Climate Change Denial, Anyone?

no ones denying climate change many people just don't think the cause is anthropomorphic climate change. please stop saying there are climate deniers. no one is denying it. we can feel it. shut up. for the love of god please just shut up. climate deniers are like 5 people living in Alabama. people just propose another reason for the climate change/. they are not denying it. can i stop saying the same thing over and over yet? have you got it? did you get it? the concept im trying to explain.

originally posted by: AVoiceOfReason
no ones denying climate change many people just don't think the cause is anthropomorphic climate change. please stop saying there are climate deniers. no one is denying it. we can feel it. shut up. for the love of god please just shut up. climate deniers are like 5 people living in Alabama. people just propose another reason for the climate change/. they are not denying it. can i stop saying the same thing over and over yet? have you got it? did you get it? the concept im trying to explain.

That's still science denialism.

people just propose another reason for the climate change

Which is invariably either physically nonsensical, or not justified by the extensive experimental and observational records, and does not address those same data which strongly point to the verified physical cause accepted by the scientific community.

Laymen don't do this for semiconductor engineering or cardiology.

originally posted by: Nathan-D

If oceans release additional carbon from global warming from human activity [they are absorbing at present], then that is a positive feedback to increase sensitivity of anthropogenic greenhouse emissions.

Well then I suppose this leads us back to the fundamental question: how much radiation-enhancement is CO2 actually producing and is it the main cause of global warming? I personally disagree with the claim that CO2 is the main cause of global warming.

OK, what is the alternate explanation and the the evidence in favor of it, and the evidence and reasons why the current evidence is flawed?

That is a legitimate position to take in this open, public debate, is it not?

If you have the data and the physics. Do you disagree with the claim that human induced changes in atmospheric chemistry (CO2 and other molecules) is the main cause of global warming through enhanced greenhouse effect?

Let's start with some basic observational facts: polar regions warm more than equatorial, night more than day, and winter more than summer and the effect is larger at higher elevations.

Last attribution I saw (if I remember correctly) put CO2 as being between 50-60% of total anthropogenic contributions toward global warming.

OK, what is the alternate explanation and the the evidence in favour of it, and the evidence and reasons why the current evidence is flawed?

One possible explanation are changes in cloudiness. Clouds have a strong net-cooling effect on the planet and so a general decrease would produce net-warming and there are many studies showing evidence that global cloud cover has decreased. One of these studies is Warren et al (2012) who estimates a reduction in global cloudiness of 1.56% from 1971 to 2009 and (assuming a general decrease) that equates to around 3 W/m2 based on Reed’s flux formula. A radiation enhancement of 3 W/m2 equates to a warming of 0.55C at the surface by the Stefan-Boltzmann law and since 1970 the Earth is assumed to have warmed by 0.6C to 0.8C. So, there is one possible explanation.

Let's start with some basic observational facts: polar regions warm more than equatorial, night more than day, and winter more than summer and the effect is larger at higher elevations.

Clouds are strong reflectors of in-coming shortwave radiation, so in the day-time their reflective property predominates and in the night-time their IR-absorption/emission property predominates. Therefore a general increase in the global cloud cover leads to cooling by day and relative warming by night.

If you have the data and the physics. Do you disagree with the claim that human induced changes in atmospheric chemistry (CO2 and other molecules) is the main cause of global warming through enhanced greenhouse effect?

I must disagree since I have not seen any compelling evidence that human emissions (mainly CO2) are the main cause. Skeptics are assuming the “null hypothesis” that the climate is changing due to natural causes.

and reasons why the current evidence is flawed?

Well, here is one such explanation as to why it could be flawed: Observations by Feldman et al (2015) show an increase in radiative forcing from atmospheric CO2 between 2000 and 2010 with an ‘atmospheric emitted radiance interferometer’ (AERI) which is used to determine the absorption characteristics of certain gases in the atmosphere and how much radiation the gases are emanating back down toward the surface. Quote from study:

Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations-the Southern Great Plains and the North Slope of Alaska-are derived from Atmospheric Emitted Radiance Interferometer spectra together with ancillary measurements and thoroughly corroborated radiative transfer calculations. The time series both show statistically significant trends of 0.2 W m(-2) per decade (with respective uncertainties of ±0.06 W m(-2) per decade and ±0.07 W m(-2) per decade) and have seasonal ranges of 0.1-0.2 W m(-2). This is approximately ten per cent of the trend in downwelling longwave radiation. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

Feldman found an increase in CO2 back-radiation of about 0.2 W/m2 from 22ppmv between 2000 and 2010 (corresponding to an increase in CO2 of 368ppmv to 390ppmv). So, it seems to me that there is no doubt that CO2 is warming the surface. But is this warming anything we should be concerned about? The observations by Feldman do not appear to be supported by the IPCC’s arguments. The IPCC’s logarithmic equation tells us that an increase in atmospheric CO2 from 368ppmv to 390ppmv would be enough to produce an extra radiative forcing of about 0.31 W/m2. This increment of radiative forcing is 1.55 times higher than what the observations show at 0.2 W/m2.

The IPCC’s logarithmic equation:


Where RF stands for ‘Radiative Forcing’; C0 is the initial CO2 concentration; C1 is the final CO2 concentration, and W/m2 stands for ‘watts per square metre’.

The 22ppmv increase in CO2 from 368ppmv to 390ppmv:


So, the IPCC’s most fundamental equation that they use to predict the climate based on future CO2 concentrations appears to be at odds with observational evidence.

A quick breakdown of Feldman et al (2015):

Scientists have observed an increase in carbon dioxide’s greenhouse effect at the Earth’s surface for the first time. The researchers, led by scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), measured atmospheric carbon dioxide’s increasing capacity to absorb thermal radiation emitted from the Earth’s surface over an eleven-year period at two locations in North America. They attributed this upward trend to rising CO2 levels from fossil fuel emissions. The influence of atmospheric CO2 on the balance between incoming energy from the Sun and outgoing heat from the Earth (also called the planet’s energy balance) is well established. But this effect has not been experimentally confirmed outside the laboratory until now. The research is reported Wednesday, Feb. 25, in the advance online publication of the journal Nature.

They found that CO2 was responsible for a significant uptick in radiative forcing at both locations, about two-tenths of a Watt per square meter per decade. They linked this trend to the 22 parts-per-million increase in atmospheric CO2 between 2000 and 2010. Much of this CO2 is from the burning of fossil fuels, according to a modelling system that tracks CO2 sources around the world. The scientists used incredibly precise spectroscopic instruments operated by the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a DOE Office of Science User Facility. These instruments, located at ARM research sites in Oklahoma and Alaska, measure thermal infrared energy that travels down through the atmosphere to the surface. They can detect the unique spectral signature of infrared energy from CO2. Other instruments at the two locations detect the unique signatures of phenomena that can also emit infrared energy, such as clouds and water vapor.

The combination of these measurements enabled the scientists to isolate the signals attributed solely to CO2. Both series showed the same trend: atmospheric CO2 emitted an increasing amount of infrared energy, to the tune of 0.2 Watts per square meter per decade. This increase is about ten percent of the trend from all sources of infrared energy such as clouds and water vapor.

a reply to: Nathan-D

so if I understand your post - of the 0.8 degree celcius increase that occurred from 2000 to 2010- we are talking that only 0.01 degrees can be attributed to CO2?

Tired of Control Freaks

a reply to: Nathan-D

So, the IPCC’s most fundamental equation that they use to predict the climate based on future CO2 concentrations appears to be at odds with observational evidence.

That fundamental equation is very fundamental indeed. It is based on a single "layer" of atmosphere. It ignores the fact that there is more going on with radiative forcing than what occurs at the surface.

So, if a skeptical friend hits you with the "saturation argument" against global warming, here’s all you need to say: (a) You’d still get an increase in greenhouse warming even if the atmosphere were saturated, because it’s the absorption in the thin upper atmosphere (which is unsaturated) that counts (b) It’s not even true that the atmosphere is actually saturated with respect to absorption by CO2, (c) Water vapor doesn’t overwhelm the effects of CO2 because there’s little water vapor in the high, cold regions from which infrared escapes, and at the low pressures there water vapor absorption is like a leaky sieve, which would let a lot more radiation through were it not for CO2, and (d) These issues were satisfactorily addressed by physicists 50 years ago, and the necessary physics is included in all climate models.

www.realclimate.org...

a reply to: TiredofControlFreaks

of the 0.8 degree celcius increase that occurred from 2000 to 2010- we are talking that only 0.01 degrees can be attributed to CO2?

No. You are confusing radiative forcing with temperature. Depending on the value used for sensitivity (0.8 is typical), the warming represented by that 0.2 w/m2 increase would be about 0.16ºC/decade. But that increase means that there is more water vapor in the air, it is a feedback effect. Something that models take into account and is pointed out in the source article:

The climate perturbation from this surface forcing will be larger than the observed effect, since it has been found that the water-vapour feedback enhances greenhouse gas forcing at the surface by a factor of three and will increase, largely owing to thermodynamic constraints.

asl.umbc.edu...

Nathan seemed to think this part of his source unimportant.

The results agree with theoretical predictions of the greenhouse effect due to human activity. The research also provides further confirmation that the calculations used in today’s climate models are on track when it comes to representing the impact of CO2.

newscenter.lbl.gov...


It should also be noted that the findings of this study directly contradict Nathan's claim that radiative forcing by CO2 is anywhere near "saturated".

That fundamental equation is very fundamental indeed. It is based on a single "layer" of atmosphere. It ignores the fact that there is more going on with radiative forcing than what occurs at the surface.

Yes, that is true and a valid point. The availability of photons of the required frequencies to be absorbed is the principal variable determining absorbtion for CO2 at the surface. Water vapour and CO2 absorb radiation on the same frequencies and so I suppose there should be a difference at the surface than in the atmosphere since water vapour will have intercepted some of that radiation. But then, since we are concerned with surface warming, does it make any difference? The warming from CO2 at the surface is still less than what the IPCC’s equation tells us and so there will be less warming from CO2 at the surface anyway. And the surface forcing from CO2 is still only 10% of the downward trend in back-radiation, which means that 90% of the surface warming is due to other things, such as water vapour clouds. Also, I am not arguing that the effect from CO2 is ‘saturated’. I believe the saturation claim says that CO2 can have essentially no effect because of its logarithmic nature. The saturation argument was first put forward by Archibald (2006) who apparently calculated the warming effect from CO2 based on MODTRAN and Lambert-Beer law:

a reply to: Nathan-D

Water vapour and CO2 absorb radiation on the same frequencies

Not the same frequencies. Some overlap, yes.

But then, since we are concerned with surface warming, does it make any difference?

We are concerned with warming. If heat is not escaping to space the result is warming. That is what the greenhouse effect is, heat being retained by the atmosphere. Heat from the lower atmosphere cannot reach the upper atmosphere due to increased forcing.

And the surface forcing from CO2 is still only 10% of the downward trend in back-radiation, which means that 90% of the surface warming is due to other things, such as water vapour clouds.

Yes, the models are aware of that. But the article does not say water vapor clouds, it says water vapor and clouds. Clouds are not water vapor and affect forcing in a different manner. And, unlike CO2 water vapor content is dependent upon temperature so warming induced by CO2 forcing has a feedback effect.

The saturation argument was first put forward by Archibald (2006)

No. It was put forward long before that. It dates back to the turn of the 20th century.

He infers, therefore, that a layer so thick as to be equivalent to that contained in the earth’s atmosphere will absorb about 16 per cent of the earth’s radiation, and that this absorption will vary very little with any changes in the proportion of carbon dioxid gas in the air.

www.realclimate.org...

You are confusing radiative forcing with temperature. Depending on the value used for sensitivity (0.8 is typical), the warming represented by that 0.2 w/m2 increase would be about 0.16ºC/decade. But that increase means that there is more water vapor in the air, it is a feedback effect. Something that models take into account and is pointed out in the source article:

That climate sensitivity figure I think is a subject of considerable dispute, as has been demonstrated already on other blogs (here are 50 papers arguing for a low sensitivity). Therefore I don’t think we can accept it as a known fact — at least not at this stage. Furthermore even if it is true we do not know that it is a result of ‘anthropogenic forcing’ and it could be due to natural causes (such as changes in the earth’s albedo). But even so, continued warming at the steady rate of 0.16°C per decade hardly seems anything to panic about to me. That’s just 1.6°C per century. (And human CO2 emissions have been essentially flat for the last 4 or 5 years too, so that 0.16°C shouldn’t be increasing). In fact, the rate of warning should decrease if human CO2 emissions remain flat. Because of CO2’s logarithmic nature, regular increments of CO2 would produce ever-diminishing increments of radiative forcing.

a reply to: Nathan-D

That climate sensitivity figure I think is a subject of considerable dispute, as has been demonstrated already on other blogs (here are 50 papers arguing for a low sensitivity)

When I said "typical", I had a reason. But if the question is the relative contribution of CO2 to temperatures the sensitivity value is not relevant to the claim that CO2 only provides 0.01º out of 0.8º.

But even so, continued warming at the steady rate of 0.16°C per decade hardly seems anything to panic about to me.

You are ignoring the influence of that warming on water vapor concentrations and other forcing factors.

In fact, the rate of warning should decrease if human CO2 emissions remain flat.

Why? What makes you think CO2 sinks are capable of dealing with current emission levels?

Because of CO2’s logarithmic nature, regular increments of CO2 would produce ever-diminishing increments of radiative forcing.

You didn't understand the argument against "saturation?" I thought you said you weren't using that argument.

Not exactly

I never said that they absorbed radiation the same over all frequencies. I said they absorb radiation over the same frequencies (i.e. there is considerable overlapping).

Yes, the models are aware of that. But not water vapor clouds, water vapor and clouds. And, unlike CO2 water vapor content is dependant upon temperature so warming induced by CO2 forcing has a feedback effect.

Typo. Yes, that should read water vapour and clouds. And I understand that water vapour is a feedback. Not sure what you mean above about me ‘not understanding’ the saturation argument. (Got work in 45 minutes, so gonna have to finish this later).

a reply to: Nathan-D

Not sure what you mean above about me ‘not understanding’ the saturation argument.

You say that CO2 forcing is not saturated then you use the argument that it is.

originally posted by: Phage
If heat is not escaping to space the result is warming. That is what the greenhouse effect is, heat being retained by the atmosphere. Heat from the lower atmosphere cannot reach the upper atmosphere due to increased forcing.

Minor point: I like a simpler, and more physically intuitive explanation: the greenhouse effect is when the upper atmosphere intercepts outgoing infrared radiation, and re-radiates half it back down again, that half which would otherwise be escaping to space. So the sky shines more in infrared, like a heat lamp, with more greenhouse effect. (Much of this infrared intercepts the ground, which gets warmer, which then subsequently transfers to the part of the atmosphere we live in).

To the average person, talking about "heat being trapped" makes them think of an oven and heat being transmitted by conduction or advection, material to material interaction common to everyday experience, instead of through electromagnetic radiation which can travel a long distance.

Also a greenhouse for plants doesn't exactly work in the same way---that works by preventing advection & convection, air motion, from taking away warm air which is literally trapped in the greenhouse.

a reply to: Astyanax

climate change is always real, sometimes it changes for good and bad. For short and long periods.
its the Earther being the Earth, mother nature doing its thing.

as for man made i very much doubt it, and if we do leave footprints its hardly doing the earth any bother.
The earth is has had asteriods, earther qukes, floodings, pole shifts and much more torture and change

do you think a pathetic plague called the human race is having any bearing to such a huge entity? i doubt it.
you made a comment that "its the hottest you have ever seen it" . just remember how long the earth has been around and how long you and the huamn race in general has been here. Just a blip on the radar. 30 years compared to billions of years is nothing. i suppose you would need to look at it 100's of thousands of years ago and build up a trend to get any clarity.

alot of climate change is down to solar activity, but the masses will jump on "humans" to make more via taxes.

a reply to: AVoiceOfReason

i dont think people denie climate change. its more if humas have a bearing on it or not

originally posted by: Nathan-D
(And human CO2 emissions have been essentially flat for the last 4 or 5 years too, so that 0.16°C shouldn’t be increasing).

On the other side: as the oceans continue to warm their ability to absorb current emissions will go down (given the thermodynamics you discussed just recently here regarding chemical equilibrium & temperature), so net atmosphere increase given a certain amount of human emissions will go up, and then the climate sensitivity can increase due to arctic melting and loss of reflective ice albedo.

In fact, the rate of warning should decrease if human CO2 emissions remain flat. Because of CO2’s logarithmic nature, regular increments of CO2 would produce ever-diminishing increments of radiative forcing.

We're a long way from that being relevant, and the details are already in the radiative transfer model (it's much more complicated than a simple logarithm in the real atmosphere, there are many components and frequencies and physics effects to deal with).

There is 30K of natural greenhouse effect already that's preventing the Earth from being a 100% frozen over near lifeless snowball. We can roughly linearize around the current operating point, but we don't even have to with the known radiative transfer models which are plenty good enough after 50 years of work.

originally posted by: lSkrewloosel

do you think a pathetic plague called the human race is having any bearing to such a huge entity? i doubt it.

Do you think that the human race could have any bearing on the millions of bison from Nature?

Take a look at this picture:

rarehistoricalphotos.com...

Yes, humans can. We wiped them out.

When CO2 concentrations go from 280 ppm to 400+, that's a major increase over natural. If it were 280 to 283, then nobody would be worried, but we can measure how much we have changed nature.

The argument that the Earth is too big for humans to change significantly is an emotional one, not a scientific one. The right way is to measure the facts, and see if it is true or not. In this case it is.