Global Warming Is Undeniable

An article by David Biello in Scientific American:

http://www.scientificamerican.com/podcast/episode.cfm?id=global-warming-is-undeniable-10-08-01

"Global warming first emerged clearly in the 1990s and has become more evident with each passing year. The last decade was the hottest such span on record and is very likely to be surpassed as the 21st century progresses.

A new report from the U.S. National Oceanic and Atmospheric Administration lists 10 indicators that global warming is happening: rising humidity; rising sea-surface temperature as well as heat stored in deeper waters; shrinking sea ice, glacier and springtime snow cover; rising temperatures over land and sea; and rising sea levels.

All point to a rapidly warming world. And all are based on actual observations, from satellites high in the sky to meteorological stations in the middle of a Kansas cornfield.

You can debate how bad global warming will be or what to do about it, but it's hard to deny it's happening anymore. The physics of greenhouse gases trapping heat are clear. 

The politics are murkier. Legislative efforts to combat climate change have failed in the U.S. But the Environmental Protection Agency plans to curb greenhouse gas emissions—noting that rising temperatures and a dangerous human impact on climate are undeniable."

global warming is neither unexpected or unprecedented, and to say that my station wagon is radically altering the atmosphere to the point that it is noticably warming the planet is junk science.

carbon dioxide does have a warming effect, but it is not a linear effect, it is logarithmic, so we would need to DOUBLE the amount of carbon dioxide in the atmosphere for every degree of warming. there is not enough carbon on the planet for us to warm it by more than a couple of degrees, and even if we could, a warmer planet is a good thing, most forms of life cope better with increases in temperature than decreases (compare how much life there is at the tropics to the alpine regions or the arctics regions).

it's not even that hot now on a geological timescale. google "roman warm period" and "medieval warm period", these periods were hotter than now, must have been all the christians the romans were burning!

The only thing standing in the way of the views given in justjoshin's post are the facts. In my experience these have never been of much concern to global warming naysayers who base their beliefs on gut feelings. "I am very attached to burning oil. Therefore global warming is false". Some factual corrections to the last post:

(1) the rate of temperature rise seen in the last century is much more rapid than any that has been occurred in the last thousand years.

(2) The CO2 emissions of one station wagon are of little significance, just like one person littering the street would not cause a big problem.  But anthropogenic CO2, a large fraction of which is from cars and other vehicles has already increased CO2 levels in the atmosphere by a large fraction. See the first graph below.

(3) the claim that temperature increases depend on the logarithm of temperature appears to be pure fiction, and is not an accepted model. The simplest physical model would be nearer linear but to do the job properly requires climatological models which are difficult enough to mean the the risks may be larger or smaller than the best estimate. The possibility that increases may be smaller than the median estimate is not adequate compensation for the possibility that they may be even greater.

(4) The claim that we would need to double CO2 for a single degree of warming is either a mathematical blunder or an estimate of warming that is lower than that of the majority of experts.

(5) The medieval warm period was simply not warmer than now. See the second graph below. More importantly, the concern is not so much about the 1 degree we may have already raised temperatures, it is about the further rises.

if you want to look at a debate (http://vimeo.com/9991090).

point 1. the last 1000 years? we had a little ice age in that time, the earth has been warming at about the same rate from around 1700AD, and the earth since the turn of the century has cooled. (http://www.drroyspencer.com/latest-global-temperatures/)

point 2. i was referring to my station wagon in the general sense, not mine individually, and if the warming effects are minimal, and the benefits to society are great (cheaper energy), then doesn't it make sense to use it?

point 3. not pure fiction (http://www.grida.no/climate/ipcc_tar/wg1/222.htm), as you can see, the climate forcing models used by the IPCC assume a logarithmic temperature effect of CO2.

point 4. ok, that may have been exaggeration, from the research i've done, the figures i've seen for temperature forcing due to CO2 vary from 1.2C to 1.8C for each doubling of CO2. The IPCC predictions ASSUME a positive feedback that would drive higher temps (with increase water vapour, and decreased planetary albedo), they don't really look at any negative feedback mechanisms (increased cloud cover for instance).

point 5. both the medieval warm period and the roman warm period were warmer than now (using the NOAA ice core data from the greenland ice sheets as using recorded temperature is not a good guide due to the urban heat island effect.)

I just want to know what kind of Kool-Aid they serve at the Global Warming summits? 

Personally I can't wait to see global warming take action! Especially since it is going to affect major areas of one the biggest climate-sinners in the world - yes I am talking about God's own country. And Australia, it seems, will go through major periods of drought, while we here in Her Majesty's Denmark get a more middeterranean climate - maybe I'll start growing palm trees.

(Of course I feel bad for all the people in Bangladesh and other countries, facing flooding, who have to procure a life west just because of the arrogance of major polluters (and the lobbyists of the oil industry))

First an enlightening piece of empirical evidence from the long term historical record (quoted from a rather good historical survey of climate change science ): "Over hundreds of millions of years, a doubled level of the gas had always gone along with a temperature rise of three degrees, give or take a degree or two". Compare this with the independent predictions below:

The problem is the current change is happening much more rapidly, so is potentially far more disruptive to ecosystems as well as humans.

justjoshin, what is your basis for disputing the second of the two graphs in my previous post? This compiles many independent estimates of temperatures over the last 1000 years and flatly contradicts your claims. The "urban heat island" effect has been well-known for decades and accounts for none of the increase shown in the graph. Similarly the common uninformed claim that recent warming has been due to changes in the sun is flatly contradicted by the data. In addition, NOAA predictions of the effect of quadrupling CO2 show a considerably worse than logarithmic dependence.

Post #4 contains several statements that are false according to the consensus view, and are contradicted by the data. See the graphs and facts.

"the earth has been warming at about the same rate from around 1700AD" See graph

"the earth since the turn of the century has cooled." See graph

"the warming effects are minimal" (eg effects are already substantial on sensitive systems such as coral, and predicted effects are several times larger up to 2100)

That would be the "Kool-aid" of empirical science and computational modelling. I find it far more appealing than the stale bread of ancient pomposity myself. Of course the bible condemns such things as intelligent discussion when it says in Cor 1:17 " "For since in the wisdom of God the world through its wisdom did not know him, God was pleased through the foolishness of what was preached to save those who believe". I would translate this as "religious leaders and cults dislike smart people but love fools because they are more susceptible to coercion."

*Gives Elroch a standing ovation* I am pleased that you take your time to dick up data to support your arguments! I read most of the, then recent, IPCC report back in 2003 while doing a project on different models of how the weather would change, and sea-levels would rise, according to different estimates of temperature increases. What was then the worst-case scenario is now the best-case scenario - now that is scary!!

LOL @ elroch for comparing skepticism to a cult.

ok, for the second graph, it is heavily disputed that it is anywhere near accurate, and it disagrees with a lot of other temperature reconstructions. this graph  shows the temperature reconstructions from a group of different proxies (this is what scientist refer to way of measuring something else when the original data was not recorded) not from different groups of scientists as you infer. Michael Mann is the man most responsible for the horrendously inaccurate "Hockey Stick graph" that has been seen in such alarmist propaganda as "an inconvenient truth".

see here for a comparison.

http://climateaudit.org/2007/11/20/loehle-proxies-2/

most of these temperature reconstructions still show the MWP as much warmer than now (for brevity they do not show the roman warm period).

the problem with the projections is they are modelling something that we do not have a complete understanding of, and are at best woefully inaccurate.

ok, since you seem to like graphs.

This graph shows the correlation between C02 and temperature reconstructions based on various Tree Ring Reconstructions published (one of the most common "proxies" used to reconstruct global temperatures).

as you can see, the highest correlation in all of these papers is just over 0.5, with most about 0.4), and I'm not sure how much you remember from high school maths, but that is not a very strong correlation at all, and while CO2 probably contributes to some warming, the level that it contributes is not known with any certainty. so to predict a global warming of around 10 - 15 degrees based on carbon dioxide emissions solely is drawing a very long bow (and that is for an increase of 400%, which i don't think we have the capacity to do).

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Similarly the common uninformed claim that recent warming has been due to changes in the sun is flatly contradicted by the data.

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http://www.space.com/scienceastronomy/sun_output_030320.html

err... actually it is supported by the data.

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Post #4 contains several statements that are false according to the consensus view, and are contradicted by the data. See the graphs and facts.

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my previous post is not designed to be misleading of coersive, and to use the term "consensus" referring to anthopogenic global warming implies there is some form of consensus amongst the scientific community. there are many scientists and engineers who do not believe that man made climate change will destroy the earth (there have been a few petitions floated like the Oregon petititon, and the Leipzieg Declaration, and the Manhattan Declaration on Climate change).To imply that I am uninformed because I disagree with what you think is arrogant.

The logarithmic effect of a gases ability to retain heat is called "Beer's Law" or "the beer-lambert law" if you want to look it up on wikipedia. CO2's effect is logarithmic. it's simple physics. Any other effects predicted by climate models are feedback mechanisms (and i've pointed out that they asume mostly positive feedback, which is why they all look like hockey sticks).

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"the warming effects are minimal" (eg effects are already substantial on sensitive systems such as coral, and predicted effects are several times larger up to 2100)

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on the coral reefs dying, it has been shown that it is not related to warming or acidification, but mostly to the 1998 El-nino event.

http://www.co2science.org/education/reports/corals/coralreefs.pdf

Thanks, justjoshin, for your contribution to the discussion.

First to correct a misunderstanding , I did not compare skeptics to a cult, and do not hold that opinion. I was responding to JimEBau's transparent comparison of "global warming summits" to the Jonestown mass murder. However, it would be accurate to say that many climate change skeptics subscribe to a huge implausible conspiracy theory. There is no historical example of a large scale conspiracy in the scientific community (a community in which I worked for many years up to 2004), there is merely a progression towards more and more accurate understanding of reality.

I will also correct a very important statistical misunderstanding. You claim a correlation of 0.5 is "not very strong". I find most people have difficulty understanding systems where several factors influence another factor in a complex way. A correlation of 0.5 (with a good sized sample of data, which is the case here) indicates two variables that have a very significant, but not single-factor causal, connection. It is consistent with a large fraction of the variation in one variable being explained by the other variable. Obviously there are other important factors such as rainfall and light levels (and even the uncertainty in the data) that will explain much of the rest of the variation in tree rings. Rather importantly, the correlation factors between tree ring width and the two factors of CO2 levels and temperatures do not provide strong bounds on the correlation between CO2 levels and temperatures. There is a triangle of correlations, and there are inequalities that relate the numbers on the three sides. It is the third correlation that is not in your bar chart that is the one of most interest. Without drawing in more data, your graph allows for (implausible) models where tree ring data is very strongly related to CO2 and strongly related to temperature, but that CO2 and temperature are only weakly related, as well as ones where they are very strongly related!

Surveying the literature, I find the general consensus these days is that only a minority of the modern rise in global mean temperature can be attributed to solar variation. There is general agreement that the larger part of the variation is anthropogenic.

It's about time I attempt to clear up the confusion about Beer's law. The relevant effect is that some infrared is absorbed by CO2 rather than been radiated into space. If you vary the amount of CO2, there is an inverse exponential relationship between the amount of radiation of a particular chosen frequency that escapes and the amount of CO2. i.e. if you increase CO2 in fixed steps (eg of 100 ppm) the amount of radiation that escapes is reduced by the same factor each time. The amount of CO2 currently in the atmosphere only absorbs a small fraction of most of the frequencies of infrared that it absorbs at all. As a result, the amount of radiation prevented from being radiated into space is approximately linearly related to increases in CO2 concentration, for all but very large increases. Obviously, if CO2 levels ever become extremely high the effect will "saturate" but this would be at a disastrously late stage.

Sorry, missed JimEBau's Jonestown reference :-P

I am willing to believe that your graph is valid, despite being from an unclear source, and supports my claim that an approximately linear relationship in the radiative forcing is valid for moderate changes,  but also shows that it is not for large ones. It also shows how dependent most of the predicted results are on more complex models - hardly surprising since we live in a world with a climate, not in a test tube with some gas in it.

I agree with your view that there are other interpretations of the relationships you presented relating tree rings, CO2 and temperature. It would be necessary to survey more research to see which model is likely to be true (I have not done so yet).

I find it amusing that you claim that more global warming would be "optimum", as if one can make such a conclusion from localised benefits in Medieval times (when global average temperatures are moreover generally agreed to have been lower than now). Global warming might be beneficial to Greenland, Scandinavia, Siberia and Canada, but that would be of little consolation to those from parts of the world that are already hot. It's a bit like if we decided to dump all our waste in tropical latitudes and agree that it would be an improvement (for all those who really matter?). The real world is a little more complex than one person's view of what might be "optimum".

I am concerned that you do not seem to understand the concept of one parameter having a strong influence on another parameter without there being a simple causal relationship between them. For example suppose you plot body mass index against calories of fat consumed per day. One would expect to find a correlation between these two things, but (obviously) the correlation will not be one (in fact it might be around 0.5). I assert it is still reasonable to believe that eating more fat tends to make you heavier; you would presumably claim that unless the correlation was near 1, eating more fat does not tend to make you heavier.

[Incidentally, I would not agree with the title of this thread. I would say that one may deny global warming exists, but that the scientific evidence shows that such a viewpoint is almost certainly wrong]

I did not claim that a warmer climate would be optimum, only that older texts (before the global warming scaremongering started in the media) refer to the medieval warm period as the "medieval climactic optimum". This is not my personal view, it was the view of thousands of scientists before 1980, when the fearmongering of the time was concerned with the onset of the next ice age.

think about the most easily populated area's on the globe, the area's most capable of sustaining life. These are the tropics, where the most sunshine is received. The heating drives evaporation and the rainfall and cloud cover regulate the temperatures. More sunshine would also act as a pump to drive more rain further inland (as the heat creates more rainbearing clouds and fuels more wind). Think about the areas least suited for sustaining life, Deserts, and areas closest to the poles, why? lack of rainfall in the deserts, (which should increase as more clouds would form from warming, and more winds push them further inland), and the polar regions would warm. So for the areas that are already hot enough, they should gain more rainfall and benefit, and for the regions that are too cold, they are warmed.

This is a simplistic view, and some areas would be worse off,  but it looks likely that more would be better off from looking at reconstructed climactic maps from the MWP and RWP.

studies on the Vostok ice core shows that CO2 in the atmosphere actually lags behind change in temperature

http://cdiac.ornl.gov/trends/temp/vostok/jouz_tem.htm

and

http://cdiac.ornl.gov/trends/co2/vostok.html

or on a pretty graph

so in your analogy of energy intake correlated to body fat, which are we using to predict the other? if CO2 is driving temperature as is proposed, wouldn't it be the other way around?

i understand the concept of correlation just fine, my argument is with the causality! CO2 may account for a very small amount of the warming that has occurred in the last 300 years, but most can easily be attributed to natural variations.

with regards to referencing, i've hotlinked all the graphs, so you can look at the link if you want to see which site i've nabbed them from. i know it's bad practice, but it's a lot quicker than downloading them, recording the site i got them from, and then reuploading and taggin them.

i do not deny that it warms or cools, i argue the cause and the effects :-)

With regard to the driving influences behind the warming of the last century, a graph of IPCC data on radiative forcing components is enlightening, for example with regard to the importance of solar variation. I could see where your CO2/radiative forcing graph came from, but it appears to be an IT site, not a scientific website. Despite your protestations, I believe we at least agree that the physics implies that more CO2 implies radiative forcing and this has a temperature-raising effect? Otherwise why did you post the graph? You claim the effect is "small", but you should realise that it is exactly those "small" numbers which have been used in all the predictive models.

With regard to the long term historical lag in CO2 levels compared with temperatures, bear in mind that there is no claim that the large scale cycle of glaciation is caused by fluctuations in CO2. It is accepted that the largest factor in these cycles are fluctuations in the Earth's orbit. The lag does provide very strong evidence for a long term historical positive feedback effect between temperature and CO2. It shows that an increase in temperature (from whatever cause) appears to tend to increase CO2 levels. This might be inferred to be true for a temperature increase that was partly caused by the greenhouse effect as well as a temperature change that was caused by the Milankovitch cycle. Note the logic here carefully.

Being new here, I only read some of the posts, so I'll do as little as I can say without possibly making statements that have been addressed here. A few relevant points might be:

1. I would take the position that global warming is good. As far as I have read in the past, food production will increase towards the north, although I have not seen many articles explaining how much the south will become more barren. I can only guess that the effect that the change would be roughly equal; at least northern countries will have more capital to be able to use this useable land, and hopefully something will be compensated for the more barren southern countries. From a larger point of view, eras where warming occured in terms of evolutionary time have resulted in increased brain size.

2. I detailed how much CO2 would be emitted per car in another different forum post around here. Multiply it by whatever data one can find for how many cars are being used per country.

strangequark, I will repeat my point that the if effects are bad for some people and good for others, you cannot simply assess them as good by creating some sort of average. I don't believe that the impoverished of Bangladesh etc. would be adequately compensated by heavy CO2 emitting countries, based on past intransigence. If one accepts that harm may be caused, it will be an instance of knowingly causing harm because it is cheaper to do so.

[Interesting general fact from SciAm, not connected to above paragraph:- if all the world's CO2 was sequestered underground, it would require 30,000 cubic km per year]

The Beer-Lambert graph in post #12 surprised me, as the effect was much more saturated than I would have guessed. However the source is dubious (an IT professional's personal blog, in which he states that reducing CO2 emissions by 95% will have an equal effect on the economy. Another version of the graph (can't claim this is definitive either, especially as the right axis is clearly incorrect, since the radiative forcing for a doubling of CO2 is about 4W/m^2). There is a nice page at the IPCC which explains the confusion (some of it probably due to me) about saturation and radiative forcing. I think I made the point above that Beer's law works separately at each frequency with a separate exponential constant multiplier.