I hear comments from time to time from climate science deniers. the examples here (in italic far below) are fairly typical and I was asked to rebut them. My rebuttal went a lot further. Add your own comments pointing out where I'm wrong or where this discussion could be improved. I'd love to hear more rational discussion on this topic. There some links to videos that may be of interest at the bottom.

Some general comments on Climate Science, Science, and Denial

When trying to learn some new scientific field you have, really, only one appropriate approach. That is to learn, first, what the experts in the field understand. This is usually hard work, it's why people go get degrees in physics, for example. Once you have mastered the material that experts think is important you are capable of becoming a critical judge of the science. Then, you can make meaningful contributions. So, what if you are an outsider, a layperson who may want to better understand some new topic like the research undertaken with the Large Hadron Collider or Climate Change science? In this case, you want to skip the hard work of getting a degree in physics, you don't want to focus on the all of the details, you just want to see what's what. Unfortunately, there is no better way to rationally undertake this programme but to find and absorb expert summaries of the field. This can be done by by seeking out excellent scientific journalism or reading what's often called review papers or, with more difficulty, by finding a recent paper on a topic that interests you and tracing backwards and horizontally through the references. The latter two methods are basically what much of graduate school consists of. A comprehensive reading of the existing literature is pretty much vital to understanding your chosen field.

Obviously not all literature on a topic is of equal value. On the one hand we have the peer-reviewed journals which are considered by practicing scientists to be the only true channel for conveying the most recent or best understood knowledge in any field. The process whereby scientists put forward new ideas and evidence is a fascinating subject on its own. I recommend reading this paper, "Are debatable scientific questions debatable?", John Ziman Social Epistemology, 2000, vol. 14, nos. 2/3, 187–199 (http://www.pitt.edu/~gordonm/Pubdeb/Ziman.pdf) for some introductory thinking on that subject. Ultimately, if you want to truly understand or debate what's happening in any scientific field the peer-reviewed literature is the only source that can be held up as being meaningful and significant.

Skipping reading the hard-core stuff we are left with what I called excellent journalism. This is more problematic. How does one know what is excellent and what isn't? One can start by considering the reputation of the source of the journalism: the author, the magazine. This requires critical judgement and isn't always obvious especially in present times where much journalism often takes place through text on web pages and it is increasingly difficult to separate blogs, rants, mere enthusiasm and the like from real journalism. We also see in this channel that political and economic interests and mere opinion have more sway. This cannot be avoided but must be identified if one wishes to really know what is real and what is not. All I can suggest here is that a rigorous approach to critically examining the material and oneself for bias is vital. If what is reported here conflicts significantly with what is filtering down to you from the peer-review channels then you know it is suspect. Could the revolutionary breakthrough that will change a field from bottom to top appear first online in a blog posting? Sure, though it's extremely unlikely. Could the big breakthrough blog be promoted by an organization with clear political or economic self-interests? Even more unlikely.

So, unfortunately for those who are not able to exercise critical judgement over their own opinions (all of us at one time or another) we are stuck with using a method, an algorithm if you will, to test our beliefs. There are various humorous crackpot scoring systems online that one could apply (e.g. http://math.ucr.edu/home/baez/crackpot.html) but these really only work on the most outrageous claims and claimants (#chemtrails, #HAARP , quantum crystal healing and the like). So we are left with forcing oneself to compare one's beliefs and the claims one is reading with the best summaries of the state of the art written by experts. It's really the only rational way to approach this process. Assume first that the experts are right. That's almost always going to be the right assumption simply because they are the people conducting the research and the most knowledgeable about the field. Then, if you can really find evidence or a new theory to support an alternate claim, present it to the experts. They are the best qualified to judge whether it's plausible (watch out for your crackpot score though). This is undeniably a difficult course of action and historically people in the this position have not always fared well at first (e.g. Alfred Wegener and continental drift). If you are truly right, though, the evidence you bring to bear will change the position, the consensus, of the scientific community. Ultimately this is how the entire edifice of science actually functions and always has. Is there gatekeeping. Yes. Are scientists human beings expressing the entire range of possible human emotions and attitudes? Yes. However, in the end practising scientists are eager to make breakthroughs and upset the system. That's how progress is made, and new things are learned.

If you are certain that an existing theory, or model, of some part of nature is wrong you have to be able to do a few things to overturn it and impose a new one. If you can actually show where the existing model breaks down you are done. If you also have a new model that you think is better you have to be able to show that it works better than the old one. Let's consider the model of the greenhouse effect due to small concentrations of carbon dioxide (CO2) in the atmosphere. This model is well grounded in several branches of physics and chemistry (radiation, fundamental physics and chemistry of gases, atmospheric circulation, fluid dynamics, thermodynamics, etc). In order to overturn the model of how CO2 acts as a greenhouse gas one would have to show that some element of our understanding of one or more branches of physics and chemistry that apply are in fact wrong, that it makes a wrong prediction. But this is extremely difficult to achieve. Radiation and radiative transfer apply in many other areas, are well studied and understood, and are demonstrably not wrong in those fields. Furthermore, the old theory was excepted because of its explanatory power and, most importantly, it's predictive power. Any new theory has to do both of those things at least no worse and most desirably, better than the old one. At this time there is absolutely no candidate whatsoever to replace the current model of trace concentrations of carbon dioxide and other particular gases (e.g water vapour) acting as so-called greenhouse gases and warming the Earth's atmosphere. Bring on the replacements! Scientists would be eager to test any new idea that is likely to improve understanding, predictive power, and insight.

Let's address some of the specific points that were raised. 

The first issue was a blog posting (https://news.vice.com/article/there-is-some-uncertainty-in-climate-science-and-thats-a-good-thing) written by a practicing climate scientist who basically is saying that scientists have not done a very good job of properly communicating uncertainty in climate change science issues. This is an opinion piece (written by a working scientist) but also an attempt to do precisely what I am doing here. That is, it's an attempt to cast light on something scientists learn as part of their (rigorous) training and is also difficult to convey to people who haven't had that training. The example in the blog of the so-called "pause" in warming is a good one but I think the author misses the point a bit. It's not clear to me that very many scientists expected that such a pause would happen in spite of knowing that it could happen. That's why, I believe, the possibility wasn't communicated to outsiders at an earlier time. But that's a subtle point and probably not very important, certainly not to the science of climate change. The existence of a so-called pause or hiatus and the fact that this wasn't explicitly predicted ahead of time doesn't undermine the whole field. Various possible explanations have arisen in the last few years and better analysis of the current suite of global climate models have shown that some of them do predict variability that matches well with what is observed.

On this article https://news.vice.com/article/there-is-some-uncertainty-in-climate-science-and-thats-a-good-thing I heard the following comments.

Its not a half bad article, but it doesn't touch on three key things that make the use of models as a driver in policy, including condemning the current third world to forever be the third world. I do like that it calls for climates scientists to speak out, but we will see how far that goes with how fast ones career is assassinated when one tries to confront the IPCC or UN.

A specific response to the points raised above is that climate scientists don't want to condemn the third world or anyone else to lives of poverty. Some political actors may be motivated to do that though but it has nothing to do with the science supporting what we know about climate change in the past and future and human contributions to that change. Scientists do speak out, more and more lately, because they understand that there is a need to ensure that political actors and voters are aware of the likely and possible consequences following action and indeed inaction on global emissions of CO2. Scientist's careers are only imperilled when they disregard the kinds of things I've written about above. That is, they ignore the process of communicating and rebutting other research. Finally, "confronting the IPCC or UN", is pretty much a meaningless turn of phrase. The UN is a political organization whose very existence is predicated on only doing what its member countries want it to do. It can't really be confronted. The IPCC is an arms length organization established by a parts of the UN, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). After it was established it was endorsed by the UN General Assembly (the governments who are members of the UN) Its purpose now is to support the United Nations Framework Convention on Climate Change (UNFCCC) which is an international treaty agreed by those parties who have signed it. The IPCC functions by dividing into subgroups and doing a thorough review of existing scientific research, in the peer-reviewed literature, which is presented in detailed reports agreed by member countries. The IPCC doesn't conduct or endorse any research in particular. It's a review body tasked with summarizing the state of the art in climate science. 

The models so far have not held true to the observations, most if not all far over predict various parts of the climate change story including sea level rise and the melting of the ice caps.

This isn't true and betrays a fundamental misunderstanding of the work being undertaken with climate models. Climate models come in many forms and degrees of sophistication. None of them are expected to exactly reproduce observations. This is so for a number of reasons. The most obvious is that the models don't encode all of the relevant physics at all spatial and temporal scales to do this. It's also true because we don't actually know the state of the atmosphere at any moment to a degree of precision to allow models to perfectly represent it. In fact we may never be able to achieve that. It also suggests that the writer doesn't really understand what is being modelled; the climate system is different from moment to moment weather (for example). The research done with the suite of models that was undertaken in support* of the most recent IPCC report, AR5, is comprehensively covered in the IPCC reports. One of the key points to take away is that the suite of models provides a range of estimates of future climate. These can be thought of as realisations of possible future climates. We wouldn't expect, because of variations in internal variability and some processes that are fundamentally random at different scales, that a climate model would ever exactly predict the precise route that the present day climate, a single realisation of many possible outcomes, actually follows. What is likely, however, is that some segments of some of the modelled climates match well with what we see in the natural system. Also, we expect that in an ensemble, the model integrations represent a range of outcomes that reflects our understanding of the range of paths the real climate system could take. They gives us an idea of error bars on future change.

* Note: "undertaken in support of" doesn't mean or imply that this work was done only at the behest of the IPCC. The efforts required to conduct research on the scale of the global climate system have become so large and complex that coordination in the form of agreed, consistent inputs, methodologies, and relevant physical processes (etc) were agreed by groups of organizations who undertake projects on this scale. That doesn't mean that models were expected or designed to be equal or that the outcomes were engineered ahead of time. It just means what it says, efforts were coordinate to reduce duplication where that is reasonable and to increase the likelihood that results would be scientifically useful without wasting the work done.

Recent papers have shown that sea levels have actually been falling the last decade, in tandem with the drop in solar activity, which is also why we have been cooling for the last decade as well, which the article plays off as at most being a stabilization of the temperature. http://www.nature.com/nclimate/journal/v4/n5/full/nclimate2159.html

I think that this is a basic misunderstanding. The linked paper is showing that the rate of sea-level rise has changed, even decreased, but sea-levels are still rising, ie the rate of change of sea level isn't negative. All of the science indicates that the rate will stay positive and increase in general given projected rates of future emissions. Part of the rise that's dominating at present is the thermal expansion of sea water that is warming due to changes at the surface. This is slow and steady, depending somewhat on the rate at which energy from the surface can penetrate to the deepest water in the ocean. A slow process. The rest is from melting land ice (and a few other details). The projections suggest that the melting from land ice will increase. It's a simple problem of geometry to calculate the maximum potential rise in sea-levels. Most of that would be from the Greenland (about 6 m) and Antarctic (about 60 m) ice sheets. Melting these completely is a long-time scale event greater than centuries. Complete melt isn't needed for this to be a big problem for coastal communities in rich and poor nations. 

Pretty much (and I dont know of one the IPCC uses that doesn't) every model assumes that a rise in CO2 means a rise in the amount of radiation we trap from the sun, thus increasing the surface temperature of the planet. And this again has been shown to be wrong with recent papers, indeed additional CO2 makes it easier for us to radiate heat, thus helping us keep cool.

This is also a misunderstanding. A rise in CO2 concentration in the atmosphere does indeed mean the atmosphere "traps" more radiation from the Earth. The sun's radiation comes principally as short-wave energy that can pass through the atmosphere to warm surfaces below. It's the Earth's radiation to space, which takes the form of longwave radiation (infra-red light) that gets trapped in the atmosphere. This is not an assumption. It's a well understood process. Furthermore many models don't make assumptions about how increases in CO2 concentration in the atmosphere will affect temperatures of the surface of the Earth, they model that specifically with sophisticated radiative balance algorithms rooted in physics. Those that don't include this code (e.g. the UVic Earth System Model, a model of intermediate complexity with a simplified atmosphere) use formulas derived from observed physics. These aren't assumptions. These are facts. That increased CO2 in the atmosphere can somehow keep the Earth cool is completely wrong.

There is no consensus on the data, nor the theory of anthropogenic climate change. There are now hundreds/low-thousands of peer reviewed papers supporting the idea that we are not impacting the earth's climate as much as we think. But through urbanization we have indeed played a role in changing the climates in population centers and neighboring areas.

This is false. There is indeed a demonstrated consensus. The consensus view is presented in the IPCC reports (for example). There are, in fact, not "hundreds/low thousands of peer reviewed papers" that oppose this point of view. The CO2 hypothesis is fact. The anthropogenic changes to the atmosphere and Earth's surface are facts. The observed warming is a fact. The changes to measurements from thermometers that may have been placed in areas whose character changed due to urbanization are also facts and are accounted for in the analysis of these observations. That's a sophisticated branch of science all on its own by the way, here's but one of many discussions on that topic http://variable-variability.blogspot.ca/2014/07/understanding-adjustments-to.html. You can also read about it from the Berkeley Earth project T). BEST an interesting project that took it upon themselves to repeat from scratch the work of other climate scientists in producing sophisticated, complete observational datasets from historical observations of weather. What did they find? Just what the others had already found: the Earth's climate system is warming and the pattern of warming fits will with greenhouse gas theory. Their results match the work of others in almost all respects and where they differ there is no significant disagreement and perhaps they have indeed presented some improved methods for dealing with problems in analyzing observational data. Confirmation is a key part of science as well so as far as I'm concerned this was money well spent.

http://www.friendsofscience.org/assets/files/documents/Madhav%20bibliography%20LONG%20VERSION%20Feb%206-07.pdf Here is a list compiled in 2007, but there are many additional papers that have been published since.

This is a great example of an easy to find resource available on the internet that is terrible. The Friends of Science is a politically and economically motivated interest group. It is not a source of unbiased information about climate change. Everything they provide should be treated as suspect until careful analysis shows otherwise. This isn't worth the time of an unsophisticated layperson who could get much more from the Skeptical Science website or, for advanced readers, the IPCC Summaries for Policymakers.

Climate change is a deep and rich subject with sophisticated scientific concepts and perhaps surprisingly deep history (e.g. John Tyndall did laboratory work in the middle 1800's that showed that carbon dioxide is a greenhouse gas). The proper way to approach

Here's Global Warming explained in 146 seconds. Global warming explained in 146 seconds

13 Misconceptions About Global Warming 13 Misconceptions About Global Warming

This (long) video is great tonic for climate denial and general anti-science malarky. There's great bit at 30 minutes in where he discusses the observed fact that engineers, especially retired, are the most prevalent occupants of the "Box". The Box, by the way, holds a collection of correspondence from cranks, lunatics, deniers, etc that have been sent to the Physics Department at Cal Poly in San Luis Obispo, CA.

The retired engineer thing is really prevalent among climate deniers on Twitter based on my informal reckoning.

Pathological Physics: Tales from "The Box"