How many scientists believe in man-made global warming?

The first way that you can understand that there is no scientific "consensus" is that scientists do not operate or condone or seek a scientific consensus! I have not ever, in 35 years as a practicing scientist heard anybody negate an argument based on "consensus". In essence scientific consensus does not ever really exist! It is only commonly accepted theory, until somebody modifies it or disproves it

As far as somebody's statement that the AAPG Membership is driving the Executive of the AAPG toward a positive position on AGW - absolute NONSENSE! I am a member and read the newsletters and editorials and positions of membership religiously. No real position, outside of an operational political stance, has been taken or is likely to be taken by the Membership. Surveys of membership have been aimed mostly at establishing a politically viable position that would provide a seat at the political table without causing 30% of the Membership to resign their memberships.

The AAPG, SEG, CSPG and CSEG are the largest geoscience membership (roughly 65,000 members) aside from the GSA and AGU (roughly 70,000 members). Most geoscientists that I know do not belong to the AGU or GSA because they are largely irrelevant to the central issues of stratigraphy and sedimentology that occupy the AAPG et al. Almost all geoscientists reference the excellent publications of both the GSA and AGU on a "need to know" basis and many geoscientists belong to both basic sets of societies in order to receive the publications and stay informed.

Of the AAPG et al group of Societies, I would doubt that if asked an appropriate polling question such as " Man is responsible for more than 30% of Global Warming observed today- True or False?" whether more than 10% would answer True!

I would also suggest that if you framed the question to the AGU and GSA membership in the same or similar fashion that they would probably answer at about 35% True and 65% False.

When a scientist answers a question containing the word "significant" then automatically the result is useless! Please understand that a 1% variation is significant and a 50% variation is dominant! In answering the question, a scientist views the question as meaning anything from 1% to 50% effect!

In answer to your question, I would suggest that of the entire Geoscience community alone, taking 18% of the AGU et al membership of 70,000 and maybe 80% ( at least) of the AAPG et al membership of 65,000 then in total maybe 64,600 geoscientists see a component of Global Warming greater than maybe 10% related to anthropogenic causes and maybe 70,400 geoscientists see an anthropogenic influence beyond 10%. This is obviously just a guess based on experience, bit I would love to have the Membership of these societies actually PROPERLY poll or survey their membership!! For that matter I would also love to see a poll or survey properly conducted of the NAS respective Sections on a stand alone basis!

I am a seventy year old scientist. I spend a lot of time in environment protection. I have planted thousands of trees, transplanted full grown trees and use various conservation methods like rain harvesting and solar energy.

The issue is not that the Global Warming is all man made. Human activities seem to be pushing the warming into an irreversible mode beyond repair.

Having said that the dinosaurs became extinct. Life did not become extinct on earth. It does not matter if humans become extinct. Something else will carry on.

We are not that important or irreplaceable. It is just desserts if we are the culprits.

Once again Jim Z is pointing you down the right road. The point that most AGW believers overlook is that while a large percentage of scientists believe that humans make *a* contribution to global warming, you need to ask how many of them think humans make a *significant* contribution to it. Even as a skeptic when I’m asked if humans make *any* contribution to warming, to make a completely factual statement I say yes. Does that make me an AGW believer? I could be considered as one by that answer, and counted as one for “their side.” I don't deny *some* human contribution, but from my study and research I’m very skeptical of it being significant.

By the same reasoning it is unfair and inaccurate to automatically group every scientist who gives this honest answer with the alarmist camp, having not quantified their answer. That commits the fallacies of suppressed evidence and hasty generalization.

So the real question is not *how many* scientists or people believe humans contribute to warming, but rather *to what extent* do humans contribute? If you were to poll scientists as to whether they think the anthropogenic factor is nearer to negligible or nearer to significant, the percentage of those who could be counted with the alarmist camp would change drastically.

You first have to define "scientist". Does a person with a B.S. in political science with no peer-reviewed publications related to climate science equated with someone with a PhD in Physics with numerous publications in peer-reviewed journals? The Dorian/Zimmer study provided in another answer sticks mainly with those having advanced degrees and also breaks down the difference between published scientists and non-published scientists and climate scientists vs non-climate scientists. The study also gives pretty good evidence of consensus on the signficant human impact at an individual level, an agreement that increases with level of expertise.

Also, this individual has put together a long list of cited climate scientists with links to their websites. You can find pretty good consensus here as well.

http://www.eecg.utoronto.ca/~prall/climate/

Alot of this stemmed from the IPCC report about mans influence on global climate change. The last source I saw indicates that almost 80 climate scientists (world wide) participated in the research that lead to the original report that has lead to all of this hysteria.

I know that there is a petition of non-agw scientists that has been signed by 32,000 scientists (in the United States) that do not believe global warming is caused by man.

The way to really look at this though, is that numbers don't matter for one side or the other. What does matter is what the scientifically provable, and reproducible data shows.

I have no idea because some of the scientists also believe that it will always happen to earth after global warming ice age will happen again means that it has a pattern

Not all scientists would have something to say about global warming.

A cancer researcher for example. Just making a point.

Sources are not hard to find. Look into temperatures for example. They've been recorded for over one hundred years now. The source would be the official weather service in your country. Geographic surveys would show larger water masses in Canada's north and Antarctica. The source would be whomever used the satellites to map areas and compare the land to water areas over the years.

So add them up and you'd get the "concensus" you refer to. Read more about it and you'll get specific references.

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Any legitamite scientist, regardless of political affiliation, believes in man-made global warming. Society cannot even combat that fact that we are adding more CO2 to the atmosphere then is being taken back down through the burning of fossil fuels and deforestation. Carbond dioxide is a greenhouse gas and increased levels of CO2 lead to higher temperatures. Just look at Venus for example. The whole planet is an example of the greenhouse effect. It's farther away from the sun than mercury, however its surface temperature is far greater.

Dana linked to Doran & Zimmerman, which is the largest and most recent poll. There's a slightly older, smaller one by STATS:

http://stats.org/stories/2008/global_warming_surve...

You can also get an indirect idea by the statements of scientific organisations:

http://en.wikipedia.org/wiki/Scientific_opinion_on...

Eg the American Association for Petroleum Geologists was the only dissenting organisation, but changed its statement under pressure from members. No supporting organisation has reported similar pressure afaik.

You can also look at papers for yourself, if you don't believe the Oreskes' study. I like googlescholar:

http://scholar.google.com/

The distribution of paper opinions gives you an idea of the author's opinions.

I had a look myself:

http://www.geocities.com/nd_wtf/Paperpositions.txt

http://www.geocities.com/nd_wtf/AGWlist.txt

Those are the first few pages of results from searches for 'climate change +fingerprint' and 'climate change +cause' iirc.