Hello Mohammad,

perhaps you could read the summary for policymakers of the IPCC working group I or its synthesis report. go to www.ipcc.ch

Or consult the main page of the global carbon project.

In any event, CO2 concentrations have already touched 400ppm in 2015 and continue to rise about 2ppm every year. You have probably read material from the 350.org website and movement, which indeed claim we need to stay at 350ppm in order not to endanger the climate system.

More in general, the IPCC and countries who are working towards reaching a meaningful climate change agreement this year in Paris think that 450ppm is an acceptable limit, one that would still carry with it some damage (global warming within 2 C) but 'manageable'.

In terms of tangible effects of higher CO2 concentrations, the recent report by NASA (www.giss.nasa.gov) shows that 2014 was more than 0.6 C warmer than the past century, a period where average CO2 concentrations were in the 290ppm range.

Best Regards,

Francesco

Thank you Francesco for your reply.

I do understand what you said. my question is: what is the difference (from the impact on the temperature viewpoint) between 350 or any other numbers of CO2 concentration?

Was it improved what is the difference? 

Mohammed the difference in air/atmospheric temperatuer due to CO2 concentration alone is difficult to correlate. I will suggest that you look at the temperature data over Qatar. I have seen over Kuwait inspite of continous upwards CO2 trend the annual temperature fluctuation is quite large and is not directly correlated with CO2 concentrations only. I am here refering to some 4-5 decade long time series.

Dear Saif, Thank you for your reply.

Exactly, that what I was trying to say, it is difficult to correlate CO2 concentration and warming. Thus, how they determine that the acceptable concentration to be (...) and not (...). I am sure that we all heard about some study those show that the current warming is a part of natural cycle (some changes in sun spots and ...etc.). Therefore, it might be not very much correct to link this warming to CO2 concentration !!

Or the relation between the concentration and the warming must be clearly expressed mathematically.  

This issue is related to the sensitivity of climate system to the external forcings including increased CO2 concentration in atmosphere. It is generally thought that the global average annual mean surface temperature will increase by 1.5C to 4.5C compared to the pre-Industrial Revolution period when the CO2 concentration in atmosphere reaches about 560ppm. There is still a large uncertainty about the climatic sensitivity.

Dear Guoyu,

how do they link that 560 ppm with 1.5 to 4.5 C? what would happen if the concentration would be e.g. 400 ppm?

since there is no mathematical relation it is hard to say ...

I am right?

Dear Mohamad Kharseh, 

Each amount of CO2 added to the atmosphere is contributing to the Global Warming. Whether is it minimum or maximum? Every ppm has an impact on global warming as well as on climate change. 

dear Vinesh,

what you said is what we were told, but is there equation links this two things together 

This is again an example of a question and questioner who does not provide a scientific reference to his remarks:

You have been given the reference to the report written under the auspices of the World Meteorological Organisation (WMO). Apparently you do not read it

http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_SPM_FINAL.pdf

or a very simple model by a DENIER:

http://clivebest.com/blog/?p=4345

Hello Mohamad,

You asked how global warming and a change in CO2 concentration are related. A simple approach is to consider Earth's energy balance:

deltaF = lambda*deltaT + H

Here, deltaF is a radiative forcing (e.g. due to a change in atmospheric CO2 concentration)  that is balanced by heat taken up by the climate system (H) and energy escaping to space ( lambda*deltaT). lambda is the climate feedback parameter and deltaT the change in surface temperatures.

Assume you change CO2 concentration and wait until a new equilbrium is reached (until H = 0), then:

deltaF_CO2 =  lambda*deltaT_CO2

Hence, the temperature change is given by:

deltaT_CO2 = deltaF_CO2 / lambda

For delta_F_CO2 there are radiative transfer models to calculate it. An approximation is given by (Myhre et al., 1998). This approximation is a best-fit to the results of complex radiative transfer models.

delta_F_CO2 = 5.35 * ln ([CO2_new] / [CO2_old])

E.g. for a doubling of CO2 concentration from CO2_old = 280 ppm to CO2_new = 560 ppm this results in a CO2 forcing of 3.7 Wm-2.

The climate feedback parameter has been estimated by numerous studies (just google it). Most studies find lambda somewhere around 1.2 Wm-2K-1, the uncertaintiy is however quite large. Using these equations you can approximately calculate the equilibrium change in global temperatures for a change in CO2 concentration.

Thank you Martin.

exactly that what I was waiting for. As you mentioned the large uncertainty is what links together the CO2 concentration and temperature change.

In another word, changing CO2 concentration from 350 to 390 ppm might be within the range of uncertainty of climate feedback

Mohamad,

No I didn't say this. When atmospheric CO2 concentration rises from 280 ppm (that's the pre-industrial level) to 390 ppm (present-day) then this implies an equilibrium warming of the Earth's global surface temperatures between roughly 1°C and 2°C (most likely is a warming of around 1.5°C). This is well-established and known since more than 30 years (e.g. Charney Report from 1979). Hence, there is uncertainty, but that does of course not imply that CO2 has no impact on temperatures.

PS: In a similar way you can calculate the warming for an increase from 350 ppm to 390 ppm.

sure there is a relation between CO2 and warming. but the question how big is this relation since there is vey big uncertainty 

You got the equations you asked for from dr Stolpe

You could also have gone to the site of dr Clive Best that I gave you with the same equations

and now you mention "there is a big uncertainty"

As a scientist you have to quantify such a remark. ResearchGate is a scientific site not a blog

I tell you were the uncertainty is an that is what water does in a warmer climate: water vapour concentration increase and water vapour is a strong greenhouse gas; this leads to an extra increase in temeperature (a so-called feed-back process)

However, more water vapour can aslo lead to more clouds and these clouds reflect solar energy and this is cooling.

Climate models indicate that the increased water vapour is more important that increased clouds and that the temeperture increases more than for CO2 alone.

Still, I very strongly suggest you read scientific publications and the Summary for Policy makers of the IPCC report is the closest to a popular scientific report one can get

ResearchGate is where scientists can exchange their experience.

thank you for your valuable answers

At the beginning of industrial epoch, i.e. before the XIX century, concentration of CO2 was equal to only about 280 ppm. Since that time it was increased until almost 400 p.m. now and it seems to be one of reasons (probably the main) of current global warming. During the XX century mean global temperature increased on 0.6-0.7 ˚C. However it should be noted that there is a lot of different factors which influence on climate, not only greenhouse gases, so that change of T is not monotonous function: global warming was stopped at the middle of the XX century (weak negative trend, close to zero, took place approximately from 1943 to 1965) and now, during last decade, a warming has been decelerated again. Nobody really knows what will be the highest dangerous level of CO2. As one knows CO2 is not air pollutant - it is constant part of the atmosphere. It should be noted that on Age of Reptiles its concentration was one order (!) more than now. In geologic scale of time growth of CO2 due to human activity is undoubtedly positive event because, following Soviet and Russian climatologists (Budyko, Izrael and others), reduce of carbon dioxide level below 200 ppm may leads to catastrophic freezing of all the planet (white Earth). However in our scale of time so quick warming is a great problem for the biosphere.  

Mohamad

please take some time to read the IPCC report

IPCC:

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts.

Harry

I do read almost all IPCC report.

I think Lokoshchenko has said important thing when he mentioned that global warming was stopped at the middle of the XX century. if the warming is results of CO2 only, how can we explained what has happened at the middle of the XX century (during and after the world war when lot of CO2 was emitted into the atmosphere.

Mohhamad

Where can I find the data of this Lokoshchenko

The signal by CO@ can only be seen in the last 50-60 years because only in this period the ACCUMULATED concentration is high; before the middle of the 20th century there was too little CO2 in the atmosphere.

50 or 60 years is too little in the life of the earth.  Do not forget the little ice age (few hundred years ago).

In another word, and again, the data show very fluctuations in the earth temperature.  So current warming might be part of this fluctuations.!

By the way: this is your own question:

"How much increasing CO2 into the atmosphere affects the global temperature?"

The answer was given to you here by several scientists. Now you give your own answer: CO2 is not important. Then why did you pose the question?

I just wanted to hear other scientists answer because of that warming is still not very clear issue. 

Warming is very complicated problem and no one knows the whole story about it.

Mohammad is right: in fact, CO2 concentration was increasing monotonously during whole the last one and half century. Nevertheless, the global air temperature was changed non-monotonously during that period with a different sign. As it is known sulfur aerosol particles after volcanic eruptions may create cooling as a result of decrease of total solar radiation. However, cooling at the middle of the XX century, from 1940s to 1960s, took place in absence of great volcanic eruptions at that time. Some scientists believe that nuclear explosions since 1945 may be cause of cooling but it seems to be doubtful because of inertia of climatic system. Thus, a nature of this cooling remains unclear yet. Real changes of the global air temperature are a result of different factors including inner oscillations of the climatic system. It should be noted as well that emissions of greenhouse gases leads to warming of the ground surface and lower troposphere but, at the same time, to simultaneous cooling of stratosphere and mesosphere. Both warming of troposphere and cooling of upper are layers are the same greenhouse effect.  

Sulphate aerosol from the combustion of coal is a cooling factor, just like the sulphuric acid from volcanoes you mention and in the time period you mentioned there were very large concentrations of sulphate, for instance in the air over Europe. The peak level in our country in the 60s was 20 times that of the present-day concentration.

At the time the concentration of CO2 was relatively low

This combine can explain the cooling after WW-II

Dear Harry, 

We should not forget thermal inertia of our planet. 

Dear Colleague Mohamad,

I am not sure what do you mean with your series of questions.

What we have is the following:

1. Unequivocal evidence that CO2 concentrations are at 400ppm currently, or more than 35% above the ''normal'' pre-industrial levels of 290ppm

2. Unequivocal evidence that the increase is linked to CO2 emissions from human activities, manly burning of fossil fuels

3. Strong evidence that GHG concentrations in the atmosphere, especially CO2 and CH4, correlate strongly with temperature signals over the last 500,000 years.

4. Unequivocal evidence that the energy balance at the top of the atmosphere is currently negative, i.e., more energy is coming in than leaving the planet, year after year, since satellite measurements are in place.

5. Strong evidence that that energy imbalance is linked to CO2 increases

6. Unequivocal evidence that the imbalance will result in planetary warming, up to a point where a warmer surface temperature is needed in order to increase radiation back to space. This is true despite of any additional mechanisms, including dumping ones, you may come up with.

In addition to this, we have simulation results done with models that summarize our knowledge of the climate system, that are warning us that those unavoidable planetary adjustments will be characterized by increased frequency of extreme events, melting of sea ice, disruption of ecosystems and food production potential.

The only ''test'' we can run now, given the inherent variability of the climate system and even larger variability of the human system that is built upon it, is to observe current changes and correlate them to what the models are saying and/or with our general understanding of the climate system. More heat trapped, more temperature increases and more powerful water cycles.

And all evidence points to the fact that what we are seeing is indeed consistent with what the climate models are predicting.

If you wait for a statistical ''smoking gun'' to tell you whether global warming is here or not, you might well risk to have a burned planet (at least from a perspective of our human species) before we can even begin responding.

the time to plan response action is now --your doubts are not useful in terms of needs for human responses now.

Best Regards,

Francesco Tubiello

Dear Francesco,

I do not need smoking gun to tell me there is warming, my doubt (like many other scientists) is that is warming really attributed only to co2? Or  was the relation between co2 and warming exaggerated?

Mahamad

You only answer with one-liners: (a) real scientists provide scientific references. You provide private us with your own feelings

Harry, 

If you don't like my question,  and if you think our discussion is private feeling,  you don't have to follow!

Mohamad,

the observed warming has been attributed by several studies to anthropogenic greenhouse gases (CO2 is the most important one of these) and the observed patterns of change of the climate system are consistent with human caused global warming (such fingerprints are e.g. stratospheric cooling, faster warming of nights than days, measured reduction in outgoing longwave radiation). E.g. one paper that attributes the observed warming:

Huber M and Knutti R (2011), Anthropogenic and natural warming inferred from changes in Earth’s energy balance, Nature Geosci., 5, 31-36

Being critcal is of course essential in science, but in order to say "I'm doubtful about this result" you need to have strong arguments to support your position. So far you didn't present arguments why you think the importance of CO2 is overestimated.

I mentioned two phenomena that can not be explained with CO2, the temperature drop at the mddil of last century and the little ice age that occurred few hundreds years ago. However, I have attached to scientific paper show that CO2 has very little effect on warming

Mohamad

The little ice age is not a warming period?!

The drop in the mid-20th century could be an anthropogenic aerosol effect

And now you bring in an author with 2 identical publications that have been shown to be incorrect by climate specialists

http://www.ltu.se/cms_fs/1.5035!/gumbel-rodhe%20gpc%20vol%2047%20p75-76.pdf

Comment on “Thermal pollution causes global warming”, by B. Nordell [Global Planet. Change 38 (2003), 305–312]

Curt Covey, Ken Caldeira, Martin Hoffert, Michael MacCrackena, Stephen H. Schneider, Tom Wigley

I mentioned little ice age as another example of climate change.  

And the publications that I mentioned and you mentioned show two different scientific explanation to warming. 

Mohammad

-The 2 publications give the same reason for the warming with a small contribution by greenhouse gases, see the central pie-chart figure

The idea has been fully rebutted in the references that I mentioned

-Little ICE AGE: yes but is explained by the solar activity minimum in that period. Of course there are fluctuations in the climate form natural causes. The difference NOW I that mankind has increased the level of greenhouse gases and every meteorologist know this results in a higher global temperature at the surface.

You asked for the EQUATIONS and they were given to you and also a reference to a site where it is explained in basic terms by a scientist who does support the IPCC-report

during LIA is explained by the solar activity minimum in that period; why NOT the current warming can be explained  by increased solar activity 

Hi Mohamad,

looking at the global surface air temperature (SAT) through the glasses of advanced methods of time series analysis, in a time-frequency-scale-modulation analysis (as I have done across the instrumental period, 1870-1997), one may see two high-rank modes within the ENSO band of frequencies (~3-7 years) of which one may be assigned to the centennial thermal evolution of the system, whereas the other one appears to reflect the secular increase of insolation. By the way: both modes are crossing each other in the time-frequency plane just during the 1930s where the Southern Oscillation was exceptionally weak, and the combined temperature fluctuation they represent perfectly matches that of the global sea surface temperature (SST). Existence of these two SAT modes appears to mean that global warming of the 20th century was influenced by the changing insolation, but there was another, likewise important component which I would suspect to belong to the increasing greenhouse effect. The overall functional shape of the leading SAT mode (global warming) does not match the overall shape of secular insolation, though there are other climate parameters wich have leading modes that perfectly match the behaviour of insolation. These studies have been sketched in a paper on the dynamical status of the climate system (part II) which you may find among the featured publications of my RG account. A more extended version is in print.

If you want to read a conclusion from these observational data analyses: forget about some sort of linear forcing-response relationship that you might have in mind. The climate system bears a set of feedbacks which make its combined response nonlinear. This includes variability fom intraseasonal to centennial and beyond. A discussion about the distinction between climate variability and climate change may be found elsewhere on RG (a couple of weeks ago).

That's it for the moment from my side.

Regards, Peter

Mohamad

"during LIA is explained by the solar activity minimum in that period; why NOT the current warming can be explained  by increased solar activity"

The answer is: there is not such a change over the past century to explain it. You can check this everywhere by googling

please read the following references, where they mentioned the hypothesis that current warming can part of a natural cycle and also you can read there the observed rise in SAT is significantly lower that most prediction of warming resulting from increase concentration of greenhouse gases...

I am just trying to question what we used to repeat about the relation between CO" and warming!!

[1] Deming D. Climatic warming in North America: analysis of borehole

temperatures. Science 1995;268(5217):1576e7.

[2] Harris RN, Chapman DS. Borehole temperatures and a baseline for 20th century

global warming estimates. Science 1997;275(5306):1618e21.

Please read the IPCC report that is much more recent 

In addition

-There is a large increase in CO2 in the last half century

-CO2 is a greenhouse gas

-temperature increases

What is wrong with this reasoning?

Harry;

you said "The answer is: there is not such a change over the past century to explain it. You can check this everywhere by googling" and I provide you with two references in the most important journal...!

What does a borehole say about the global temperatures: you need thousands of observations to obtain an average.

We are not speaking about the temperature, we are speaking about the reason...

Yes

Your question is what is the reason and the answer is:

Extremely likely it is CO2 and the other greenhouse gases of which the atmospheric concentration has so rapidly increased, as you mention in your subquestion, in the past half century (now to even OVER 400 ppm).

.

Increasing GHG in the atmosphere is an explanation of warming, however there are other explanations...

It is not an "explanation" it is basic physics that every climatologist and meteorologist learns during his education

I have posted many references link the warming with other reasons than CO2...

What do you mean with that : a scientist has to assess this sources and also read the comments made in the same journal. And the fact that some articles are accepted does not mean that the results are "true". There are ample examples of new hypes like cold fusion based on bad chemistry etc etc. A journal cannot check the way the experiments or model calculations are actually carried out

What aboutscience journal?

what i mean, there is scientists have other explanation to thewarming 

I agree that Science is a very important journal; however even this journal has  publications that were shown to be frauds after all

And I agree that there are good scientists who have other ideas. But in climatology scientists who are experts are the climatologists/meteorologists

There are meteorologists who do not believe that the warming will be very strong but they all write that an increase in greenhouse gases means warming of the lower atmosphere according to the EQUATIONS that you ask for in your subquestion and which have been given by Martin Stolpe

Regarding the "borehole-temperature" papers:

Mohamad,

On a small spatial scale, the time when a warming signal emerges from internal climate variability (that is the time when you are confident that the warming is signicantly stronger than the natural variability) occurs later than on a larger scale. That is because internal variability tends to cancel out on a larger scale. The studies you cited only try to reconstruct temperatures in North America, but not global temperatures.

Later, Pollack et al. (1998) took all the availabe borehole temperature reconstructions (also the two you cite Mohamad) and thereby have a more global view of the changes. Their results are clear:

Analyses of underground temperature measurements from 358 boreholes in eastern North America, central Europe, southern Africa, and Australia indicate that, in the 20th century, the average surface temperature of Earth has increased by about 0.5°C and that the 20th century has been the warmest of the past five centuries.

Pollack et al., (1998), Climate Change Record in Subsurface Temperatures: A Global Perspective, Science

So what did you add Martin,  the papers are very clear! 

Hi all,

the question has been answered for long, the debate is fruitless for long. Mohamad simply does not want to accept any argument that is at variance with his predetermined opinion (belief system). But as Harry mentioned also long ago, this is a place to seriously consider scientific arguments, not just a blog. Martin and others, you waste your time. I unfollow.

Regards, Peter

I just wanted to discuss the reason behind the warming,  I do not want to repeat what has been said about the relationship between warming and CO2. I have mentioned a lot of very high scientific publications that suggest other explanations of warming. 

Peter; if you do not like to hear other scientists opinions you should not follow. ...

ResearchGate is to discuss and learn more about what you know.  If someone has an explanation for something there are other have others explanation. 

This is the science,  research is still going and will never end.

Mohamad mentioned some other explanations of warming which you can either agree with or not.

Lobna

Who told you that science works this way. Science is about what is more likely based on physics. What do you mean with "something"? What about your own discipline you also have this attitude there?

Mohamad, Lobna et al.,

I have carefully looked myself at the climate data of the instrumental period - and have also read a pile of papers in this context - so as to be able to critically evaluate results, conclusions,  'opinions' etc - and debates. My own modelling results (using a small GCM) 'speak' their own language as well about how the climate system might be organized, and both the modelling and data analysis experience together provided me with some view as well how global change (including global warming) appears to proceed. I'm very interested, nevertheless, to learn about new facts and new serious interpretations of them - but I'm tired of the present "proxy" debate which does not dig into observational facts and the physics behind but remains at the surface in form of a kind of "battle" - and (sorry to say) dishonesty. To give two examples of the latter, Mohamad: You quoted the works of your co-author Bo Nordell without conceding that there was serious criticism - which you were well aware of, I'm sure. The same holds for the borehole 'case', you did certainly knew the paper that Martin has pointed to before, but you remained silent about it, and even affront a young scientist who was about to take your words serious. Just this event and style has caused my retreat from the debate. Read your most recent, immense response to Martin again and beg him for pardon if you are a honest man and scientist!

Regards, Peter

Dear Peter we are here not to teach other how to behave.  We are here not to address other personality, not to evaluate each other.  You said in your previous response that you will not follow,  so please do what you said;  you are in wrong place. 

Thank you

Mohamad

Mohamad

It does not fit a scientist to ask a question to others and when they provide expert answers to repeat his own subjective opinion

Me too defollow now

What shall you do if you want to desscuss an indea, do  not you ask question?

please Harry do so!

It always like that,  when a new idea faces resistance

Lobna

NEW idea?

Yes it is new idea!

Explaining warming by other reason than only CO2 is an idea.

it is your problem if you do not agree or if you do not like to hear something different to what you were taught. 

It doesn't matter if a new idea is correct or wrong.  It is still new and that is enough to be respected. 

All new ideas or theories have not accepted quickly ( do not forget Galileo Galilei and his inea about the solar system).

By the way,  I see you are still here Harry. Do not you say that you will not follow? !

I do not like arguments.  Please if you there have clear evidence that current warming can not be party of natural change in the sun, share it with us and do not address the personality. 

Lobna

The IPCC report written by dozens of experts has been published last year.

It is a report of the World Meteorological Organisation of about 1000 (Thousand) pages in which all knowledge is provided and secifically the sun as a source has been ruled out.

Here is the FULL report:

http://www.ipcc.ch/report/ar5/wg1/

Your remark is answered in section 8.4 subsection 8.4.1

Solar Irradiance pg 688-691

in Chapter 8 titled

Anthropogenic and Natural Radiative Forcing

I have seen this before. 

Have you all seen the accuracy of the measurements?

the earth is presently absorbing 0.85 W/m2 more than it emits into space. In another word, the trapped energy due to GHG ( if we follow the theory that links warming with CO2) might be within the range of the measurements accuracy.

The natural constituent greenhouse gases are water vapor, which causes about 36-70% of the of the heating, carbon dioxide (CO2) about 9-26%, methane (CH4) about 4-9%, and ozone about 37%.

so if co2 concentration increased by 11% (from 350 ppm to 390 ppm) this means the greenhouse effect of co2 share will increase by (11*9-26%)=1-3%

Great

I just wanted to rise question about what most research try to link warming and co2

Consider the last 500 000 years, when temperature rised in the presence of a high CO2 level - as it was already mentioned early in the discussion.

The problem is less the temperature reached now and which are the other influences.

CO2 increases rapidly and its effects will appear in the following decades not only at the temperatures, changing the ph value of oceans and soil, diminishing the variety of species and others.

I find a more serious question is, how to diminish the exhaust of CO2 with a variety of means or to help natural forces as photosynthesis to reduce the CO2 level,

very little, I have writen and documented and detailed described that, and discovered the mechanisms involved

https://www.researchgate.net/profile/Dimis_Poulos

 I do agree with you, Dimis, very little effect.