Global warming - where is the evidence to back up the skeptics claims?

Question

Any number of claims are made by skeptics and deniers arguing the case that manmade global warming doesn't exist. But where is the evidence to back up these claims?

FROGHUGGER - Thanks for the answer but you've just done what I'm asking about, where is your evidence? Is the moon warming, or Neptune, or Mercury, has the sun's output increased?

WILLIAM P - Yep, most skeptics get their info from unreliable sources. There are however some better informed ones that use more credible sources.

JACQUELYN - That's a good place to get you info from, consists of the world's leading scientists, is completely impartial, independent and even has the Royal seal of approval.

DANA - There's a lot of invented data around, that's why many skeptics find it impossible to back it up with anything.

TOMCAT - I notice you opted not to answer my question - why? I've responded previously with regard to troposheric warming / cooling, there's no need for me to respond again (it would be about the 5th time if I did). With all due respect, you seem to be getting somewhat confused about the role of the causes and effects of global warming in respect of the troposhere and vice versa. Might I suggest further studying in order to obtain a clearer understanding (you may then want to revisit the graph you linked to and correctly interpret it).

VLADOVIKING: I think that's more of a legal definition of the world 'evidence'. A more realistic use would be that based on the literal definition 'see-cause' and in this respect we can quite clearly see what the causes of global warming and climate change are.

G_U_C: Whilst those claiming that global warming exists have a reponsibility to validate their claims so too do the skeptics when they make statements, you can't have it just one way.

E-NESS: Thanks for the informative answer, I hope people read it and follow your link. I didn't know about Northern Sweden, went to Siberia and studied the melting permafrost there, very strange seeing trees leaning at strange angles and buildings half sunk into the soft ground.

MADNOELLE: I think you might be onto something there. There's certain people on here who invent their own science then attempt to pass it off as fact, could this be coming from voices in their heads?

BOB: It's not hard to find the evidence to back up statements relating to anthropogenic global warming is it? So why do some skeptics have so much trouble, it could almost make you think they didn't have any.

SOPHIEB: All of that is true but please remember, sometimes the media go overboard and make things out to be worse than they really are, they also have a habit sometimes of apportioning blame to global warming even if it hasn't yet been established as a fact. It's bad but it's not the end of the world.

PERMACULTURE BELLA: A good mix of links there and some of them do present seemingly credible arguments against manmade global warming. Interesting that it's a GW beleiver who is the first person to provide any 'evidence' against manmade GW.

JABLOB: Your answer has disappeared, it can happen if you post a really long answer.

ALFRATTA437: If you source your data from unreliable sources it's going to get questioned / dismissed. Exxon etc are quite clearly biased, they make claims that fall at the fist hurdle because they have no substance to them. There are genuine scientific concerns that have been raised regarding global warming and our greater understanding of the climate, if skeptics were to use these sources their arguments would have much greater credibility.

JBTASCAM: The AGW advocates have produced the evidence you mention and have been doing so for 100+ years, the best scientists in the world can't refute it or provide alternative explanations, e.g. increasing atmospheric greenhouse gas concentrations leads to increased retention of thermal radiation - that's indisputable, so too is the fact that we're emiting ever increasing amounts of greenhouse gases into the atmosphere.

You're illustrating the point of my question pefectly in that you're making claims but not validating them. For example, you state positive feedbacks required...aren't happening in the real world. Positive feedbacks don't cause global warming - they compound or accelerate it, the feedbacks we expected to see are happening (as has been mentioned in earlier answers) and the rate of warming is in fact faster than previously thought (as will be stated in the next IPCC report due next month).

FYZER: It's a good point you make and yes, both sides are guilty. I can understand 'challengers' not jumping into line too quickly - as a scientist myself I don't form opinions or take sides without a thorough examination of all the evidence. However, remove the dogma of the greenies and those with a vested interest and there's still the hard science and evidence remaining.

LARRY: The only answer to include a valid reason to question certain aspects of our understanding of historical climate (not AGW).

The solar contribution argument isn't really valid, we can measure to 6 decimal places the energy from the Sun, there may have been under / over estimations in the past but today it's down to a fine art. The arguments about clouds is outdated and distorted and may stem from the that early climate models that didn't acccount for clouds. More recent ones do and the most recent ones include very complex cloud simulations; be a bit wary of co2science.org and check out the people behind the site.

The last point has some validity to it in that there isn't an ideal correlation between historical CO2 level and temperatures. There is some correlation and when other factors are taken into account there is a good correlation for much of the 542 million years for which we have climate data but there are some as yet unexplained anomalies.

However, these are events spanning thousands and millions of years and are not related to the circumstances giving rise to the current warming trend.



FINAL COMMENT - Thanks to all for the answers. A couple of people mentioned sources that have some credibility although they're not related to the claims that skeptics have been making, I guess we'll never get to find out where they got their information from.

Answer 1

Some solar physicists say that the climate models underestimate the solar contribution to climate change.

http://www.esa-spaceweather.net/spweather/workshops/eswwII/proc/Session2/ESTECsww_20051.pdf

Some say the models underestimate the influence of clouds.

http://www.co2science.org/scripts/CO2ScienceB2C/subject/m/summaries/inadeqclouds.jsp

Paleoclimatologists say "There is no statistical correlation between the level of carbon dioxide in the atmosphere through the last 500 million years and the temperature record in the interval."

http://www.geocraft.com/WVFossils/Reference_Docs/The_Geologic_Record_and_Climate_Change.pdf

Answer 2

Well, let's see. We've got GW researchers emails admitting jimmying the data to change the data. See link 1. Then of course, there's been no warming for over 15 years now, and another year or two of similar results will essentially put global temperatures outside of the best and worst case ranges for GW models. In other words, the models are crap. But what really convinces me is how every Big Government / Socialist group has latched on to Global Warming as an excuse to regulate our lives even more and an excuse to increase the size and spending of government.

Answer 3

Excuse me, but you've completely turned the idea of "science" on it's head with this question. The "skeptics" have to prove nothing. They are making no "positive" assertion.

The people who have to prove something are the "Anthropogenic Global Warming" advocates. That's the way science works. The AGW advocates have to produce evidence that (a) the world is warming at an unprecedented rate, and (b) mankind is behind it. All the skeptics have to do is knock down this hypothesis by answering the claims of the AGW crowd.

And knocking down these claims isn't difficult, once you really understand what the claims are, what the counter arguments are.

1) Is the world warming? The almost universally accepted answer is that the world warmed during the 20th century. Was there anything "unprecedented" about it? Well, we don't know, because we've never had any accurate measure of "Global Temperature" before 100 years ago, and even now the AGW people can't tell us what "surface temperature" actually means.

2) Is mankind behind it? This is the hairy part, because while the CO2 theory of catastrophic warming sounds good, when you look at the evidence it just doesn't hold much water. All of the "positivie feedbacks" required to make the warming catastrophic just aren't happening in the "real" world, as much as modelers want us to believe. To which the AGW crowd replies "Who you gonna believe, us or your lying eyes?"

Answer 4

Well here are some facts...

Thawing tundra can is being measured in Northern Sweden. Rising atmospheric temperatures are causing the disappearance of permafrost and its replacement with marshland or open water.

Large mammals are threatened by changes to arctic ecosystems due to the warmest temperatures in at least 400 years.

The last years of the 20th Century were the warmest years of the past thousand, and the first years of the 21st continue a long-term trend toward a much warmer climate. Scientists report that since the mid 1970s, the average global surface temperature has increased at a rate of more than .2° C per decade.

For many years, it was thought that tropical rainforests were essentially unaffected by climate change Now studies are showing that not only were they changed during past events like ice ages, but some areas are being affected right now by warming.

Coral reefs are probably the most complex ecosystems on the planet, home to hundreds of thousands of species. They protect and support the lives of millions of people around the tropical zones, and are a font of wealth from fishing and recreation. The damage being caused to reefs by warming seas is one of the most serious effects of global warming.

There are so much more facts. If your really interested go to this website. It has pics and information on how you can help.
http://www.worldviewofglobalwarming.org/index.html

Answer 5

The CHALLENGERS, I dislike the term skeptics as I consider it is an unjust term, do provide sources in many of their answers. I always read sources from both sides of the debate. Here are a few sources that I have bookmarked to read later from GW CHALLENGERS: See links below.

I think that SOME of the sources used by the Challengers are valid but sometime challengers misunderstand the reports, do not interpret the graphs/data correctly.

This is totally understandable as the issue is a very complex one and more than a rudimentary understanding of the issues is time consuming. Which is far more of an investment than I am prepared to give the subject. Just to be transparent, I am convinced and I am a GW 'believer'.

Answer 6

The Royal Society, the leading foundation on scientific issues in the UK, has a website in which it addresses this issue. Here is an excerpt:

"The Earth's climate is complex and influenced by many things - particularly changes in the Earth's orbit in relation to the Sun, which has driven the cycles of ice ages in the past, as well as volcanic eruptions and variations in the energy being emitted from the Sun. But even when we take all these factors into account, we cannot explain the temperature rises that we have seen over the last 100 years both on land and in the oceans - for example, eleven of the last twelve years have been the hottest since records started in 1850."

It addresses other misleading arguments as well.

Answer 7

It's not just evidence, it's also the interpretation of evidence.
Both sides of the discussion, use what they have to prove their point and ignore the rest.
Some cited sources are suspect at the very least.
But the reasoning behind the "challengers" is possibly the tendency not to jump into line too quickly and accept the dogma of the greenies, and those with a vested interest thereof.
GW may very well be happening, but are we really, primarily responsible?
Personally that's my point, and I don't need to provide evidence, that's for the doomsayers to do to convince me.

Answer 8

well I know there are dead spots where fish are dieing because of lack of oxygen because of the heated water; and I know that the coral in the Gulf here and all around the world is being bleached out and all the little critters there have died because they have no place to live because the grasses there have died. I have seen documentaries that show that if we didn't have the carbon clouds that we would be a lot worse off because the sun would come thru much stronger. I've seen the pictures of Antarctica snow melting. I've seen the lakes here drying up, and I've heard about the amoeba and other organisms that (cause brain damage from swimming in these lakes as it invades thru the nose while swimming) are beginning to form because of the heat.

Answer 9

The evidence is the same that is always been, the mid troposphere has not warmed at the predicted rate relative the surface over the last three decades.

Do you dispute this?

EDIT:

Bob

You call those references? You posted a bunch of rhetoric, I do not care about opinions or consensus if a bunch of quacks, I am a scientists, show me the data or shut up.

I am still waiting Trevor?

http://www.ssmi.com/rss_research/climate_change_plot.html

The tropical troposphere should have warmed 1.6 time faster than the surface. Since you claim this your business and you always claim that you know what you are talking about, lets hear your expert opinion why the atmosphere in the tropics shows very little warming.

EDIT2:

Jablob do you even understand the theory? The atmosphere must warm up at a faster rate than the surface to be the cause, my gosh, I am going to send Hansen a consulting fee for educating some of you people.

"The corrected temperature records show that tropospheric temperatures are indeed rising at roughly the same rate as surface temperatures"

Which says what? that the surface warmed the atmosphere.

.
.

Answer 10

Great question. No answers so far. One attempt but just the same old retoric.

Lets take one small unresolved inconsistency and claim that the entire theory is invalid. Lets keep doing it even after the descrepency has been resolved, just to confuse people.

Here is another link on the tropospheric temp. anomaly:
http://environment.newscientist.com/chan...

If there was a smoking gun for a non-anthropogenic cause for global warming it would be big news.

Digital modeling is new. However, humans have been using analog modeling since the dawn of time; the sundial, Stonehenge, mechanical clocks, the abacus, mechanical calculators and the Antikythera mechanism are examples.

Early computer models of the climate were able to show the direction of the change and some hints at the magnitude, and confirmed earlier theoretical predictions. Later models confirmed the trend and narrowed the range of uncertainty.

Surely models are imperfect and are constantly improving, but this is not the point. As different investigators approach the problem with different computational methods, the different models all show the same trends and general outcomes.

As greenhouse gasses increase, average temperature increases. Warming will be greater at the poles. As atmospheric moisture increases due to the ability of warmer air to hold more moisture, precipitation events will become more intense. These effects are occurring now exactly as the models predicted.

Digital modeling is not some sort of alchemy. Theoretical science is based on mathematics. Mathematics is internally consistent and irrefutable. A theoretician uses mathematics to prove that his theory is internally consistent. The theory may have no practical application at this point, but it is a valid framework for further study and application. Empirical scientists design experiments to test the theory. After the theory and the mathematics have been proven to be correct by direct measurement through experimentation, the same mathematics from the theory is used to design the model.

Models are used to design nuclear weapons, chart spaceflight, model astrophysical phenomena like star and galaxy lifecycles, model particle interactions in nuclear physics, model biochemical reactions for the design and efficacy of drugs, model population growth, model economic systems, model thermodynamic systems for combustion and engine design, model material behavior for structural design, and more I haven’t thought of. The point being that the models aren’t “tweaked to get the answer you want”. They are used every day around the world by scientists and engineers to make things that work.

Computer modeling has opened a new chapter in science. Empirical scientists were once limited by that which they could construct and observe. Now we can take models, which are proven to be internally consistent because they arrive at the same results obtained from direct measurement, and drive them beyond the directly obtainable. We can drive them into the future, into the past, speed them up, slow them down, enter parameters that would be unrealistic or uneconomic or impossible for a researcher with practical constraints. Sometimes the models produce nonsense. Sometimes they produce results that the researchers are unable to explain, and thus open a new field of inquiry. It is a new frontier.

It amuses me that people use weather models as proof they are no good. “We can’t predict the weather next week, who is to say what will happen in 100 years?” The point is we can predict the weather next week with some accuracy. We can predict the weather tomorrow within a degree or two of temperature and an hour or two of when the precipitation will arrive. That is an incredible achievement.

“The concentrations of greenhouse gases produced by man has risen significantly during the historical record and it is absolutely known (by reproducible, verifiable lab experiments on the physical properties of these gases) that these gases cause warming by absorbing the outgoing radiation from the earth. The skeptics have not produced any evidence that this rise in the greenhouse gas concentrations occurred by some natural process and they have also failed to explain how all the industrial emissions could have been absorbed by some natural process during the recent historical period. There is no way to explain the observed greenhouse gas concentrations without human interference, and there is no credible way to claim that the increase in greenhouse gas concentrations has not caused a warming of the Earth’s surface. While there are other natural processes at work and while the climate system is highly complex, trying to discount the role of human involvement in recent climate change is speculation and opinion, not science.” - Asher Siebert.

EDIT:
>we have none.
>
>why?

Because you don't have any.

You are making a scientific claim: "The current warming is a natural occurance or at the least no one can prove it is not a natural occurance."

But we have a very good theory and mountains of evidence to back it up.

Where is your theory and evidence that challenges the prevailing theory?

You have none.

I'll be sure to ask this question again in various forms and I predict right now we will never get a coherent answer.

When the smoking gun for the non-anthropogenic cause is found it will be big news.

EDIT2
“The corrected temperature records show that tropospheric temperatures are indeed rising at roughly the same rate as surface temperatures”

"The atmosphere must warm up at a faster rate than the surface"

Like I said, “Lets take one small unresolved inconsistency and claim that the entire theory is invalid”

Here is the entire quote in context:

[The corrected temperature records show that tropospheric .temperatures are indeed rising at roughly the same rate as surface temperatures. Or, as a 2006 report by the US Climate Change Science Program (pdf) puts it: "For recent decades, all current atmospheric data sets now show global-average warming that is similar to the surface warming." This one appears settled.

There is still some ambiguity in the tropics, where most measurements show the surface warming faster than the upper troposphere, whereas the models predict faster warming of the atmosphere. However, this is a minor discrepancy compared with cooling of the entire troposphere and could just be due to the errors of margin inherent in both the observations and the models.]

From realclimate.org: I suppose you've read Chandrasekhars' book?

[There are two ways to look at what the “real” physics is. One is to acknowledge that calculation of radiation transport through a partially opaque atmosphere is one of those problems that seems easy until you try to write down the equations, and then you find it’s a monster - the great mathematical physicist S. Chandrasekhar spent years working on it and wrote a book full of equations on stellar atmospheres that I think hardly anyone in atmospheric physics even tries to read. In practice you can’t figure out what’s going on without plenty of computer time.

The other way of looking at “real” physics is to back off and see the overall process. The first scientist to report the carbon dioxide greenhouse effect was John Tyndall. In 1862 he wrote, “As a dam built across a river causes a local deepening of the stream, so our atmosphere, thrown as a barrier across the terrestrial [infrared] rays, produces a local heightening of the temperature at the Earth’s surface.” I don’t think anyone’s said it better since. To say it a bit worse but in modern lingo: to maintain radiative equilibrium, the planet has to put out a certain amount of heat, and if it can’t radiate it out from the surface, the lower atmosphere somehow has to get warmer until there’s some level that radiates the right amount. In practice a lot of the ferrying of energy up towards the right level is done by convection (S. Manabe was the first one to get this right in his computer calculations), so a lot of the radiative gymnastics doesn’t even count for much.]

>Which says what? that the surface warmed the atmosphere.

Exactly. The surface warms the atmosphere via reradiation.