Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Settings

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Bluesky Facebook LinkedIn Mastodon MeWe

Twitter YouTube RSS Posts RSS Comments Email Subscribe


Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...



Username
Password
New? Register here
Forgot your password?

Latest Posts

Archives

How we know global warming is still happening

Posted on 28 September 2009 by John Cook

Skeptics proclaim that global warming stopped in 1998. That we're now experiencing global cooling. However, these arguments overlook one simple physical reality - the land and atmosphere are only one small fraction of the Earth's climate (albeit the part we inhabit). Global warming is by definition global. The entire planet is accumulating heat due to an energy imbalance. The atmosphere is warming. Oceans are accumulating energy. Land absorbs energy and ice absorbs heat to melt. To get the full picture on global warming, you need to view the Earth's entire heat content.

This analysis is performed in An observationally based energy balance for the Earth since 1950 (Murphy 2009) which adds up heat content from the ocean, atmosphere, land and ice. To calculate the Earth's total heat content, the authors used data of ocean heat content from the upper 700 metres. They included heat content from deeper waters down to 3000 metres depth. They computed atmospheric heat content using the surface temperature record and the heat capacity of the troposphere. Land and ice heat content (eg - the energy required to melt ice) were also included.


Figure 1: Total Earth Heat Content from 1950 (Murphy 2009). Ocean data taken from Domingues et al 2008.

A look at the Earth's total heat content clearly shows global warming has continued past 1998. So why do surface temperature records show 1998 as the hottest year on record? Figure 1 shows the heat capacity of the land and atmosphere are small compared to the ocean (the tiny brown sliver of "land + atmosphere" also includes the heat absorbed to melt ice). Hence, relatively small exchanges of heat between the atmosphere and ocean can cause significant changes in surface temperature.

In 1998, an abnormally strong El Nino caused heat transfer from the Pacific Ocean to the atmosphere. Consequently, we experienced above average surface temperatures. Conversely, the last few years have seen moderate La Nina conditions which had a cooling effect on global temperatures. And the last few months have swung back to warmer El Nino conditions. This has coincided with the warmest June-August sea surface temperatures on record. This internal variation where heat is shuffled around our climate is the reason why surface temperature is such a noisy signal.

Figure 1 also underscores just how much global warming the planet is experiencing. Since 1970, the Earth's heat content has been rising at a rate of 6 x 1021 Joules per year. In more meaningful terms, the planet has been accumulating energy at a rate of 190,260 GigaWatts. Considering a typical nuclear power plant has an output of 1 GigaWatt, imagine 190,000 nuclear power plants pouring their energy output directly into our oceans.

Figure 1 only goes as far as 2003 as the ocean heat data used (Domingues 2008) only goes that far. What has global warming been doing since then? Since 2003, ocean heat data has been measured by the newly deployed Argo network. However, there have been teething problems with the Argo buoys experiencing pressure sensor issues that impose a cooling bias on the data. Consequently there have been several data analyses on ocean heat since 2003. One reconstruction of ocean heat show  cooling since 2003 (Willis 2008). Other analyses of the Argo data show ocean warming (Levitus 2009, Leuliette 2009, Cazenave 2009).

How do we determine which analyses are more accurate? Ocean heat data can also be independently determined through other empirical means. Cazenave 2009 uses satellite gravity measurements to create two independent estimates of ocean heat - both find warming. Sea level has been inexorably rising since 2003. As a large portion of sea level rise is due to thermal expansion from ocean warming, this is an indirect confirmation of warming.

Lastly, the planet's energy imbalance is confirmed by satellite measurements of incoming and outgoing radiation. Earth's Global Energy Budget (Trenberth 2009) examines satellite measurements for the Mar 2000 to May 2004 period and finds the planet is accumulating energy at a rate of 0.9 ± 0.15 W m?2. This is consistent with the amount of heat accumulating in the ocean. Preliminary analysis on the latest CERES satellite data shows an increasing energy imbalance from 2004 to the end of 2008 (although this data is yet to be published, more on this later).

So the point to remember when considering short term cooling trends in surface temperature records is that the atmosphere is only one small part of a planet which is in energy imbalance. Empirical measurements show the planet continues to accumulate heat. More energy is coming in than is radiating back out to space. Global warming continued past 1998 and is still happening.

Acknowledgements: Many thanks to Dan Murphy for graciously sharing his heat content data and John Cross for his comments and advice.

0 0

Printable Version  |  Link to this page

Comments

1  2  Next

Comments 1 to 50 out of 84:

  1. John, Great post. It really puts us humans in perspective, does it? If .9 W/m2 translates into 190,000 GW power plants, the more than 340 W/m2 of total solar irrandiance is a pretty big number.
    0 0
    Response: Don't fall into the "sun big, me small" trap. As far as the sun and climate is concerned, it's solar variations that make a change to our climate. If the sun is shining away at a steady 340W/m2 without changing and the climate was in equilibrium, then the Earth's global temperature wouldn't change - the energy coming in from the sun would equal the energy radiating back out and the planet would be in energy balance. However, if solar activity changes (eg - the sun gets hotter), then the energy coming in is greater than the energy out. The planet is in energy imbalance and starts accumulating heat. As it gets hotter, the energy it radiates back into space increases until it's back in equilibrium.

    The amount that solar activity changes is relatively small. The amplitude of the solar cycle is about 1 W/m2. This translates to a radiative forcing of about 0.25 W/m2 and is estimated to have an effect of around 0.1C on global temperatures over the 11 year cycle. Similarly, the long term changes in solar activity are relatively small - upper limits of radiative forcing from the Maunder Minimum until now place it at around 0.23 W/m2.
  2. Manuel, Are you implying the AGW warming is insignificant compared to the sun? When was the last time the sun managed to heat the earth at a rate of 0.9W/m2?
    0 0
  3. How We Know that the Planet isn't Warming Your first egregious error - as shown by Harrison and Carson – is that 20 to 30 years of increase in ocean heat content is not sufficient to determine longer term trends in systems with inherent multidecadal variability - such as has been shown repeatedly and consistently in ocean/atmospheric interactions. ‘Is the World Ocean Warming? Upper-Ocean Temperature Trends: 1950–2000 D. E. HARRISON NOAA/Pacific Marine Environmental Laboratory, and Joint Institute for the Study of the Atmosphere and Ocean, and School of Oceanography, University of Washington, Seattle, Washington MARK CARSON Joint Institute for the Study of the Atmosphere and Ocean, and School of Oceanography, University of Washington, Seattle, Washington JOURNAL OF PHYSICAL OCEANOGRAPHY (Manuscript received 25 July 2005, in final form 10 January 2006) ABSTRACT Subsurface temperature trends in the better-sampled parts of the World Ocean are reported. Where there are sufficient observations for this analysis, there is large spatial variability of 51-yr trends in the upper ocean, with some regions showing cooling in excess of 3°C, and others warming of similar magnitude. Some 95% of the ocean area analyzed has both cooled and warmed over 20-yr subsets of this period. There is much space and time variability of 20-yr running trend estimates, indicating that trends over a decade or two may not be representative of longer-term trends. Results are based on sorting individual observations in World Ocean Database 2001 into 1° _ 1° and 2° _ 2° bins. Only bins with at least five observations per decade for four of the five decades since 1950 are used. Much of the World Ocean cannot be examined from this perspective. The 51-yr trends significant at the 90% level are given particular attention. Results are presented for depths of 100, 300, and 500 m. The patterns of the 90% significant trends are spatially coherent on scales resolved by the bin size. The vertical structure of the trends is coherent in some regions, but changes sign between the analysis depths in a number of others. It is suggested that additional attention should be given to uncertainty estimates for basin average and World Ocean average thermal trends.’ The second error is in opportunistic evaluation of recent ocean heat content. Warming or cooling since 2003 in any of the studies mentioned is not significant. It is like saying that 2005 in the annual GISSTEMP record warmer than 1998 when the 2 results are well within error bounds. Scientific nonsense in other words – intended only to mislead and deceive an unsuspecting and naïve public. Physical oceanic evidence suggests cyclic warming and cooling and this has been linked to Hale periodicity in solar output. Please note especially the comment on amplification of weak solar signals. As an example – Solar Physics (2004) 224: 455–463 C _ Springer 2005 HALE CYCLICITY OF SOLAR ACTIVITY AND ITS RELATION TO CLIMATE VARIABILITY O. M. RASPOPOV1, V. A. DERGACHEV2 and T. KOLSTRO¨M3 Abstract The periodicity of climatic processes along the Russian Arctic Ocean coast has been studied by analyzing the tree-ring chronologies for the regions close to the northern timberline. The wavelet analysis of annual series of conifer tree rings for the period 1458–1975 has revealed climatic oscillations with periods of 20–25 years. The amplitudes and periods of climatic oscillations in the region of Russian Arctic Ocean proved to exhibit appreciable changes. Especially strong climatic variations in comparison with the recent ones were found to occur during the Maunder minimum epoch when the period of oscillations increased from 22–23 years to 24–29 years, and oscillations with periods of 15 years appeared. After the Maunder minimum, the periods of oscillations and their amplitudes again decreased, and the 15–16-year maximum disappeared. Analysis of solar activity based on of radiocarbon (14C) concentration in annual tree rings has revealed a similar pattern in changes of periodicity before, during, and after the Maunder minimum. This suggests that quasi-bidecadal climatic oscillations and variations in solar activity can be connected with each other. A possible solar forcing of periodic climatic processes and its nonlinear influence on the atmosphere-ocean-continental system are discussed. The intense quasi-bidecadal climatic oscillations can be, in all probability, interpreted as resulting from amplification of a weak solar signal in the atmosphere-ocean system that has its own noises whose frequencies are close to the 22–23-year solar cycles. It would be astonishing on other lines of evidence if the oceans were warming at all strongly. Observations (see Project Earthshine) show an increase in Earth albedo since 1999 of about 1% - or 2 W/m2. This followed a decline in albedo from 1984 to 1998 - equivalent to additional shortwave forcing of 3.7W/m2. It has been suggested that the amplification mechanism involves clouds – either as amplification of small changes in solar irradiance or in response to variation in atmosphere ionisation by cosmic rays. I refer also to Trenberth and Fasula who suggest that the ‘main warming between 1976 and 1998 from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.' How do we know that the planet isn't currently warming? Because neither the atmosphere or oceans are currently warming at all - a result that is utterly inconsistent with IPCC reporting regardless of the time period.
    0 0
    Response: So 30 years of warming oceans is not sufficient to establish a warming trend and yet alleged ocean cooling (which is doubtful considering all the evidence) over the last few years is sufficient to disprove IPCC reporting?
  4. re #3 Oh dear Robbo…that’s a horribly cherrypicked selection. Let’s have at one of your assertions “Trenberth and Fasula” (sic). Let’s compare what they said with what you said they said: Here’s what Trenberth and Fasullo said[***]:
    Global climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) are examined for the top-of-atmosphere radiation changes as carbon dioxide and other greenhouse gases build up from 1950 to 2100. There is an increase in net radiation absorbed, but not in ways commonly assumed. While there is a large increase in the greenhouse effect from increasing greenhouse gases and water vapor (as a feedback), this is offset to a large degree by a decreasing greenhouse effect from reducing cloud cover and increasing radiative emissions from higher temperatures. Instead the main warming from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.
    Here’s what Robbo pretended they said:
    I refer also to Trenberth and Fasula who suggest that the ‘main warming between 1976 and 1998 from an energy budget standpoint comes from increases in absorbed solar radiation that stem directly from the decreasing cloud amounts. These findings underscore the need to ascertain the credibility of the model changes, especially insofar as changes in clouds are concerned.'
    For some reason you’ve added the tiny phrase "between 1976 and 1998" to their abstract…..??? In fact Trenberth and Fasullo are commenting on the results of global climate models and their observations highlighted in their abstract relate to late 21st century effects. In fact (according to Trenberth and Fasullo) the absorbed solar radiation (ASR) has decreased through the middle to late 20th century (due to aerosolic effects amongst other things including clouds) and this has countered the enhanced greenhouse-induced warming to date. It’s expected to continue to do so through to about 2040 after which there is a marked increase in ASR that drives rather significant further warming through to 2100 [***] K. E. Trenberth and J. T. Fasullo (2009) Global warming due to increasing absorbed solar radiation Geophys. Res. Lett, 36, L07706 (abstract in blockquote above)
    0 0
  5. As well as the growing number of recent papers that demonstrate a continuing uptake of heat into the worlds oceans, the following paper has just been published: K. von Schuckmann F. Gaillard and P.-Y. Le Traon (2009) Global hydrographic variability patterns during 2003–2008 J. Geophys. Res. 114, C09007, doi:10.1029/2008JC005237 abstract below [***] This analysis indicates that if ocean heat content to a depth of 2000 m is assessed, that there has been a rather larger continued uptake of heat into the oceans (compared to, for example, the Levitus data that analyzes heat in the upper 700 m of the oceans; see Levitus data here) [***]abstract: Monthly gridded global temperature and salinity fields from the near-surface layer down to 2000 m depth based on Argo measurements are used to analyze large scale variability patterns on annual to interannual time scales during the years 2003–2008. Previous estimates of global hydrographic fluctuations have been derived using different data sets, partly on the basis of scarce sampling. The substantial advantage of this study includes a detailed summary of global variability patterns based on a single and more uniform database. In the upper 400 m, regions of strong seasonal salinity changes differ from regions of strong seasonal temperature changes, and large amplitudes of seasonal salinity are observed in the upper tropical and subpolar global ocean. Strong interannual and decadal changes superimpose long-term changes at northern midlatitudes. In the subtropical and tropical basin, interannual fluctuations dominate the upper 500 m depth. At southern midlatitudes, hydrographic changes occur on interannual and decadal time scales, while long-term changes are predominantly observed in the salinity field. Global mean heat content and steric height changes are clearly associated with a positive trend during the 6 years of measurements. The global 6 year trend of steric height deduced from in situ measurements explains 40% of the satellite-derived quantities. The global freshwater content does not show a significant trend and is dominated by interannual variability.
    0 0
  6. The addition '1976 to 1998' is relevant and placed in brackets to indicate that I added it - I obviously have to spell everything out or take the risk of silly and irrelevant comment. This is the only period of surface warming in the last 50 years - and the warming was associated with decreasing cloud from 1984 to 1998 as shown in the ISCCP records - about 3.7W/m2 increase of shortwave radiation from 1984. The surface temperature record shows cooling to 1975, warming to 1998 and cooling since. This is apparent in the monthly anomalies in any of the records. So we have had 22 years of net warming in the 50 year record. It is simply a fact of life. The IPCC is explicit is attributing most of the warming in the last 50 years to anthropogenic influences - and very little to natural variability. There is no strong heating or cooling in the ARGO record. These records are subject to endless revision despite which the evidence for heating and cooling is still not definitive. To claim that the evidence shows continued warming is nonsense. The conclusion is inescapable - there is no evidence of continuing ocean warming (or cooling) within the limits of error. However, there is an expectation of ocean heating and cooling in line with the scientific evidence for cyclic ocean states. You guys can continue to deny cyclic ocean states for as long as you like - it takes strength of character or an extreme foolishness not susceptible to evidence. Anything that shows complexity and uncertainty and challenges Chris' simplistic understanding is confidently labelled cheery picking. Some warming, of the oceans in particular, from 1975 to 1998, comes from changes in clouds. Amy Clements et al describe this as a positive global warming feedback. It has turned around however and is consistent with established patterns of multidecadal ocean cyclic states. Multiple lines of evidence rather than a stubborn refusal to accept evidence of anything that suggests a lower climate sensitivity to greenhouse gases. I am not skeptical at all - the question is how much warming was due to AGG and how much is natural variability. The only sensible way of approaching this problem is to consider net warming over a full cycle of 20 to 30 year warming and 20 to 30 year cooling. For the 1945 to 1998 period - this is a net warming trend of 0.08 degrees C/decade from all other factors - less than half of what is assumed by the IPCC. 20 to 30 years of an ocean warming record is not sufficient to disentangle natural cyclic variation on multidecadal timeframes from AGW. This is simply a scientific and statistical truth. Pointing to ocean warming in a rising phase and insisting that this proves something is nonsense. The lack of recent strong ocean warming is not consistent with climate forcing as determined by the IPCC. Surface warming has not been 0.2 degrees C/decade over the last decade as predicted by the IPCC - you can rabbit on about natural variability without being specific at all - and project vastly increased warming in future decades - or you can look for the causes of natural variability operating now and in the recent past and consider rationally the implications for AGW theory. This is why the lack of recent ocean and atmospheric warming falsifies IPCC theory – it is simply not consistent with the Earth energy budget with the theorised forcing – it is a problem that requires reanalysis of the forcing rather than pillorying of anyone who has the temerity to suggest that the emperor’s clothes are in tatters. It is entirely reasonable to expect – as with Swanson and Tsonis, Keenlyside etc – a lack of global ocean or atmospheric warming for 20 to 30 years from 2000.
    0 0
  7. Oh well Robbo, in order to make your point you have to tell porky pies. Two lies now. First you took a paper whose observations and analyses are completely at odds with your non-scientific position...and inserted a phrase into the abstract to pretend that the paper agreed with your false analysis. And now you say that: "The addition '1976 to 1998' is relevant and placed in brackets to indicate that I added it." But that's obviously not true as inspection of your post #3 clearly shows. You put the entire (nearly) two sentences in brackets two signify that the section was a direct quotation (which it almost is as can be seen from my reproduction of what Trenberth and Fasullo actually wrote). You didn't place your sneaky and false addition in a seperate bracket to indicate that you added it, at all. Surely if you have to tell porkies to attempt to shore up a position, there is something seriously wrong with your point of view...at the very least it's not a scientific one. Just to be very clear the paper that you have attempted to misrepresent (Trenberth and Fasullo) analyzes models to determine the attribution of warming from 1950 through to the end of the 21st century. They find, in complete contradition to your false assertion, that during the period 1976 to 1998, the absorbed solar radiation (ASR) has decreased, and thus this has ofset some of the anthropogenic greenhouse-induced warming. This is largely the result of enhanced aerosolic screening. This situation is expect to persist up to around 2020-2040 after which absorbed surface radiation will increasingly dominate accumulating surface warming in greenhouse-enhanced world. Note that the published evidence indicates that the oceans are continuing to take up heat as expected in a warming world [see papers cited in the top article and also the von Schuckmann et a (2009)] paper in my post #5. Note also that you've misunderstood Swanson and Tsonis and Keenleyside, both of whom are pretty mainstream with respect to scientific understanding of the earth's response to enhanced athropoenic greenhouse forcing. The world is going to get a whole lot warmer in both of their analyses. To be specific: Keenlyside et al. [*] These authors use a model that incorporates analysis of sea surface temperatures and estimates of ocean current effects to make hindcasts and forecasts. They project (see their hindcast/forecast in their Figure 4) that a rather marked surface warming of around 0.5 oC in the period 2010 and 2025. Swanson and Tsonis [**] It's worth looking at the most recent paper on his subject by these authors. They analyze 20th century surface warming and attributons to "tease out2 anthropogenic greenhouse forcing contributions and natural variation. The conclude that the anthropogenic forcing has been (and continues to be a monotonic, accelerating warming during the 20th century). This has been modulated by natural contributions, especially ocean current effects on surface temperature, the net contribution of which to 20th century warming has been close to zero. These authors remark on the possibility that natural variation might result in a suppression of surface warming for a period. However they also point out that "However, global warming could likewise suddenly and without any ostensive cause accelerate due to internal variability.". None of this contradicts our understanding of the earths temperature response to enhanced greenhouse forcing, although recent analyss does reinforce the expectation that the time progression of warming is modulated by natural fluctuations. [*] N. S. Keenlyside et al. (2008) Advancing decadal-scale climate prediction in the North Atlantic sector Nature 453, 84-88 http://www.nature.com/nature/journal/v453/n7191/abs/nature06921.html [**]K. L. Swanson, G. Sugihara, and A. A. Tsonis (2009)Long-term natural variability and 20th century climate change. Proc. Natl. Acad. Sci. USA (in press) http://www.pnas.org/content/early/2009/09/09/0908699106.abstract
    0 0
  8. Robbo: You said "The surface temperature record shows cooling to 1975, warming to 1998 and cooling since. This is apparent in the monthly anomalies in any of the records." I would disagree with this. For example if you look at the GISS record you can not pick a starting point in 1998 that gives you a slope of less than 0.098 C/decade (increasing). Also, but I am not sure I followed your comments about the IPCC projections for warming trends. However, as Deep Climate shows here the trends are actually quite accurate. Regards, John
    0 0
  9. One of my very first science lessons from the school yard was that you couldnt create or destroy matter. Then at some later point in time, I learned that the same applied to energy. If you cant destroy energy, where does all that excess heat from human activities go? Thanks to God, heat radiates into outter space, (and by the way, the rate of blackbody radiation is nonlinearly proportional to temperature. This helps us stay cool globally speaking, but it is very possible for some heat to accummulate, all depending on overall comparative rates. I agree with this article that the oceans would be the ultimate storage area for this excess energy given the associate volume, fluidity and heat capacity. Furthermore, probably the best way to know if there is Global Warming is to track ocean temperatures. That said, I find myself in the skeptics camp as far as believing that Global Warming is due to CO2. I believe that Global Warming is real, not only because of the type of data presented in this article, but as I am 50 years old, I have noticed the effects of climate change directly in a variety of locations around the world. In most ways, these changes have been for the worst, however it may be just a matter of maladaptation. I cant imagine more prosperity coming from an ice age. The reason I do not believe the greenhouse theory even after attending Al Gores seminar live, is that CO2 comprises such a small fraction of the mass of our atmosphere, something like .04%. I have a very hard time believing that such a small fraction of the total atmospheric mass could possibly contribute to runaway greenhouse warming. The greenhouse theory as purported by Al Gore is that the full spectrum of radiative solar energy makes its way through the atmosphere warming objects on the Earth. These objects on the Earths surface later radiate heat back in the form of IR. CO2 in the atmosphere then absorbs the IR warming it such that the incremental CO2 due to fossil fuel burning is causing what we are perceiving as Global Warming. For one thing, since the 1970s we were supposedly going to run out of fossil fuels by the year 2050. Not sure why then this is a problem?? But that is besides the point. It turns out that a lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere? I do not deny IR can be absorbed by CO2 at groundlevel, however this effect should be compensated in kind by 1) the same mechanism in the upper atmosphere blocking IR coming from the Sun. 2) a general increased rate of cooling up there due to the nonlinear nature of black body radiative mechanisms. But what seems to weigh against CO2 as the ultimate culprit for Global Warming is simply the compartively small percentage that CO2 represents in terms of its overall mass next to other atmospheric gaseous components. So what is causing Global Warming if it is not CO2? That appears to be the million dollar question. I for one (skeptic) believe it is simply the increased rate of human activities (generally speaking exothermic) on top of any possible fluxuation that may be due to nature.
    0 0
  10. RSVP wrote: "A lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere?" Answer: The radiation blocked by CO2 is mostly long-wave IR, not the full spectrum of IR. The radiation coming from the Sun is a lot of wavelengths other than long-wave IR, which make it past the CO2 on the way down. Those other wavelengths of radiation from the Sun are absorbed by the Earth and the energy contained in those wavelengths is re-emitted by the Earth as long-wave IR, which the CO2 blocks (well, absorbs and re-emits, actually).
    0 0
  11. "Swanson and Tsonis [**] It's worth looking at the most recent paper on his subject by these authors. They analyze 20th century surface warming and attributons to "tease out2 anthropogenic greenhouse forcing contributions and natural variation. The conclude that the anthropogenic forcing has been (and continues to be a monotonic, accelerating warming during the 20th century). This has been modulated by natural contributions, especially ocean current effects on surface temperature, the net contribution of which to 20th century warming has been close to zero. These authors remark on the possibility that natural variation might result in a suppression of surface warming for a period. However they also point out that "However, global warming could likewise suddenly and without any ostensive cause accelerate due to internal variability.". I think the point is that GW has (most likely) already accelerated due to internal variability from the late 70s to the late 90s and is now decelerating. IMO, the most likely cause for this is the shift in PDO regimes. Cheers, :)
    0 0
  12. RSVP, it does not add up. There is not enough energy emitted by human made exothermic activities to achieve what's been observed. By far.
    0 0
  13. RSVP -- don't you think that if human exothermic activities were responsible, the warming would be greatest near the largest sources of those activities? Instead the Arctic shows the most warming and alpine glaciers are melting. As for something in low concentrations having a large effect, think of DDT, CFCs, ozone, stratospheric sulfur, etc.
    0 0
  14. To Tom Dayton: Are you implying that all IR emitted by Earth heat resonates with IR absorption wavelenghts? I dont think you are, and I have seen the aborption spectrum of IR which is relatively narrow. To Stevel L: I started my entry saying that energy cannot be destroyed. I hold my ground. The atmosphere accumulates energy from all people in all nations carrying it all around the world. The first place you will notice Global Warming is in the Artic and the Alps. That does not mean that it started there. Next time you get to a stoplight, if you turn off your engine, you will help delay Global Warming. About as long as it takes the light to turn green.
    0 0
  15. RSVP wrote: "A lot of the incident energy coming from the Sun is also IR. How does this energy make its way down to the Earths surface if it is blocked by CO2 in the upper atmosphere?" Answer: The radiation blocked by CO2 is mostly long-wave IR, not the full spectrum of IR. The radiation coming from the Sun is a lot of wavelengths other than long-wave IR, which make it past the CO2 on the way down. Those other wavelengths of radiation from the Sun are absorbed by the Earth and the energy contained in those wavelengths is re-emitted by the Earth as long-wave IR, which the CO2 blocks (well, absorbs and re-emits, actually).
    0 0
  16. RSVP: Of course I am not implying that all IR emitted by Earth is absorbed by CO2! It doesn't matter that not all of it is absorbed. What matters is that enough is absorbed to make a difference.
    0 0
  17. RSVP wrote: The reason I do not believe the greenhouse theory even after attending Al Gores seminar live, is that CO2 comprises such a small fraction of the mass of our atmosphere, something like .04%. I have a very hard time believing that such a small fraction of the total atmospheric mass could possibly contribute to runaway greenhouse warming. Answer Part 1: You shouldn't focus on the fraction of the atmosphere that CO2 comprises, because it is not relevant all by itself. You need to combine that fraction with the number of molecules of all kinds that are in the atmosphere, and with how much volume they fill in between the ground and outer space, to come up with the number of CO2 molecules sitting in front of a long-wave IR photon leaving the ground headed toward outer space. The bottom line is the probability of a long-wave IR photon hitting a CO2 molecule before making it from the ground to outer space. (Okay, it's also important how close to this CO2 molecule, are the other CO2 molecules that could capture the photon emitted by this molecule, but that doesn't change the essence of the answer to your question.) For example, Mars has a much higher fraction of CO2 than Earth does, but the total number of molecules of all kinds in the Martian atmosphere is so much smaller than in the Earth's atmosphere, that far fewer CO2 molecules sit between the Martian ground and outer space, than between Earth's ground and outer space. So the Martian atmosphere traps far less long-wave IR emanating from the ground, than the Earth's atmosphere does. That's one reason Mars is much colder than Earth. So contrary to your intuition, the fraction of the atmosphere that CO2 comprises is in fact sufficient to trap long-wave IR enough to cause significant warming. The amount of trapping is not just theoretical. For more than a hundred years, scientists have been filling tubes with various mixtures of gasses, sending IR radiation through those gas-filled tubes, and measuring how much gets through to the end of the tube. They've also measured IR transmission in the atmosphere at multiple heights. You might wonder that if the fraction by itself is not relevant, why do climatologists talk about CO2's level in the atmosphere in terms of parts per million (PPM)? That's a convenience that suffices because the other factors that I wrote in my first paragraph are, for practical purposes, constant for the Earth. Answer Part 2: With regard to global warming, it's not even the absolute number of CO2 molecules currently present that is important. Rather, the change in number of CO2 molecules is important, because it's the change in the temperature that is the problem. The change in CO2's PPM since the 1800s is huge--an increase of one third! The change in the amount of heat trapped by that extra CO2 is correspondingly large (though not exactly the same amount of change--its more complicated than that). Answer Part 3: The greenhouse warming on Earth is not and will not be "runaway." Probably you were using that term loosely to mean "increasing at an increasing rate." But you shouldn't use that term, because it really means increasing at an increasing rate due to positive feedbacks that feed back at ratios greater than 1. The Earth's CO2-caused greenhouse effect instead always stops feeding back, because the feedbacks (e.g., CO2 causes warming which causes more water vapor which causes more warming which causes more water vapor,...) cause increases smaller than the increases that triggered them. The feedbacks cause the temperature increase from adding a unit of CO2, to be larger than the temperature increase just from the CO2 itself. But that amount of heating due to a unit of increase of CO2 is finite, not infinite. You can think of the feedbacks as a finite amplifier of CO2's heating effect. The reason the temperature keeps increasing year after year is not that the feedbacks run away, but that we keep adding CO2 to the atmosphere year after year.
    0 0
  18. Tom Dayton wrote: "The amount of trapping is not just theoretical. For more than a hundred years, scientists have been filling tubes with various mixtures of gasses, sending IR radiation through those gas-filled tubes, and measuring how much gets through to the end of the tube." Would you know of a link that points to these results? What I have seen are graphs comparing IR absorption between gases, but I have never seen a graph that shows steady state temperature vs. concentration around the values of CO2 that we are talking about. With a fixed IR source in a controlled environment, I would assume this would be very telling. My expectation is that any measurable increment in temperature will be directly proportional to the incremental percentage of CO2 with respect to the nominal steady state temperature, which of course would always be smaller for higher temperatures. --------------------------------------------- Moving on... Another way to look at the issue of CO2 is to invert the concept of a lossy system. Imagine that the only energy trapped by the Earth was due to CO2. If so, then the doubling of CO2 in the atmosphere regardless of the concentration would most likely double the heat retention. We know however that CO2 is NOT the only thing that holds onto heat. Heat is stored in the oceans, mountains, buildings, and 98% of the gas that you and I breath everyday. I am getting ahead of myself without the data from the test I described above, but doesnt it make you a little suspicious that CO2 levels have been tracked for the last 100 years somewhere on the top of a volcano in Hawaii? Nothing wrong with this in general, but I get the feeling its as if someone out there needs to justify the data taking, and if we were into Global Cooling, someone would be making an argument that the cooling was due to CO2. Here's my real theory... There is a correlation between soda pop drinkers and those that believe in global warming. The extra CO2 is lodging between their brain cells and causing their body temperatures to rise ever so slightly.
    0 0
  19. RSVP re: "..... but doesnt it make you a little suspicious that CO2 levels have been tracked for the last 100 years somewhere on the top of a volcano in Hawaii? Nothing wrong with this in general, but I get the feeling its as if someone out there needs to justify the data taking, and if we were into Global Cooling, someone would be making an argument that the cooling was due to CO2." Knowledge is the scourge of suspicion RSVP, and if one is really interested in atmospheric CO2 measurements one should know that Mauna Loa is only one of a large number of sites for monitoring of atmospheric greenhouse gases. Analysis of atmospheric CO2 data from many different parts of the world gives a very consistent measure of this atmospheric gas: http://gaw.kishou.go.jp/wdcgg/wdcgg.html Additionally, one should know that atmospheric CO2 levels are continuously monitored remotely by satellite, nd these measures are entirely consistent with atmospheric CO2 measured at Mauna Loa and elsewhere: http://photojournal.jpl.nasa.gov/jpegMod/PIA11194_modest.jpg Of course no informed individual "would be making an argument that the cooling was due to CO2", since CO2 is well understood to be a greenhouse gas, the increased concetration of which drives the Earth's surface temperature towards a higher equilibrium value (all else being equal of course). I can't think why anyone would attempt to make arguments that are completely opposed to basic physics and empirical and theoretical consideration!
    0 0
  20. Chris wrote: "I can't think why anyone would attempt to make arguments that are completely opposed to basic physics and empirical and theoretical consideration!" When a train on an east west rail starts or stops, its change in velocity affects the Earth's rotation. That is what the physics says. No one is concerned with this problem because the mass of the train next to the Earth is minute. The argument is quantitative, not qualitative. Aside from my bad joke about cola, I will admit that I expressed my self poorly when I made that reference to a lossy system. (Perhaps if you are non skeptic, it wont matter.) What I was trying to say was that if CO2's job conceptually was to trap the Sun's energy, and any energy that it did not trap was considered a loss, I would agree that the energy trapped would be in direct proportion to the increase in CO2's numeric concentration, no matter how small its concentration was. But, as we know, there are many more factors that cause the Sun's energy to be retained, including the rest of air's chemical components. In fact, when CO2 is produced through combustion, oxygen is removed or displaced in this reaction. What do you think CO2 is warming up anyway? It is passing heat convectively to the nitrogen and oxygen that surround it. I am not denying that CO2 is a contributor to Global Warming, however I would like to see meaningful data before concluding that it is the main culprit to this problem. The kind of testing I described above would be a good starting point.
    0 0
  21. RSVP, the history of the discovery of CO2's effect answers a couple of the questions you've asked here, and anticipates questions that you'd likely ask next. See Spencer Weart's The Discovery of Global Warming, the section The Carbon Dioxide Greenhouse Effect. I think your time in asking individual questions would be saved by reading some short overviews that answer many of those questions at once and in context. A excellent one is cce's The Global Warming Debate. In that particular site, the section 1. Primer and History covers CO2's absorption of radiation, with links to online versions of the sources of that info; in some cases you'll want to go to the links on those linked sources to see the actual scientists' publications. But I strongly recommend you read the entire site, not just section 1. See also A Saturated Gassy Argument, which is a posting on RealClimate. Another good resource, though not as integrated as cce's site, is RealClimate's Start Here section.
    0 0
  22. Just for the sake of clarity and proper conception of what is going on when greenhouse gases absorb IR radiation, it must be stated that nothing is trapped as is commonly stated. The radiation absorbed ceases to exist, having been converted to kinetic energy of the molecule. This energy is then emitted again by the molecule as IR radiation or the newly acquired kinetic energy is transfered to adjacent molecules, O2, N2 etc.. The atmosphere is warmed. Adjacent greenhouse gas molecules again absorb the proper resonant radiation countless times and emitted in all directions, some up and some back down. If the atmosphere were transparent to IR it all would escape from the surface to space unimpeded, but due to greenhouse gases the energy is slowed in that escape by countless repeated absorptions and emissions of IR. Nothing is trapped, the flow of outward energy is constant but slowed by countless repeated absorptions and emission.
    0 0
  23. Good reminder Weather Rusty. I think the best, shortest, clearest description was given on RC by one of the contributors: the greenhouse effect impairs the cooling of the surface. Increased GH effect means higher equilibrium temperature. It's rather simple. Thinking of it this way also shoots down all the silliness about the 2nd law of thermodynamics that some throw in for more confusion.
    0 0
  24. "Thinking of it this way also shoots down all the silliness about the 2nd law of thermodynamics that some throw in for more confusion." Absolutely...It is the surface that warms the atmosphere. Earth's average surface temperature at 288K is some 33K degrees warmer than the equilibrium black body temperature of Earth as viewed from space at 255K. The 255K emission is on average given from high in the troposphere (~16,000'), without an atmospheric greenhouse effect the 255K emission would come from the surface. The stronger the greenhouse effect the higher in the troposphere is the 255K emission. The atmosphere does not warm the surface because it is warmer than the surface (it isn't), it does so by inhibiting cooling of the surface. The loss of thermal energy continues outward toward space on average, a cooler atmosphere is not radiatively warming a warmer surface which would violate the Second Law. Sorry if this seems off topic.
    0 0
  25. To Tom Dayton... I have gone to the sites you posted and these bring a lot to the table. Almost too much, in that there is an overriding sense when reading it that even the experts cant agree with each other. For instance, the bit on whether IR absorption saturates, and inacceptance of extensive and laborious computer modeling, etc. At any rate, what I find all this quibbling really points to is that the effect of CO2 on global warming is not violent in the way volcanic eruptions have plunged the Earth into ice ages. In fact, with all the endemic global warming you can imagine from CO2, the effects of a single volcanic eruption could leave us all freezing and starving to death from lack of vegetation within a growing season. Given the theory that average temperatures depend on such a fragile balance of the sunlight's heat, (and with so many experts abounding), it should be a no brainer to explain how exactly the Earth comes out of an ice age without going past a point so hot that it becomes inhospitable to life???? as there seems to be hard feedback mechanisms that take the Earths temperature up from ice ages and hold it steady past this point and others that are ignored when referring to the effects of CO2. Or is CO2 in charge of everything? My last little word would be that it might make some sense that CO2 concentrations as discovered in ice core samples correlate not because CO2 drives temperatures around, but because living organisms that produce CO2 do better when things warm up.
    0 0
  26. Revising wording from above... ...it should be a no brainer to explain how exactly the Earth comes out of an ice age, and what keeps it from warming to a point so hot that it becomes inhospitable to life???? Please use delicate sunlight balance theory.
    0 0
  27. RSVP: You have not read those sites carefully enough. The experts do agree with each other. And the other issues you just now raised are dealt with in those sites, as well as here on the Skeptical Science site. (Click on "View All Arguments" at the bottom of the thermometer at the top left of this page.) You need to read those sites. All the way through. It won't take long, even if you read thoroughly. Hold your questions until you've read all that material.
    0 0
  28. ANYONE can say, "hold your question until youve read all that material" to ANY QUESTION. That is a copout! ANSWER THE QUESTION! By the way, in a GREENHOUSE, light is REFLECTED BACK into the chamber. CO2 ABSORBS IR! It CONVECTS energy into the surrounding mass of air around it. Thus the observation that it would saturate. And if it happens to re-radiate, the radiation is isotropic unlike the surface of glass in greenhouse which points the light downward. Now please use the delicate balance theory to explain how the Earth comes out of an Ice Age, without skirting the question::::
    0 0
  29. Just visiting briefly today -- rsvp, I don't really understand what you're asking. I half gave up on trying to understand you when you replied to my question in 14 with a bunch of nonsense about people carrying the energy all around the world such that the Arctic is the first place we should notice warming. But with the all caps and exclamation marks, it seems very important for you to get an answer to your question. Try laying out your reasoning and asking the question again. PS. I agree with Tom that you should do more reading. Right now you're diluting potentially interesting questions (we'll see) with junk about greenhouses being inadequate analogies for the enhanced greenhouse effect (which is old, well-known, and irrelevant).
    0 0
  30. To Steve L. For one thing, I dont think it is so inappropriate to point out that the term GREENHOUSE is misnomer. The point here, is that the term was chosen based on a hypothesis, not a theory. If the hypothosis turns out to be in error, keeping the name around only creates more confusion, which apparently is what many people appear to be thiving on. As far my nonsense. I was saying that energy pollution from an automobile for instance is cummulative in a global sense, and if not lost into outer space spreads out wherever the wind takes it. The edges of glaciers and ice caps are the easiest places to observe the effects of global warming. And for the third time my question. The question is simple. What caused ice ages to end? If the Earth maintains a delicate equilibrium as per the CO2 greenhouse model, why in the absense of fossil fuel burning did the temperature of the Earth rise? And why did it stop rising? or did it stop? I hope I did not loose you this time.
    0 0
  31. RSVP asked "What caused ice ages to end?" Orbital mechanics (a.k.a. Milankovitch cycles) followed by feedbacks such as greenhouse gases and ice and snow. At the top left of this page, click the link "Climate's Changed Before." Also see the section titled Milankovitch cycles (finally) explained on this page of cce's "The Global Warming Debate" site.
    0 0
  32. Well, I guess what's appropriate depends to some degree on what the topic of the post is and whether or not anybody is relying on a particular bit of misinformation (eg from a misnomer) to support an argument. You're not going to get rid of the name -- too much history, etc, and I don't think anybody here gets confused by it (who is thriving upon it?). But, whatever, it was just a PS. Your response regarding your nonsense is also worthy only of a PS. Wind doesn't concentrate heat at ground level thousands of km from global point point sources. Further, it takes more heat to melt ice than to raise air temperature, so for this and other reasons I dispute your assertion that the Arctic and alpine glaciers are the easiest places to detect global warming. Finally, on to your question. Don't worry, this time I didn't get loost. Response 1: That's your question? Then what about all that other stuff about "inhospitable to life". I was going to refer you to PETM. Response 2: What don't you like about any of the internet resources already available that explain the end of ice ages? Check out "ice ages" or "Milankovitch" on Wikipedia. Response 3: Google didn't find much with "delicate sunlight balance theory".
    0 0
  33. A real glass greenhouse interior is warmed more by the suppression of convection between the interior and exterior by the glass barrier than by absorption of IR by the glass. The tropopause between the troposphere and stratosphere is a barrier to convection also due to a temperature inversion. Nearly all energy leaving the troposphere and most leaving the glass of a greenhouse is in the form of radiation. This is why the forcing for a doubling of CO2 (3.7W/m^2) is measured from the tropopause I believe. When have volcanic eruptions sent the Earth into Ice Ages?
    0 0
  34. A real glass greenhouse interior is warmed more by the suppression of convection between the interior and exterior by the glass barrier than by absorption of IR by the glass. The tropopause between the troposphere and stratosphere is a barrier to convection also due to a temperature inversion. Nearly all energy leaving the troposphere and most leaving the glass of a greenhouse is in the form of radiation. This is why the forcing for a doubling of CO2 (3.7W/m^2) is measured from the tropopause I believe. When have volcanic eruptions sent the Earth into Ice Ages?
    0 0
  35. Socrates said, I know I know nothing. (You can even argue about what he really said). My understanding of this statement is that you cant really know anything for sure. I find the spirit of this discussion poisoned by fanaticism, as opposed to skepticism. It is one thing to assert that CO2 has the effect of trapping solar energy, and quite another to conclude that it is the main cause of global warming. Why even bother to continue investigating this subject? Its a done deal. It should be a crime to burn fossil fuels. I suppose that is coming. If not, for sure the price of oil will be going up, and the question of who is thriving on it will be a little more clear. To answer WeatherRusty The major ice ages precede recorded history, but there have been periods of strong cooling in recent times. http://www.drgeorgepc.com/Volcano1883Krakatoa.html Here is an abstact from this article. ---------------------------------------- Upper Atmosphere Effects Ash from the eruptions was propelled to a height of 50 miles (80 kilometers) in the upper atmosphere blocking the sun and plunging the surrounding region into darkness for two and a half days. Climatic Changes It has been estimated that at least 21 cubic Km (appr. 11 cubic mile) was ejected from the eruption of Krakatoa and that at least 1 cubic mile of the finer material was blown to a height of about 17 miles (27 Km). The volcanic dust blown into the upper atmosphere was carried several times around the earth by air currents. This volcanic dust veil not only created the spectacular atmospheric effects described previously but acted also as a solar radiation filter, reducing the amount of sunlight reaching the surface of the earth. In the year following the eruption, global temperatures were lowered by as much as 1.2 degree Centigrade on the average. Weather patterns continued to be chaotic for years and there were major climatological changes which affected the entire globe. Temperatures did not return to normal until five years later, in 1888. ------------------------------------- Whether this was an ice age or not, my question remains. After this cooling, what brought the temperature back to "normal"? This is not directed to anyone in particular, especially readers who only believe a thing is true if it can be answered by a Google search. Preferably a person who can think independently. What brought the temperature back to "normal"?
    0 0
  36. Steve L wrote... "Wind doesn't concentrate heat at ground level thousands of km from global point point sources. Further, it takes more heat to melt ice than to raise air temperature, so for this and other reasons I dispute your assertion that the Arctic and alpine glaciers are the easiest places to detect global warming." It's not about what you can measure, although I can possibly understand the temptation. I was referring to a physics concept not a meteorological concept. The physics concept being that you cant destroy energy and then applying this to a closed system called Earth. The first place you might notice the effects would be in a snow line etc. The method I am using to deduce this possibility is called thinking. Independent thinking as opposed to Googling.
    0 0
  37. RSVP asked what brought the temperature back up to "normal" after the Krakatoa eruption. Answer: The falling out of the atmosphere, of the solar-radiation-reflecting aerosols that the volcano had thrown into the atmosphere. Technically, it's not simply a matter of gravity causing the aerosols to fall out; that is one contributor, but other processes also contribute to the rapid removal of those aerosols. See the page It's volcanoes (or lack thereof) here on the Skeptical Science site for more info. That page contains references to peer-reviewed scientific publications from which you can get all the details you care to see. Or you can go to the US Geological Survey's site, because studying volcanoes is one of their primary jobs. They even have a page titled Volcanoes and Global Cooling. Even more detail is at the USGS page Volcanic Sulfer Aerosols Affect Climate and the Earth's Ozone Layer.
    0 0
  38. RSVP said: "Socrates said, I know I know nothing. (You can even argue about what he really said). My understanding of this statement is that you cant really know anything for sure. I find the spirit of this discussion poisoned by fanaticism, as opposed to skepticism." Science is a logical methodology employed to aid in our understanding of the world. It works rather well, we have learned a great deal of how the world works even if that knowledge is incomplete. We understand quite well the physics as to how material objects are warmed and cool. The Earth is just a body floating in space and warms and cools based on the same physics as any other body. Scientists have much of this figured out. It is not like we know very little, to the contrary what we know is demonstrably the essence of what is responsible for the warming and cooling of Earth. What we don't know very well are some of the details, but the big picture is rather clear. The Earth is warming as a matter of empirical observation and the basic physics as to why that is occurring are well established. This gives us a logic basis for an expectation for a continuation of that warming and an estimation of what that warming will be, allowing for the uncertainty inherent to the less well understood details. What you view as fanaticism derives from a strong confidence in well established physical principles as they are applied to the issue of climate change.
    0 0
  39. RSVP said: "Socrates said, I know I know nothing. (You can even argue about what he really said). My understanding of this statement is that you cant really know anything for sure. I find the spirit of this discussion poisoned by fanaticism, as opposed to skepticism." Science is a logical methodology employed to aid in our understanding of the world. It works rather well, we have learned a great deal of how the world works even if that knowledge is incomplete. We understand quite well the physics as to how material objects are warmed and cool. The Earth is just a body floating in space and warms and cools based on the same physics as any other body. Scientists have much of this figured out. It is not like we know very little, to the contrary what we know is demonstrably the essence of what is responsible for the warming and cooling of Earth. What we don't know very well are some of the details, but the big picture is rather clear. The Earth is warming as a matter of empirical observation and the basic physics as to why that is occurring are well established. This gives us a logic basis for an expectation for a continuation of that warming and an estimation of what that warming will be, allowing for the uncertainty inherent to the less well understood details. What you view as fanaticism derives from a strong confidence in well established physical principles as they are applied to the issue of climate change.
    0 0
  40. RSVP, "a closed system called Earth." Do you really mean that?
    0 0
  41. Tom Dayton answers my earlier question, "what brought the temperature back up to "normal" after the Krakatoa eruption." The answer unfortunately is not consistent with the radiation budget of greenhouse models that imply that without a net surplus of radiative energy (as in the case of extra CO2 in the atmosphere) average temperatures should remain at steady state. The model is oversimplied of course, which is the whole point of the question. An analogy may help visualize things. Assume you have a 5 gallon jug vessel containing 3 gallons of water. Water is dripping into the jug from a faucet at the same rate being lost through a hole at the bottom of the vessel, (assume no evaporation). Under these conditions, the level remains at 3 gallons forever, until one day, 1 gallon is removed. All things being equal in terms of flow rates, the level then stays at 2 gallons. There is no reason for the level to return to 3 gallons. At least I have not given one. Likewise, the greenhouse global warming theory assume equilibrium that is disrupted by CO2 levels rising. Without this happening, the Earths average temperatures would remain exactly where they are forever. And applying this same simple incomplete model to the situation after the Earths temperature drops from a volcanic explosion, it should remain low forever as well. You did not explain where the extra energy comes from to get the temperature back to "normal", nor did you explain why it should stop rising when it gets to "normal".
    0 0
  42. Philippe Chantreau at 17:40 PM on 4 October, 2009 RSVP, "a closed system called Earth." Do you really mean that? --------------------------------- The expression is appropriate given that we are considering the Earth as a whole and a discussion that presupposes no changes in solar activity (which of course is not true).
    0 0
  43. WeatherRusty said What you view as fanaticism derives from a strong confidence in well established physical principles as they are applied to the issue of climate change. ------------------------------- What I view as fanaticism is OVER confidence in theories that are based on well established principles. 1 degree divided by 300 K = .003333 0.3% is in the noise, and is due to many factors.
    0 0
  44. RSVP, your water jug analogy is incorrect. The aerosols increasing and decreasing due to a volcano are instead the equivalent of a valve decreasing and increasing the flow of water into the jug. CO2 increasing is like moss growing in the hole at the bottom of the jug, reducing the flow of water out of the jug.
    0 0
  45. I have no idea why my posts are in duplicate, I hit submit only once. RSVP, "1 degree divided by 300 K = .003333" 288 K is the average surface temperature of Earth and nearly all of that is due to radiation received from the Sun including 33 K amplification due to the greenhouse effect. "0.3% is in the noise, and is due to many factors." The "noise" is not random...it is forced and the job of science is to quantify the forcing. The ~1 K increase is part of a long term trend forced by 1.6W/meter^2 increase in radiative forcing, much of which is being absorbed by the oceans.
    0 0
  46. WeatherRusty, the duplication of your entries is due to your browser (or the server?) retaining the code for posting your comment, even after the page has reloaded to show your comment. When you reload that page by clicking your browser's reload button, that same code for posting gets sent again. It's happened to me multiple times (sorry, everybody). You might get an alert box after you click the reload button, warning that the browser will "repost" or somesuch phrasing. If you see that, click the Cancel button in that alert box. To avoid all the above, I suggest that after you post, you go to any other page, which will force the posting code to be flushed.
    0 0
  47. In the analogy of the water jug, the level of the water is the Earths temperature. Water dripping in is incoming radiation. Water flowing out is outgoing radiation. If outflow is reduced the level will rise. I dont think this is different from the idea that CO2 is causing less heat to escape the Earth. Now assuming a perfectly balanced flow situation for the jug where the level never changed at 3 gallons, this would be analogous to a level of CO2 in the atmosphere wherever nature had it say 500 years ago or so. But now someone comes along and removes one gallon, which would be like volcanic ash blocking the sun in a big way for 3 years. The two gallons left would be like the temperature of the Earth dropping to say ice age conditions. As I describe, there is no reason for the water level to come back to 3 gallons. It will remain at two gallons forever unless the flow rates are altered. Similarly, after ten years, all the volcanic smoke clears, and the atmosphere is pristine again. The sun shines as before, and the processes preceding the eruption take over. The temperature should stay where it is. So far, no one has provided an answer that explains why global temperatures go back to "normal" in terms of the CO2 mechanisms described to explain recent global warming. An explanation of this type would require excess CO2 following the eruption, and CO2 subsequently reducing over time to reach stasis. However, the data supposedly shows the opposite. That CO2 rises when the Earth warms.
    0 0
  48. RSVP, you are correct that if the Earth's input and output were in equilibrium before and after the temporary reduction in input, then afterward the system would indeed remain at a lower temperature. But the Earth's (the whole thing including the atmosphere, seen from outer space) input and output were not in equilibrium before, say, Mt. Pinatubo's eruption. The input was outpacing the output. (The water level in the jug was increasing.) This is where the jug analogy breaks down, because the Earth's rate of output to space increases with the temperature of the Earth. You'll have to pretend that the jug's hole lets more water out the more water is in the jug. The Earth's temperature was on its way up toward a new equilibrium output to suit its new, higher, equilibrium temperature. Then the eruption reduced the input a little bit, for a little while. That was enough to slow down the system's progress toward its still-not-reached equilibrium output rate and temperature. After the aerosols cleared, the system continued to heat up (and to increase its output rate) still in pursuit of that before-eruption equilibrium temperature and output rate. Actually, the system's goal equilibrium temperature and output rate post-eruption are lower than they were pre-eruption, because the amount of heat in the system is lower (slightly); but those new, lower goals still have not been met, so the system continues to heat on its way toward that new goal. Meanwhile, of course, the output rate is being reduced by a factor independent from all the above: The greenhouse gasses continue to increase. (Moss is growing to block the hole in the jug.) That moves the equilibrium goal even higher, continuously. The system never reaches its equilibrium goal.
    0 0
  49. So, correct me if I am wrong in understanding your reply, you are saying basically that processes are non linear and to a point self limiting, and (perhaps implied) generally driven by the Earths distance from the sun, its rotation, etc. And that our burning of fossil fuels are taking the mean temperature upward. I dont see this as unreasonable, and my opinion isnt going to keep the Earth any cooler.... ...however. I am not so convinced that its just the CO2 that is the culprit. I came to this website in the first place because of an independent discussion about what a relatively mass concentration CO2 has in the atmosphere and how could it possibly be taking the Earths temperature up. I believe something else is going on besides the incremental heat trapping effect of CO2, and that if nations only attack this issue, it may be just a big waste of effort and time.
    0 0
    Response: CO2 isn't the only thing going on - there are a number of forcings that affect climate but CO2 is the dominant forcing:

  50. RSVP, the Earth is not a closed system, no matter how you cut and slice it. Any way to look at it as a closed system is wrong. Your own water jug analogy describes an open system. "I believe something else is going on." What is? What quantitative analysis are you basing this on? In which science papers has this analysis been published? The warming effect of CO2 alone is fairly well known, based on radiative physics. There is more debate on the feedbacks, which condition the total sensitivity. Which part of that exactly does not add up for you and, again, what quantitative analysis is there to support your doubts? Considering the vocation of this site, I'd like to see science publications as support.
    0 0

1  2  Next

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.


The Consensus Project Website

THE ESCALATOR

(free to republish)


© Copyright 2024 John Cook
Home | Translations | About Us | Privacy | Contact Us