's giant computer models all the way down.

Jan 29, 2012 at 10:05 PM | Unregistered CommenterAlex

You can check the yields yourself here.

2000 = 27785 Hg/Ha
2001 = 27081 Hg/Ha
2002 = 27621 Hg/Ha
2003 = 26100 Hg/Ha
2004 = 27132 Hg/Ha
2005 = 26016 Hg/Ha
2006 = 26188 Hg/Ha
2007 = 27079 Hg/Ha
2008 = 28022 Hg/Ha
2009 = 29074 Hg/Ha
2010 = 28299 Hg/Ha
Hg = Hectogram
Ha = Hectare

Mind you, this is real world data and not yields inferred from a satellite image.

Jan 29, 2012 at 10:07 PM | Unregistered CommenterTerryS

I don't know how many of you have done any form of image processing but the colours green and brown cover a lot of territory (green especially).
If the satellite uses 24 bits for the colour then there are more than 16 million possible colours for each pixel. There will be, perhaps, as many as a million possible values for the colour green. By choosing what range of values to use to identify "green" wheat and what range to use as "brown" wheat it would be possible to obtain large differences in the final results. It would be interesting to have his data and code and see what results could be obtained with minor changes in values.

Jan 29, 2012 at 10:28 PM | Unregistered CommenterTerryS

Jan 29, 2012 at 10:28 PM | TerryS

Don't hold your breath on seeing any of it any time soon.


Jan 29, 2012 at 10:31 PM | Unregistered CommenterSandyS

Surely the colour change just means the wheat has been picked already?


Jan 29, 2012 at 10:42 PM | Unregistered CommenterMailman

Doug Proctor Jan 29, 2012 at 9:49 PM
"Maybe the problem is the publish-or-perish type: guy does a study, reports more "brown" wheat or more brown wheat, earlier. Hypothesises crop yield. Gets a paper published. Three months later, takes his study and compares it to crop planting, and gets another paper published. Third paper, comparison of plantings and yields over time. One subject, 3 papers. University/funders pleased. Then comes ...."

....being chosen as a lead author on a chapter of an IPCC report?

After all, he's now an expert in the field.

Jan 29, 2012 at 10:51 PM | Unregistered Commenterartwest

Satellite data from MODIS can be problematic. 'Pixel corruption' from haze and clouds is always an issue. This has been observed over the Amazon, and Betts is probably the best person to address this issue. Recall the Samantha/Saleska standoff...

But, satellite imaging is used for studying crop yields - no questions there.

The thing is, the basic methodology is suspect in a whole range of studies of this type - as explained here and of course, in Mike Hulme's paper discussed here recently. Not sure about this paper though as I don't have access (I used to have access to Nature Climate Change).

The authors could be emailed. They are usually kind in providing an MS.

Jan 29, 2012 at 10:52 PM | Unregistered CommenterShub

Missed your comment above. I've done my share of image processing, morphometry and analysis.

Jan 29, 2012 at 10:53 PM | Unregistered CommenterShub

I see no sufficient barrier right now to this kind of paper in the current culture, not even paper supplies. But I like to think the limits to the patience and the tolerance of decent and scientifically inclined people are being pushed beyond their breaking point, and that that break will provide a constraint in due course. In the meantime, we can at least admire what you have done - drawing wider attention to them with a hint of scepticism to encourage some thought.

Jan 29, 2012 at 10:53 PM | Unregistered CommenterJohn Shade

I would have thought nine seasons was an insufficient sample to conclude anything.

Jan 29, 2012 at 11:15 PM | Unregistered CommenterJames Lane

Apologies if this is a little tangential, but isn't it sad that the amount it takes to build the necessary food storage is approx £1bn. The UK gives that in aid in four years. How much are we spending on wind turbines etc? How much is spent globally on programmes that produce nothing? Programmes that quite possibly exacerbate poverty due to corruption and enrichment of the well off?

Quite how those in government can look themselves in the mirror in the morning I can't understand.

Jan 29, 2012 at 11:17 PM | Unregistered CommenterCumbrian Lad

Remote Non Sensing

Jan 29, 2012 at 11:34 PM | Unregistered CommenterPharos

I hate this sort of "lazy" science. The guy sits in an office somewhere and looks at some satellite imagery and then thinks he knows the full story and gets a paper with grant money to come his way almost surely because he has found a way onto the global warming publishing bandwagon. This is just lazy science.

Jan 29, 2012 at 11:52 PM | Unregistered CommenterFrederick Bloggsworth

The state of science publishing is "worse than we thought"™.

Jan 29, 2012 at 11:57 PM | Unregistered CommenterMichael J

Ooer, I'm going to have to stick up for the dark side on this occasion, but that's what being a seeker of the truth is all about.

Wheat yields have a very linear relationship with how long you can keep your crop's leaves green, particularly the big ones at the top (flag leaves). Premature senescence either through drought or disease (such as rusts, septoria or mildew) *always* reduces yield.

Wheat yields also provide excellent evidence to show that tree rings are not proxies of anything at all - not much rain, little growth; too hot, little growth; too cold, little growth; defoliation by pests/diseases, little growth. Cereal production, along with plant growth in general, is favoured by moderately warm, well-watered growing seasons. Heat = stress = less growth.

Jan 30, 2012 at 12:09 AM | Unregistered CommenterSayNoToFearmongers


What you are saying might be true, but why hasn't the author of the paper used real data instead of processing satellite imagery to guess it?

I've previously given the yields per hectare, here is the annual production (1000 MT) together with the percentage change from the previous year.

2000 = 76369 7.90 %
2001 = 69680 -8.76 %
2002 = 72770 4.43 %
2003 = 65760 -9.63 %
2004 = 72150 9.72 %
2005 = 68640 -4.86 %
2006 = 69350 1.03 %
2007 = 75810 9.32 %
2008 = 78570 3.64 %
2009 = 80680 2.69 %
2010 = 80800 0.15 %

Since 1979 the total increase in wheat production is 227%

Jan 30, 2012 at 12:34 AM | Unregistered CommenterTerryS

"Any worse-than-we-thought-paper should be taken with a grain of salt." --Hans Erren

Studies have shown that the words "studies have shown" are followed by blatant untruths over 50% of the time.

Jan 30, 2012 at 12:37 AM | Unregistered Commenterjorgekafkazar

@ TerryS

If the data don't agree with the dogma then the data must be wrong.

Jan 30, 2012 at 1:05 AM | Unregistered CommenterJustice4Rinka

One thing that strikes me is that modern varieties are nearly all of shorter growing season -- if you get the planting and growing right you can get 2 (different) crops each year -- maybe wheat then cottoen or wheat then sorghum. As Indian farming moves to modern varieities the green-to-brown (browning -off) which is a sign of ripening happens earlier.

Jan 30, 2012 at 1:28 AM | Unregistered CommenterAndrewKennett

seems lots of room for improvement per ha, UK average is over 7 tonnes per ha, on Terry Ss numbers they're less than 3 tonnes per ha.

Jan 30, 2012 at 3:11 AM | Unregistered CommenterFrosty

James Lane,
9 seasons is short, isn't it? But there has been enough milking of the MODIS products to last ~200 papers though.

Also, the authors define >34C as extreme temperature. Going by this, almost all of wheat-producing North India would be baking in 'extreme' temperatures every summer, most of summer.

Sounds like a very interesting paper to get one's hands on.

Jan 30, 2012 at 3:35 AM | Unregistered CommenterShub

I am getting to the point that any science tha tinvolves models is suspect. Probably a casualty of climate science.

Jan 30, 2012 at 4:16 AM | Unregistered Commentertimg56

Those yields are going to go higher not lower. The farming techniques used can be improved to increase productivity substantially. India is decades behind other countries in farming, and is catching up fast.

Jan 30, 2012 at 4:25 AM | Unregistered CommenterMikeN

Having worked on satellite imagery years ago, I know that it is possible to use multispectral satellite data to not only tell what crop is growing in a particular field, but also the health and yield of the field. The US CIA used such data for 40 years and even published it in Atlases by country, by year. You can order it here CIA Factbook.

Of course, these are summaries, but data exists down to hectare plots, with certain areas getting it down to meter resolution.

DEA also use these data to look for drug crops.

So, before you poo-poo the satellite data, it is there, it is detailed and it is very good.

Now, as to just what this report is all about, I would have to read it carefully as Richard Betts suggests. I would also question the conclusions drawn. Many things effect the production of crops -- rain being one of the most important. Was there a flood or drought? When did it rain or not?

Jan 30, 2012 at 4:57 AM | Unregistered CommenterDon Pablo de la Sierra

Like many probably I thought about the wheat strains improving. What about the pesticides? What about the fertilisers?

And this is only said in minor jest, I bet growth in wheat production is a good proxy for Internet access for Indian farmers. Or at least to those who are contact points in their lives.

This is the age of communication, of knowledge sharing, but it must be CAGW...

Jan 30, 2012 at 5:51 AM | Unregistered CommenterJiminy Cricket

Ah, but models and satellites, Bishop, models and satellites. And one idle Professor Lobel in idle Academia. You can't beat science. Nor are you allowed to climb those ivory towers.

To speak seriously, this infantalism is getting irritating. I mean I have seen a Prof. walking down our street with no clothes but he was a notorious drunk (in his latter years, his lectures were always and only about Malcom Lowery!) but this continual digging around for the next 'disaster' is really becoming more naked than shame. Yes, I'm sick to death of these idiots, or worse, cowards attempting to bring down their intellectually better neighbours to their own loutish level!

This is not germane but I tried yesterday to teach George Osborne to suck eggs, ie speak the truth, because I'm really losing my rag (I even wrote to the German Embassy to tell them to 'pay their debt'!):

First of all, no one understands economics. What has happened is very clear:
1) The western world (Europe, in particular!) ‘nationalised’ the ‘recession’
2)To ‘de-nationalise’ or ‘privatise’ this recession is going to be very painful. To ‘unemploy’ capital.
3)We know, by definition, that if we had allowed the banks, the ‘world’, to collapse we would be in a better position now.
4) Capital is about the rate of profit. There are two elements to that. First, raw cost. Ie what you must buy. And second how much it costs to employ people. The former we cannot control but the latter we can or should be able to. The reason, in the East, they are doing so well is because the labour costs are so low. Politically we can not be there so we compete on ‘value added’ goods. But they have stolen our patents and can produce them much better than we. Therefore, we must compete in the same labour market. Hence….
For the reasons for this recession are numerous. But, strangely enough, economics is very simple. If you can have an economy that raises the rate of profit, then you can have an economy. And how do you do that? Think.

Jan 30, 2012 at 6:41 AM | Unregistered CommenterLewis Deane

I'm sorry for the tail end of my latter comment but I really needed to 'dump' it somewhere. Your welcome to excise and edit. As I say, I'm just sick of infantile thinking and, yes, angry. Passionately angry. But, I suppose, to be buffeted by the winds of Lobel and his ilk should be beneath one. O well!

Jan 30, 2012 at 7:03 AM | Unregistered CommenterLewis Deane

"The reason it's going to rot away is lack of storage."

Another consequence of man-made global warming (it's too hot for them to build any more silos, rather be at the beach).

Jan 30, 2012 at 7:22 AM | Unregistered CommenterGeorge

So, let this be an addenda, Bishop, which you can and should excise but this was my 'letter' to the German Ambassador, which I thought you might want to see (out of curiosity if nothing else):

Dear Ambassador,

It's quite clear what has happened and what is happening. For ten, fifteen years you imposed, via the ECB, a ruinous, zero credit, negative credit, massively inflationary regime on States that, by definition, could not afford it. Hence, they bought your uncompetitive, over-expensive goods. And, of course, no one else could do so, could afford to. But, of course, this merely bankrupted the aforesaid states. But until the 'financial' crises of 2007/8, this was hidden - because 'money was free' and they thought you would always pay, some time or other, the very late but due bill. They forgot that Germany never pays, nevermind acknowledges a debt.
So this 'recession' came along, whose historical antecedents I will not go into. But what did all Western states do? They 'Nationalised' this 'recession', they dumped on the taxpayer the burden and cost of a massive market failure. The Southern States of the EU merely followed everyone's lead, here. You might blame Greenspan, you might blame Gordon Brown, it was a general disease. And, strangely enough, irony of ironies, no one - not the taxpayer, not the bond market, not even mortgaging our children, could pay for this 'nationalization' So let's 'privatise' the 'nationalised' 'recession'! But how impossible!
By imposing on Greece, Italy, Spain, Portugal zero or negative interest rates via the ECB, by imposing upon them German, uncompetitive goods, it was you who incurred the debt and by impoverishing the rest of Europe, made yourselves temporarily rich. But where, pray, will you be, when no one is left to pay for your goods? Even you heavy machinery is already reversed engineered by the Chines. So I say pay back the debt, pay what you owe, and leave off your attempted putsches in Greece and southern Europe. Pay up.

Jan 30, 2012 at 7:24 AM | Unregistered CommenterLewis Deane

The North India Plain, the wheat growing area, has had declining temperatures over the last century.

This is primarily due to increased tropospheric aerosols, which as noted above makes any colour analysis problematic.

FYI, the aerosols accumulate through the year and are mostly 'washed' out of the air by the monsoon. The wheat growing season starts after the monsoon, so all the study may have measured is increased aerosols through the wheat growing season.

Jan 30, 2012 at 7:56 AM | Unregistered CommenterPhilip Bradley


Absolutely right - the Green Revolution has probably benefited India more than any other nation on Earth, but yields can vary from one year to the next. The numbers suggest that preceding years did not suffer from early senescence in the wheat crop.

I'm assuming that it was looking at this year - if the paper claim that this effect has been going on for several years it appears to be in error (haven't read it yet).

Jan 30, 2012 at 8:32 AM | Unregistered CommenterSayNoToFearmongers

There's another paper in the same journal - see abstract here that seems to confirm Doug Proctor's prediction:

"[...] guy does a study, reports more "brown" wheat or more brown wheat, earlier. Hypothesises crop yield. Gets a paper published. Three months later, takes his study and compares it to crop planting, and gets another paper published. Third paper, comparison of plantings and yields over time. One subject, 3 papers."

The new paper, in its abstract says:

"Crop models predict that recent and future climate change may have adverse effects on crop yields. Intentional deflection of sunlight away from the Earth could diminish the amount of climate change in a high-CO2 world. [...] Here, we carry out high-CO2, geoengineering and control simulations using two climate models to predict the effects on global crop yields. We find that in our models solar-radiation geoengineering in a high-CO2 climate generally causes crop yields to increase, largely because temperature stresses are diminished while the benefits of CO2 fertilization are retained. [...]."

Lets hope this idea gets looked at again before it gets implemented...

Jan 30, 2012 at 8:43 AM | Unregistered CommenterJeremy Harvey

More CO2 --> higher yield.

Jan 30, 2012 at 8:58 AM | Unregistered CommenterJohn Silver

Ah! New Scientist. I think I posted this before:

A warming world could leave cities flattened

Yes, you heard it here second. There's really no limit to the stupidity of New Scientist's AGW reporting.

Jan 30, 2012 at 9:02 AM | Unregistered CommenterRobinson

@Frosty: " ... lots of room for improvement per ha, UK average is over 7 tonnes per ha, on Terry Ss numbers they're less than 3 tonnes per ha."

As a general rule, wheat quality as measured by protein content is inversely proportional to yield. Which is why it is so tricky to produce wheat fit for breadmaking in the UK, and why a very large proportion of all the wheat produced here is fed to pigs, poultry or cattle.

Jan 30, 2012 at 9:21 AM | Unregistered CommenterFilbert Cobb

I'll be interested to hear what Richard Betts actually has to say when he's read the paper but this looks like one of two possibilities.
Either they've spotted earlier than normal (what is normal?) browning of the wheat and have decided to spin this to suit the narrative in which case they are knaves,
or they have seen the same thing and the mindset refuses point blank to consider the alternative, namely that higher CO2 levels and (perhaps) higher temperatures are combining to produce an earlier crop, in which case they are fools.
It's also possible that they may be correct but given the figures for the last couple of decades (which unlike some people's data are not squirreled away where we can't see them) that seems less likely and anyway they can't possibly tell without going out and looking for themselves so why not STFU until they know what they're talking about.
For a fee they can consult Mrs J who will tell them that if you sow turnips in April they take about two weeks to germinate and seven or eight weeks to mature; sow them in June and they germinate in about half the time and are ready to eat after about five weeks. At least that's what happened last year. For a refresher we'll let them know what happens this year as well!

Jan 30, 2012 at 9:29 AM | Unregistered CommenterMike Jackson


Hectograms/hectare? That seems a daft unit, presumably chosen for its matching prefixes and/or by someone who thinks larger numbers are more impressive! Divide by 10,000 to get tonnes/hectare and the figures are far more digestible.

Jan 30, 2012 at 9:37 AM | Unregistered CommenterJames P

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