First most of the climate models have been found to be wildly inaccurate predicting recent temperature rises which have simply not occurred. Not that the temperature isn't rising, it is, just not as drastically as the models predicted. Nor is it anywhere near rapid enough to come close to the UN's IPCC worst case, or likely scenarios (please note this was the previous scenario not the recently released scenario which are still high compared to actual observation). All the models predict a temperature that is much higher than actual observed warming. This indicates a non rational bias towards positive temperature forcing in both the models and literature supporting them.
As a matter of fact while the temperature has risen it is statistically insignificant meaning that it is indistinguishable from normal background variation. To be clear the period of temperature insignificance is half of the period of modern satellite records, which we have had for about 33 years. At this point you can almost claim that non warming is more the norm than warming. Strangely enough even with this observable data that technically falsifies the claims for CAGW there is an insistence that a mysterious cooling effect is in play and that warming will recommence, just wait and see I suppose. In some cases models are adjusted to try to back forecast observed temperature using various hypothesis as to what the mysterious force may be. It would seem that there is again a non rational bias or belief in warming that persists in the face of data.
The initial statements were to simply wait for the fifteen year mark before we get to call CAGW bullshit. After 16 years of no warming we now have to wait for 20 years to declare the models incorrect. While I appreciate the calls to patience, and understand that given the timescale of warming forces its important to wait, ten years ago with only about 15 years of data warmists were calling for doom and gloom, emergency action the green economy and scrambling for Nobel prizes. To be clear 15 years of warming data are enough to call for action but 20 (or more) years are needed to call these theories bunk. It just seems biased.
Now even if we hit the 20 year mark and start to see statistically significant warming again shouldn't we wait another 40 years before declaring that warming is the norm? What if significant warming cycles are simply periodic oscillations? What if temperatures are to suddenly plummet? what happens to the models then?
How far off are the models? well the least wrong is twice as high as actual climate. The SAR model predicted a temperature increase over the past decade of about .3 degrees and what we've actually seen is an increase of .12-.16 degrees. The IPCC estimated over the next century to be up to 6.4 degrees. Literally in order to hit this value wed need to see warming over the next 10 decades that is 4 times greater than a rate of warming we have ever seen.
That satellite record is important because while we do have temperature records dating back 150 years or so the farther back you go the less accurate they are. There are issues with quality control, widespread deployment and accuracy, as well as precision. Don't forget 30 years or so ago while computers did exist they were incredibly expensive and remote data collection methods were almost non existent and at best primitive. While we do have records that extend back 150 years, sampling errors and convenience bias are likely to create an impression of warming. But what about those records dating back hundreds or even thousands of years.
Those temperature records the ones that go back hundreds or even thousands of years have a large amount of scientific debate over them. The oldest temperature records come from tree, ice and rock samples. They are called proxy records as they approximate a temperature. There is ample arguments over their validity and they don't paint a perfect AGW or CAGW picture like say the hockey stick.
Michael Mann created this out of a set of data from tree rings and the subject matter is called dendrochronology. While there is ample scientific debate around the legitimacy of tree ring temperature proxies, the hockey stick graph once appearing in the IPCC's report on climate change has since been removed. The reason for this fall from grace was a simple statistical test, using a set of random junk data Mann's analysis algorithm produced a hockey stick.
So in short it didn't matter whether he took actual results or not he still got a similar shape. In Mann's defense the peak was smaller but a smaller hockey stick is still a hockey stick and thus both pieces of evidence are irrelevant. Since then the data has been reevaluated and several algorithm's show no massive uptick in temperatures and histroical temperatures that may eve be higher.
If you want to argue dendrochronology keep in mind that there is no means of recording or controlling the conditions which the trees grew in outside of the past few hundred years. As such tree ring data could proxy rainfall, sunlight, drought, CO2 and/or temperature. Of course there was a recent article in nature which indicates the roman period may have been warmer than once believed, So take that as you like it
the ice cores that Al Gore used in his presentation were kind of a problem.
See how those two lines are seperated rather than overlapping? Well that's because the CO2 graph lagged the temperature graph by about 20 years. So for years this has kind of been a problem for the pro warming community because it didn't support their theory. Granted it does make sense because of something called Raoul's law which deals with liquid gas saturation. The oceans hold CO2 and as they warm the gas is expelled colder oceans can hold more CO2. A warming period would have to start and warm the oceans before the gas is released thus validating the graph. The graphs were held apart to show the similarity between the curves without revealing the time function. This was literally disinformation.
That being said a recent study in nature found some way of having temperature lag CO2 if they start from the assumption that CO2 drives climate change and work backwards. Maybe Im exggerating but thats ind of how the abstract reads
"The co-variation of carbon dioxide (CO2) concentration and temperature in Antarctic ice-core records suggests a close link between CO2 and climate during the Pleistocene ice ages. The role and relative importance of CO2 in producing these climate changes remains unclear, however, in part because the ice-core deuterium record reflects local rather than
global temperature. Here we construct a record of global surface temperature from 80 proxy records and show that temperature is correlated with and generally lags CO2 during the last (that is, the most recent) deglaciation. "
Personally that is literally stating 'I believe this, haven't been able to prove it and here's how I'm gonna do it'. That's not to say this is malicious, but it is seriously compromised objectivity. Attempting to explain the methodology, they didn't like the results from one inferred temperature record so they used other inferred temperature records to correct the previously inferred record.
The geological proxy records are a bit more interesting from a skeptics point of view. not because they hold more weight or show some profound secret its because of what they don't show. See the geological proxy records show that we are not rising faster nor are we hotter than other warm periods. They also tend to be less stable and last for shorter periods of time than the extended ice ages in between.
See that graph it shows the relatively short period of warming lasting about 11500 alongside the relatively long 100000 year glacial periods. We are well within natural variation
That graph also shows CO2 and its pretty clear that there is a correlation. That being said fossil fuels have only been utilized for 150-250 years human beings have only been around for about 120,000 years so what was the climate driver 300,000 400,000 or 800,000 years ago. If our fossil fuel emissions are whats driving climate now, then there would have to be some natural effect producing CO2 at the rate of a modern industrial society in a cyclic variation every hundred thousand years. Not only that but that the factor driving climate has to suddenly disappear at the end of the warming cycle.
So lets have a synopsis of this information.
1. The models showing catastrophic warming don't agree with observed data.
2. The proxy records of historical warming don't find our current levels or rate to be outside of the historical norm.
3. There seems to be a bias towards warming in data and results even to the point of some data being misrepresented.
4. There doesn't seem to be any major reason to assume catastrophic warming 6 degrees in 100 years
5. The IPCC estimates for temperature change range between 2-4x the rates ever observed.
Clearly the science behind the theory is solid, but there is no evidence that we are going to hit the levels required for catastrophic warming within the next century. The prediction models are wrong, and there doesn't seem to be enough data to suggest doing anything at the moment much less the drastic and expensive policies being pushed by warming proponents. This has led to a bevy of research into what I like to call warming catastrophe now tertiary studies. These studies will not be studying temperature related effects on a population they will be field studies that attempt to be causally linked to a warming planet. They always start with the conclusion the AGW can be observed through a trend and if no trend is observed they look for confounding variables.
There are lots of exaples of these such as this study in nature which found that phytoplankton, the oceanic food chain building block, was in decline. This would be devastating if true but thankfully a rebuttal was offered in nature. This rebuttal clearly illustrated the "observed" biomass loss was predominantly due to methodology not global warming. So there was an alternative explanation that accurately accounted for the observed phenomenon which was not considered pas AGW. Guess which publication was picked up and distributed by the Associated Press.
What about those poor polar bears? Al gore had them s the mascots of his presentation. suspended on ice that was disapearing.
No this isnt the inconveneint truth picture its awesomer (yes its a word)
The thing is polar bears don't spend their time living on ice flows they hunt on some sea ice after hibernation but then travel sometimes tens or even hundreds of miles to better feeding grounds. In fact the whole arctic goes quiet in the winter months waiting for warmer waters that allow food to reproduce. but there was concern over polar bears and they became the mascots of the environmental movement against climate change. a study even found their population was on decline. But like I said a study as in one. because that study used a method called convenience sampling to only test the population of polar bears that was convenient to access from a human village where polar bears are considered a pest problem. Almost every other study has found the opposite.
The Inuit natives have been complaining about the polar bears increasing number. In fact the Hudson bay area where polar bear populations were thought to be on the decline was surveyed and found there were about 1000 bears doing just fine. to be clear models predicted that the Hudson bay bear population should have dwindled to 650 individuals since 2004 but in fact there has been no change. No doubt that will also be blamed on climate change but there certainly isn't a mass polar bear extinction about to happen.
What about our food supply, all those droughts and what not? Well yes we had a bad drought but nowhere near as bad as the droughts in the 1950's or 1930's. IS it due to global warming? That's harder to answer. did it affect the food supply? a little bit but we still have more than enough to stuff our faces with whatever we want. But that's not the only global warming may be affecting our food supply research with no actual evidence.
There was this study in science which said that our food production has dwindled. this was based on a model predicting food production made in the 1980's and it ignored population growth. So while we are producing less food than anticipated our populations has grown by less than anticipated and our food growth has matched our population growth. Not to mention this assumes food production only from the top 5 grains and does not include the variety of foods which are now available due to increased household wealth and globalization. Does that mean the conclusion was wrong.... um yes?
There are lots of other examples, pretty much anytime an association is made between warming and a population or trend there should be healthy skepticism. Not because its all false but because there is an inherent bias or assumption going into the study. Correlation does not equal causation and the best example of this comes from the Flying Spaghetti Monsterism proof.
Score One for the FSM
Before posting editing corrections understand this is a summary article and my opinion is tl;dr