http://www.woodfortrees.org/plot/gistemp...
I find it funny that even though denialists love to claim that current global warming is not unprecedented, they talk about the supposed pause as if if were not only real, but unprecidented.
But, suppose that global warming did pause. Would that mean that AGW has stopped?
1. If the cause were humans switching to clean energy, then the answer would be yes.
2. If the cause were anthropogenic greenhouse gases reaching a concentration at which adding more would have no effect, the answer would be yes.
3. If the cause were a spike in aerosols, vocanic or anthropogenic, the answer would be no. Volcanic aerosols would eventually return to normal and global warming will return with a vengence. Even anthropogenic aerosols do not accumunlate like carbon dioxide does. Sulfate aerosols are condensate which results from the reaction of sulfur compounds, such as sulfer dioxide and hydrogen sulfide with oxygen and water vapor.
4. If the cause were a "Maunder Minimum" the answer would be no. Solar activity will eventually return to normal and global warming will return with a vengence.
For a persistent uninformed and mentally challenged denier (a common type found on this website), clutching at all forms of illogic in order to deny and lie about science, sure.
With a more intelligent anti-science denier such as DaveH here (the immediately prior answer), cleverer subterfuges are used.
Nonetheless, his crass and unsupported claim that a pause in temperature rise is "contrary" to all projections, does not make this claim true. Most projections deal with the long term, not the short term, which is of course what counts with climate change.
No. Whether it has "stopped" or not depends on over what time length it is measured. Deniers say it has stopped because on an annual basis it does not look like it is rising very fast. That is a very short-term perspective. What if you look on a decadal basis? Then the last 10 years have been the warmest in the instrumental record, so clearly it has not stopped.
Global "mean" temperature is a very imperfect measure at best. It is based on representative points, NOT the entire globe, so if we the had the "true" global mean surface temperature, it may very well still be rising.
Year-to-year fluctuations have a lot of noise in them, so on a short-term basis the trend may be buried in the interannual variations.
Here's another point to ponder. Suppose I put a pot of water on the stove and measure the temperature as I heat it. The temperature will rise very fast initially, but slow down and actually stop rising while the water is boiling. Has the heating stopped? No, it's just that the energy is going into the phase change rather than into temperature rise. Similarly there are other places for the AGW heat to go, rather than just into temperature rise. That doesn't mean anything has stopped.
I really don't think anyone knows quite what to make of this pause. Certainly no one has come forward with a definite cause and the observations to verify it. There seems to be no certainty, and this is particularly disappointing. We have put the climate increasingly under the microscope in the last few decades, but despite measuring everything we can think of, no one is able to pinpoint what's happening here. It seems we still have a great deal more to learn about the forces that drive our climate.
In respect to "does this mean that AGW has stopped?", I don't think you could make this claim with any confidence at all. A quick glance at any long term temperature record reveals many periods of this duration with indistinct trend.
E.g. http://mclean.ch/climate/Eng_Scot/Fig_01...
A pause of this duration, or even temporary a reversal of trend, can be entirely within natural variability...
... but this pause is contrary to ALL the projections.
The biggest lesson I get from this is that we don't yet know enough about how our climate works to be able to model it successfully. The models aren't yet secure enough to rely on for policy making.
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Edit Rolando. "Where this heat goes, it seems it is difficult to get a consistent answer for, but it is not radiated out into space as from what I understand energy in and out of the system is measured using satellites."
Indeed it is measured by satellites. Unfortunately the records are short, and we don't have good knowledge of the whole spectrum, but there is clear evidence of some recent increased loss to space.
Here is a chart of outgoing longwave radiation. The infrared wavelength covered is 10.5-12.5 μm.
[A caution to Hey Dook here. Warning! "Technical mumbo jumbo" follows.]
http://www.climate4you.com/images/OLR%20...
The red line is a three year centred average. Notice how outgoing LW radiation rises sharply from 2001 to 2005 and then stays there.
This feature is most pronounced at latitudes 60n to 90n.
http://climexp.knmi.nl/data/inoaa_olr_0-...
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Edit pegminer.
Re your last thing to ponder. "Has the heating stopped? No, it's just that the energy is going into the phase change". Did it occur to you that the same might be happening in the oceans? Increased evaporation cools the ocean. More water vapour means cloud forms more readily. Cloud is water vapour condensed. Condensation in clouds is heat, taken from the ocean and released at altitude. Heat released at altitude escapes to space more than heat released at the surface.
See the two links above. The frequency of OLR in those charts is in the water vapour absorption/emission range.
OM –
>>The temperature rise during the last part of the 20th century appears to have leveled off.<<
Based on what? And, even if it has leveled off, how do you explain the fact that it has leveled off at a mean value that is higher than every other mean value for every comparable period in the historic record?
>>There several possibilities for the factors or combination of them. I don't believe we exactly know<<
That is a Bullshlt cop-out. Of course we do not know “exactly.” If we knew “exactly” then we could “exactly” predict the “exact” mean global temperature for every year to come and “exactly” explain the value of every past temperature.
Regardless, we do know some things. We know that there is no physical evidence or scientific explanation indicating a stoppage in the process that has been driving global temperature upward. We know that the excess heat must be going somewhere. We know that the heat is not exiting the system. Therefore, we know that it is being converted or stored internally as potential energy.
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Sagebrush --
>>Ha! Ha! Just look at the Grifter, he has no clue that he is taking his figures from corrupted data.<<
Ha!Ha! Just look at Sagebrush, he is lying about something – again - that he has been shown to be a lie. And, moreover, he has no clue that even if his lie was not a lie, his “evidence” in no way supports his claim, At best, it is hearsay – hearsay by a known biased and prejudicial source (i.e., a known pathological liar).
>>AGW is a dead issue among the well educated true scientists. <<
As opined by someone who has never known or read a single word by any scientist and whose education is defined by a complete absence of any scientific knowledge.
Translation: AGW is a dead issue among scientifically illiterate knuckleheads.
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OM --
>>the rush to explain it<<
Is that part of the same epistemology as the blindly, ignorantly, at-all-costs, faster than the speed of light "rush to deny"?
At what point is science "rushing?" Is there some mandatory waiting period? Where is the point between rushing and stalling?
Sensitivity is not the issue - atmospheric chemistry and the greenhouse effect are.
I use to think there were no stupid questions.
AGW can not stop until humans stop burning fossil fuels.
The global temperature trend is hiding somewhere.
The significant factors involved is the denier campaign propagating the idea that scientist predicted something other than hiding heat and natural variability masking the AGW signal.
The trend will either be AGW prediction matching up with reality, or revised predictions and a continued push to shame deniers who are simply fed up with massive uncertainty factors, hidden variables, unforeseen effects of nature getting in the way, failed predictions and the everyone is out to get climate scientist conspiracy theory.
Well first, there has been no pause in GW, that is pure BS
It is over the last 3 decades that GW has established itself with both the global average temp and CO2 levels rising.
Over the last 15 years, we have had the 10 warmest years globally out of 132 years with 2012 showing as the 10th warmest. So there definitely has been no pause in GW. In fact
March 2013 for land and ocean temps combined were tied for the 10th warmest March on record and for surface temp only it was the 11th warmest March on record You think that indicates a pause in GW http://www.ncdc.noaa.gov/sotc/global/201...
NOT!
The next few decades will see an increasing CO2 levels with an increase globally in heat waves and drought for part of the globe resulting in desertification in some areas. Other areas will see torrential rains, typhoons and flooding which will destroy some crops.
I believe by 2030 we will sea the oceans rise an average 8-10 inches creating critical drinking water shortages for some island nations as well as India and South Korea
AGW never started. You can't stop something that never started.
All of the slight warming we've experienced over the last several decades is well within the range of normal variability.
We've had very high SOLAR activity since about the mid 1950's, that's where the warming came from, NOT HUMAN ACTIVITY !!
Just have a glance at this, no rational person could deny it: (but all alarmists do)
http://lasp.colorado.edu/lisird/tsi/hist...
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Ha! Ha! Just look at the Grifter, he has no clue that he is taking his figures from corrupted data.
http://www.c3headlines.com/fabricating-f...
Just look at GISS 1999 and GISS 2011. James Hanson has been caught red handed ( No wonder he retired) and the scientifically handicapped still follow his corrupt data because they have nothing else to rely on.
http://www.woodfortrees.org/plot/hadcrut...
This woodfortrees graph gives lie to the statement that GW hasn't paused. Notice I didn't go back to 1998 where El Nino was claimed to have an influence. Notice that I took RAW data. (There is nothing up my sleeve, folks.) Also the man made claim is connected to man's increase in CO2 output raising the temperature. Well, CO2 went up and, as you can see, temperature actually went down. TSK. TSK. Even Mother Nature has betrayed your theory.
For direct answer: Nothing out of the ordinary. AGW is a dead issue among the well educated true scientists. We will just have to let nature take its course. Man is not good at predicting.
Quote by Noel Brown, UN official: "Entire nations could be wiped off the face of the Earth by rising sea levels if the global warming trend is not reversed by the year 2000. Coastal flooding and crop failures would create an exodus of "eco-refugees," threatening political chaos."
NO, in order for agw to have stopped it needs to have been happening at some time, There is no evidence to prove that agw has ever existed. It is as it always was, a crackpot theory for the tin foil hat brigade.
As for the next few decades, maybe Yuri Geller has a take on that one.
What are your thoughts on the global temperature trend over the last few decades?
What are the significant factors and what does this mean in respect of AGW?
What do you think will happen to the trend over the next few decades?
The temperature rise during the last part of the 20th century appears to have leveled off.
There several possibilities for the factors or combination of them. I don't believe we exactly know. What it means to AGW is that climate sensitivity is possibly lower than we thought.
Given what we don't know, I don't think anyone can reliably predict the next few decades. I do however think we are going to learn a lot more about solar influence if solar activity heads south.
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Edit@Gary F: "Based on what?"
Based on the rush to explain it. (e.g. Trenberth-ocean heat content, Hansen-Chinese aerosols/ENSO, Solomon-stratospheric water vapor, various-PDO,etc.)
"We know that the excess heat must be going somewhere."
No we don't. We speculate that because of the AGW theory of high climate sensitivity, there must be extra heat which we can't currently locate. You can't say "we know" to a claim based on a hypothesis.
"indicating a stoppage"
What's this "stoppage" you are talking about?
