All scientists are, by definition, skeptics. Hence the motto of the Royal Society of London, one of the world's oldest scientific academies (founded in 1660), Nullius in verba: "Take nobody's word." Skeptics and good scientists question and change their minds when presented with competing and convincing evidence. Indeed, scientific reputations are made by identifying flaws in current thinking, developing and testing new hypotheses, and by being right, not wrong. And while all scientists (and all people) make mistakes, good ones acknowledge their mistakes, correct them, and refine our knowledge. Bad ones dig in their heels, defending a faulty paradigm to the bitter end.
While a huge amount of effort is put into debunking the bad science promoted by climate deniers, scientists work to correct errors in understanding about climate on all sides. Here is a good example of honest climate science at work, in this case to correct a technical error in a report from an Argentinean food security NGO overstating some climate risks.
Earlier this week a small Argentinean non-governmental organization (FEU) released an embargoed copy of a new report on the food implications of climate change. It is well understood that climate changes will have very significant and varying impacts on the agricultural sector and the ability of different regions and the world to produce food. This new report makes a simple, but important error about climate science, which led to an exaggeration of the severity (and especially the timing) of agricultural impacts. Very simply, the authors confused the "equilibrium" and the "transient" temperature increases associated with future concentrations of greenhouse gases in the atmosphere. As a result, they argued that temperature increases in the coming years will be far higher than they are expected to be by climate scientists. This "transient versus equilibrium" problem is well understood and discussed (see here for a fine summary by Scott Mandia, and another nice review and comment by Steve Easterbrook). It's like turning up the thermostat in your house: the temperature doesn't increase instantly - it takes some time. Adding greenhouse gases to the atmosphere does the same thing: a certain concentration in the atmosphere implies a commitment of a certain temperature, but the change isn't instantaneous: it takes time to reach that temperature because of lags in the system. The FEU report didn't understand the idea of "lag."
When the embargoed report was made available to the climate science community, the error was seen, identified, and called to the attention of the authors of the study. FEU chose not to fix the error and went ahead and released the report (to the detriment of their own credibility - while I doubt their error was intentional, they had the opportunity to correct it when scientists pointed it out to them and they chose not to do so). The climate science community has responded quickly with an explicit criticism of the science error - an excellent example of how climate scientists work to correct errors, no matter the direction. [Indeed, there is a new group dedicated to rapidly responding to mistakes and misunderstandings in the press and other forums about climate.] Gavin Schmidt, for example, a NASA climatologist, quickly wrote: "2.4C by 2020 (which is 1.4C in the next 10 years - something like six to seven times the projected rate of warming) has no basis in fact."
Unfortunately, I'm sure we'll see some media stories simply parroting the report's conclusions, without bothering to check with climate scientists. Whatever happened to fact-checking, especially unusual claims?
Climate deniers, who promulgate error after error (from misreporting satellite data, to misrepresenting historical temperature records, to misinterpreting paleoclimatic data, to much more) do not do the same - they simply deny the evidence (hence the term). And they will never admit their mistakes, despite the fact that their arguments are repeatedly, soundly, proven wrong. Nothing can convince them that climate change is real because they are not real skeptics. Their minds are not open to new information or evidence. [Here is a fine summary that debunks each of the various repeated and incorrect arguments of climate deniers.] Even worse, the least ethical of them will probably claim this example to be an error of climate science when it is the exact opposite: climate scientists got it right but an NGO got it wrong, even after being called on their error by scientists.
Do real scientists sometimes make mistakes? Sure. But it is precisely their willingness to identify, acknowledge, and correct mistakes when they are found that sets them apart from climate deniers. Science moves forward, in fits and starts and sometimes significant jumps. But the willingness to be simply wrong, and to acknowledge and correct mistakes (with the understanding that being wrong sometimes is the price for being right in the long run), is what makes science such a powerful and invaluable tool.