Decades of drought in central Africa reached their worst point in the 1980s, causing Lake Chad, a shallow lake used to water crops in neighboring countries, to almost dry out completely.
The shrinking lake and prolonged drought were initially blamed on overgrazing and bad agricultural practices. More recently, Lake Chad became an example of global warming.
U.S. Library of Congress
Sulfate-laden aerosols coming out of a U.S. smokestack in 1942. Emissions rose steadily until legislation was passed in the late 1960s and ’70s.
New University of Washington research, to be published in Geophysical Research Letters, shows that the drought was caused at least in part by Northern Hemisphere air pollution.
Aerosols emanating from coal-burning factories in the United States and Europe during the 1960s, ’70s and ’80s cooled the entire Northern Hemisphere, shifting tropical rain bands south. Rains no longer reached the Sahel region, a band that spans the African continent just below the Sahara desert.
When clean-air legislation passed in the U.S. and Europe, the rain band shifted back, and the drought lessened.
Related research by the UW researchers and their collaborators shows that global warming is now causing the land-covered Northern Hemisphere to warm faster than the Southern Hemisphere, further reversing the pre-1980s trend.
Previous research has suggested a connection between coal-burning and the Sahel drought, but this was the first study that used decades of historical observations to find that this drought was part of a global shift in tropical rainfall, and then used multiple climate models to determine why.
“One of our research strategies is to zoom out,” said lead author Yen-Ting Hwang, a UW doctoral student in atmospheric sciences. “Instead of studying rainfall at a particular place, we try to look for the larger-scale patterns.”
Wikimedia / Annabel Symington
The road to Timbuktu, in the Sahel region, during more normal conditions.
To determine that the Sahel drought was part of a broader shift, the authors looked at precipitation from all rain gauges that had continuous readings between 1930 and 1990. Other places on the northern edge of the tropical rain band, including northern India and South America, also experienced dryer climates in the 1970s and ’80s. Meanwhile, places on the southern edge of the rain band, such as northeast Brazil and the African Great Lakes, were wetter than normal.
To understand the reason, authors looked at all 26 climate models used by the Intergovernmental Panel on Climate Change. Researchers discovered that almost all the models also showed some southward shift, and that cooling from sulfate aerosols in the Northern Hemisphere was the primary cause.
“We think people should know that these particles not only pollute air locally, but they also have these remote climate effects,” Hwang said.
Light-colored sulfate aerosols are emitted mainly by dirty burning of coal. They create hazy air that reflects sunlight, and also lead to more reflective, longer-lasting clouds.
People living in the Northern Hemisphere did not notice the cooling, the authors said, because it balanced the heating associated with the greenhouse effect from increased carbon dioxide, so temperatures were steady.
UW / Y.-T. Hwang
Global precipitation change between 1931-1950 and 1961-1980. The African Sahel, center, is much drier, while east Africa and east Brazil are wetter.
“To some extent, science messed this one up the first time around,” said co-author Dargan Frierson, a UW associate professor of atmospheric sciences. “People thought that a large part of that drought was due to bad farming practices and desertification. But over the last 20 years or so we’ve realized that that was quite wrong, and that large-scale ocean and atmosphere patterns are significantly more powerful in terms of shaping where the rains fall.”
The models did not show as strong a shift as the observations, Frierson said, suggesting that ocean circulation also played a role in the drought.
The good news is that the U.S. Clean Air Act and its European counterpart had an unintended positive effect beyond improved air quality and related health benefits. Although shorter-term droughts continue to affect the Sahel, the long-term drought began to recover in the 1980s.
“We were able to do something that was good for us, and it also benefited people elsewhere,” Frierson said.
The work was funded by the National Science Foundation. Sarah Kang at the Ulsan National Institute of Science and Technology in South Korea was a co-author.
###
“To understand the reason, authors looked at all 26 climate models used by the Intergovernmental Panel on Climate Change. Researchers discovered that almost all the models also showed some southward shift, and that cooling from sulfate aerosols in the Northern Hemisphere was the primary cause.”
Right. But by now it’s pretty certain that the models are over-sensitive to aerosols, isn’t it?
“People living in the Northern Hemisphere did not notice the cooling, the authors said, because it balanced the heating associated with the greenhouse effect from increased carbon dioxide, so temperatures were steady.”
So, now we know, huh.
/sarc.
How does that song go?
“how do I know, the models tell me so…”
Over sensitivity? Blasphemer! Now say 20 “hail Mannies” and ask the science gods for post-modern forgiveness…
They may have modelled not this world, as there appears to exist no AMO and PDO in their model world.
First the claim that the Clean Air Act saved Atlanta from drought, and now:
“The good news is that the U.S. Clean Air Act and its European counterpart had an unintended positive effect beyond improved air quality and related health benefits.”
Hmmm.
Would somebody please defund this idiocy?
Aerosols emanating from coal-burning factories in the United States and Europe during the 1960s, ’70s and ’80s cooled the entire Northern Hemisphere, shifting tropical rain bands south. Rains no longer reached the Sahel region, a band that spans the African continent just below the Sahara desert.
When clean-air legislation passed in the U.S. and Europe, the rain band shifted back, and the drought lessened.
Related research by the UW researchers and their collaborators shows that global warming is now causing the land-covered Northern Hemisphere to warm faster than the Southern Hemisphere, further reversing the pre-1980s trend.
Aerosols caused the cooling and decreased Sahel rain and then reversed the trend, but now global warming, which isn’t happening continues the same trend. What utter nonsense.
Although you could interpret this as equating decreased aerosol caused warming with global warming.
With so many aerosol studies coming out recently, I sense the GHG warming dam is begining to break. Which means the next tactic of the AGW obscurantists is too blur carbon pollution (ie CO2 emissions) into aerosol and and black carbon emissions.
In fact their tactics makes me think they knew this was coming and have been positioning themselves for the shift in the science. I’m not normally given to conspiracies, but this doesn’t pass the smell test.
Talked about this at Chiefio’s back in 2010…
http://chiefio.wordpress.com/2010/12/27/lake-chad-is-rising/
“People living in the Northern Hemisphere did not notice the cooling, the authors said, because it balanced the heating associated with the greenhouse effect from increased carbon dioxide, so temperatures were steady.”
Proof?
It is all about finding ways to blame the west.
So model based rubbish then, especially based on climate models we all know are wrong to start with.
Lake Chad is following the same route as the Aral Sea, over irrigation leads to water loss.
As far as I am aware, sulfates don’t travel that far. The clean air legislation got rid of the soot, then the trees a short distance downwind started to die because they were losing their protective coating of soot. So those processes that weren’t already capturing the sulfates (simple technology from at least 1951) had to catch up.
This paper whether correct or not will serve two purposes
1) it allows the emphasis on aerosols to flourish so current warming hiatus can be explained in the near future.
2) Reparations
I’m sorry, and with all due respect to the authors of this paper, who I’m sure are all very sincere and are just trying to find meaning in past events, I had to take 3 tries reading this because I was laughing so hard!
This sounds like a child’s conclusion, something kids in third grade might come up with. A simple, neatly wrapped up explanation for something when they don’t have even close to all of the information, or the real world experience to back up their ideas.
Then I sobered right up, because I realized that there are a lot of adults, intelligent people, who also don’t have close to all of the information or real world experience, who will believe this and demand action.
So, unknown to early electrical pioneers, they weren’t just building coal fired power stations, they were building a thermostat for the planet!
I remember reading 50s era SciFi about weather control. This isn’t much different.
OK. Now add in all the emissions from India and China and run your model.
Before the warmists were paid the sums they ended up being paid a paper was published which looked at drought in Ethiopia and no mention of global warming was made.
Go to this link and click on the download button to read it.
There is a table of past droughts and the effects of el nino over the past few centuries.
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1589710
Load of hose$#!t…
“Shrinking African Lake Offers Lesson on Finite Resources
Hillary Mayell
for National Geographic News
April 26, 2001
Lake Chad, once one of Africa’s largest freshwater lakes, has shrunk
dramatically in the last 40 years. Two researchers from the University
of Wisconsin, Madison, have been working to determine the
causes.
In a report published in the Journal of Geophysical
Research, they conclude that human activities are to blame for the
shrinking of Lake Chad.
The question of interest to Jonathon A. Foley and Michael T. Coe is applicable to many other natural phenomena as well, such as melting ice caps, retreating glaciers and warming oceans: Are the dramatic changes we are now witnessing the result of natural variation over millennia, or more or less a direct function of human activities?
The lake’s decline probably has nothing to do with global warming, report the two scientists, who based their findings on computer models and satellite imagery made available by NASA. They attribute the situation instead to human actions related to climate variation, compounded by the ever increasing demands of an expanding population.
“Humans in the system are the big actors here,” says Coe, a hydrologist. “What has happened to Lake Chad may be an illustration of where we’re heading.”
Denying climate change in order to make place for the Orwellian Climate Change.
The wording almost sounds like the sulfate problem went away on the passing of the clean air act, not some time following the act and after rules had been promulgated and implemented. I missed the time lag from the wording. Also, we had cooling in the northern hemisphere that we didn’t notice because of GHG warming? Is that saying it would have been warmer, but it wasn’t because of aerosols? I’m not sure how to measure unnoticed cooling.
Search engines reveal some number of “scientific” papers published since about 2008 which attempt to explain the lack of warming by citing the increased aerosol emissions of China and to a lesser extent, India. Models all the way down.
Oh, I see. Aerosols. Again. They do give them a handy way out. They’re the magic secret ingredient, the fudge factor, along with the “hidden” heat in the oceans.
They do have a problem though: If sulfate aeorosols were the primary cause of cooling in the 60s-80s, with warming recommencing after Clean Air legislation, where does that leave sensitivity of climate to C02?
These two statements appear to be contradictory
““People living in the Northern Hemisphere did not notice the cooling, the authors said, because it balanced the heating associated with the greenhouse effect from increased carbon dioxide, so temperatures were steady.””
“Aerosols emanating from coal-burning factories in the United States and Europe during the 1960s, ’70s and ’80s cooled the entire Northern Hemisphere, shifting tropical rain bands south. ”
The first says that the Northern Hemisphere temps were ‘steady’, i.e., they didn’t warm or cool. The second says the Northern Hemisphere cooled and that is what affected the Sahel. If the first statement is accurate, then how did the Northern Hemisphere temps shift tropical rain bands south?
Your title for this post should begin with “Academic Consensus Scientists say…” The report is really just the conflation of two false academic streams I was made aware of 20 years ago, 1) the war on coal-burning power plants, and 2) the war on “greenhouse” carbon dioxide emissions. Surprisingly, I have made contributions toward a better understanding of the real physics in both of these areas, first with 1) my earlier work on analysis of IMPROVE (Interagency Monitoring of Protected Visual Environments) aerosol measurements (see Huffman, “Atmospheric Environment”, Vol. 30-1, Jan. 1996, pp. 73-83 and pp. 85-99)–which indicated diesel fuel-burning emissions as the big culprit in aerosol pollution, away from urban centers, along with internal mixing of added sulfates–from natural and agricultural sources, not the typically scrubbed emissions from coal-burning plants) and 2) in 2010 and afterwards, with my Venus/Earth temperatures comparison (which disproved the carbon dioxide “greenhouse effect”, with the definitive evidence of not just one, but two detailed atmospheres). They are beating two dead horses at once, totally unwilling to admit the science has failed utterly.
Is there any observational data to support this idea, or is all just models? What happened to the Sahel with gigantic volcanic eruptions in the 1800s? I agree with previous posters. This is just a way to divert the issue and intensify the pressure on power generation if the global warming gig doesn’t work out.
We are back to witch trials and the time when humans were sacrificed to placate some malevolent god who caused the crops not to grow and the rivers to dry up. Don’t laugh. That statement could become true unless more voters from the other side shed the wool over their eyes. The scary part is that I believe the politicians on the other side are more than willing to buy votes with free phones and other giveaways.
Buyer beware. In exchange for those trinkets, your heating bill, food bill, and transportation costs will sky rocket.
“… then used multiple climate models to determine why.”
Even if the model outputs corresponded to the observed temperatures, that would not demonstrate the models to be a faithful representation of the reality.
The fact that the models cannot even replicate the observations tells, for sure and certain, that the models are wrong.
1) We were rising in the 1980s from the minimum (1978) of a cold phase.
2) We were lowering aerosol emissions as of the CLean Air Act of 1970 and again in 1990.
3) Grazing and farm practices were clearly major contributors to desertification. Recent developments in grazing and farming strategies have significantly altered plant survivability and increased ground cover.
4) Rising CO2 has been allowing plants to be more temperature tolerant in both directions and be more efficient with water and nutrients.
There is no way that these factors can be separated as they all occurred at the same time. The first two both reached their extremes at roughly the same time and all four have contributed since 1980. Making proportional attribution here is no better than a crap shoot.
“Related research by the UW researchers and their collaborators shows that global warming is now causing the land-covered Northern Hemisphere to warm faster than the Southern Hemisphere, further reversing the pre-1980s trend.”
This “related research” totally ignores the natural 60 cycle caused by ocean currents, the PDO and NAO. They attribute everything to human caused air pollution and claim that we cooled up to the late 1970s due to air pollution and then warmed after we cleaned up emissions.
They simply ignore all cycles and focus on only greenhouse gases warming and aerosols cooling
Ah, and it’s down with MODELS! This is not science.
Soooooo, I guess global warming is a good thing. Thanks. Could you please pass that along to the politicians.
I think whatever happened could be successfully graphed against the cumulative age of baby boomers and a valid correlation shown — and that’s all the help I am going to give them!
Blaming a disaster caused by African mismanagement on the West. IPCC models used for racist purposes. Notice how China and India are not mentioned. Only United States and Europe are cited. RACISM, RACISM, RACISM!
Posts-sanity science! Frightening!
I thought those effects in the 60s to 80s were the negative PDO phase. Why would the article refer to particulate pollution as “global warming”? The warmists use the pollution as an excuse for the current lack of warming. Or am I just confused?
Was it cooling from sulfides, or the cool phase of the PDO?
Manfred says:
June 7, 2013 at 1:18 am
They may have modelled not this world, as there appears to exist no AMO and PDO in their model world.
—-
Basic assumption does seeem to be that, absent man, the world doesn’t change.
Pamela Gray on June 7, 2013 at 5:30 am
‘Buyer beware. In exchange for those trinkets, your heating bill, food bill, and transportation costs will sky rocket.’
Well said.
“Aerosols emanating from coal-burning factories in the United States and Europe during the 1960s, ’70s and ’80s cooled the entire Northern Hemisphere, shifting tropical rain bands south. Rains no longer reached the Sahel region, a band that spans the African continent just below the Sahara desert.”
“For hundreds of years, the Sahel region has experienced regular droughts and megadroughts. One megadrought, from 1450 to 1700, lasted 250 years.[3] There was a major drought in the Sahel in 1914, caused by annual rains far below average, that caused a large-scale famine. From 1951 to 2004, the Sahel experienced some of the most consistent and severe droughts in Africa.[4] The 1960s saw a large increase in rainfall in the region, making the northern drier region more accessible. There was a push, supported by governments, for people to move northwards. As the long drought-period from 1968 through 1974 began, the grazing quickly became unsustainable, and large-scale denuding of the terrain followed. ” Wikipedia
What coal-burning factories were around between 1450 and 1700?
What caused the large increase in rainfall in the 1960s?
And why was this not noticed in the Washington University paper?
And the second go round will be a mess up too, and the third and the fourth. It was perfectly clear to everyone from the beginning that climate models were not ready for prime time, but the alarmists, that was a feature, not a bug. They could frame the models to do whatever they wanted in support of their pre-conceived political agenda, then had the chutzpah to call those who refused to put creedence in their unfounded claims “anti-scientific.”
Pamela Gray says:
We are back to witch trials and the time when humans were sacrificed to placate some malevolent god who caused the crops not to grow and the rivers to dry up. Don’t laugh.
Not laughing. That is absolutely true.
For the vast majority of human history, making shit up has been one of the primary sources of political power. Scary stories of gods and devils and saints and witches that are conveniently aligned for and against the political goals of the person telling the story have been a means to herd the sheep and eliminate competing shepherds for millennia.
The Enlightenment temporarily reigned that in, by introducing the scientific method and the principal of separating church from state. But politics abhors a power vacuum, and the hole in the power structure once occupied by priests and shamans is now being recolonized by story tellers in caps and gowns instead of mitres and robes. “The Science tells us” is the new “The Lord thy God commands”.
This article is a fine example …
B as is BARBARA, S as in Streisand…B.S.
Adults get PAID for this nonsense? Just reading a book, “The Forth Part of the World”, about the history of MAPS and “exploration”. Interesting how much PURE GARBAGE existed as “reliable information”, and how the true INFORMATION came out by ONE WAY…empirical observation. Still true today. EITHER DIRECT EXPERIMENT, or modeling which is BACKED BY DIRECT EXPERIMENT or, virtually WORTHLESS in all accounts!
(Don’t forget however, it was some of the “mis-information” which drove some folks to the “experimentation” or “exploration” that resulted in the TRUE information…so MAYBE that is the value of this nonsense!)
This is obviously the work of some of the 97%’ers.
Why do these things always have the feel of watching a small child with his new Etch- A Sketch in a made- for- TV movie: “Look Daddy, see what I made”? Layers and layers of fiction…
Who are these people that want to make life more difficult than it is? It appears that they want all industrialization to stop, and be reversed. No cars, no electricity, no transportation, no food, no hot water except for the “politically connected” “top of the heap”. Do you seriously believe that any of the U.N. representatives don’t live like KINGS. They are above all U.S. laws, “Diplomatic Immunity”. They have their own concubines. But that is not enough, so under “Climate Change” they want more power, more control.
They will have it all and we [the few who remain] will live in stick huts, gather our own food, and basically starve. OR, we will be direct slave to the owners given the table scraps.
There has always been a hatred for the middle class life style of the West that came about due to industrialization! Now they have a reason for their hatred: we are the cause of all of the worlds problems, including Climate Change!
Sounds like aerosols are the up and coming CYA tool of preference to explain away the failure of CO2 alarmist climate models. I’m sure there is some effect from aerosols and CO2, but when the models appear to not account for natural variability and known cycles like the PDO…it looks like more junk science we’ll have to pay for decades to disprove. Are we seeing the CO2/CAGW grant gravy train transfer over to the aerosol grant gravy train, with past model failures gradually consigned to the memory hole?
I think we need to assign more money to study natural variability to try to establish processes and parameters for “what is the range of normal?”. More effort should go into observation and evidence collection, less on model simulations and runs. I’m all for supporting real science, but this stuff frequently sounds like scare story shake downs of the tax payer.
If true, we will get to see real soon.
Love the way China and India have left the Northern Hemisphere.
Perhaps someone close to these “dear Leader” authors could enquire as to their current location .
Lake Chad is, like Lake Eyre in Australia, a residual of a larger lake formed during the last Pluvial (from the Latin pluvium for rainy) period. Its formation and size are determined by the longer climate cycles of the Ice Ages and the shorter drought cycles of its latitude.
When there is a Glacial Period in polar latitudes the desert zones formed on the poleward side of the Hadley cell shrink and the regions become grassland and parkland. So a Glacial period is accompanied by a Pluvial period and an Interglacial by an Interpluvial period.
Evidence includes everything from the massive aquifers under the Sahara created during the Pluvial period to variations in the organic content of sediments off the African coast,
http://www.columbia.edu/cu/pr/95/18727.html
http://www.gps.caltech.edu/~als/research_articles/2010/niedermeyer-et-al-2010.pdf
These are confirmed by rock paintings of people hunting grassland species in around the Tibesti Mountain range in the central Sahara.
http://www.africanrockart.org/index.php?option=com_content&view=article&id=83&Itemid=83
In the 1980s a proposal was made to divert water from the Congo basin to replenish waters in Lake Chad.
El-Chichon dominated the climate during the 80’s, more so than anyone will ever realize.
Lake Chad is a small remnant of one of several ‘megalakes’ (much larger than the modern Great Lakes) that existed at the end of the last glaciation.
http://climatesanity.files.wordpress.com/2007/11/africa_with_megalakes.jpg
It is a small fraction of its former size The other three have already completely dried up.
http://climatesanity.wordpress.com/2007/11/18/the-shrinking-of-lake-chad-cannot-be-blamed-on-anthropogenic-co2/
The advent of ‘air pollution’ with industrialization can hardly be blamed for the massive evaporation of the lakes which preceded it.
I’m not following. Aerosols from fossil fuel burning cooled the northern hemisphere but then CO2 from fossil fuel burning cancelled out the effect so nobody noticed but the cooling part caused lake Chad to dry up? How perceptive of lake Chad.
Lately we’ve read several theories about why desertification in the Sahel has advanced and retreated. This one has to be the most far-fetched yet. I believe what we are seeing is a group of people grasping at straws because their current expectations are proven to be wrong when faced with reality.
So the US is going to blame China’s aerosol emissions for the recent droughts in the southwest and central plains states?
Spurious correlation.
Could this above study as well as more co2 partly explain the greening of the Sahel?
Abstract – (31 May 2013)
““People living in the Northern Hemisphere did not notice the cooling, the authors said, because it balanced the heating associated with the greenhouse effect from increased carbon dioxide, so temperatures were steady.””
So, if temperatures were steady, then there wasn’t any cooling, right? Unless we are to believe that the Sahel is clever enough to ignore the heating and only accept the cooling.
– Polluting industry
– causes famine in Africa
– says the computer.
Triple Truthiness!
Fact: 94 & of American scientists are liberals!
It shows.
Before 5000 BC Lake Chad (Lake Mega-Chad) used to cover an area of 400,000 km2. In 2000 it covered 1,500 km2. It seems prolonged drought episodes is not unique to modern times.
http://hol.sagepub.com/content/10/3/293.short
Got to spend Christmas in N. London in 1968 and was surprised at how clean the air seemed. When I returned to the states in 1970 and lived in NYC, the air was markedly cleaner than I remembered. Many of the old Con Ed coal fired power plants had been retired once the Indian Point atomic plants had come online. Not sure where this pollution into the 80’s comes from.
generally speaking models are not good at hindcasting rain…but whenever they are ..we can trust the models…
we can trust the models
we can trust the models…
“One of our research strategies is to zoom out,” said lead author Yen-Ting Hwang…..
Zoom out? I’ll say! One wonders if they are even on the same planet as the rest of us?! They certainly are NOT on the same plane of reality…..
MtK
Stephen Singer says:
June 7, 2013 at 9:28 am
So the US is going to blame China’s aerosol emissions for the recent droughts in the southwest and central plains states?
I like the way you think Stephen!
Sure, That’s The Ticket! And they caused the Dust Bowl in the US, back in the 1930s too! Yeah, that’s what they did! Reminds me of Jon Levitz’s character ‘The Pathological Liar’….
http://youtu.be/pkYNBwCEeH4
Our gov is a global embarrassment but… ‘Buyer beware. In exchange for those trinkets, your heating bill, food bill, and transportation costs will sky rocket.’
We don’t have much variety on this shopping trip.
Since we’re shopping… how about 3 trillion for Ahmadinejad’s antique Persian carpets? That’s what Mitt Romney was shopping for to put in his presidential library. With his close friend, Benjamin Netanyahu. I just have to stop in Dallas and see Saddam Hussein’s trillion dollars + pistol on display. What a bargain! What a deal, we get more tax cuts for the wealthiest as icing on the cake, too. Lose our jobs as the country’s whole infrastructure like roads and bridges crumble and debt spirals sky high!
Why mess around with little trinkits? Let’s just go shopping for big time stuff like Vladimir Putin’s 4 yachts and 58 aircraft. That’s a bargain at around oh, what… 5 trillion? Heck, yeah, that’s such a bargain ya’ sop it up with a biscuit!
Thank you, Mac the Knife, for sharing the hilarious Jon Lovitz. I just love that guy. He’s so funny.
Almost every other DAY, I think of his pathological liar routine as I read WUWT and encounter the wild speculation and outright li-e-s of the Human-caused Climate Change advocates.
****************
And I NEEDED a laugh after reading all the nonsense in the post above at 5:24PM. “I’m not even going to try,” I thought as I read it, shaking my head in disgust.
So let me get this straight: First climate scientists say that warming causes drought. So we need to ban fossil fuels. Now cooling causes drought, so ban fossil fuels?
My “take home” conclusion is they are claiming that the Clean Air Act caused global warming?
But more seriously, doesn’t this mean that, if the Clean Air Act has been fully in place back in say 1900, the temperature record over the last 113 years would have shown us a rate of warming well within the bounds of natural variability?
Janice you just plain can’t do it. Facts are stubborn things. Who in their right mind gives big tax cuts and immediately proceeds to launch 3 trillion dollars + in wars. Look around you at a lot of our boys in uniform being driven by spouses and family to the outpatient clinics with bandaged stumps. Then recall the thousands of talking points of propaganda to justify that costly mistake. I did.
But over the last 20 years or so we’ve realized that that was quite wrong, ….
So suddenly after being wrong this answer is so certainly right we have to be guilty and fork out a fortune to them. Pull the other one,. If you were wrong last time there is and even bigger chance you are wrong this one given the political pressures to conform. No matter what the cause it has one common factor, the west have to fork out to compensate the third world now that people are too fed up with just giving aid all the time with the result there are an even larger population needing aid than before..
Isn’t it time scientists stopped prostituting themselves to the dogma of the trendy lefties.
I see other factors. One is AMO (Atlantic Multidecadal Oscillation), and anything loosely linked to it in the Pacific. It largely correlates with the periodic component visible in HadCRUT3:
http://www.metoffice.gov.uk/hadobs/hadcrut3/diagnostics/global/nh+sh/
AMO appears to me as a north-south oscillation of global heat balance, especially at the Atlantic surface and on nearby land areas. North-warming makes global temperatures warmer because the Arctic greatly and the Antarctic only-hardly have strong regional surface albedo positive feedback. Likewise, global warming is modeled to disproportionately affect the Arctic.
As north-south balance shifts, climate zones – such as the rainy intertropical convergence zone – also shift.
Another factor: Historically over the past several thousand years, when the globe was warmer, the intertropical rainforest band was wider. When the world was cooler, that rainforest band was narrower.
wait “the cooling was masked by warming”!?!?! wow, that’s a new one!!! LMAO