Deniers: What would it take to convince you?

First of all proof of global warming, is proof that humans are the cause, and that increases in temperatures will have catastrophic results.

From empirical evidence we know that there is a very good correlation between the sun, PDO and temperature trends. Both the sun and PDO are in phases that should cause cooling. If warming resumes within the next couple of years, I will reconsider my hypothesis.

Although I don't consider myself a denier (which to me means that one believes AGW is a hoax regardless of the science) but a genuine skeptic, I'll answer the question anyway. Well, I'll answer a slightly altered version of the question because human activity is almost certainly causing at least minimal warming of the planet. "What evidence would I have to see in order to accept that I am wrong and that human activity is indeed causing catastrophic warming of the planet?"

Like Peter.Jungmann said: Make a prediction that is correct. I don't mean a "let's throw everything at a wall and see what sticks", but a comprehensive prediction that is correct *and* the absence of a plethora of other predictions that aren't. In other words, 100 wrong predictions and one correct one don't count. The prediction cannot be explained by any other cause, like natural climate cycles we all know exist. Ideally, this same prediction would incorporate correctly hindcasting the last 110 years of earth's climate history. Simply saying "It's going to get warmer!", or "The poles will be most affected first." don't count.

To use an example, when Einstein came up with his General Theory of Relativity, he made several predictions that would "prove" his theory. These included, but are not limited to, explaining the observed error in the precession of the orbit of Mercury, and his prediction that the same star would be seen in two different places at the same time during a solar eclipse. I understand here that this "Killer AGW Prediction" isn't likely to be as neat as the two I just mentioned, but it is a noble goal to shoot for. If the alarmists (*not* used as a term of derision) speak with a single voice and say "This is what is going to happen." and the world watches as their predictions come true almost to the letter, there would be no more debate.

It would also be nice if the alarmists could actually agree on and explain the causes of millennial scale climate changes that have been happening with amazing regularity at least throughout Phanerozoic time and all over the globe .

Oh, it would be nice, too, if deniers and alarmists alike didn't use Y!A to wage their own little cyber spit-wad fights and instead actually engaged in meaningful dialogue. Propaganda tactics that could serve as a textbook for totalitarian regimes have no place in a debate as important as this one is. You know who you are.

In science a hypothesis normally requires supporting empirical data and practical testing that can be independantly verified and recreated. Once a comprehensive physics based explanation has been developed, than models can play their part.

Models once developed would need to be based entirely in known lawss of physics and must pass validatation and testing. Only once we can match the earths climate history with models and make future predictions that are accurate could we then identify any human signal.

Also important is falsification, ways in which the theory are proven wrong need to be considered and covered in depth. I scientist should always try to prove a hypothesis wrong, then if he can not prove it wrong and has exhausted every other possibility, the hypothesis is likely to be correct. This is good science, cheery picking data to support the hypothesis is wrong.

There are also many claims made to support AGW which are immediately contradicted. These issues need to be addressed, not ignored.

Most studies show a MWP warmer than today and most show a LIA. Mann and his chums work is in the minoirity, yet the IPCC dont consider the others.

Most ice cores show co2 much higher than today this interglacial, as does stomal data and chemical gas analysis, so co2 levels are not unsual and didnt trigger catastrophe when they occured.

Many studies based on empirical data (including works by Keeling and Revelle) show the co2 lifecycle is around 7 - 7.5 years, making the enitre subject a non-issue.

Why does the co2 growth rate anomalie follow SST and not human output?

Also important is logic, if co2 levels in the past caused no warming, then why would they today? Science is the explanation of that what is observed, proving that something that isnt observed exists is theology.

When the greenhouse effect was hypothesised due to a difference between 2 crude equations, things might be a little different if they had known about the laws of thermal dynamics or if they had considered an earth with and without a sea instead. This area should also be revisited and some attempt make to prove the effect exists, as AGW assumes it does.

Receding glaciers, ice mass at the poles, temperature record, droughts etc... are evidence of nothing as these things have always ocurred naturally, and it should be assumed natural until proved otherwise.

Unfortunetly like the big bang theory it will never be proven and it will be a case of looking at the evidence to support each theory and picking the one best supported by empirical data. For example we know the sun at similar levels this centuary to the levels that caused the warmer MWP, hence it should be assumed it is the sun again until proven wrong (as scientifically it is better supported by observation), especially when SST explains most the observed warming and the sun warms the sea.

For one, a resumption of the warming.

After that, how about some direct, tangible proof of human causation?

At the very least, the models could actually predict something - this has yet to happen. It's amazing to me that people whose models are so consistently wrong insist that "science is on our side."

If your predictive model consistently fails to make accurate predictions, then it does not accurately model every factor, does it?

Mountain glaciers have shrunk before - the Alps have had less ice during at least three periods since the last Ice Age than they have today.

During the MWP, Lake Naivasha in Kenya DRIED UP for 200 years. Despite much greater use of the water, it has not dried up during this phase of "global warming."

I will answer your last question first that's easy, as the population of the world grows so they drink more water, and when they drink it all away they then die of thirst, so we reduce the population that is causing global warming, there by bringing everything back into harmony?

Now to get serious, nobody has yet proved to me it is anything to do with human activity, it is just another example of the earth going through a warm cycle, and people taking notice of the stupid remarks of scientists as the weather has just bit back with the cold spell in England. (so bring on global warming) now there predictions have just been disproved. As they were when they predicted of the end of civilisation with the deforestation of the Amazon Jungle. In a few years time when they see there prediction's were unfounded it will die a death like all the other theories, it is Armageddon that will kill us all, not the ravings of a few "ex-spurts"!!

Please note "deniers" is a unit of weight used to measure the fineness of silk that is used in the manufacture of stockings!

Proof beyond a correlation (weak one at that) that CO2 is as effective as you say at warming the earth.

Explain the times that the earth was colder than now with higher CO2 concentrations.

Explain why the Maunder Minimum correlated with the Mini Ice Age, and the Medieval Warm period coincided with a period of high sunspot activity.

And... the biggie... make a prediction that is correct.

I've been making the prediction of much colder temps than normal for the last two years, based on the sunspot cycle, and what do we have? Much colder than normal winter for ALL of the northern hemisphere, and much colder in the southern hemisphere as well. Go figure.

I know Australia just had a heatwave, but I'd say the combination of snow in Baghdad, snow in the UAE, the ridiculously cold weather over all of north america, and the ridiculous blizzard in the UK kind of trumps a little bit of warm in Australia.

Edit:

I'm not the one who keeps carping about greenhouse gasses, specifically CO2. You guys do. If you were honest, you'd worry publically about water vapor which has the biggest effect of the climate, but even a fricking monkey can recognize that it's stupid to think we can control that.

Some robust scientific proof.

At present all we have is models that can't predict the future better than a coin toss, but have been tweeked to hind-cast the last 100 years of climate.

For me the physical properties of CO2 do not appear conducive to anthropogenic warming. CO2 absorbes a narrow range of radiation, the atmosphere is already opaque to that range and any increase in atmospheric absorbtivity implies and increase in atmospheric emissivity as well.

(edit) I'd want proof that changes are actually caused by human activity. The natural world is not static, it's always changing. Whenever there is an observable change in the natural world, environmentalists are very quick to blame human activity, but the sea levels have been rising since the last ice age. Some glaciers are melting, others are growning and the Earth hasn't warming since 1998.

If the Earth would start warming again, and continue for at least a few years.

The problem is, skeptics demand "proof" in the way that we can "prove" a geometry theorem. Of course, real science does not work in such simple and easy terms. In that sense of the word, there is no "proof" either for relativity, the laws of thermodynamics, evolution, the link between smoking and lung cancer, even Newtonian physics--yet most scientific 'skeptics' of global warming have no problem accepting these things as fact.

i think maybe if you showed me facts, or any scientific video etc. just prove that will show me that global worming is true... something that is based on humans using or eating or needing to survive and that is disappearing slowly or whats changing that can affect us in the future.