From the Roger Pielke Sr. has been saying this for years department comes this paper where Dr. Richard Betts of the UK Met Office is a co-author. h/t/ to Betts Twitter feed today. It is published in Climate Dynamics. Unfortunately, it has a $40 price tag, since it is part of Springer publications, so I can’t offer much more than the abstract. It does look interesting though, even though it is not observationally based, but model based. However, despite that limitation, when the climate modelers start looking at things other than CO2, that can only be a good thing.
Other efforts include this database from the Université de Lausanne that shows just how much has changed over the last nearly three millenniums: (1000BC to 1850 AD)
Clearly, it is a global scale forcing when viewed at this scale.
The money quote from the new paper is this:
Our results suggest that land-use changes over the past century may represent a more important driver of historical climate change then [sic] previously recognised and an underappreciated source of uncertainty in global forcings and temperature trends over the historical period.
Effective radiative forcing from historical land use change
The effective radiative forcing (ERF) from the biogeophysical effects of historical land use change is quantified using the atmospheric component of the Met Office Hadley Centre Earth System model HadGEM2-ES. The global ERF at 2005 relative to 1860 (1700) is −0.4 (−0.5) Wm−2, making it the fourth most important anthropogenic driver of climate change over the historical period (1860–2005) in this model and larger than most other published values. The land use ERF is found to be dominated by increases in the land surface albedo, particularly in North America and Eurasia, and occurs most strongly in the northern hemisphere winter and spring when the effect of unmasking underlying snow, as well as increasing the amount of snow, is at its largest. Increased bare soil fraction enhances the seasonal cycle of atmospheric dust and further enhances the ERF. Clouds are shown to substantially mask the radiative effect of changes in the underlying surface albedo. Coupled atmosphere–ocean simulations forced only with time-varying historical land use change shows substantial global cooling (dT = −0.35 K by 2005) and the climate resistance (ERF/dT = 1.2 Wm−2 K−1) is consistent with the response of the model to increases in CO2 alone. The regional variation in land surface temperature change, in both fixed-SST and coupled atmosphere–ocean simulations, is found to be well correlated with the spatial pattern of the forced change in surface albedo. The forcing-response concept is found to work well for historical land use forcing—at least in our model and when the forcing is quantified by ERF. Our results suggest that land-use changes over the past century may represent a more important driver of historical climate change then previously recognised and an underappreciated source of uncertainty in global forcings and temperature trends over the historical period.
Andrews, T., Betts, R.A., Booth, B.B.B. et al. Clim Dyn (2016). doi:10.1007/s00382-016-3280-7
Note: At the suggestion of Dr. Roger Pielke Sr. The title was updated to say “the global climate heat budget” instead of just “global warming”.
“land-use changes over the past century may represent a more important driver of historical climate change then previously recognised”
No shit Sherlock!
Supports the Agenda 21 “sustainability” doctrine, the only way to save the planet is to reduce the human population though.
Cant ruin the planet by farming and cities as well as feeding too many mouths can we.
http://endoftheamericandream.com/archives/al-gore-agenda-21-and-population-control
http://endoftheamericandream.com/archives/from-7-billion-people-to-500-million-people-the-sick-population-control-agenda-of-the-global-elite
Says it better than I.
Cheers
Roger
http://www.thedemiseofchristchurch.com
I’m reminded of a P.J. O’Rourke chapter headliner:
“Population Control- way too many of you, just the right amount of me.”
My first response exactly!
Luckily, True Climate Believers actually float over the earth like angels and have no impact on the ground at all.
You’d think that at $40 for the paper they could afford a proofreader. [/rant]
Hoist with my own petard.
Muphry’s law.
Thanks, I’ve added a [sic]. This is a clear case of mental infill that occurs when reading. We “expect” to see “than” and the word “then” gets morphed in our minds to “than” it takes a keen eye to spot such things.
Even MS-Word doesn’t catch it, I tested it on Word 2010 and it slips through unnoticed in the grammar and spell checker.
The problem with grammar checkers is that they don’t understand what is written. I once had a student whose written English was hard to understand. I put his work through a grammar checker and it became completely incomprehensible. The grammar checker and spell checker were happy with the result though.
The thing that really gets up my nose is essay marking software. In the spirit of Spy vs. Spy, we also have essay writing software.
Of course ‘Effortlessly’ means ‘Without learning anything.’ I’m obviously in a seriously grumpy mood today.
“The thing that really gets up my nose is essay marking software. In the spirit of Spy vs. Spy, we also have essay writing software.
Create Your A+ Essay Effortlessly!
Of course ‘Effortlessly’ means ‘Without learning anything.’ I’m obviously in a seriously grumpy mood today.”
Kind of like trying to learn how our climate reacts to something by having a computer do the work for you.
I saw this a few years ago – and have kept it handy . . . .
I halve a spelling checker,
It came with my pea see.
It plainly marks four my revue
Mistakes I dew knot sea.
Eye strike a key and type a ward
And weight four it two say
Weather eye am wrong oar write
It shows me strait aweigh.
As soon as a mist ache is maid
It nose bee fore two long
And eye can put the era rite
Its rarely ever wrong.
I’ve scent this massage threw it,
And I’m shore your pleased too no
Its letter prefect in every weigh;
My checker tolled me sew.
Smiles
Auto
PS – an even older one that works with almost any kind of kit, from batteries to bookkeeping, from PowerPoint to pet-breeding: –
ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS! DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKEN. IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS. ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN.
“The effective radiative forcing (ERF) from the biogeophysical effects of historical land use change is quantified in the Met Office Hadley Centre Earth system model HadGEM2ES using a fixed-SST atmospheric GCM experimental design. The global-annual-mean ERF at 2005 relative to 1860 is found to be −0.4 Wm−2, making it the fourth most important anthropogenic driver of climate change over the historical period (1860–2005)—behind CO2 (1.5 Wm−2), SO4 (−1.3 Wm−2) and CH4 (0.5 Wm−2), as diagnosed in this model (see Andrews 2014). ”
and they argue consequently that ECS may be higher than we think.
landuse change is a negative forcing.
Well, it’s a model, not observations of reality. So this isn’t surprising at all.
I love a thickly vegetated Sahara with many lakes in 1850. Go models!
Isn’t it miraculous: they can report forcings on the order of 0.5 to 1.5 Wm^-2 using climate models that can’t resolve the climate energy state to better than about 150 Wm^-2, and without knowing the surface energy budget to better than about (+/-)17 W^m-2.
But, of course, when they take anomalies against an equilibrated base-state simulation, all the model errors subtract away. <– climate modeler fall-back defense.
“Well, it’s a model, not observations of reality. So this isn’t surprising at all.”
You’re assuming that Mosher knows the difference, Anthony.
There is little or no evidence that that is in fact the case, certainly none of his posts seem to indicate so.
Missing the point .
If they CLAIMED it was observations you would have a point.
But they dont,
so you killed a strawman.
cat
get the paper.
Read it.
I did.
its free if you have half a brain and know how to search
The text is OK for a scientific or technical paper, but a little hard to read as a blog comment.
“Human population in India increased from 20 to 120 crores by 1880 to 2010 [and projected to reach 137 crores by 2025].” Crore = 10 million,
Suggested for blog, “Human population in India increased from 200 million to 1200 million from 1880 to 2010, and is projected to reach 1370 million by 2025.”
Also,
“That means, only in 54 Mha more than once crops are cultivated in a crop year on the same piece of land.”
Suggested for blog, “That means only 54 Mha (about 38%) of land is cropped more than once per year.”
The reason I suggest adding the percentage figure is that most readers have to stop and do the mental arithmetic. Most readers would probably grasp 540,000 square kilometers more readily than 54 Mha.
I find it very hard to believe that land surface change has caused a net cooling effect. This is likely yet another example of models being manipulated to show anything the authors want.
No, it’s a consequence of the fact that they hold other assumptions constant in the model, therefore it has to become negative. If they let climate sensitivity to CO2 vary in the model, it would probably go positive, but climate sensitivity would become much, much smaller.
Concurring with CG at 3:40. I also noted the thickly vegetated Australia. This has been “the wide brown land” for a long time. It is also very likely that the areas that could have been regarded as “vegetated” were under human management back in 1000 BC, so “naturally” vegetated might be a stretch. See Bill Gamage “The Biggest Estate on Earth”.
@ur momisugly Martin Clark and Curious George, The article does say ” Natural vegetation” so if that includes natural desert “vegetation” I presume they are talking about any thing that would grow as “native” vegetation . If you look at it that way the deserts in all those years were “covered” with that. The map is kind of correct but clearly misleading as far as the color code is concerned..
Sand as a natural vegetation. In models, OK. How about lakes?
“The map is kind of correct but clearly misleading as far as the color code is concerned..”
The map is confusing to those who start trying to criticise without reading what it represents.
Since the Sahara does not have any vegetation, it would be hard for it to have less than 100% of nothing.
All of these ‘parameter’ are just tweaked to get something looking a bit like the (adjusted) historical record. There are hundreds of ways they could be semi-arbitrarily tweaked and still produce a reasonable fit to 1960-1990 , fail to produce the early 20th c. warming and get the post 2000 plateau wrong.
This allows modellers to choose the set of parameters which best fits their preconceived ideas and play one thing off against another. This is why the whole modelling process is uninformative. There way too many poorly constrained variables and so the results tell us nothing.
Hansen 2005 clearly states that you can get pretty much any sensitivity you want out of a model by choosing the parameters. I discussed this here:
https://judithcurry.com/2015/02/06/on-determination-of-tropical-feedbacks/
Volcanic forcing was scaled down after Lacis et al 1992 ( GISS group ) and this meant sensitivity to volcanic aerosols went up… and this allowed senstivity to CO2 to go up too. Works fine until you run out of volcanoes, then the model runs hot.
Here is what volcanic forcing used to look like when they were doing proper physics based calculations and what it changes to when they started trying to “reconcile” model output with the climate record ( whilst maintaining a high CO2 forcing).
My study of ERBE data came out with a value very similar to the old Lacis et al value.
Greg, if I remember correctly, Sahara supplied the Roman Empire with grain. Do you maintain that it was all sand over 3,000 years?
I am fairly certain that it was Egypt that was supplying Rome with grain, not the Sahara
…Wow, it is sad that “intelligent” people replace reality with models……
By negative forcing you mean it decreases surface temperature? Trees stop solar radiation dozens of meters above the underlying soil in the tropics or in non-tropical summer, when the radiation is strongest.
They also contribute to a healthy hydrological cycle, wherein clouds form and block the sun. Both via moisture management and also via having a strong effect on particle formation (via the organic compounds they give off).
Has anyone considered all of the conversion of sunlight into plant growth that occurs, versus it hitting dirt/rocks/streets and simply turning into heat?
Then there are indirect effects, like the typical slash-n-burn agriculture — or agriculture where trees are cleared and used for fires — which releases a fair amount of CO2 into the atmosphere.
Can you make a case for how it would help cool temperatures, directly or indirectly? (Besides a model, which has variables “to control for” things?)
I think that there are some things that get overlooked in assuming a negative forcing resulting from clearing land. Anyone who walks from a forest into a bare, plowed field, or from a park into the developed city, observes that the bare area is hotter. The reflectivity of bare soil can vary widely, depending on the color of the soil. Claiming that removal of vegetation results in a negative forcing is painting with an overly broad brush because of differences in the color and texture of bare soil. Part of the problem is that vegetation uses transpiration to grow, and in the process cools the air above the vegetation. Another factor is that despite the low total reflectance of vegetation (only green light and near-IR is reflected) the blue and red light does not produce heating in vegetation, but is used in photosynthesis to produce cellulose and sugar. Since this article’s claim is based on a model — whose assumptions cannot be examined easily, — instead of empirical evidence, we should be cautious about accepting it at face value.
I agree Clyde, and what about the cooling of trees and vegetation via photosynthesis that is lost when the land is cleared. A warming effect. And should not all the concrete and pavement in the urban areas get a lot warmer than trees. I have a infrared thermometer to prove it. On a sunny day at about 80F air temp, grass reads about 80 to 85 while concrete of blacktop show well 100F. Seems like land use change gives warming, not cooling.
Mosher says “landuse change is a negative forcing.” Has that been measured?
It strikes me that to do this modeling correctly, there should be a multidisciplinary team working on it. As it is, I think that some of the ‘climatologists’ are in over their head and wouldn’t even know how to go about doing a sanity check on their assumptions, or the output of the models.
“Mosher says “landuse change is a negative forcing.” Has that been measured?”
The paper we are discussing says that the radiative forcing effect of landuse change is negative.
Andrews, Timothy, Richard A. Betts, Ben BB Booth, Chris D. Jones, and Gareth S. Jones. “Effective radiative forcing from historical land use change.” Climate Dynamics (2016): 1-17.
I have read most of the comments here and believe that most are off the mark. The idea of the paper is that *** if everything else is held constant *** then landuse change increases albedo. An increase in albedo will produce negative radiative forcing. This is very elementary theoretical physics. See R. M. Goody, Y. L. Yung
Atmospheric Radiation: Theoretical Basis, Oxford University Press,1995.
However, climatology is not about theoretical physics, but applied physics. Most critical comments here mention other variables that affect albedo and other phenomena. These are simply additional variables that have to be taken into account to estimate net radiative forcing.
The existence of these other variables and their impact on climate does not change the theory. However, because of the unaccounted for variables, the theoretical conclusion of this paper does not have much to do with assessing real world net radiative forcing.
Both James Hansen and Nir Shaviv have used the world ocean as a calorimeter to estimate net radiative forcing.
“The inferred planetary energy imbalance, 0.58 ± 0.15 W m-2 during the 6-yr period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change.
Hansen, James, et al. “Earth’s energy imbalance and implications.”Atmospheric Chemistry and Physics 11.24 (2011): 13421-13449.
Shaviv, Nir J. “Using the oceans as a calorimeter to quantify the solar radiative forcing.” Journal of Geophysical Research: Space Physics (1978–2012)113.A11 (2008).
Hansen concluded “The inferred planetary energy imbalance, 0.58 ± 0.15 W m-2 during the 6-yr period 2005-2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change.”
His estimate purported to include all effects, including GHGs, aerosols and landuse changes.
Hansen’s peers within NASA, other Federal agencies and contractors, commented on his results.
What did Dr Hansen’s colleagues think? First they rounded 0.58 to 0.6 W m-2. And then they said that such precision is not possible with existing technology.
“The net energy balance is the sum of individual fluxes. The current uncertainty in this net surface energy balance is large, and amounts to approximately 17 Wm-2. This uncertainty is an order of magnitude larger than the changes to the net surface fluxes associated with increasing greenhouse gases in the atmosphere (Fig. 2b). The uncertainty is also approximately an order of magnitude larger than the current estimates of the net surface energy imbalance of 0.6 ±0.4 Wm-2 inferred from the rise in OHC. The uncertainty in the TOA net energy fluxes, although smaller, is also much larger than the imbalance inferred from OHC. (TOA means top of the atmosphere).
Stephens, Graeme L., et al. “An update on Earth’s energy balance in light of the latest global observations.” Nature Geoscience 5.10 (2012): 691-696.
URL: http://www.nature.com/ngeo/journal/v5/n10/full/ngeo1580.html
To make certain readers don’t miss the point, I summarize. Dr. Hansen told us that the Earth’s energy imbalance of a little over half a Watt per square meter compared to 240 Watts incoming “confirms the dominant role of the human-made greenhouse effect in driving global climate change.”
His peers said that the uncertainty in the net radiative balance is 17 Watts per square meter. More meaningful error bars would be +0.58 +/-8.5 Watts per square meter. This implies that the uncertainty in radiative balance is not merely the quantum, but also the sign of the imbalance.
Dr Hansen’s data cannot tell us whether Earth was warming or cooling.
“landuse change is a negative forcing.” defies even junior high school physics.
Bingo. Thanks, Mosh.
Beat me to it Andy, Mosh tends to state these things as if the are empirical facts, that could be very misleading, well in fact it is, the general public have been totally misled into thinking models are the real world
Nic Lewis’s post says that the forcing from land use changes used in energy balance models was −0.19 W/m2. https://climateaudit.org/2016/01/21/marvel-et-al-implications-of-forcing-efficacies-for-climate-sensitivity-estimates-an-update/
IF the forcing from land use change produced by HadGEM2ES model were more accurate than the mean ERF of the IPCC’s other models, that roughly 10% decrease in total radiative forcing would represent a 10% increase in climate sensitivity. Not much to write home about – if Betts et al are correct. Is there any reason to believe that the HadGEM2ES model is any better than any of the other models at predicting the forcing from land use changes? Is there any observational evidence that proves HadGEM2ES does a superior job reproducing forcing from land use changes? Or is this example of cherry-picking among unvalidated differences between models in an attempt to subtract a few tenths of a W/m2 from anthropogenic forcing here and thereby reduce the gap between EBMs and AOGCMs?
landuse change is a negative forcing.
This is one of these really dumb claims that keeps getting repeated.
We had forest on our property next to cleared land. The forest was ambient temperature at the top where the leaves were to ambient or less on the ground.
Cleared land is almost as bad as asphalt (as is obvious from surface engineering studies).
You could feel the heat from the cleared land and it was painful to walk on barefoot but not quite as bad as asphalt.. Grass as anyone who has walked on it in the summer knows never gets much warmer than ambient.
The satellites should be able to reconstruct actual land temperature from fitting the transparent IR wavelengths to a Wein/Planck curve. The a-train passes over at 1:30 PM which is pretty close to peak surface temperature.
A clear sky surface temperature map would make it pretty obvious if land use increases or decreases temperatures.
Still can’t spell H2O, eh Steve?
Doesn’t the first graph say 1000 BC? Not 1000 AD? That would be 2850 years.
Right above the graphs…”Other efforts include this database from the Université de Lausanne that shows just how much has changed over the last nearly three millenniums: (1000BC to 1850 AD)”.
That’s the latest revision, previously it talked about 850 years, from 1000 AD to 1850AD.
I missed that.
MarkW I made that clearer, thanks. Now says: “…shows just how much has changed over the last nearly three millenniums: (1000BC to 1850 AD)”
not to nit pick but it’s millennia for successive thousand year increments
Then don’t nitpick!
What would you say: one stadium, two stadi…?
No, stadia is the plural of stadium. Like maxima , minima and millennia.
American simplified dialect English tends to use s for plurals except “mass media” which for some reason is preserved and not called “mass mediums”.
[? Stadia, in surveying, are also the crosshairs on the reticle of a theodolite or other surveying instrument that allow stadiametric rangefinding. mod]
Some reason . . Mass ~ Big, Medium ~ not Big ; )
[In physics,
mass => presents distort space-time,
mediums => past ghosts distort present time. .mod]
The way the media reports on CAGW I believe it should be mass mediums,
@ur momisugly JohnKnight
According to the Einstein’s original paper (1905) mass is a measure of amount of energy contained in a body:
“If a body gives off the energy L in the form of radiation, its mass (K) diminishes by L/c^2”
Original Einstein’s equation (later simplified to E=mc^2) was given as
K0 − K1 = 1/2 * Lv^2/c^2 .
This is a most welcome and important piece of work. Many of us have thought that changes in albedo due to agriculture and urbanisation have affected climate, at least locally, but haven’t been able to test this hypothesis. The reason for this belief is that albedo effects are far more powerful than the effects that may or may not be due to the weak optical gas CO2. But there may be more to this than just radiation effects. Natural vegetation uses water to both transpire minerals up to the leaves and as a substrate along with CO2 in photosynthesis (hence fixing both it and CO2 into organic compounds). Hence the released water vapour is much, much less from a native biome than from irrigated land, where the amount of water vapour released is likely to be up to 90% of the irrigation volume. Water in the atmosphere is a very powerful optical factor (oops, showing my age – it should be driver). Clouds (water vapour) reflect and water (both as a gas and as vapour) absorbs many wavelengths strongly. That the sky is blue is NOT due to CO2!
But a bit of warming maybe a very good thing since the almost irrefutable downward trend in mean temperature over the last few millennia (albeit with a few ups and downs) is evidence that we are headed for another ice age far earlier than most estimates of its inception of 10,000 years in the future. If we do plunge into an ice age in 50 to 200 years it won’t be pleasant and will make a sick joke over our current concern with global warming. However, global warming may delay or even prevent this disastrous occurrence. and must be a good thing surely? We can cope easily with a moderate amount of warming, but we could not cope with an ice age given our present global economy and population.
Clouds, sea ice coverage and snow coverage are the main items that determine albedo.
Global warming is already a sick joke.
Changes) presented few examples relating to land use changes. One of the figure presents the series of maps compares the changes in urban, agricultural and forested lands in the Patuxent River watershed over past 140 years [1850-1992]. This did not included the changes in area under water resources.
Human population in India increased from 20 to 120 crores by 1880 to 2010 [and projected to reach 137 crores by 2025]. This resulted large changes in land use patterns. Forests reduced from 89 to 63 Mha during the same period with relatively greater deforestation during British rule [1880-1950] and in contrast to forests, cropland area has increased from 92 to 140.1 Mha during 1880-2010. Greater cropland expansion has occurred during 1950-1980s that coincided with the period of farm mechanization, electrification, and introduction of high yielding crop varieties. The rate of urbanization was slower during 1880-1940 but significantly increased after the 1960s with modern technological innovations in infrastructure to meet the modern life styles. In future, to meet the growing population, the changes in land use and land cover change further.
India’s total geographical area is 329 Mha of which 195 Mha is gross cropped area and 141 Mha is net cropped area. That means, only in 54 Mha more than once crops are cultivated in a crop year on the same piece of land. In the net cropped area the net irrigated area is only 65.3 Mha and the rest of the cropped area is rain-fed.
In this context suggested two parameters, namely heat-island effect [it is in use since 1880] and cold-island effect [coined by myself]. When compute average temperature of the region, we must have met stations uniformly. Without this, the effect of wind speed and direction [moist air or dry air] on surrounding temperature will not be accounted.
This global temperature curve construction is biased by the met stations spread. So, simply land use changes cause cooling is a misnomer and misleading inferences [it is only theoretical] as the land use change in its totality is not accounted in the averaging of global average temperature curve [this is the reality] as the met network present dense over urban areas and sparse in rural areas. However, this is not so, with satellite data and thus with the land use change cooling effect, present little change in temperature which includes natural variability and other factors like El Nino-La Nina, Volcanic activity, etc. The so-called global warming is less than 0.2 oC and with the time this will come down for the same period as the CO2 impact on energy conversion has reached nearly flat condition as the energy available is not infinity but very limited.
Dr. S. Jeevananda Reddy
In my book “Climate Change: Myths & Realities” [2008] under chapter 7 (Ecological
This is the first sentence — missing, sorry for the inconvenience
Dr. S. Jeevananda Reddy
Again this period of time in the climate is not unique, therefore anything used to try to justify this climate period of time has no real substance.
Past history shows this period of time in the climate is nothing special.
http://dandebat.dk/eng-klima7.htm
More data from the past which shows this period of warmth is NOT unique.
I am going to keep harping on this to expose how misleading the AGW enthusiast when presenting their case to the public.
Five cornerstones from where I come from on the climate issue are as follows:
1. Past history shows this period in the climatic record is not unique.
2. Past history shows that each and every time solar enters a period of PROLONGED minimum solar activity the global temperatures have responded down. I have listed the criteria (in the past) which was last met in the period 2008-2010. With that said I think there is an excellent chance of this criteria being met presently and this time the duration could be much longer.
3. There is a GHG effect but I maintain it is more a result of the climate/environment rather then it being the cause of the climate.
4. If one looks at the climate just since 1950 -present(to take a recent period of time) and factors solar, volcanic activity, global cloud cover and ENSO versus resultant temperature changes one will find a very strong correlation.
5. Temperature data of late must be met with suspicion. I maintain satellite temperature data is the only valid temperature data.
Remember if global cloud coverage should increase and snow coverage/sea ice coverage should increase in response to prolonged minimum solar conditions that would accomplish the albedo to increase. Even a .5% to 1% increase would wipe out all of the recent warming.
Albebo is hard to change and at the same time it takes very little change in it to have climatic effects.
It is similar to Ice Age conditions versus Inter-Glacial conditions; hard to go from one regime to the other but at the same time the change required is very minimal. It is a balancing act which most of the time is in balance but every so often factors conspire to throw it out of balance which we know when we look at the climatic history of the earth.
CLIMATIC HISTORY – which is totally being ignored by the AGW movement has to be kept in the forefront and I am going to do that each and every time I combat their notion that this period of time in the climate is somehow unique.
I wonder what it is going to take to get the truth out about this period of time in the climate which is by no way unique?
I’ve gone over the article (I can read it for free where I work.) The authors of the paper argue that the effect of land surface changes have resulted in a NET COOLING of the Earth, with a radiative forcing of -0.4 W/m^2, opposite in sign to the effect of greenhouse gases. I just find that very hard to believe: that changing forests and prairies into fields and cities has a net cooling effect. But then, in model world, anything is possible!
It looks like “Steven Mosher” noticed the same things as I did, and posted it before I did (though it didn’t show up until after I had posted my comment.)
can you provide a copy for me to examine? See the contact form under “About” menu item.
I just sent you a message. Let me know if you didn’t get it for some reason. The subject has the title of the paper in it “Effective radiative forcing from historical land use change”.
http://sci-hub.bz/10.1007/s00382-016-3280-7
use sci-hub to get past paywalls.
“http://sci-hub.bz/10.1007/s00382-016-3280-7
use sci-hub to get past paywalls.”
Ding ding ding..
pssst lets keep this a secret
k, mosh.
i just wanted to make sure anthony got it.
a discussion about abstracts can go all over the place and end up nowhere.
So it’s worse than we thought. Man, I sure didn’t see that coming. /s
If anybody is interested, A paper which reviewed precipitation and temperature change was published last year in HESSD which came to the same conclusion. http://www.hydrol-earth-syst-sci.net/20/1765/2016/hess-20-1765-2016-discussion.html This paper was reviewed publicly, so it has changed a lot since it’s initial findings (of note: Roger Pielke, Sr. was the first to comment on the paper in the public forums.)
“Our results also show that LULCC alone causes warming in the extremes of daily mean and maximum temperatures by a maximum of 1–1.2 °C, which is comparable with the observed increasing trend in the extremes. Decrease in forest cover and simultaneous increase in crops not only reduces the evapotranspiration over land and large-scale convective instability, but also contributes toward decrease in moisture convergence through reduced surface roughness. These factors act together in reducing significantly the moderate rainfall events and the amount of rainfall in that category over central India.”
In my opinion, this should be regarded as much more significant component of anthropogenic climate change than carbon dioxide. We’ve seen this effects many times — until recently, 1934 had been the warmest year on record in the United States. There is a clear cause for this effect — a major LULCC known as ‘the dust bowl.’ We are seeing the same effect in Syria right now. The government engaged in non-sustainable agricultural methods for over a decade to try to keep themselves in power. The result has been their own drought and warming cycle.
Following the devastation of the extreme wind erosion experienced during the dust bowl years, hedgerows and shelter belts were planted throughout the US Southern and Central Plains. Those hedgerows are a thing of the past and no longer exist, having been ripped out and put to the plow, to grow corn for ethanol production. Formerly tree- lined country roads in Kansas are now treeless and some farmers have even been known to run their seed drills a foot or so out into the roads, to maximize their planted acreage. Gotta harvest that political dollar- and what else could you call the US ethanol fuel program?
Soil conservation and other environmental goodness have been tossed aside to fulfill the ethanol- CO2 reduction scheme. In similar vein of Green hypocrisy, we hear- “oh, but cats kill birds”, in response to concerns about windgens and raptor deaths.
Because it is model based I am reminded of Peter Franks presentation at Heartland on error propagation in models. If his analysis has not been performed on the model it might be as useless as the GCMs he reviews.
DMA, do you mean this talk? 🙂
I was compiling a key for one of the oldest detailed maps of the world (the 1750 William Roy map of Scotland) and started to look for “forest”. After searching and searching I finally found one!! – Indeed it appears that in 1750, Scotland was largely treeless.
This is not the case today, which strongly suggests that the large use of fossil fuels that replaced that of wood far from doing harm, has actually allowed the native tree cover to regrow. In other words, the map suggest that there is more woodland now than in 1750.
And just as an after thought – who can doubt that if the map showed more forest in 1750 – that every single academic in the field would have reproduced it time and time again to “prove” how much damage fossil fuel use had done. But because it shows and increase … we hear nothing!
I think it’s recorded that all the woods in Fife were used in the construction of The Great Micheal at the start of the 16th century. Probably accounts for the lack of forests in that part of Scotland.
Along a similar line of reasoning Africa and other nations with large populations of impoverished citizens must scavenge what is around them to meet their daily needs. As an analogy “they are eating their land”, as they use the woodlands and brushlands for fuel and building materials.
And don’t forget the goats, which eat anything herbaceous that pokes its head above ground. For sedentary herders, in arid climes and semi desert areas goats are a curse for natural re-greening /regeneration of the Sahel and beyond.
Maybe so, but goats are also very durable animals which will supply milk as well as other necessary products in the long run.
Goats get blamed for expanding the Sahara’s reaches. They might just be guilty.
This is probably also true for much of New England, which was initially cleared for farms that have been abandoned. One can walk in the woods and find old stone walls that used to mark the field boundaries.
Our results suggest that land-use changes over the past century may represent a more important driver of historical climate
The above from the article which once again apparently does not take into the account the historical climatic record, such as the Holocene Optimum for starters which was much warmer then today with very little change in land use back then.
How do you square it?
The Milankovitch cycle squares that. At it’s peak point during and after the breakout from the depths of glaciation, global temps were warmer.
My point goldminor.
No that was my point. You asked the question “What squares that?”
I have said that many times over and over again.
goldminor that is why I responded the way I did. I have said this about 100 times or so.
Salvatore Del Prete
August 6, 2016 at 5:31 am
The bottom line is this period of time in the climate is in no way unique or different from previous warm spikes the climate has had since the Holocene Optimum. This period of time is not only not as warm as previous spikes of warmth in the climate such as the Roman and Medieval warm periods to name a few but does nothing to alter the fact that the climate since the Holocene Optimum some 8000 years ago has been in a gradual cooling trend with spikes of warmth within this gradual cooling trend.
If one evaluates the climate since the Holocene Optimum until today and takes into consideration Milankovitch Cycles and superimposes solar activity upon this and further refines this with volcanic activity and more recently more reliable ENSO data a very good correlation will be shown to be established between these factors versus the resultant climate. Further if CO2 is put into this mix one will find a zero correlation between the climate and CO2 concentrations.
Then why did you ask this question?…”How do you square it?..”.
Those are your words. What did you mean when you posted that? What am I missing? I think you are full of it with your attempt to state otherwise. Was that your evil twin brother who made the original comment?
Good to see an article like this but why are the deserts like Sahara showing 100% vegetation?
Ground water extraction is not mentioned which is a significant aspect of changes in land use. Ground water has fallen over nearly all densely populated areas of the globe which means less evaporation and therefore hotter surface temps.
Greener Earth produces more water vapor. Transpiration is what makes clouds above tropical islands and rain forests.
Again I have to say it all of these articles that keep coming out about the climate are acting as if the climate is in some uncharted territory and nothing could be further from the truth.
Enough said. I can’t wait until the global temp. trend is in a definite downward trend.
By then, China will already have all our coal and a One-World Socialist dictatorship will rule us.
We are all waiting Salvatore.
OK, it’s 100% natural vegetation, but when there isn’t any or very little in the big deserts!
https://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/
This is another look or perspective on albedo which I think is more relevant.
https://wattsupwiththat.com/2010/03/03/spencer-using-hourly-surface-dat-to-gauge-uhi-by-population-density/
http://www.drroyspencer.com/wp-content/uploads/ISH-station-warming-vs-pop-density-with-lowest-bin-full.jpg
“The following plot zooms in on the lower left corner of the previous plot so you can better see the warming at the lowest population densities.”
http://www.drroyspencer.com/wp-content/uploads/ISH-station-warming-vs-pop-density-with-lowest-bin-full-0-to-200.jpg
I have been self-taught over my career in writing computer code to always ‘test’ the extreme’s of the data on your new algorithm. So let’s apply this to a thought experiment on land use changes.
Assume humans never existed so there is no anthropogenic changes to land. Apparently this would mean the Earth would be warmer than with humans, absent other anthropogenic effects. This means IPCC should be calling for massive new deforestation to help reduce global warming.
Now assume that man has plowed under every square centimeter of Earth and planted crops. They have to supply water to the crops so a huge increase in water evaporation must be present. The crops are harvested and replanted, so at least 25% of the time the Earth is more barren than when mature crops are present. Apparently this cools the Earth.
My own experience tells me this is wrong – its cooler inside the confines of a forest than standing in a cornfield. The effect is so large it is obvious to anyone who pays any sort of attention to it without any tools to measure it. (maybe the lack of direct sunlight striking me instead of air temperature?)
Massive irrigation should have a net warming effect due to increased moisture in the air, unless there is a corresponding increase in convection cell activity to transport heat upwards. I think back to standing in irrigated fields and remember oppressive humidity and heat.
All of this is testable:
– Compare the temperatures of plowed fields versus nearby forests using satellite data.
– Look for increased clouds downwind of plowed fields – increased convection should result in increased cloud cover.
Robert
FWIW
In this area we have a mix of open tussock grasslands and savanna woodlands.
It came as a suprise to notice that on a hot day (around 38 C or so) a vehicle’s engine temperature reads higher where the road is going through the woodland. I presume it comes from any breeze in the area being around ground level over the grassland and a boundary layer over the trees in the woodland.
And further on the boundary layer – in a truck of marginal power you can gain up to around 20 kph in the woodland when it is a headwind.
http://sci-hub.bz/10.1007/s00382-016-3280-7
use sci-hub to get past paywalls.
The first question I always think of when contemplating an article like this is: Which is cause and which is effect? ie Does the farmer clear more land and change the ecosystem because the climate temperature allowed him to grow crops where he couldn’t before OR did he have to quit farming places like the Sahara or Gobi desert because of lack of water where it existed before? AND, what are the consequences of these actions on man’s ability to thrive (or not) at the time these changes began?
As far as I can tell these types of questions are not even considered in the model presented in this paper. ‘Chicken/Egg’ questions cannot be assumed without at least a logical and plausible explanation of the reasons for the choices.
Have they taken Center Pivot Irrigation into account for land use changes – even in the deserts?
There is a lot of that going on, irrigation in general:
https://en.wikipedia.org/wiki/Center_pivot_irrigation
Personally, I think that the role of center-pivot irrigation is a very under-rated modifier of local, relative humidity.
2.2. The Postsatellite Era
Estimates of Earth’s albedo have remained largely unchanged from the value of 0.30 deduced from earliest
measurementfirst from the Explorer-7 satellite observations in 1959 [Kandel and Viollier, 2010]. This value was
later confirmed from the Nimbus satellite measurements byVonder Haar and Suomi[1971] andJacobowitz et al.
[1984]. This value is also only slightly different from the current estimate of 0.29 from CERES observations
[Wielicki et al., 1996] described later. While
these satellite-based values have changed
little over time, the confidence level of the
estimates has greatly increased as both
accuracy of instruments and algorithms to
derive albedo improved. The accuracy is
estimated to be 2% for the ERBE shortwave
scanner instruments and 1% for the CERES
SW instruments [Wieliki et al., 2006; Loeb et al.,
2009]. The estimated stability of the observed
reflectedflux by CERES instruments is
0.3 W m
2
per decade [Loeb et al., 2007]
I tend to think this is correct but could change if cloud coverage, snow coverage and sea ice coverage were to increase, in a permanent more meaningful way associated with this prolonged solar minimum which is n progress. Time will tell.
Albedo changes going forward are key to what the future climate may or may not do even a slight change will have impacts.
The so-called albedo is an underestimate of total reflectivity because the 71% of the Earth that is covered with water reflects primarily by specular reflection and unless the sensor is directly in line with the sun, it will measure only negligible scattering from waves. Even diffuse reflectance from soil, snow, and vegetation has a strong forward reflectance lobe that isn’t measured by albedo measurements. Albedo is best restricted to measuring the relative brightness of celestial bodies without water and vegetation.
The most recent large scale and arguably detrimental land use change in North America has occurred with vast swathes of marginal grazing and woodlands being cleared, plowed and planted in corn, just to make ethanol. Bare earth exposure to the Sun always increases air and soil temps in the local area of the plowed fields.
Plowing also causes organic matter which has been stored in undisturbed soils to then be rapidly released to the atmosphere, due to exposure to air and subsequent aerobic bio- conversion to CO2. The plowed ground then has a reduction in moisture retention, as well. Another environmental impact results from ever greater wind and rain erosion of those plowed, marginal soils and finally, there is an increase in runoff of applied fertilizers and other agri- chemicals, resulting in just the sort of eutrophication as is occurring in the over 200- mile dead zone in the Gulf of Mexico, offshore of Mississippi.
Alan
Glider pilots look for thermals from ploughed fields
This reinforces my belief that cities are “evil” for the climate.