Layman Answers to some Climate Denial Arguments
This one goes out to those of you who are somewhat confused about climate change and where the most recent science lies. I’ll try to keep the questions and answers as non-technical as is possible. I’m not going to go over the details with a fine tooth comb, think of this more like a quick primer on how to defend yourself from common climate denial arguments. Much of the information I’m going to pull from comes straight out of the March/April 2010 issue of Skeptical Inquirer, and an article by David Morrison.
As a quick preface it’s useful to mention that the scientific argument over whether the planet is warming has died down considerably over the last decade. Note that I say ‘scientific’ argument as there remains a small but dedicated group of ideologically driven denialists who dispute even this. Since the IPCC’s (Intergovernmental Panel on Climate Change) latest report many who didn’t support the warming hypothesis have been swayed. The real scientific questions now lie in extracting the degree to which humans are forcing climate change. This human induced climate change or change acceleration is referred to colloquially as AGW (anthropogenic global warming). The questions that remain to be resolved are all a matter of degree, very few people and almost no climate scientists deny that the planet is warming at all.
I will now attempt to (very) briefly cover some of the most common arguments put forward by people who are either intentionally distorting the facts to serve an agenda or are too lazy to properly research climate change. These arguments range in goal from questioning whether climate change is a negative to disputing the accuracy of recordings and even accusations of fraud. Thanks once again to David Morrison’s fantastic article for most of this info.
1) What we are seeing are “natural variations” caused primarily by variations in solar output.
Unfortunately for those making this argument, it’s just plain incorrect. Monitoring of solar intensity has been going on for 30+ years and any variations that have occurred are already accounted for in the most accurate warming models. In other words whenever you see a graph showing human induced change the numbers have already been modified to remove this variable. It’s true that some changes have been recorded, mostly small and they almost completely counteracted by large volcanic eruptions (which have a cooling effect). Our natural variations like El Nino and shifts in ocean circulation are also well understood by climate scientists and never overlooked.
2) While temperatures seem to have been rising in the lower atmosphere (troposphere), they are dropping in the stratosphere.
A key fallacy (false premise) in this argument is that such an event disputes AGW. Rather it is exactly what would be predicted to take place if AGW were real. It’s really quite basic when you think about it, if external forces like the sun were the cause of apparent warming then we’d expect to see both the troposphere and stratosphere heating (directionally). The way the greenhouse effect works is that is inhibits the flow of heat from the Earth’s surface to the upper atmosphere, trapping it in the troposphere.
3) The warming trend during the 1990’s is no big deal; temperatures are actually lower than they were in the medieval warm period.
Again this is just factually incorrect. Temperatures are currently the highest they’ve been in the last 1000 years. While accurate measurements have only been around for 100 years or so scientists still have imperfect but significant methods of modelling historical climate. One such method being the examination of tree growth ring sizes, fluctuations in which are accounted for by varying temperature. Since 1990 temperature has passed the record high from 1000 years ago and we are now entering climate territory unseen by human civilization.
4) While there was warming in the 1990’s, this has stopped and the world is now beginning what may be a long-term cooling cycle.
This claim isn’t straight out ridiculous like some others, but is still untrue. This particular claim stems from misinterpretations of recent temperature measurements which show a minor down-ward fluctuation, an expected and insignificant effect when placed on the overall trend. Often those who make this argument begin their data with the abnormally high temperatures from 1998 (caused by major El Nino) and of course subsequent years since then tend to be lower. Mathematically speaking this process is referred to as ‘regression to the mean’ and involves the statistical anomaly where an abnormally high initial recording will tend to be closer to the average after long-term recording.
5) More carbon dioxide is good, since it makes plant grow better
True, more carbon dioxide would be good for plant growth but as this increase is coupled with increasing temperatures the net result is a loss. High temperatures cause stress for plants and force them to spend more of the day with the pores in their leaves (stomata) closed to prevent water loss, a byproduct of which is an inability to take in gases for photosynthesis. In addition to this, higher CO2 levels will decrease the ocean’s overall pH (making is more acidic) which is devastating for coral reefs and the oceans microorganisms (i.e. zooplankton).
6) There is no consensus; many scientists disagree about global warming
Not true at all. Most dissenters are not climate scientists, and any work they have had published seeks only to criticize the works of others (they have no alternatives models to explain the data). The national scientific bodies in every industrialized country have endorsed the findings of the IPCC, which represents the strongest scientific argument for AGW to date.
7) How can we trust climate scientists when numerous e-mails from the U.K. climate scientists show that they have distorted their data and actively suppressed dissenting opinions?
These scientists are just people, and nothing shared between them in private e-mails contradicts the empirical data they have presented. There is no evidence that these scientists actually forged or suppressed any data, by all accounts it seems they were just blowing of a little steam. For clarity and in the name of good science they are currently the subject of an investigation. If this investigation turns up any evidence of fraud then appropriate measures will be taken, publicly. Even if this is the case it does nothing to undermine the overwhelming scientific consensus based on data from thousands of other climate scientists.
As a conclusion I will recommend two fantastic and reliable websites for anybody interested in further reading. The first is RealClimate, climate science from climate scientists. The second is SkepticalScience, examining the science of global warming and it’s interaction with skepticism.
Hope this was informative!