Arguments
Did global warming stop in 1998, 1995, 2002, 2007, 2010?
What the science says...
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Global temperatures continue to rise steadily beneath the short-term noise. |
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Climate Myth...
Global warming stopped in 1998, 1995, 2002, 2007, 2010, ????
"January 2008 capped a 12 month period of global temperature drops on all of the major well respected indicators. HadCRUT, RSS, UAH, and GISS global temperature sets all show sharp drops in the last year" (source: Watts Up With That).
The flaw in this interpretation is in drawing conclusions about long term climate change over a relatively short period of time. Only over a period of decades can you confidently discern climate trends. Otherwise, you run the danger of mistaking weather for climate.
Nevertheless, several important questions remain - what's caused the warming of global surface temperatures to slow in the short-term?
Solar Minimum
The general consensus among skeptic blogs is that diminished solar activity is the cause. The sun is currently at solar minimum - cycle 23 just ended and cycle 24 is having trouble kicking along. It's as cool as it gets in the solar cycle.
However, a temperature drop of 0.6°C would require a dramatic reduction in Total Solar Irradiance (TSI). According to theoretical calculations at Atmoz, TSI would need to fall to 1347.65 W/m2 to produce a global cooling of 0.6°C. In other words, 13 W/m2 less than current levels. This is ludicrously large considering the solar cycle varies only around 1.3 W/m2.
Alternatively, Camp 2007 adopts an empirical approach to calculate solar influence on global temperature. He determines the solar cycle contributes 0.18°C cooling to global temperatures as the sun moves from maximum to minimum. Employing back of a napkin calculations, TSI would need to fall roughly 4.3 W/m2 to provide 0.6°C of cooling.
Either way, TSI needs to drop considerably to be considered the driver of 2007 cooling. So what has the sun been doing over the last few years?
Figure 1: TSI Composite and Sunspot Numbers (graph courtesy Greg Kopp).
Satellite measurements show no dramatic drop in TSI over the past several years. Instead, the solar cycle is following its usual 11 year cycle, flattening out as it reaches solar minimum. So if not the sun, what's causing the cooling?
La Niña
Currently, the Pacific Ocean is in a La Niña phase. During La Niña, cold waters upwell to cool large areas of the equatorial Pacific Ocean. This has the effect of cooling the atmosphere. During the La Niña episode of 1999, global temperatures dropped around 0.5°C.
The Southern Oscillation Index (SOI) is a measure of La Niña. Positive SOI corresponds to a La Niña phase. In 2006, the Pacific Ocean was in El Niño phase (negative SOI). However, in late 2006, El Niño subsided and in mid 2007, crossed into La Niña phase. La Niña peaked around January 2008 and is the strongest La Niña since 1999. In the Eastern Pacific, sea-surface temperatures are about two degrees colder than normal over an area the size of the United States.
Figure 2: Southern Oscillation Index (graph courtesy bom.giv.au).
In fact there was a preponderance of El Niño events in the 1990s and a preponderance of La Niña events since 2000. If we just look at the surface warming trend for El Niño years, for La Niña years, and for neutral years, in each case the trend is very consistent (Figure 3).
Figure 3: NOAA annual global surface temperatures from 1968 through 2012 with La Niña years in blue, El Niño years in red, ENSO neutral years in black, and volcanic years as orange triangles. Linear trends for 1968–2012 for each of the three categories (excluding volcanic years) are shown in the final frame.
Signal vs. Noise
Ultimately arguments that global warming has magically stopped are based on a failure to differentiate between short-term noise and long-term global warming signal (Figure 4).
Figure 4: Average of NASA GISS, NOAA NCDC, and HadCRUT4 monthly global surface temperature anomalies from January 1970 through November 2012 (green) with linear trends applied to the timeframes Jan '70 - Oct '77, Apr '77 - Dec '86, Sep '87 - Nov '96, Jun '97 - Dec '02, and Nov '02 - Nov '12.
Foster and Rahmstorf (2011) used multiple linear regression to filter out the effects of the El Niño Southern Oscillation (ENSO), and solar and volcanic activity (Figure 5), and found that the undelying global surface and lower atmosphere warming trends have remained very steady in recent years (Figure 6).
Figure 5: Temperature data (with a 12-month running average) before and after the exogeneous factor removal
Figure 6: Average of all five data sets (GISS, NCDC, HadCRU, UAH, and RSS) with the effects of ENSO, solar irradiance, and volcanic emissions removed (Foster and Rahmstorf 2011)
In fact, when removing these short-term effects, the warming trend has barely even slowed since 1998 (0.163°C per decade from 1979 through 2010, vs. 0.155°C per decade from 1998 through 2010, and 0.187°C per decade for 2000 through 2010). This excellent video from Kevin C illustrates the point beautifully:
Oceans are Still Accumulating Heat
As Nuccitelli et al. (2012) (Figure 7) and Balmaseda, Trenberth, and Källén (2013) (Figure 8) demonstrated, the oceans have continued to accumulate heat over the past decade even while the warming of surface temperatures has slowed.
Figure 7: Land, atmosphere, and ice heating (red), 0-700 meter ocean heat content (OHC) increase (light blue), 700-2,000 meter OHC increase (dark blue). From Nuccitelli et al. (2012).
Figure 8: Ocean Heat Content from 0 to 300 meters (grey), 700 m (blue), and total depth (violet) from ORAS4, as represented by its 5 ensemble members. The time series show monthly anomalies smoothed with a 12-month running mean, with respect to the 1958–1965 base period. The vertical colored bars indicate a two year interval following the volcanic eruptions with a 6 month lead (owing to the 12-month running mean), and the 1997–98 El Niño event again with 6 months on either side.
And in fact most of the heat accumulation resulting from global warming goes into the oceans (Figure 9).
Figure 9: A visual depiction of how much global warming heat is going into the various components of the climate system for the period 1993 to 2003, calculated from IPCC AR4 5.2.2.3. Note that focusing on surface air temperatures misses more than 90% of the overall warming of the planet.
In fact Meehl et al. (2011)found that climate models expect 'hiatus decades' to occur, during which surface temperatures don't warm significantly because more heat is transfered to the deap oceans. This is what appears to have happened over the first decade of the 21st Century.
Last updated on 24 March 2013 by dana1981. View Archives
http://www.npr.org/templates/story/story.php?storyId=88520025
The Argo system, the best data available, is showing no rise in ocean temperatures at all (indeed, a slight cooling) since it was deployed in 2003. This data raises a lot of questions. If the heat isn't in the atmosphere, and it's not in the oceans, where is the Global Warming heat supposed to be?
Initial results from the Argo system contained a cooling bias due to issues with the pressure system. The latest results from Argo show warming. This is particularly the case when the results down to 2000 metres deep are considered (the upper waters show more variability while the overall warming trend is more apparent when viewing the 2000 metres heat content).
Bottom line - the oceans are still warming.
1. Argo only measures to 2km. Oceans are much deeper than that.
2. If La Nina is bringing cooler water to the surface, you would *expect* that Argo would show a cooling at the surface.
Argo shows an averaged temperture for various zones. You need to look at maps that contain smaller snapshots to see the changes wrought by both El Nino and La Nina.
The effect actually begins as a localized cooling (La Nina) or heating (El Nino) along the Peru-Chile (or South American) subduction zone. The change in ocean surface temperature over the zone causes changes in both ocean currents and wind direction* (*towards the Andes mountains or away from them).
This type of phenomena is not restricted to El Nino/La Nina but occurs in lesser degrees all around the "Ring of Fire". Since these changes in the subduction zone are reflections of what is occurring in the mantle it follows that the tidal movements in the mantle are the actual cause of a very strong climate driver.
As we know that tidal effects are heavily influenced by gravitational pull of large extraterrestrial objects we can show that there is significant climate forcings from our neighbors in the solar system. To what degree remains a question.
See the arguments in "Its the Sun" for references.
You may recall that I had mentioned that the solar activity causing changes to the magnetic field rang a bell but I cound not put my finger on it. Well I just did in my last comment. It is starting to come together.
The heat transferred in an El Nino is from the earth itself, indirectly through the ocean. It's a form of vulcanism known as a subduction zone (see comment 4).
As a skeptic I find this site the most open minded of all the climate blogs I have visited, especially when compared to our American sites. I find the links and graphs especially useful and highly recommend this site to others who often comment on the web.
Logical assumption. The upwelling flow, warm or cold, effects ENSO and the Air currents, hence weather and climate.
The resulting flows within the ocean I have not looked into but it would be interesting to know. Anyone?
If I were to chose a collarobator to make a discovery, I might choose you. Open minds tend to prevail in science.
What I see that is difficult about understanding the climate is that there appear to be 10 variables, all dependant on the others. In basic Physics, theories are easy to test because there were only a few variables, all easily measured and constrained.
No such situation exists with climate and weather. The complexities are more like String theory or Chaos theory.
And, Quiteman, you are correct about the sites. Most sites are more Political Science, that science.
Tom
Are we debating science or philosophy? Facts or wishful thinking?
"What is happening and how it may affect the earth" and "Do we want this to happen" are two different issues depending on whether you are human or not. As soon as you ask a question like that you move from 'hard' sciences to Behavioural sciences to How I Feel About Life And All That. Not science.
There are probably thousands of lifeforms out there only too happy to see CO2 levels going up with the temperature. Others that don't. Where did we get the right to decide what the future of this planet and it's associated lifeforms should be? From just being the 'dominant' species? We talk about the kind of planet we want to hand down to our descendants but nobody has put up a specification as to what that might be. And if you did, there will be a load of people disagreeing with you.
Change will happen, with or without us burning off fossil fuels. The real question is Will there be a catastrophic event as a result of our activities and How do make sure we survive it?
Just as we have had to find ways round the problems our ancestors gave us, so will our descendants have to do the same. If we can make it easier for them, fine. But our basic imperative is to make sure man as a species survives. Isn't that what evolution is all about?
You make some very good points. Unfortunately if we are correct in our argument for natural causes there are no "fixes" and this whole carbon (CO2) issue will ruin the industrialized world as we know it. It is already having a very damaging effect on several countries.
So I see both scenarios as compelling reasons to get the science right before taking any action.
"When in doubt, do nowt", or as I think you said in another post..."doing nothing is an option"
Industrialised societies as we know them will end if we do not develop viable alternatives to fossil AND nuclear fuels simply because we will run out of them sooner or later. That seems to me to be a much greater ( and certain) problem than whether we survive a few degrees rise in temperature. Yes life might be a bit more difficult and unpleasant, but survivable by just about everybody. A global industry collapse ( with war as a precursor)will probably not be survivable.
BUT before we ever reach that point - however far away that may be - an energy 'war' will start,( arguably has already started)and it will escalate as the energy required to extract these fuels approaches the energy derived from them.
Concerns about the effect of a slight rise in temperature over the next century and the consequences thereof are irrelevent in this context: our civilisation will survive the predicted global warming scenario, it will not survive if we do not develop alternative energy sources that are independant of fossil fuels.
"Doing nothing" refers to direct action to reduce CO2 emissions; I would argue it is better to do nothing in that context and spend the money 'saved' on exploring and developing alternate energy sources. (Which has the long term effect of reducing CO2 from FF's )
I am probably wrong but I often wonder where all this fossil fuel came from.
Back in my school days (35 years ago) I was taught that is was from the Dinosaur days.
The Earth was much hotter, Plants grew much lusher ( More CO2) .
There was abundant Plant life that grew and died and rotted in swamps eventually forming Oil.
This will not happen today. This planet is cold. It has been 11,500 years since the last Ice Age. The next Ice Age is due. We need millions of years of heat and increased CO2 to give the Earth a fighting chance.
I am probably wrong but I often wonder where all this fossil fuel came from.
Back in my school days (35 years ago) I was taught that is was from the Dinosaur days.
The Earth was much hotter, Plants grew much lusher ( More CO2) .
There was abundant Plant life that grew and died and rotted in swamps eventually forming Oil.
This will not happen today. This planet is cold. It has been 11,500 years since the last Ice Age. The next Ice Age is due. We need millions of years of heat and increased CO2 to give the Earth a fighting chance.
This 'slight' rise in temperature could be enough to raise sea levels by seven metres just from Greenland alone in the next hundred years.
Even in 2008, 634 million people live within 10km of coasts.
Do you see that as irrelevant?
The next ice age can not begin until after the current one ends. We ARE IN an ice age, Ice Age 4 known as the Neogene-Quarternary Ice Age. This is an interglacial period within the confines of Ice Age 4. In other words this is colder than normal and slowly returning back to earth normal (hot). Before you ask what is normal, you should know that all 4 of the ice ages only constitute about 10% of the earths history (but a much higher percent, maybe 40%, if you only count from the beginning of life). That means that 90% of the earths history (or about 60% of its inhabited history) is a HOT earth (but habitable despite extremely high CO2 levels ay times). The information is available at both government and university sites. I suggest becoming familiar with the scientific terminology at these sites and then look at the graphs of paleoclimates. The alarmists like short terms, 30 years rather than say 50 or 100 and for paleoclimates no more than a few hundred thousand years rather than millions because it makes AGW look pronounced and they can't account for high temps and low CO2 or low temps with high CO2 because it does not fit their models or their agendas.
In the context of the survival of civilisation, yes I do see it as irrelevent. That does not mean I am not concerned!
Bubonic plague killed over half the population of Europe in the 14th century (estimated 35 million people) and a quarter of the worldwide population. The population in Europe recovered within a century.
The 634 million you mention represent 10% of the world population so the effect of that 7 metre rise ( even if it killed them all) would have less effect on civilisation than the bubonic plague.
The timescales are roughly the same..100yrs, the difference is that we have the ability circumvent the effects of rising sea levels so the net outcome will not threaten civilisation.
It depends on what your perpective is, survival of the individual or survival of the species; marked global cooling would be a lot more difficult to survive than the equivalent level of global warming.
Mankind in general ( and politicos in particular) is often very myopic when it comes to 'proving' a current view is THE right one. It is interesting to note the shift in emphasis from Global Warming to Climate Change.
You can't argue against one of these...guess which?
You are correct, the overall slope is negetive. I am referring to the current slope of the past 5 million years as positive.
The notion that one can change reality or somehow diminish real world implications with semantics is a dismal notion...it's politics, not science. The world is warming..the evidence indicates that the massive enhancement of greenhouse gases is a dominant causal factor....our understanding of the climate system and its response to enhanced greenhouse effect indicates that we're very likely to get a considerable amount of additional warming. That's "global warming"...and it's already causing "climate change"...
As for the "shift in emphasis" from "Global Warming" to "Climate Change", much of that "shift" has come from the sectors of the political spectrum, especially in the US, that has had such a degrading effect on the entire US sociopolitic during the last several decades:
So, for example, it was Frank Luntz, the Republican party strategist, that urged Republican candidates in a memo some years ago, to use the phrase "climate change" rather than "global warming", because (in his words):
"Climate change is a lot less frightening than global warming".
At that time, Luntz's aim was to misrepresent the science and to play the "uncertainty" game ("there's no proof that cigarette smoke causes cancer"..."there's no proof that aspirin enhances the liklihood of Reyes syndrome in children".."there's no proof that CFC's denude high altitude ozone concentrations" etc. etc. ad nauseum). Happily, like an awful lot of people that combine politics with at least a semblance of honesty, Luntz has shifted his viewpoint, such that he said in an interview a couple of years ago:
"It's now 2006...I think that most people would conclude that there is global warming taking place and the behaviour of humans is affecting the climate..."
The take home messages are, first, that the natural world sadly doesn't bow to ones' political pursuasions (see King Canute's political advisors!), second, that on the supposed use of semantics to politicise/downplay real world consequences, one should be a little more careful in assessing where the politicizations are coming from....
....and third, if one considers that it is appropriate to misrepresent and deliberately misunderstand the science in pursuit of political agendas, one might consider who is actually benefitting from one's contrived misrepresentation...one might discover at some future time that one was being treated as a chump to service someone else's agenda!
That's incorrect. The overall trend of the last 5 million years has been a mildly cooling one.
Re #21
There's no such thing as "normal" temperature in relation to the Earth. The Earth is on a journey through time, and it's properties (atmosphere, temperature, biosphere, geology and so on) evolve according to a whole range of intrinsic and extrinsic factors. For human kind and the current biosphere, "normal" only really has a meaning in relation to evolutionary adaptedness. The biosphere in its current state is adapted (i) to the relatively cool period of the last several million years, and (ii) to a world with rather more continuous and connected environments that has, until the recent past, allowed migration as a fundamental means of adapting to climate change.
Isn't this what the graph shows? Lows of around 1360.25 to highs of 1363.5...roughly 3.25W/m2 or around .45C of cooling?
Not really Mizimi. Remember that the effect of a forcing (whether a warming or a cooling forcing) relates to the temperature change at equilibrium....
...at equilibrium...
Note two things about the influence of the solar cycle on the Earth's temperature response:
(i) the solar cycle has a rather rapid sinusoidal variation. The entire cycle takes only 11 years to evolve from its maximum TSI to its minimum TSI and back again
(ii) The Earth's surface temperature response is damped, and it comes to equilibrium much more slowly than the few years "allowed" for it to "track" the solar cycle variation.
So the tracking of the Earth's temperature response to the solar cycle is continuously "frustrated" (very much like the temperature response to a thermostat). The atmosphere follows the solar cycle most faithfully. The ocean and land surface is much slower to respond. So the effects of the solar cycle is damped, and the entire effect of the solar cycle is to contribute around 0.1 oC of temperature difference at the Earth's surface, between the solar maximum and solar minimum (Tung considers that the solar cycle contribution is a bit larger...around 0.18 oC).
If the solar cycle were to stop and the sun emit solar radiation equivalent to 1363.5 W/m2 for a long period (say 30 years to come close to equilibrium)...and then the sun switched to a constant TSI output equivalent to 1360.25 W/m2 for 30 years to establish the new equilibrium temperature, the temperature difference at the Earth's surface would be your 0.45-ish oC of cooling (all else being equal).
..but these temperature changes in response to forcings are equilibrium changes..
These seasonal fluctuations are much greater than the solar cycle and I suspect the small warming of the solar cycle gets overshadowed somewhat rather than retarded.
But just like the damped solar cycle contribution to the Earth's surface temperature, so the seasonal temperature variation is damped. For example if, rather than a seasonal drop in insolation where you live, the sun changed its output to give a constant insolation corrsponding to the cold season insolation, the water in the sea where you live would get a whole lot colder than 17 oC. But it would take a while for this new horribly cold temperature to settle at a new chilly equilibrium temperature.....
ScienceDaily (Jan. 31, 2001) — Much of the Earth has warmed over the last half-century, but the eastern half of the United States has shown a cooling trend. NASA-funded research indicates cooler temperatures in the eastern U.S. are caused by an increase in sun-shielding clouds produced by warmer ocean temperatures in the Pacific.
Yes, the cooling was confined pretty much to the first half of the year. You can assess this by inspecting the monthly-averaged temperature anomalies. Here's the UK Hadcrut3 global temperature analysis:
http://www.cru.uea.ac.uk/cru/data/temperature/crutem3gl.txt
The temperatures in early 2008 through May were highly suppressed (except oddly for March). Temperatures recovered in the second half of the year so that the last half of 2008 was as warm as the second half of 2007. And 2007 was one of the top three warmest years on record.
Overall 2008 will be cooler due to the cold start. Despite that it's one of the top 10 warmest years on record.
The prediction that warming would start again in mid 2008 was not a prediction from computer models. It was a prediction based on our basic understanding of the Earth's temperature response to rising greenhouse gas forcing, our understanding of the temporal evolution of La Nina events and so on...
Is there not a serious threat from these hydrates both in the warming deep sea and permafrost that would contribute to global warming since methane hydrate is 20 to 30 times more dangerous as an absorber of heat than CO2? Is it likely that this coming Spring, as it warms and the hydrates that have formed during the winter start fighting to survive the warmer weather, they will dissociate especially in Russian, Canadian and Scandanavian permafrost?
https://www.llnl.gov/str/Durham.html gives a brief outline of methane hydrate properties which are totally different to methane gas - which I suspect you are confusing it with.
And as for the sun. I am just a journalist, but professor Kees de Jager from the Netherlands has recently published about this in a peer reviewed journal. He still thinks that the larger part of the warming from the past century can be explained by the sun. See: http://www.cdejager.com/sun-earth-publications/
His cv may be interesting as well: http://www.cdejager.com/about/
Cheers,
Theo Richel
Re cooling subsiding in 2008, La Nina did subside and then flipped right back into strong La Nina conditions again (see graph in the next comment). Thus demonstrating the difficulties in predicting short term ocean cycle variability.
As for the sun, many peer reviewed papers examine the link between sun and climate. They all note that the sun has showed little to no trend since the 1950's and hence has had a minimal contribution to global warming over the past 4 decades.
This other article say "The correlation between sun and climate ended in the 70's when the modern global warming trend began."
So, if i understand, before 1970 the sun was the cause of climate variation. And in the graph i see that (before 1970) a variation of less than 1 W/m2 causes a temparature increasing of almost 0.4 degrees. It is not that a contradiction?
I'm sure i'm missing something...
Thanks
The sun was not necessarily the primary cause of climate variation before 1970. In fact, the forcing from solar variation is not particularly large. The breakdown in correlation is just to show that the sun cannot be the cause of global warming in the last few decades.
The earth's albedo is not constant and is dominated by cloud cover. Increased cloud can warm or cool the earth depending on the type and altitude. More high level cloud increases the albedo but traps more heat resulting in warming. More mid-low level cloud increases albedo but relects more radiation causing cooling. Goode & Palle (2007) suggest small changes in albedo produce changes in radiation levels over twice as high as GHGs. Charting albedo from 1985 to 2004 shows an interesting correlation to GMT. Albedo declines some 3% from 1984 to 1995 and drops fast (by another 8%) between 1995 to 1998 where it is at a minimum.....and 1988 was of course a very warm year.
Since then the albedo has increased ( albeit hesitantly)by 4% up to 2004, which is possibly a major factor in the present downtrend in GMT.
http://bbso.njit.edu/Research/EarthShine/literature/Goode_Palle_2007_JASTP.pdf
Note that the TIM data is 4-5Wm(-2) below other instruments, and the averaged version of the graph has lowered previous records to match the TIM data. TSI is not a settled matter. The graph used on this page would be better used to demonstrate the solar cycle argument, where the image is slightly out of date (2000)
As to whether current sea-level rises matches the current level of ice loss, the water budget seems to be closed quite well. eg Willis
"The interesting thing about the GISS anomaly map above is the choise of base=line (1951-1980). This was a relatively cooler period of time and to use that to show Arctic warming may distort what has recently been going on. I went to the GISS page ... GISS Arctic temp map using 2000-2010 as the baseline. "
A baseline needs to be a long time period -- its supposed to represent an average condition, so that anomalies are relative to that average. Your 10 year baseline doesn't accomplish that.
It is interesting to choose an historically relevant baseline and look at the relative anomalies. Prior to 1946, carbon emissions were increasing at a steady rate; however, after WW2, carbon emission rates exploded. So much so that the cumulative CO2 emissions from fossil fuels after WW2 virtually eclipses all CO2 emissions in the prior 150+ years (you can verify this with data and graphics readily available at CDIAC). So 1900-1946 is a relevant baseline period.
Here is the anomaly for 1970-1980.
Here is the 1980-1990 anomaly.
Fast forward, here is the 2000-2010 anomaly.
Look at the numbers in the upper right hand corner, which are the estimated global means for the period mapped. It's obvious that warming rates dramatically increased in the '80s, nearly 4 decades after the rapid increase in CO2 emissions began. Considering that it takes time for the warming effect of CO2 to be fully realized (see the 40 year delay thread) that result is not surprising.
(Reconciling anthropogenic climate change with observed temperature 1998–2008)
"Given the widely noted increase in the warming effects of rising greenhouse gas concentrations, it has been unclear why global surface temperatures did not rise between 1998 and 2008"
Are they aware of the exceptionnaly warm 1998-niño-year flaw in their decadal trend ?
If Kaufmann and co-author's findings are validated by other research, it's not good news. Sulfate aerosols have a short atmospheric lifetime, and when the Chinese stop pumping out all that extra sulfate pollution, it's going to unleash some warming. And yes they have to at some point, for health reasons and to prevent Ocean Acidification.
Thanks for your answer anyway.
[Source]
Shows over, folks. No warming here, nothing to see.
[DB] Fixed images.