Ethiopia is praying for rain according to a recent report from the Guardian, and ReliefWeb suggests that a lack of rain may be linked to malnutrition in Tchad, as well as reduced crops in Niger.
The African rainfall deficit appears to be widespread: the Cairo Review reports severe droughts that have been experienced across the Sahel, the Horn of Africa, and Southern Africa in 2011 and 2020. But the picture is also more complicated, as heavy rains have unleashed massive flooding across South Sudan according to the Red Cross.
A similar ambiguity can also be seen in the future prospects for this region. The recent Intergovernmental Panel on Climate Change (IPCC) report (Assessment Report 6, often referred to as ‘AR6’) presents maps showing projected changes in the precipitation, e.g. in Figure SPM.5 and the IPCC Atlas.
The most recent precipitation projections reveal a remarkable dark green blob covering parts of Sahel and Sahara in addition to the Arabian peninsula, suggesting that this dry region may be blessed with more rainfall in the future (e.g. Figure 1).
Figure 1. A map from Figure SPM.5 from IPCC AR6 slides, showing percentage change in annual mean precipitation from a historical baseline (1850-1900). These results represent the Coupled Model Intercomparison Project phase 6 (also known as ‘CMIP6’) Global Climate Models (GCMs).
However, increasing rainfall amounts may indicate a break with previous analysis for the region comprising Sahel and southern Sahara, as historical observations suggests diminishing rather than increasing rainfall in the same region (e.g. NOAA NCEI and CICS-NC Fig 1.7). It also differs from similar projections based on the previous CMIP5 generation of GCMs and the CORDEX-Africa results (both of which are available through the IPCC AR6 Atlas).
One problem with Sahel, Sahara and the Arabian Peninsula is a lack of observations, a fact that is acknowledged in Figure SPM.3 showing how agricultural and ecological drought tendencies have changed since 1950. Lacking ground data makes it harder to evaluate model simulations and calibrate the projections.
So how to interpret this information? We don’t have much local data to examine, but there is global data, such as the ERA5 reanalyses, that nevertheless may provide some useful analysis, even if it doesn’t reflect the African rainfall with as high an accuracy as we would like.
ERA5 and rainfall trends 1950-2020.
The wet African blob in the projections presented in Figure 1 indicates proportional changes in annual rainfall amount over a region where it hardly rains at all. We are talking about one day of rainfall per year or even less, according to the ERA5 reanalysis (see figure below).
Figure 2. The annual average number of rainy days is of the order of 1 rainy day or less per year over parts of Sahara according to the ERA5 reanalysis (threshold 1 mm/day).
A 50-year baseline for such a dry region may contain about 50 rainy days or less. Each rainy day is subject to weather’s randomness, and if the number of cases is small enough then they also are insufficient for providing reliable statistics.
In other words, a 50-year baseline may be unstable if the rain is so rare that a few downpour events can alter the statistics. This is not a problem for regions where it rains frequently, however.
It’s also tricky to combine different trend estimates from models with different biases and tendencies (models are not perfect). If we compare the proportional trend in rainfall amount from ERA5 and the trend in terms of mm/year, as in Figure 3, then it is clear that regions with very low baselines easily can have high proportional trends.
Figure 3. Trend estimates of the rainfall amount over Africa in terms of percentage change per decade (upper) and mm/year per decade (lower).
We can estimate the proportional change for each simulation, and then take the mean to estimate the ensemble mean. In this case, models with a lower baseline in regions with really rare rainfall events may carry more weight than those which happened to simulate more random rainfall events in the same period.
It’s also possible to take the average of the trends from each model in terms of mm/year per decade, and then estimate the proportional change based on ensemble mean. Models that overestimate rainfall will then carry more weight.
Replication of the projected precipitation trends
We can try to replicate the results presented in the IPCC AR6 projections to affirm its conclusion. Below is an ensemble mean trend map for simulated trends over the period 1950-2020 that has a similar wet blob over Sahel, Sahara and the Arabian Peninsula. This analysis was based on 37 different CMIP6 models and a larger ensemble than the IPCC Atlas, which used 33 different models.
Figure 4. A 37 CMIP6 model ensemble mean of the proportional trend for annual rainfall amount simulated over 1950-2020.
The ensemble mean of the proportional trend estimates of the selected CMIP6 simulations in the replicated analysis shows a similar pattern as reported in the IPCC AR6. Hence, my replication also shows that the simulated historical trends for the Sahel and southern Sahara region indicate increasingly wetter conditions with a similar spatial pattern as Figure 1, but with opposite trends to those found in the ERA5 reanalysis shown in Figure 3.
Does the discrepancy between CMIP6 simulations and the ERA5 reanalysis really mean that the models have shortcomings? Not necessarily for really dry regions, such as the Sahara and Sahel, because it only rains very rarely and the rainfall statistics may not be robust over the driest regions.
The ensemble mean is of course estimated from a number of different GCM simulations, all of which are presented in the animated GIF below:
Figure 5. Animated maps of the individual ensemble members that form the basis of the ensemble mean shown in Figure 4.
When we check the trend map of each GCM, it is apparent that they show a wide range of different trend patterns. We see that few of the individual simulations resemble the ensemble mean. One of them even resembles the ERA5 results.
So I would argue that the solid wet blob in Figure 1 potentially gives a misleading impression. But it is possible that the future may bring a few more heavy downpour events with even greater amounts of rainfall, increasing the risk of flooding, and that such a tendency wasn’t captured in the CMIP5 and CORDEX-Africa simulations.
A small increase in the number of rainy days and their duration can give an exaggerated impression of a change in exceptionally dry regions such as Sahara and Sahel. It would perhaps be useful to look at other statistics such as the average number of rainy days per year (or the wet-day frequency) and the mean rainfall intensity, because they may provide more robust results.
The IPCC Atlas does, however, provide information about the annual maximum one-day and five-day rainfall (the rains in this dry region don’t last many days) as well as consecutive number of dry days, which all are projected to increase in this dry region. But even if they or the annual rainfall were to double throughout this century, Sahara and Sahel will still be very dry.
Another question is whether the ERA5 reanalysis provides a representative picture of past trends.
In other words, I wouldn’t bank on Sahel and southern Sahara being blessed with more steady rain in the future. We also need to dig deeper into the question whether the simulated change in rainfall over Africa is real and has a physical explanation.
Hi Rasmus, nicely done. Thanks.
In my understanding the future is unclear. Even if annual rainfall doubles, Dahara and Sahel remains dry, means dessert or almost dessert. Even like this, Sahara is beautiful. I was around Timboucot, Mali. The route down South, first crossing the River and then by dirty no asphalt road to Douentza. Around the mountains, called Hombori or so. And that was the most beautiful landscape I had never ever seem in my life (i am 58).
I know the life over there is hard. But,,,,even knowing that. Do we humans have the right to destroy something so beautiful as dessert? Because dessert ARE beautiful, I have seen some, not so much. I know it is very hard or even impossible to live there (for humans and animals, too), but thyt beauty is striking. It is Divine. It is Nature itself. Beauty. Eternity. And so on…thanks for your article. MM
Yeah. The number of dry days in a row is an important metric. Two flash floods per year with sun sun sun in between does not make for paradise (though I’ve read that the aquifer under the Sahara is the biggest in the world).
Some works show that due to anthropogenic aerosols, the amount of precipitation decreases. This masks the increase in precipitation from climate change. Central Africa and the Arabian Peninsula are the main sources of anthropogenic aerosols near Sahara
https://www.science.org/doi/10.1126/sciadv.1501572
Benestad
I came to think of the fameous petroglyphs in Sahara, and looked after.
It is from Tchad showing cows, dromedars and humans. The landscape is heavily weathered sandstone with caves, and formations not unsimilar to Kvitskriuprestine in Otta, that is high remaining pillars with flat stones on their heads.
That documents an arid landscape with rain coming quite rarely but in strong showers.
Dated from 10 000 to 2000 years ago.
It is obvious and surely cro magnon and fancy artistic sapiens- paintings apparently from “Max holocene” as we call it, after which Sahara has dried up. So there we have a climatic history document..
Then I see on Fig 1 that Pakistan the indus valley is marked very green, different from its neighbourhood. : That looks more like wishful thinking in Urdu.
But look at central Asia. That landscape seems to have been more wet also during max holocene and dried up in the last 2000 years. . So that a lot of people gave up earlier rich pasture lands and fruit gardens, entered the horseback with bow and arrows, and migrated as warrior nomades in masses to the more wet and green western Europe and ruined the Roman Empire.
The same may have happened in the east, but there, the Emperor of China built a great wall against such barbarians.
I have looked over it by google maps and google earth to study the worlds large rivers.. The Meanderings tell us about the age of the landscapes. And in that grey stony and sandy landscape raging all through the worlde from China to Morocco via central Asia and the middle east, we find relicts and fossils of old rivers and dried out river deltas all the way, And human marks, evidence of agriculture from which people did withdraw back into the remaining wet sites that show very intense and tight oasis- culture.
If you whish to become unpopular in this world, then take in by an Arab and begin stealing his water. But if you whish opposite then bring enough water with you and give out a glass of water first. Then all doors open.
And if this is true, then we can expect more rain in Sahara and in central Asia due to AGW.
Max holocene seems clearly to have been more wet in the worlds largest desert and arid area.
Carbomontanus.
I like what you say about desserts and rivers.
I have something about rivers.
The lenght of any given river is not coincidence. It follows a pattern. The pattern is known as Law of Benford. Try it for any given region, for example any state on the planet.
Of course, there are conditions. You need enough rivers (I would say at least 100, but that is not sure just my guess), different lenghts (at least two or three orders, lets say from 1 km to 500 kms), maybe it is enough, not sure.
Then apply Benford. Works. I do not know why, but it works.
There must be some Natural law behind Benford.
Do you agree? Does anybody agree on this? Thanks for any insight. Martin
Martin,
You should read the Wikipedia article on Benford.
Yes!
C. – ” Then all doors open.
And if this is true, then we can expect more rain in Sahara and in central Asia due to AGW. ”
— what you can always expect with AGW is more evapotranspiration – (that`s for sure).
If you would please note that 10% higher evapotranspiration(mm) in a 1,5°C warmer world will need 10% more rain(mm) – to compense.
Increasing precipitation (somewhere in the desert) will not mean, that there is automatically more global vegetation. Plants need more water in a warmer atmosphere, desertification still remains an observed trend and drained continents contribute ~ 8% to SLR.
But welcome among the people that welcome more water over land – more evaporation
– and more EARTH – COOLING !!! clouds !
In the max holocene “8 billion homo sapiens” fucking down the global water cycles didn`t exist.
Nein, Hr Schurly, ich meine ernst.
Mein Kollege war mit Landrover durch Sahara. Und dachte wenn schon in Sahara, dann vielleicht ein extra reserve tank mit Wasser im Auto einbauen.
Und das hat sich wirklich gelohnt!
This winter is surprizingly dry here where I live, Oslofjord east. And it has been very steady and strong onland oceanic winds in all western Norway with several storms and gusts of hurricane, extreme snow and all roads from east to west blocked. Rather Föhnwinds here.
We discuss furtherv the hydroelectric situation and the extreeme electricity prices, Ukraina and Putins Nordstream 2.
Norway delivers all it can of hydroelectric and gas to the EU
Northern Norway is not connected to the EU net. They have electricity prices down to Zero.
Schürle
If it falls rather in intense showers and even as snow, which is rather mostly the case, snow on the Temple hill in Jerusalem and on the Sphinx and on Haga Sophia,…. then it is due to local chill, and it may sink before it evaporates.
If there are trees, then it melts and sinks even better. That seems to be an evolutionary principle and adaption. The vegetation improoves its enviromental premises.
I also believe in H2O in all its natural forms.
“–What you can allways expect with AGW is more evapotranspiration- (that`s for sure) ”
But,…. what goes up must fall down according to Aristoteles. (Space rockets were not yet invented)
So when there necesserily will be more evapotranspiration at sea that is very large…. where shall all that water fall down?
Landcrabs, I call it,… Landcrabs…. That is for sure.
If you look over the occurance of Löss- soil in the world, you find it in Saxen, the hungarian Puzda, in Ukraina, in Kasakhstan, further in southern Siberia to northern China. And then further in America, The wide prairies and the Bread basket Kentucky.
maybe also the Argentinean Pampas.
That is the relicts and frossiles of a very dry situation with enormeous and frequent “dust- bowls” south of the glaciers. And that very dry climate situation with löss- formation on lower latitudes is sustained by extreemly low atmospheric CO2- content during the ice ages.
It gives me hope for some advantages of the AGW- situation and I also believe that cloud formation will save much of the situation. But at the same time we must be aware that 400-500 ppm and even more CO2 in the atmosphere is really extreme and has not been for the last 10 million years at least.
Carbomantanus. Yes cloud formation can act as a negative feedback, but it hasn’t stopped warming so far of over 1 degree c over a period of 100 years, and there is no sign warming is slowing down. Its not at all clear how clouds would change that. Its not as if a little bit more warming will suddenly generate a truly massive influx of clouds. Why would it?
Nigelj
I knjow that it is the Lindzen Iris- theory. But it is plausible to a lesser extent than Lindzens postulates due to other principles, “Cloud formation can act as a negative feedback”. It seems to stabilize the night and day and summer winter temperature contrast first of all. Then you have further the definite cooling function of sulphate aerosols.
And we have only one history and canjnot compare recent warming with a history of less cloud formation exept maybe for shorter periods correlated to sulphur more or less.
If I were to ruin the IPCC CO2-AGW theory, then I would suggest and proove an effect that makes it clear up during day and cloud over during night. And find it stupid of them, that the surrealistas could not suggest and sell that instead
It was my very first spontaneous thought to the climate dispute..
@Nigelj:
” …there is no sign warming is slowing down. Its not at all clear how clouds would change that. Its not as if … Why would it?”
— If you don’t believe in the facts that are on my website… then please at least take note of the information that perpetuates the quintessence of climate science in the IPCC reports for everyone to see.
https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter_07.pdf
You can find links to chapters 7.2.1 & 7.2.4.2 also on my website.
If you (and also Lady C.) could finally perceive that we have lost ~2-2.5% of global cloud cover in the last ~50 years, then you could someday also understand the difference between cloud effect and cloud feedback. .. unless you want to produce a large number of highly senseless, nebulous “Cloud Bubbles” with as little brain content as possible.
In short, the loss of 2-2.5% cloud cover means that the cooling effect of clouds (-20W/m²) decrease & results in a warming feedback of (+0.4-0.5W/m²).
@Carbomontanus:
“According to Aristotle, what goes up must fall.”
— The much more interesting reverse conclusion would be: what does NOT go up – can’t fall back either.
This includes the water volumes, which has been affecting our climate for thousands of years due to many man-made factors (sealing of soil, drainage of forest areas and moors, channeling of rivers,…etc. — “fucking the water cycle”).
This ever-decreasing amount of H²O evaporation over land surfaces not only impedes cloud formation, but also the cooling transport of heat (-38W/m²) from the surface into the atmosphere. By my definition of AGW, I see our ill-handling of the water cycle parallel to the even more ill-handling of carbon cycle. Of course, both influence each other.
C: ” So when there necesserily will be more evapotranspiration at sea that is very large…. where shall all that water fall down?
– ! dry regions gets drier – wet regions get wetter !
The wettest region I know is the (middle of the pacific) ocean – so the answer is clear:
– large part will fall down to the oceans.
C: ” It gives me hope for some advantages of the AGW- situation and I also believe that cloud formation will save much of the situation. ”
” … Landcrabs…. That is for sure. ”
– Landcrabs in the desert ??? — I`m not sure at all.
We know from pictographs that were produced thousands of years ago depicting life in the Sahara region that there was an abundance of animal life and with that, human life. The climate models are unable to explain how this was the case while the story that comes from the Greenland ice cores presents the reason why the Sahara region was green and full of life—It was perhaps 2.5 C warmer 4000 years ago.
Jørgen Peder Steffensen is an Associate Professor at the University of Copenhagen and one of the world’s leading experts on ice cores. Using ice cores from sites in Greenland, he has been able to reconstruct temperatures there for the last 10000 years. So what are his conclusions?
• Temperatures in Greenland were about 1.5 C warmer 1000 years ago than now.
• It was perhaps 2.5 C warmer 4000 years ago.
• The period around 1875, at the lowest point of the Little Ice Age, marked the coldest point in the last 10,000 years.
• Other evidence from elsewhere in the Northern Hemisphere confirms this picture.
His final comment is particularly telling :-
I agree totally we have had a global temperature increase in the 20thC – but an increase from what? ..Probably an increase from the lowest point in the last 10,000 years.
We started to observe meteorology at the coldest point in the last 10,000 years.
We Live in Cold Times
6,221 views
Apr 26, 2021
https://www.youtube.com/watch?v=WE0zHZPQJzA
JDS: We know from pictographs that were produced thousands of years ago depicting life in the Sahara region that there was an abundance of animal life and with that, human life. The climate models are unable to explain how this was the case
BPL: Are they? Who says? You? Which models, and which study or studies are you referring to? [CITATION NEEDED]
JDS: while the story that comes from the Greenland ice cores presents the reason why the Sahara region was green and full of life—It was perhaps 2.5 C warmer 4000 years ago.
Jørgen Peder Steffensen is an Associate Professor at the University of Copenhagen and one of the world’s leading experts on ice cores. Using ice cores from sites in Greenland, he has been able to reconstruct temperatures there for the last 10000 years. So what are his conclusions?
• Temperatures in Greenland were about 1.5 C warmer 1000 years ago than now.
• It was perhaps 2.5 C warmer 4000 years ago.
BPL: You have temperatures in Greenland confused with global average temperatures.
I have nothing confused. Explain how it would be warmer in Greenland at at the same time not be warmer around the globe.
[Response: Orbital changes that increase solar energy to the poles while decreasing it in the tropics, variations in the overturning circulation of the North Atlantic that increase ocean heat flux to the high latitudes, Rossby wave responses to variations in ENSO, jet stream variations driven by planetary waves. Would you like more? – gavin]
Gavin wonders if I would like more information and I will provide him with what I really want and that is the truth. I did not see his name as a contributor to this scientific information that did not mention, “Orbital changes that increase solar energy to the poles while decreasing it in the tropics, variations in the overturning circulation of the North Atlantic that increase ocean heat flux to the high latitudes, Rossby wave responses to variations in ENSO, jet stream variations driven by planetary waves”. Does Gavin imagine that these conditions were what made the Earth’s temperature perhaps 2.5 C warmer 4000 years ago? It is a forgone conclusion that Gavin A. Schmidt will not allow this comment of mine ever to be seen by his loyal sycophants due to the fear that they may learn some of the facts regarding the Earth and its climate that CO₂ has nothing to do with.
“Harmonic Analysis of Worldwide Temperature Proxies for 2000 Years
Abstract
The Sun as climate driver is repeatedly discussed in the literature but proofs are often weak. In order to elucidate the solar influence, we have used a large number of temperature proxies worldwide to construct a global temperature mean G7 over the last 2000 years. The Fourier spectrum of G7 shows the strongest components as ~1000-, ~460-, and ~190 – year periods whereas other cycles of the individual proxies are considerably weaker. The G7 temperature extrema coincide with the Roman, medieval, and present optima as well as the well-known minimum of AD 1450 during the Little Ice Age. We have constructed by reverse Fourier transform a representation of G7 using only these three sine functions, which shows a remarkable Pearson correlation of 0.84 with the 31-year running average of G7. The three cycles are also found dominant in the production rates of the solar-induced cosmogenic nuclides 14C and 10Be, most strongly in the ~190 – year period being known as the De Vries/Suess cycle. By wavelet analysis, a new proof has been provided that at least the ~190-year climate cycle has a solar origin.
[…]The Fourier spectrum of a global temperature record G7, composed of high quality temperature proxies worldwide and recent instrumental data demonstrate the dominance of three climate cycles with ~1000 (Eddy cycle), ~460 (not named but frequently reported), and ~190 year periods (De Vries/Suess cycle). These three sines represent the 31-year running mean of G7 with the remarkable Pearson correlation of 0.84 indicating their importance for climate.
G7, and likewise the sine representations have maxima of comparable size at AD 0, 1000, and 2000. We note that the temperature increase of the late 19th and 20th century is represented by the harmonic temperature representation, and thus is of pure multiperiodic nature. It can be expected that the periodicity of G7, lasting 2000 years so far, will persist also for the foreseeable future. It predicts a temperature drop from present to AD 2050, a slight rise from 2050 to 2130, and a further drop from AD 2130 to 2200 (see Fig. 3), upper panel, green and red curves).
https://benthamopen.com/FULLTEXT/TOASCJ-11-44
@ J.D. Swallow
Is this a class warfare & political racisms againt a hockeystick again?
I have looked through your litterature list. It shows Svensmark and Scafetta. That settles it.
If you are to sell fouier- analyses of weather and climate history, then do yourself a favour and do not fight categorically the impact of CO2 to climate history together with it.
Interesting commentary. What about other regions with predicted large increases in rainfall? Are the historical records showing an increase? Surely some regions have decent historical records? This would obviously help validate the models.
The obvious candidate is the Galapagos Islands.
Initial reading says no, the results are not validated
Get the full dataset from here:-
https://www.darwinfoundation.org/en/datazone/climate/puerto-ayora
Here is a rolling 12 month plot:-
https://photos.app.goo.gl/iABxoRzuSuRP23iH8
I am sorry, I was unable to find a dataset that had been adjusted to fit the narrative, you will just have to put up with raw data. I am sure there will be a reason why the early years were recorded incorrectly
When I look even closer to Fig 1, I see that the fameous Taklamakhan- desert in China is marked especially green..
That is an even more exotic problem.
Early invaders and settlers like Kaukasian type Europeans, Hellenism, Buddhism is found there, died out and blown over by sand. It is an old, very large inland lake, dried out and blown over.
Today it seems inhabited mostly by turks.
Looking further , it seems that the original Taklamahan- sea is well over one million years old, that is, has existed during the many ice ages. But maybe been wet rainy landscape mostly in the many inter- gacial periods since then.
JDS
666 subscribers to that channel :)
https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change
I’m reasonably sure that the National Geographic, having the unproven claim that it is CO₂ that drives the earth’s climate, will not want to acknowledge that during the Medieval Warm Period it was far warmer than it is now or this below would have not been the case.
“The farm under the sand
Researcher challenges conventional thinking on disappearance of Viking community
“The Norse arrived in Greenland 1,000 years ago and became very well established,” says Schweger, describing the Viking farms and settlements that crowded the southeast and southwest coasts of Greenland for almost 400 years.
“The Greenland settlements were the most distant of all European medieval sites in the world,” said Schweger. “Then the Norse disappear, and the question has always been: what happened?”
Cross-sections of the GUS soil show the Vikings began their settlement by burning off Birch brush to form a meadow. Over the next 300 to 400 years, the meadow soil steadily improved its nutritional qualities, showing that the Greenland Vikings weren’t poor farmers, as McGovern and others have suggested. “At GUS, the amount of organic matter and the quality of soil increased and sustained farming for 400 years,” says Schweger. “If they were poor farmers, then virtually all the farming in North America is poor farming.”
https://sites.ualberta.ca/~publicas/folio/38/16/03.html
Your source is 20 years old, and reflects a much earlier state of inquiry into the Greenlandic Norse culture. There’s been much investigation since, and not a little discussion of it on these very boards. So your post is more than a little disingenuous.
However, that’s a bit by the by, because nothing in it actually suggests–much less demonstrates!–that Greenland was any warmer during the Norse period than it is today.
https://polarjournal.ch/en/2021/03/05/agriculture-in-greenland/
Kevin McKinney says; “Your source is 20 years old, and reflects a much earlier state of inquiry into the Greenlandic Norse culture”. Does this mean that to Kevin McKinney that the information such as what I have presented has a shelf life? It never occurred to Kevin McKinney to take his concerns up with the people that did something that he has never done, actual research into the Vikings in Greenland, and get their up to the minute report on a subject that he has no credible knowledge about, why the Vikings left Greenland.
Does Kevin McKinney know nothing about the Vikings in Greenland and how, when the climate changed to the cold side, they had to leave because they could not exist using agriculture to sustain themselves? Does Kevin McKinney believe that “carbon pollution” caused the climate to cool to the point that the Vikings could not exist using agricultural practices that they had used to live in this far north area for 400 years; so, they had to give up and leave Greenland?
“The Norse arrived in Greenland 1,000 years ago and became very well established,” says Schweger, describing the Viking farms and settlements that crowded the southeast and southwest coasts of Greenland for almost 400 years.
“The Greenland settlements were the most distant of all European medieval sites in the world,” said Schweger. “Then the Norse disappear, and the question has always been: what happened?”
“If they were poor farmers, then virtually all the farming in North America is poor farming.”
https://sites.ualberta.ca/~publicas/folio/38/16/03.html
Climate change killed off Viking settlement on Greenland
http://www.earthtimes.org/scitech/climate-change-killed-viking-settlement-greenland/942/
Norse ruins at Brattahlid.
http://www.greenland-guide.gl/leif2000/history.htm
Kevin McKinney reads the disjointed rant J Doug Swallow posts and, seeing no coherent point being made, shakes his head sadly.
Is Mr Swallow incapable of of reading and digesting in full what KM said? namely “Your source is 20 years old, and reflects a much earlier state of inquiry into the Greenlandic Norse culture. There’s been MUCH INVESTIGATION SINCE,, and not a little discussion of it on these very boards.”
The Norse colonised a small green coastal area of Greenland for a period. Greenland still has green coastal areas today. Things like the medieval warm period were regional events not global and temperatures were significantly below what we have seen over the last couple of decades.. Refer:
https://skepticalscience.com/medieval-warm-period.htm
I now see that whatever Jørgen Peder Steffensen, who is the foremost expert on Greenland ice cores, and he has published 127 journal articles on this subject, has to say about Greenland is not good enough if his findings do not align with the desired agenda that the anthropogenic climate change proponents want to have their followers see and read; so they go with what an avowed alarmist site, Carbon Brief, puts forth.
Carbon Brief did show a rare amount of honesty when they allowed this to be found within their article and that is exactly what Jørgen Peder Steffensen has been maintaining that has so riled the believers that it is only the essential for all terrestrial life on Earth trace gas, CO₂, that can regulate the Earth’s temperature.
“While periods during the early Holocene – 7,000-11,000 years ago – may have been warmer in Greenland than the present day, if the present rate of warming continues, the Earth should pass well beyond any temperatures experienced in Greenland during the Holocene by 2050.”
The true believes in this hoax about CO₂ being what determines the Earth’s climate and temperature will not want to believe what scientific research has found to be the case.
The last two abrupt warmings at the onset of our present warm interglacial period, interrupted by the Younger Dryas cooling event, were investigated at high temporal resolution from the North Greenland Ice Core Project ice core. The deuterium excess, a proxy of Greenland precipitation moisture source, switched mode within 1 to 3 years over these transitions and initiated a more gradual change (over 50 years) of the Greenland air temperature, as recorded by stable water isotopes. The onsets of both abrupt Greenland warmings were slightly preceded by decreasing Greenland dust deposition, reflecting the wetting of Asian deserts. A northern shift of the Intertropical Convergence Zone could be the trigger of these abrupt shifts of Northern Hemisphere atmospheric circulation, resulting in changes of 2 to 4 kelvin in Greenland moisture source temperature from one year to the next.
https://doi.pangaea.de/10.1594/PANGAEA.786474
Astoundingly bad writing by JDS there; that 2nd paragraph is entirely indecipherable.
But the general drift seems to be that Carbon Brief was somehow disagreeing with Dr. Steffenson. I don’t see any evidence that that is the case.
Oh, and also that:
Except that no-one actually believes that CO2 is the *only* thing that determines terrestrial temperature. We’ve had numerous discussions about it here on these very boards, discussing the influence (real or potential) of the sun, cosmic rays, oceanic quasi-cycles, albedo change, vulcanism, and aerosols (both anthropogenic and natural).
So that last quoted paragraph is one big ol’ Strawman.
Dude, you expect to find eloquence from a denialist? I’m just happy when they’ve mastered bowel control.
JDS: The true believes in this hoax about CO₂ being what determines the Earth’s climate and temperature
BPL: It’s not a hoax. Stop breaking the ninth commandment.
JDS: the unproven claim that it is CO₂ that drives the earth’s climate
BPL: Science doesn’t deal in proof, it deals in evidence. Proof is for mathematics or formal logic (or measuring alcohol content). Science is not deductive, it is inductive.
But as for the evidence that CO2 drives the Earth’s climate, try here:
https://www.jstor.org/stable/pdf/40931614.pdf?casa_token=AETh59Ui5PkAAAAA:y2AtlCcbZVuSDkhfFrii1F7PpBzxyU04aYj7CGGuVDC9p1yHzpDHktTy4lmNGsCaiNwo7sie864IRoQ6nl2hQqyc7OjdseZyWNveUNDKelSghDia36Y
JDS: will not want to acknowledge that during the Medieval Warm Period it was far warmer than it is now
BPL: No, because it wasn’t. That’s just flat-out wrong.
No Mr Levenson
Science also deals with proof, with axiomatic dedeuctive systems, and with formal logics.
C: Science also deals with proof, with axiomatic dedeuctive systems, and with formal logics.
BPL: Science may use reasoning, but its methods of discovery are empirical, not deductive.
As if logical empiricism and axiomatic deduction is not a vital part of it.
A “discovery” will hardly be valid and enter theory unless also proof is stated.
C: A “discovery” will hardly be valid and enter theory unless also proof is stated.
BPL: Not once in all my years of reading the scientific literature have I ever seen a syllogism or a proof in the propositional or predicate calculus.
“Not in all my years of reading the scientific litterasture have I ever….”
What more do we have to know about Genosse Commissarius Bart P. Levenson?
Levenson
I can give you more than one exampe of having rather to take to science to state proof and know for sure and dare to deliver, whenever there is something rather strange and unknown and FACIT is not yet written about it. That is often called discoveries.
I found a quite obscure and strange flintstone that I was not able to identify. So. It came in our stone – collection for 20 years at least until a lecture with examples was held about asteroide craters, meteorites, and tectites. I saw a slight resemblance to the shown tectites.
:…. no that is too light… that is n9o tectite. No, it is to0o0 heavy, that is no tectite…. No, that is py7rite, I have seen it before. Saw through it, and you will see that I am righjt!”
First I had do disqualify all those expereienced teachers of science.
And had to design an analytic proof procedure for tectite yes or no.
That scientific way of thinking and of doing it with my given remedies and experience takes logical empiricism and deduction, where I first had to think out and re- construct the possible physsics of an asteroide impact that was only poory described in the books..
And found by morphological examination botanical lense and carefully designed chemical mineralogical procedures that could decide by just one tiny grain of the possibly very valuable sample material,… how to dissolve a stone out in water for elementary chemical analysis, And for zero blind test and checking the procedure, local strongly weathered freshwater clay.
And found by its chemical content that it was a plausible, natural hi- tech fireproof glass good enough for masonry under the wings of the space- shuttle, that had been flying in the air in fused, , white hot condition and landed in water without cracking.
Then I dared to go to the geological museum without telling them what I thought it was.
– A tectite! he said, and repeated”a tectite! Even from 2 geologists independently.
Then I had the fameous 3 systematically independent experimental procedures for scientific empirical proof and could publish it with procedures..
People will hardly find theirv own tectites but I wrote about how to orientate and to think systematically for the general case, and to identify and state possible proof on higly implausible and incredible and very rare things in Nature and elsewhere. .
Moral:
Do not teach people on scientific theory and philosophy and procedure Genosse Levenson. Because very valuable material samples and discoveries may get lost if younger and more unexperienced people take you for serious on scientific research..
We have better learnings and better books, better Prophets and GURUs than what you seem aquainted to,
And with your manners you are standing in the way for that.
C: Do not teach people on scientific theory and philosophy and procedure Genosse Levenson.
BPL: Thanks, but I’m qualified to do that and you are not, so I think I can ignore your advice.
That makes it even worse, also telling people that you are qualified to do that
BPL & Carbomontanus, Perhaps you guys are talking past each other? I think BPL is saying you cant prove a scientific theory, which is true. Carbo is talking about proof of small parts of scientific issues, which is possible.
You are both clever guys and its interesting discussion. Please dont get too shouty there is enough of that already on this website.
Nigelj
“I think BPL is saying you cant proove a scientific theory, which is true.”
NO!
That is popular vulgar surrealism along with the ages of STALIN adolph and Mussolini and Nitsche, “Umwertung aller Werte”, and current civil war against The Royal Society, driven by the CATO and Heasrtland institute known as “thinktank”, alltogether The Republican War on Science!
Einstein of that same age said:
§1, To the extent that anything is physical, it is not sure
§2, To the extent that anything is sure, is not physical
Discussion:
There are enough old candidates and comrades walking around on the Campus at any time, teaching us that they are more intelligent than Einstein,
But they are those “higher” spirituals in charge, similar to Shamans in furs and Horns and naked skins with ink- tattoos on common ground, performing in the marble palace on capitl hill.
. It seems that we even have someone from the University of Pittsburg Pennsylvania here.
Those bodies allways come from some fameous University. That is also magician, sales promotion and Spindoctor-whitchdoctor professional routine.
But, we are neither operating in the fields and domaines of general relativity theory here, nor in the domaines and fields of sub- atomic particular reality and phaenomenology, Higgs bosons and such popular things……..
………… when we should discuss rain in Sahara, yes or no.
C: That makes it even worse, also telling people that you are qualified to do that
BPL: It’s a fact subject to verification. If you don’t believe me, you’re free to contact the University of Pittsburgh and ask if they awarded me a degree in 1983. Maybe you can even get a transcript.
Here we have it again.
SCRIPTVM EST. Levenson prooves on paper in virtual reality that he is sane.
To which Galileo replied:
“The doctrine of the movements of the earth and the fixity of the sun is condemned on the ground that the Scriptures speak in many places of the sun moving and the earth standing still… I think that in the discussion of natural problems we ought to begin not with the Scriptures, but with experiments and demonstrations.”
“To assert that the earth revolves around the sun is as erroneous as to claim that Jesus was not born of a virgin.”
Cardinal Bellarmine, during the trial of Galileo, 1615
“One Galileo in two thousand years is enough.”
Pope Pius XII
“Because I have been enjoined, by this Holy Office, to abandon the false opinion that the Sun is the center and immovable, …I abjure, curse, and detest the said errors and heresies…contrary to the said Holy Church.”
Galileo Galilei, recanting his beliefs under threat of torture and death by the Holy Church, June 22, 1633
http://www.freethought.mbdojo.com/galileo.html
Sorry, but you brought this on yourself. I really think, Mr. Swallow, that you could achieve scores not seen since the Timecube guy.
https://math.ucr.edu/home/baez/crackpot.html
I wonder how, this idiot that lives off of my tax dollars, Ray Ladbury, can be so stupid as to suggest that, by posting what I did, that I was comparing myself to Galileo?
“40 points for comparing yourself to Galileo, suggesting that a modern-day Inquisition is hard at work on your case, and so on.”
https://math.ucr.edu/home/baez/crackpot.html
I do stand by this quote that Ray Ladbury comes to personify.
“To compel a man to subsidize with his taxes the propagation of ideas which he disbelieves and abhors is sinful and tyrannical.” Thomas Jefferson
JDS: I wonder how, this idiot that lives off of my tax dollars, Ray Ladbury, can be so stupid as to suggest that, by posting what I did, that I was comparing myself to Galileo?
BPL: Because that’s why pseudoscientists like yourself usually post idiocy about Galileo.
Well, J D Swallow, ain’t you lucky that you don’t pay taxes for my words and wit in RC. This has nothing to do with my day job, which you do, presumably want to pay for unless you like satellites falling out of the sky . Should you wish to actually consult those civil servants whose day job it is to study climate, there are links in the Start Here section. However, I don’t think those will be any more to your liking, as civil servant scientists are bound by their profession to state the truth.
And unfortunately, your quarrel is not with me or my fellow civil servant scientists, but with the truth.
Puh-leeze… the tritest and falsest of false equivalences.
So… Scientist disbelieved by denialists in authority. Got it. Some things don’t change so much.
I am tempted to give a long lecture on Bruno and Gallilei, and 4 popes at least. All children of their own time.
Copernicus was never prosecuted nor burnt at the stake nor excommunicated nor put on INDEX.
Speaking of the Sahara .. Why is its annual average temperature higher than the Congo given the Congo has so much more water vapor which you claim accounts for 80% of the greenhouse effect driving global temperature per https://www.giss.nasa.gov/research/news/20101014/ https://upload.wikimedia.org/wikipedia/commons/a/aa/Annual_Average_Temperature_Map.jpg?20080215093644
Freddie, the average annual temperature of a place depends on more than just the amount of water vapor above it.
And AFAIK, your assertion that climate scientists claim that water vapor accounts “for 80% of the greenhouse effect driving global temperature” is false. Atmospheric water vapor is a positive feedback mechanism; not a forcing. See, for example, this RealClimate article.