Also, artist depictions of people ice skating on the Thames show the level as the same as it is today. I guess all those artists back in the 1500s were liars.
Go to the 1990 IPCC report on page 202 in section seven, it shows that the Earth was hotter in the Roman Empire than it is now. So unfortunately for you your argument is full of holes. It is extremely bad when one who claims to know such matters, pontificates in such an injudicious manner, and expresses pure garbage that even the AGW and Climate Change proponents verify that what you are spewing is nonsense.
In direct answer to your question: It was the Sun. There might be other factors, but primarily it is the Sun. We do now know that the rise in the 90s was not due to CO2. That much is for certain.
I really don't know, it looks like solar minimum was the cause of the LIA but was the return to a more normal sunspot activity enough to return to a warmer climate I am not sure
My belief is that there is a lot more going on with our climate than we know about.
edit.
No I am aware of the nearly 100yr sunspot lack, but in the 1800's solar activity returned at a moderate level, would that be enough pull out of a LIA? and nothing like the huge activity during middle 1990's and early 2000's
@climate realist: I have to agree with this guy that your graphs and explanations of solar forcings are not convincing. Of course, his arguments against solar forcing are equally unconvincing.
There is a degree of correlation, especially with sunspot activity and the Little Ice Age but more research is needed. I'm not entirely knowledgeable of the relationship between solar activity and ocean cycles like PDO or AMO. There could be some sort of lag. Anyways, it's all science that needs exploration. To call it "settled" or to say there is a "consensus" is non scientific and more and more people are recognizing that. Let's get this right. That's what would be best for everyone.
The argument favoured by skeptics goes something like this: A decline in total solar irradiance led to the period known as the Little Ice Age (LIA) that peaked some 300 years ago, we are now coming out of the LIA and the recent warming is natural.
Unfortunately that argument falls flat on it’s face the moment it’s pointed out that the recent warming takes temperatures way above those that existed prior to the LIA. A point conveniently ignored by the skeptics.
In the 1,000 years that preceded the onset of the LIA the average global temperature (AGT) fluctuated between 13.5°C and 13.9°C. The LIA was the culmination of 700 years of gradual cooling in which the AGT fell from 13.9°C to 13.3°C. At no time since at least the last but one ‘ice-age’ had the AGT exceeded 14.1°C (that happened 8,000 years ago). Today the AGT is 14.7°C.
Following the LIA, the TSI returned to normal levels quite quickly and temperatures quickly recovered. Due to the amplification caused by feedbacks, when there is natural variation in the AGT there is a far more pronounced warming period than cooling, this is why ‘ice-ages’ have 85,000 years of cooling but warm back up again in just 10,000 years.
The sunspot led recovery out of the LIA was completed within 100 years and the AGT was back to pre LIA levels. Thereafter there was little change in solar activity but temperatures kept going up. When solar activity decreased temperatures continued going up. If your hypothesis was valid then this couldn’t have happened.
Just out of interest, are you able to explain why skeptics tend to take one isolated piece of evidence and create their own conclusions from that, rather than looking at all the evidence? It’s almost as if they’re deliberately being deceptive by ignoring everything that goes against their ideas.
PS – The reference to the ‘Thames River’ is of little relevance. Historically it frequently froze but as London and the southeast of England became urbanised the floodplains were drained, the meanders straightened and the river was substantially narrowed by the construction of embankments. Today the river is much narrower and flows considerably faster than it used to. Even if conditions similar to those of the Little Ice Age were to return then the river wouldn’t freeze.
- - - - - - - -
EDIT: TO SAGEBRUSH
Please don’t tell me about the River Thames. As I write this I’m about one minute away from it, I’ve lived/worked/studied in London for the last 30 years.
The River Thames is tidal (I assume you do know that). I could take a photo now and in an hours time and the water level would be different, I could take photos at different phases of the moon and the levels would be different, they would be different with the changing of the seasons, even the weather causes depressions and bulges in the water level. So explain how a 500 year old painting proves that river levels were the same as they are now. Tell me what the precise river level was at the time the picture was painted and what it is now. If you fail to do so it proves you’re talking nonsense.
As for the IPCC graph? Yet more nonsense. It’s from FAR1 and shows temps up to c1980. Guess what, temps have risen a lot since then and go considerably beyond the peak of the MWP. And in any event, I was talking about the LIA and that temps post LIA exceeded the temps pre LIA – thankyou for linking to a graph that proves my point.
Do you pretend to be stupid or does it just come naturally?
- - - - - - - -
RE: YOU ADDED DETAILS
“I'm not aware of any period where TSI ranged below normal but temperatures continued to increase”. Historically TSI and AGT had a pretty good correlation but in recent decades that link has been broken – TSI has declined whilst the AGT has risen significantly. If the “it’s the Sun” argument were to explain global warming then temps should have been falling for the last 30+ years.
http://en.wikipedia.org/wiki/Solar_varia...
And I wasn’t name-calling, it’s a genuine question. I believe Sagebrush to be an intelligent person but some of the stuff he comes up with defies all possible comprehension. I’ve explained in previous answers the psychology behind such actions but essentially the obsession to counter the GW argument overrules rationality and normal thought processing.
Oh, wow, Maxx. You're a frigging genius. You figured out that the yellow ball in the sky influences climate. It is very interesting that your article comes from NASA. You know who worked for NASA until very recently, much more recent than the 1957 sunspot maximum? That's right. Jimmy Hansen. You don't suppose that he also figured out that the Sun influences climate?
< I've figured out that the yellow ball in the sky DRIVES climate --- when will you figure it out?>
The Sun influences climate =/= the Sun is the only influence on climate. The resolution in your second link is too low to see what the Sun has done lately. From a more detailed diaagram, you can see that if the Sun were the only inrluence on climate, Earth would have been cooling for decades.
http://www.woodfortrees.org/plot/sidc-ss...
There is a ten year lag
http://www.mps.mpg.de/dokumente/publikat...
Nevertheless, other things being equal, if solar activity stops rising, Earth's temperature will also stop rising. That is simple physics. Solar induced warming causes infrared radiation to increase to balance the incresed heat from the Sun. The only exeption would be if high solar activity triggered feedbacks causing runaway warming. And I am pretty sure that that hasn't happened.
Solar cycles 21 and 22 were not higher than cycle 19 and cycle 23 was not higher than 21 and 22.
From the link
"Researchers still aren't sure how small changes in the Sun's output nudge Earth's climate in one direction or another. To find the answer, they need to monitor our climate and keep a finger on the Sun's "pulse" for many decades running."
Another reason to stop burning fossil fuels. If we keep carbon dioxide in the atmosphere constant, we can get that clean data as to how Earth's climate responds to the Sun, other things being equal.
Actually, I don't know how any rational person can believe that you can keep on putting a substace that traps heat in the atmosphere can have no effect. You must have a lot of faith in Rush Limbaugh for that.
It's difficult to tell without being able to plot trend lines. Do I have to plot another woodfortrees graph?
http://www.woodfortrees.org/plot/pmod/fr...
edit
Is GRETTA, Gangnam Style Rapper Psy Gua in drag.
Heat
If you look back over the years, it has always fluctuated up and down, up and down... But current pollution levels are increasing this. It will still go up and down, but at an even higher level. So to answer your question.... maybe something to do with teletubbies and the moon alignment?
ni way its global warming only
-----------------------
NASA article on the Little Ice Age (Maunder Minimum) says:
... small changes [in solar activity] can affect Earth in a big way. For example, between 1645 and 1715 (a period astronomers call the "Maunder Minimum") the SUNSPOT CYCLE stopped; the face of the Sun was nearly blank for 70 years. At the same time Europe was hit by an extraordinary cold spell: the Thames River in London froze, glaciers advanced in the Alps, and northern sea ice increased.
An earlier centuries-long SURGE in SOLAR ACTIVITY (inferred from studies of tree rings) had the opposite effect: Vikings were able to settle the thawed-out coast of Greenland in the 980s, and even grow enough wheat there to export the surplus to Scandinavia.
http://science1.nasa.gov/science-news/sc…
(emphasis mine)
-----------------------
