Guns: control, ban or do nothing?

The debate about gun control is one of the most heated debates in the United States today, with both sides making a multitude of claims ranging from self-defence to homicide rates to firearm-related deaths. In this post, I look at the relevant literature to assess these claims, and their implications.

Number of guns vs. firearm-related deaths.

The statistics in developed countries where similar factors are largely the same largely demonstrate that the fewer guns there are, the fewer gun crimes there are. While this remains a correlation, it is likely that it is largely a causation as well: the stricter gun control is, the less likely people are able to access guns and therefore there are fewer gun crimes. The literature is almost universally consistent in finding this correlation – Bangalore and Messerli (2013) found a strong positive correlation between the number of guns and firearm-related deaths, as did Killias et al. (2001).

Number of guns vs. overall homicide rate

Nevertheless, there are mixed results when it comes to overall homicide rates and gun ownership. For example, Hepburn and Hemingway of the Harvard School of Public Health, in 2004, conducted a review of the literature that concluded: “places with higher levels of gun ownership are places with higher homicide rates. Most studies, cross sectional or time series, international or domestic, are consistent with the hypothesis that higher levels of gun prevalence substantially increase the homicide rate.” Miller and colleagues also found that, across US states, those “with higher rates of household firearm ownership had significantly higher homicide victimization rates of men, women and children.” Killias et al., though, in the study cited earlier, found no correlation between overall homicide rate and gun ownership. However, unless every single murder committed with a gun is instead committed with another weapon (which would be harder to murder with anyway), it seems more reasonable than not to assume that banning guns will result in a net decrease in the number of murders – murder rates in general will depend on a variety of socio-cultural factors within each country, so the fact that a consistent correlation between gun ownership rates and overall homicide rates has not been found doesn’t mean that banning guns in each country won’t reduce overall rates in each country compared with the rate of homicide that would have existed had guns not been banned.

Background checks, assault rifle bans and other assorted “control” techniques

If we want to fully combat gun crime as far as possible, the weight of the evidence suggests that better background checks and assault rifle bans, for example, are not enough: from mass shootings which occurred from 1982-2013, nearly half (49.7%) of the weapons used were semi-automatic handguns. Moreover, better background checks will still, invariably, fail to prevent guns from being sold to people who have no recorded history of mental illness. Indeed, as a study by James Alan Fox stated, in at least 93 mass shootings the perpetrator did not have a criminal history nor a history of mental illness.

Guns and self-defence

Some against banning guns may argue that guns are useful for self-defence and that overall crime rates will increase if guns are banned. However, as Bangalore and Messerli (2013) show, there is no correlation between overall crime rates and gun ownership rates, leading them to conclude that their study “debunks the widely quoted hypothesis purporting to show that countries with the higher gun ownership are safer than those with low gun ownership.” While guns may be more likely to be used for self-defence in the United States than in other countries, it is unlikely that the lives saved from self-defence outweigh the lives lost due to gun crimes, and the Harvard School of Public Health have conducted extensive research into this issue and have found that guns are used far more often to intimidate than they are used for self-defence.

Conclusions

The weight of the evidence suggests that firearm-related deaths will almost certainly decrease as a result of a ban on all guns, and it is more reasonable than not to believe that net deaths will decrease as a result of a ban on all guns. The evidence also strongly indicates that guns do not make a nation safer, but also suggests that gun-control proponents who do not support a full ban on guns are misguided, as better background checks or bans on certain types of weapons wouldn’t have prevented a number of mass shootings from occurring in the past.

This is not to say that a ban is at all realistic in the United States, but citizens of the US, in accordance with the evidence, ought to support a ban.

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Carrier’s Argument Against Vegetarianism

On December 9th 2011, Richard Carrier, a prominent atheist, made an argument against vegetarianism. This is an analysis of his argument.

Firstly, Carrier asserts:

“factory farming” tends to be misreported. When you investigate the actual conditions on most farms, especially those vending major industries like KFC or McDonalds, you find they are not as bad as PETA videos claim. They tend to mix ancient footage with recent (thus representing as current, conditions that have long since been abandoned), overstate the frequency of outlier events (e.g. accidents), and misrepresent farms in violation of existing laws or their own contracts with vendors (farms which then went out of business or underwent severe reforms after being exposed) as being the norm (that’s where a lot of their “horrific” video comes from: gotcha investigations of criminally negligent enterprises, not statistically common farm conditions).”

However, Carrier neglects to provide any citations for these claims. He states that we can investigate the actual conditions on most farms, but the reality is that most factory farms are closed to the public – they do not allow filming or photographs. Secondly, it’s not just PETA who make investigative videos of factory farms. Considering the number of videos produced which are easily accessible on YouTube, testimonies from farm workers as well as documented practices, the weight of the evidence still suggests that it is highly likely that factory farms make life for their nonhuman animals not worth living.

He then asserts, presumably from industry statements, that

“The industry is actually a lot smarter and cleaner than propagandists represent. In fact many of the conditions rights activists complain about are actually so bad for actual production efficiency and profit margin that no rational business would ever engage in them anyway, even if animals were vegetables.”

However, tail docking, debeaking, gestation crates and cages all increase efficiency, not decrease it, as it provides more control over the animals and their actions. Further, fattening up chickens, for example, up until a point at which their bodies undergo severe stress, causing health problems such as cardiovascular problems, is, again, efficient in terms of profit – getting the animals large enough that they are on the brink of death maximises profits, and while there are quite a few deaths judging by investigations of factory farms, would it be rational for farmers to simply increase the fattening period because of a few deaths? Of course not. At this point, my admission that the majority of chickens do not die despite intense fattening regimes may be used against me, but, as I’ve already said, even if the chickens do not die, they still undergo massive amounts of stress due to the fattening.

Next, Carrier asserts

“Animals need a lot less than we do in order to be content and to experience normal stress levels or less (normal being the amount of occasional stress, highs and lows, that they would experience in the wild). Chickens, for example, are not miserable when in large crowded communities. There is a limit beyond which comfort declines (California state law, for example, now recognizes this), but their “personal boundary” space is a lot closer than it is for people, and often chickens voluntarily mass together for warmth and comfort. Thus seeing a hanger full of clucking chickens brushing against each other should not evoke tears. Animal quality of life has to be measured in terms of what is comfortable for that animal, and must recognize such facts as that animals aren’t aware of most things, and don’t aspire to be or do anything, and have no prospect of becoming anything, and thus should not be hastily anthropomorphized in these ways.”

Again, contrary to his self-proclaimed characterisation of the article as a rational analysis of vegetarianism, he provides no evidence for his assertions here.

It should be noted at this point that Carrier fails to mention the suffering that the nonhuman animals endure during transportation, which often involves long trips. He also fails to mention slaughter, apart from another assumption that slaughter is humane. Indeed, he assumes that humane slaughter is something we can engage in, with ease, if we want to. However, the empirical evidence suggests a different story, namely that even so-called humane methods of slaughter such as stunning and electrocution are inadequate in a significant proportion of cases. A middle-of-the-road estimate that I have found comes from a 2013 paper by Atkinson and colleagues, which found that 12.5% of stuns were carried out inadequately, and that even the most experienced shooters would be inaccurate 5% of the time. When a stun is carried out inadequately, the nonhuman animals experience pain and often turn frantic and try to get away from the source of the stun. In some cases, the animal will have to be slaughtered while conscious, which causes significant suffering, while in others, the animal will have to be stunned for a second time. However, other studies, conducted in 2007 and 2012 found that 32% and 35% of cattle were inaccurately shot, respectively. Considering the number of cattle who are slaughtered every year, this is a staggeringly high amount of suffering that is occurring. This is occurring in developed countries in which humane slaughter laws exist and are enforced according to the industry.

In his final point on ethics, Carrier writes

“I also find vegetarians irrational in their acceptance of non-vegetarians. Either eating meat is not all that immoral, or everyone they know is a villain, horrifically consuming the flesh of concentration camp victims. And yet they befriend us. Strange. It’s as if we were all serial child molesters, while they refused to have sex with children because it’s wrong, but then come to laugh at our dinner parties, have sex with us, and help us move. Perhaps vegetarians think taking animal lives is no more awful than flouting traffic laws or being mean to street urchins, but that would make little sense. That’s not the rhetoric I hear. The strong drive they have to maintain their lifestyle seems attached to a belief that animal lives are “only slightly less valuable” than human lives and that killing them is a revoltingly awful thing to do. And that makes no sense of their tolerating us as if we were nothing more than casual traffic violators. It would seem vegetarians don’t really believe in their own convictions.”

This is nothing more than a fallacious appeal to hypocrisy and has no bearing on whether vegetarianism is the morally correct diet to adopt. Even then, though, there are significant differences between a child molester and a meat eater. Firstly, the meat-eater is not, usually, directly killing the nonhuman animal and many, in my experience, have admitted that if they had to kill the nonhuman animal, they wouldn’t eat it, which highlights the irrationality of eating meat in the first place. Secondly, meat-eating is widespread: around 95% of the population in the West eat meat, so it’s hard to avoid meat-eaters. Child molestation, by contrast, is very rare. Those who opposed slavery didn’t run into a corner and isolate themselves from the world – they challenged the slave-owners and those who condoned the practice, just as vegetarians often do today (much to the chagrin of meat-eaters who often have a violent emotional reaction to the mere word ‘vegetarian’.)

Carrier then moves onto environmental arguments, and starts this section by stating

“It’s also not rational to be a vegetarian “to save the planet,” for the same reason it’s not rational to vote for third party candidates in U.S. presidential elections. It’s literally the most useless thing you can do to effect any change or prevent harm. As it happens, relying on local produce is worse for the environment. Factory farms are vastly more efficient.”

Firstly, by his logic, even voting at all is useless when effecting change. However, the more people who do it, the less demand there is for animal products and, thus, there is a lower supply. Secondly, he constructs a convenient strawman argument when he states that relying on local produce is worse for the environment. How does he come to the conclusion that all vegetarians rely on local produce, or that a vegetarian diet necessarily entails relying on local produce? Secondly, his citation for this assertion is a blog post with links to other articles and blog posts – no scientific studies. Third, the blog post’s links simply state that local food is not always better for the environment and that food miles should not be considered on their own, but as part of a life-cycle assessment of products that incorporates all greenhouse gas emissions. In short, products should be evaluated on a case-by-case basis. Factory farms may be more efficient than local farms, if Carrier is correct, which I think he may be, but is the meat product less environmentally damaging than a typical plant-based food? The evidence suggests that the answer is an emphatic no. For example, the Environmental Working Group found that all animal products, apart from 2% milk and yogurt, are associated with more carbon dioxide-equivalent emissions than common plant-based foods, and a 2014 study published in Climactic Change estimated that UK vegans have approximately half the total CO2-equivalent emissions associated with their diet than UK meat-eaters, and significantly more than half for the most regular meat-eaters. Vegetarians had a higher carbon footprint for their diet, fish-eaters even higher still, with low meat-eaters, medium meat-eaters and high meat-eaters having the highest emissions (in order from low to high).

Carrier next addresses the total environmental impact of the livestock sector.

“For example, take the claim that “factory farming (specifically for meat) is one of the greatest contributors to global warming.” That’s simply not true.”

Many do claim that the meat industry is one of the greatest contributors to global warming. Whether or not this is true, however, is irrelevant to whether a plant-based vegetarian diet is going to be more or less environmentally damaging than a diet that includes meat in it. As shown above, a vegetarian diet is most likely necessarily less environmentally damaging than an omnivorous diet. Nevertheless, we can look at Carrier’s analysis of the total impact on global warming that the livestock sector has, however he uses an outdated 2006 FAO report, whereas I will use a 2013 FAO report which states that the livestock sector is responsible for 14.5% of global greenhouse gas emissions, which is still a significant amount. Firstly, Carrier claims that these types of estimates are skewed because the clearing of forests to expand ranches is a one-time effect. I would question this, however – the carbon dioxide taken from the atmosphere for use in photosynthesis is an ongoing effect, so clearing forests to expand ranches is detrimental to mitigating global warming in the long-term. Secondly, he asserts that forest clearing goes on a decline as countries’ economies improve, but provides no evidence for this. Third, pasture expansion only accounts for 6% of the total greenhouse gas emissions. Carrier then states that nitrous oxide emissions from fertiliser used to grow crops for feed would be cancelled out by emissions from fertilisers used to grow alternative plant-based foods. This is questionable, however, as plant-based agriculture requires a lot less land. Nevertheless, even if we grant Carrier this, nitrous oxide emissions from fertiliser only account for around 7.7% of total greenhouse gas emissions. Next, Carrier states that inefficient farming practices in third world countries skew the total figure even further. So, using data from the 2013 FAO report pertaining only to North America and Western Europe, we find that, per tonne of protein, roughly 68.4 million tonnes of CO2-equivalent emissions are produced. If we set this as the baseline for South Asia, Latin America & Caribbean, East Asia and sub-Saharan Africa, we find that 3901 million tonnes of CO2-equivalent are produced each year by the livestock sector globally, which is a 45% reduction from the 7100 million tonnes originally stated by the FAO report. This is still around 8% of global greenhouse gas emissions, however. If we grant Carrier all of his arguments concerning pasture expansion and nitrous oxide emissions from fertiliser, we still find that 6% of global greenhouse gas emissions come from the livestock sector. Of course, this is a minimum estimate, but even this is still significant and, if everybody were to adopt a vegetarian diet, greenhouse gas emissions would decrease.

In order to attempt to minimise the effect of giving up meat on greenhouse gas emissions even further, Carrier writes

“You are ruining the environment just as much when you shower as when you eat a hamburger. In fact, if we set an average shower’s greenhouse impact at about 2 units, a hamburger rates about 3…while the impact for a serving of winter tomatoes is 50. That’s right, vegetarians. Perspective is a bitch.”

The first thing to note about this passage is that it is self contradictory – if a hamburger has a higher greenhouse impact than a shower, then it clearly is ruining the environment more than the shower, yet Carrier asserts that you are ruining the environment just as much: this is sloppy reasoning and highlights the desperate attempt to try to minimise the impact on the environment of meat-eating as much as possible. The whole of this passage, in fact, is a specious comparison between different activities, using the logic of ‘two wrongs make a right’. Essentially, Carrier is saying that we should not halt our consumption of meat because its impact on global warming is comparable to that of a shower. This completely misses the point of the whole endeavour to reduce one’s impact on the environment – it’s not about being perfect, it’s about minimising unnecessary impacts. Eating meat is unnecessary for a healthy diet. We do not need to do it. If we adopted plant-based alternatives, our impact on the environment would be lower. And, as for a serving of winter tomatoes, the simple solution is not to buy out of season tomatoes in the first place and adopt some of the strategies suggested in the article that Carrier himself cites for these figures! Perspective is important and, from the perspective of minimising one’s impact on the environment, eating no meat will contribute towards this, as confirmed even by the article that Carrier cites, suggesting he either ignored any arguments refuting his position or simply missed that part when he was writing his piece.

Third, Carrier expresses concern for those working in the agricultural sector in general, stating that we do not boycott food simply because workers are treated badly; rather, we pursue alternatives. Firstly, the fact that there are alternatives allows us to pursue these alternatives (by definition), but, as Human Rights Watch, among others, has noted, the meat and poultry industry is, relatively, incredibly dangerous for its workers simply because efficiency is everything. If we decrease the efficiency, then its impact on the environment will be greater. Whereas plant-based agriculture is mostly about workers’ pay, the workers in the meat and poultry industry are doing a job that is, to a large extent, intrinsically dangerous. If we want to reduce our impact on the environment and improve workers’ conditions (i.e. workers in the meat industry move to other jobs), a boycott is permissible. A world with no meat industry is better than any world that has the meat industry; a world without no agriculture in general is far worse than a world in which ethical agriculture is practiced. Thus, Carrier’s analogy is flawed. Indeed, boycotting essentials is irrational, but boycotting meat, which is unnecessary, is not.

Finally, Carrier moves onto arguments from health. Here, he argues that we should be looking at all-cause mortality, not just specific diseases such as cardiovascular disease and diabetes of which studies have consistently found that vegetarians have a lower risk. Some studies have actually found that vegetarians have lower rates of all-cause mortality, though others haven’t – the difference appears to be in the amount of Vitamin C and fibre in the vegetarian diet. In any case, assuming Carrier has conducted a thorough search of the literature, he states that a vegetarian diet at most might give one two more years. He dismisses this as insignificant, but if I were dying at age 90 and someone were to ask me whether I would have preferred to die two years earlier, I’d almost certainly answer ‘no’. In any case, health-conscious meat-eaters, and pescetarians can probably be just as healthy as vegetarians who are on a well-planned diet, but a vegetarian diet may make it easier to avoid certain diseases and may make it easier to increase longevity.

Vegetarianism: the healthy choice?

The topic of eating meat can often devolve into both sides of the debate making defensive, emotionally-charged arguments. This post will examine the health issues, and cut through the propaganda on both sides.

The big health debate

Fad diets are prevalent in Western society today, with people looking to lose weight quickly. They have, in many cases, become comparable to ideologies – science is regularly distorted so that businesses catering to a specific diet can continue to make money. Seeing as this post is about vegetarianism, I won’t look into these specific diets today, but many of the same arguments about what is good for one’s health and what is bad come up in the discussion of these diets as well.

I’ll start off by criticising the claims of some vegetarian and vegan activists. Firstly, an oft-cited study purporting to demonstrate that meat is responsible for a plethora of health issues is The China Study. Nevertheless, it has been subjected to many valid criticisms, in particular relating to its misrepresentation of data. Even more demonstrative of the tendency of some vegetarian activists to misrepresent science to show that animal products are responsible for any scary disease one can think of is the People for the Ethical Treatment of Animals’ (PETA) claim that dairy products cause autism. Dr. Steven Novella of the Skeptics’ Guide to the Universe convincingly demonstrates that they misrepresent the literature to suit their own ideology.

On the other hand, those who promote paleo-diets, which contain a lot of meat, as well as some meat-eaters in general, also misrepresent the science about a vegetarian diet to cater to their own views. For example, they may assert that a vegetarian or vegan diet invariably involves certain nutrient deficiencies, whether it’s of Vitamin B12, calcium, Vitamin D, protein or iron. What they often fail to mention is that protein, iron and calcium are present in plant-based foods, and that Vitamin D can be taken in with adequate amounts of sunlight. Moreover, Vitamin B12 is in many fortified vegetarian and vegan foods, and can also be taken in supplement form. Summarising the evidence, the American Dietetic Association has stated:

“It is the position of the American Dietetic Association that appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. Well-planned vegetarian diets are appropriate for individuals during all stages of the life cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.”

The association then specifies further the diseases that vegetarianism may help to prevent, including heart disease, cancer and diabetes. I will now examine these diseases, in relation to the vegetarian diet, in more detail.

Heart disease and the vegetarian diet

The scientific literature as a whole demonstrates a sustained association with the vegetarian diet and a lower risk of cardiovascular disease compared with the average omnivorous diet in the West. Studies have repeatedly found that vegetarians have a lower risk of heart disease than meat-eaters. A particularly well-designed study was the EPIC-Oxford cohort study, the results of which were published in 2013, which included a sample size of 44,561 men and women, and a particularly high proportion – 34% – of vegetarians. Having controlled for age, smoking, alcohol intake, physical activity, educational level and socioeconomic background, as well as other risk factors for heart disease, the authors found that vegetarians had a 32% lower risk of heart disease than those who ate meat and fish.

This corroborates previous findings, such as this analysis of 5 prospective studies, which found a 24% lower risk of heart disease in vegetarians compared with non-vegetarians.

The mechanisms as to why vegetarians would have a lower risk of cardiovascular disease are also quite clear. As the authors of the 2013 EPIC-Oxford study stated:

“The lower risk of IHD among individuals consuming a vegetarian diet can be largely explained through reduced levels of well-established risk factors for IHD, such as non-HDL-cholesterol concentrations and systolic blood pressure. Vegetarians had a better lipid profile than did nonvegetarians, probably because of a higher ratio of polyunsaturated to saturated fat in their diet and a lower BMI.”

There is one caveat, however: the aforementioned analysis of 5 studies, when it looked in closer detail at the kinds of diets that were being studied, found:

“Further categorization of diets showed that, in comparison with regular meat eaters, mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans.”

While the association with lower risk of heart disease of both lacto-ovo vegetarianism and pescetarianism (people who eat fish but not meat) is clearly stronger than the association of occasional meat-eating, these results do suggest that it is still possible to reduce the risk of heart disease to some extent as a meat-eater. Despite this, these results, as well as the fact that meat in general is high in saturated fat, which causes an increase in levels of LDL cholesterol, also suggest that it is harder to reduce one’s risk of cardiovascular disease as a meat-eater than as a vegetarian, particularly if the saturated fat in meat is being replaced by polyunsaturated – and most likely monounsaturated – fats in a vegetarian diet. Indeed, as this detailed review of the evidence on healthy eating states:

“…the evidence from epidemiologic, clinical, and mechanistic studies is consistent in finding that the risk of CHD is reduced when SFAs are replaced with polyunsaturated fatty acids”

All of this means that every piece of meat being eaten is a wasted chance to replace some saturated fat in the diet with healthier unsaturated fats, thereby reducing one’s risk of cardiovascular disease.

Cancer and vegetarianism

Red meat, particularly processed meat such as bacon, salami, ham, and sausages, has been strongly linked with an increased risk of cancer. A 2012 study conducted by researchers at Harvard University, pooling the results from two large cohort studies, giving a total sample size of over 120,000 men and women who were followed for a number of years, found that both unprocessed and processed red meats increase the risk of cancer. This was after controlling for a number of factors, including body mass index, age, smoking status, consumption of grains, fruits and vegetables, family history of cancer, alcohol intake and physical activity level.

However, another study, published in 2013 by Oxford University, only found that processed meat increases the risk of cancer, not unprocessed meat. Therefore, it is reasonable to conclude that processed meat should be kept off the menu, and that further research into unprocessed red meat should be carried out.

In the meanwhile, various mechanisms by which red meat and processed meat could contribute to an increased risk of cancer have been proposed, meaning that these correlations can plausibly be instances of causation, particular as various other factors, particularly in the Harvard Study, were likely ruled out.

Do these associations of processed meat, and possibly red meat, with a higher risk of cancer have any real effect on the cancer risk of vegetarians as a group, though? There is conflicting evidence on this issue.

Some studies have found a decreased risk of overall cancer in vegetarians compared with non-vegetarians, although in the majority of studies which have found a link, it is only of certain cancers that there is a decreased risk. Some, meanwhile, have found no decreased risk. The literature taken as a whole, though, does support the hypothesis that there is a lower rate of cancer incidences in vegetarian populations.

If it is only red meat, or processed red meat, that causes cancer, and the evidence is somewhat misty when it comes to studying vegetarian and non-vegetarian populations in terms of cancer, then this once again suggests that health-conscious meat-eaters can reduce their cancer risk. Again, however, it may be harder for them to do so – vegetarians are much less likely to be tempted by the hot dog while at a restaurant and the bacon rasher that’s sitting in the freezer.

Diabetes, obesity and vegetarianism

Obesity is one of the key factors leading to diabetes, which is why obesity and diabetes have been grouped together in this section. Other factors include genetics, physical activity and diet.

A number of studies have shown that meat intake may be associated with obesity. This 2009 study, for example, found “positive associations between MC and risk for obesity and central obesity.” Meanwhile, this 2011 study of European adults similarly found that “protein from food items of animal origin, especially meat and poultry, seemed to be positively associated with long-term weight gain.”

More specifically, some studies have found that processed meat and red meat consumption in particular is linked to an increased risk of diabetes. A 2002 study of 42,504 males found that frequent consumption of processed meats may increase risk of type 2 diabetes. Meanwhile, even after adjusting for other variables, this 2011 Harvard study found that consumption of both unprocessed and processed red meat was linked with an increased risk of diabetes, and that replacing one serving of red meat per day with a serving of nuts, low-fat dairy and whole grains per day could decrease risk of Type 2 diabetes by up to 35%.

If meat is associated with an increased risk of obesity, which in turn leads to an increased risk of diabetes, as well as an independent increased risk of diabetes, particularly from processed meat, then we should see vegans and vegetarians contracting diabetes less. And this is precisely what this 2009 analysis of the Adventist Health Study-2 found, concluding:

all variants of vegetarian diets (vegan, lacto-ovo, and pesco- and semi-vegetarian) were associated with substantially lower risk of type 2 diabetes and lower BMI than nonvegetarian diets. The protection afforded by vegan and lacto-ovo vegetarian diets was strongest.

Indeed, prevalence of diabetes in vegans was 2.9%; in lacto-ovo vegetarians it was 3.2%; in pescetarians it was 4.8%; in semi-vegetarians it was 6.1%, while in non-vegetarians it was 7.6%. This appears to show a clear spectrum between amount of animal products eaten and prevalence of diabetes.

Another 2011 analysis of the Adventist Health Study-2 found broadly similar results, with a vegan diet offering the most protection against diabetes and diabetes being most prevalent amongst those eating a non-vegetarian diet. Specifically, cases of diabetes developed in 0.54% of vegans, 1.08% of lacto ovo vegetarians, 1.29% of pesco vegetarians, 0.92% of semi-vegetarians and 2.12% of non-vegetarians. Importantly, the study controlled for a number of factors, including age, gender, education, income, television watching, physical activity, sleep, alcohol use, smoking and BMI. It concluded that “vegetarian diets were associated with a substantial and independent lower incidence of diabetes [amongst] non-Black and Black participants, indicating the potential of these diets to stem the current diabetes epidemic.”

The literature, therefore, is consistent in finding that a vegetarian diet is highly likely to protect against obesity and diabetes.

Overall mortality and vegetarianism

As we would expect from the information above, studies have found that vegetarians have a lower total mortality than meat-eaters, with this 2013 study concluding: “vegetarian diets are associated with lower all-cause mortality and with some reductions in cause-specific mortality.”

It is worth noting that another study by Key et al. in 2003, which included “health-conscious” meat-eaters as well as vegetarians, found no significant difference in overall mortality between vegetarians and non-vegetarians. This, again, suggests that health-conscious meat-eating is a perfectly viable option, but that, without consciously thinking about health, a vegetarian diet is more suitable.

Conclusions

It is very likely that the average vegetarian is at lower risk of suffering from heart disease and diabetes compared with the average meat-eater. Concerning cancer, the weight of the evidence does suggest that vegetarians have a lower risk of contracting certain cancers compared with the average meat-eater, but more research should be done on this issue. As for morality, it is likely that the average vegetarian has a lower risk of premature mortality than the average meat-eater. But, for many of these issues, a health-conscious meat-eater would probably have the same risk as the average vegetarian.

Put simply, it is easier to be healthy on a vegetarian diet and, if you’re willing to keep away from sugary products such as sweets and soft drinks, but you’re not willing to do in-depth research into nutrition, a vegetarian diet will keep you healthier than an omnivorous diet. An average vegetarian like this will have a lower risk of contracting the above diseases than the average meat-eater, simply because saturated fat causes an increased risk of heart disease as well as the fact that red meat, particularly processed meat, has been linked to an increased risk of both cancer and diabetes.

Vegetarianism – the moral, eco-friendly choice?

The topic of eating meat can often devolve into both sides of the debate making defensive, emotionally-charged arguments. This post will examine the moral and environmental issues and ultimately list some common objections to vegetarianism and why I reject them. In a later post, I will examine the health claims made by proponents of both omnivorous diets and vegetarian/vegan diets.

The moral argument – animals

Nonhuman animals, including cows, pigs, chickens, ducks and other animals whose flesh we consume, are sentient beings; that is, they have the capacity to feel pain and suffer. Many lines of evidence appear to demonstrate this. Firstly, using argument-by-analogy, we can observe the same behaviours in nonhuman animals that we do in humans when they are in pain and are suffering: screaming, writhing, facial contortions, attempts to avoid the source of the pain, and so on. Secondly, all vertebrates have nocicpetion – the process by which the body detects harmful stimuli and initiates a reflex response. Third, the evidence suggests that many nonhuman animals, particularly mammals and birds, have some form of consciousness. For example, Cambridge University released the Cambridge Declaration on Consciousness, which had this to say:

“The neural substrates of emotions do not appear to be confined to cortical structures. In fact, subcortical neural networks aroused during affective states in humans are also critically important for generating emotional behaviors in animals. Artificial arousal of the same brain regions generates corresponding behavior and feeling states in both humans and non-human animals. Wherever in the brain one evokes instinctual emotional behaviors in non-human animals, many of the ensuing behaviors are consistent with experienced feeling states, including those internal states that are rewarding and punishing. Deep brain stimulation of these systems in humans can also generate similar affective states.”

Thus, it is not surprising that many of the responses to pain that nonhuman animals have: respiratory and cardiovascular changes, the secretion of stress hormones and unusual behaviour patterns, are “complex and coordinated” responses rather than simple reflex actions. In other words, they involve the brain. So, while nonhuman animals cannot verbally communicate their suffering to us in terms of language, it’s clear that they most likely are suffering and do feel pain – newborn babies and severely intellectually disabled humans can’t use language either, but we nevertheless assume that they can feel pain and suffer using argument-by-analogy as well as looking at their physiology.

Having established that nonhuman animals can feel pain and suffer, most people would agree that it is our duty to minimise the suffering in the world, and according to one of the most basic ethical principles, adhered to in various cultures, the Golden Rule, we wouldn’t like to be treated in a way that would make us suffer, so we shouldn’t treat other beings in ways which make them suffer. Indeed, we should be respecting the preferences of sentient beings, and the more preferences adhered to, the greater the good. Some people may posit that only human preferences matter, but this is based on nothing more than speciesism – the irrational discrimination against other species. Some may argue that humans are worth more because they’re more intelligent, more emotional, or both, but intelligence and complex emotional and social bonds have been observed in many nonhuman animals, from elephants to chimpanzees to pigs. Furthermore, not all human beings are as intelligent as nonhuman animals; for instance, newborn babies and severely intellectually disabled human beings are not as intelligent as some adult non-human animals, but would making them suffer be justifiable? The vast majority of people would answer ‘no’ to this question, but may still postulate that these individuals’ membership of the species homo sapiens is enough to make them more worthy than nonhuman animals. Again, no rational justification is given for this: it’s pure speciesism. Thus, we have established that we should minimise the suffering of all sentient beings, whatever the species, and one of the best ways to do this is vegetarianism, as it reduces the suffering and stress that nonhuman animals go through in the often long-winded process of meat production.

The Environmental Argument

According to the United Nations Food and Agriculture Organisation, the livestock sector contributes to at least 14.5% of global greenhouse gas emissions, roughly in line with its previous estimate, published in its 2006 report Livestock’s Long Shadow, which estimated that it contributes to 18% of greenhouse gas emissions. The magnitude of the figure, however, is disputed – the highly respected Worldwatch Institute, for instance, states that the livestock and meat sector actually contributes to 51% of global greenhouse gas emissions. Taking the conservative figure of 14.5%, around the magnitude of the transport sector’s contribution to global warming, the livestock sector is still one of the top three contributors to global warming.

The reasons are straightforward – the predominant way of producing meat in the United States – intensive farming, is spreading elsewhere. This means that the meat industry produces greenhouse gas emissions by having to run farms to produce grain, which is then transported to the livestock farms in which the animals are kept, which itself uses energy to run. On these farms, the cows in particular produce copious amounts of methane, another greenhouse gas. They are then transported in CO2 emitting vehicles to the slaughterhouse, which itself uses fossil fuel energy. Finally, the meat is then transported to the shops. On top of this, however, we have to add the impacts from deforestation, which is occurring to gain more land to raise animals on.

These figures have led the United Nations Environment Program to urge people to become vegetarian and vegan:

“Impacts from agriculture are expected to increase substantially due to population growth and increasing consumption of animal products. Unlike fossil fuels, it is difficult to look for alternatives: people have to eat. A substantial reduction of impacts would only be possible with a substantial worldwide diet change, away from animal products.”

The moral argument – humans

Back to morality, now, and the moral argument against meat-eating doesn’t merely involve the status of nonhuman animals. Humans, it appears, are also negatively affected by the meat industry.

Indeed, simply breeding animals for consumption can also have a negative effect on human health. As Dr. Thomas Frieden, director of the Centers for Disease Control and Prevention wrote in a letter to the US Congress, there is “a clear link between antibiotic use in animals and antibiotic resistance in humans”. The existence of this simultaneously potential and existing problem, as attested to by Dr. Frieden, is corroborated by numerous studies into the link between use of antibiotics in animal feedstock and antibiotic resistance. Further, it is widely acknowledged that the agriculture industry is among the most dangerous in the world for workers, with the International Labour Organisation stating that agriculture is one of the three most dangerous, on par with mining and construction. Indeed, the World Bank, in 2008, reported that around half of all on-the-job fatalities occur in the agricultural sector. While it could be argued that conditions simply need to be improved, the job of slaughtering nonhuman animals is intrinsically dangerous and traumatic. An industry which cannot even protect the welfare of its workers is unlikely to be able to protect the welfare of its products, namely nonhuman animals. Its treatment of its workers is indeed a microcosm for the treatment of its nonhuman animals: both are treated as economic units in an industry in which efficiency is everything – as Human Rights Watch has noted in its detailed criticism of the meat and poultry industry, “[a]utomated lines carrying dead animals and their parts for disassembly move too fast for worker safety.”

Conclusions

Moral judgements, under which judgements about the environment come, are up to the individual, and individuals often have different outlooks on morality. The information above is “merely” factual: consuming meat causes harm to sentient beings and the environment. It is up to the individual to act upon facts though, and decide whether they want to act upon them at all.

Mobile phones and cancer: what does the evidence suggest?

Current evidence shows that there is no link between mobile phone usage and cancer.

The largest study of its kind ever carried out, Interphone, which examined the long-term effects of mobile phone usage, was published in 2011. The authors concluded:

“Overall, no increase in risk of glioma or meningioma was observed with use of mobile phones. There were suggestions of an increased risk of glioma at the highest exposure levels, but biases and error prevent a causal interpretation.”

Indeed, while it was widely reported in the press that high exposure levels led to an increase of glioma, a further analysis of the study put forward a number of reasonable explanations for this result. For example, “phone use was under-estimated by light users and over-estimated by heavy users”, as evidence from a sub-study showed.

The study was partly funded by the Mobile Manufacturers’ Forum and the GSM Association. However, provision of funds to the INTERPHONE study investigators via the UICC was governed by agreements that guaranteed INTERPHONE’s complete scientific independence. Thus, the study was not commercially biased in any way. Moreover, the fact that some anti-cell phone activists, such as Mercola, have seized on the suggestions of an increased risk of glioma at the highest exposure levels suggests that they are not concerned about the partial funding by the Mobile Manufacturers’ Forum either.

In the absence of any known plausible mechanism by which mobile phones can cause cancer, any outliers should be viewed with scepticism. As the National Cancer Institute summarised:

“It is generally accepted that damage to DNA is necessary for cancer to develop. However, radiofrequency energy, unlike ionizing radiation, does not cause DNA damage in cells, and it has not been found to cause cancer in animals or to enhance the cancer-causing effects of known chemical carcinogens in animals.”

Another line of evidence demonstrating that mobile phone usage is unlikely to be causing brain cancer is the fact that, according to the National Cancer Institute:

“rates for new brain and other nervous system cancer cases have been falling on average 0.2% each year over 2002-2011.”

If mobile phone usage were causing brain cancer, we would expect, at the very least, a correlation between brain cancer rates and mobile phone usage. By contrast, mobile phone usage has gone up whereas brain cancer rates are decreasing.

Global Warming: The Evidence

Global warming remains a highly contentious and politicised issue, and is one of many unfortunate examples in which the scientific evidence and consensus is subject to denial by large portions of the population.

What is clear is that global warming is not a contentious issue within the scientific community. The Intergovernmental Panel on Climate Change has stated:

Scientific evidence for warming of the climate is unequivocal.

Therefore, it’s unsurprising that a 2013 study found that around 97% of climate scientists agree that global warming is occurring, a figure derived from both evaluations of the abstracts of 4,013 peer-reviewed scientific papers as well as 1,200 authors’ own ratings of their peer-reviewed scientific papers in terms of the position they took on anthropogenic global warming. Indeed, the latter approach found that “97.2% endorsed the consensus” that the theory of anthropogenic global warming is in line with the evidence, while the former found that 97.1% endorsed the consensus.

Some climate change deniers have attempted to undermine this consensus, claiming that only 52% of meteorologists believe that global warming is mostly caused by human activity. The information that they often omit is that the survey which found this only included the opinions of 25% of people in the American Meteorological Society, many of whom are not experts in the field of climate science. Indeed, the survey in question actually found that among the meteorologists whose primary field of expertise is climate science, “78% of climate experts [in the survey] actively publishing on climate change” believe that humans are the primary cause of global warming. It’s also important to stress that the 97.2% figure comes from a survey of thousands of peer-reviewed scientific studies in the field of climate science from around the world. This survey, by contrast, collects the opinions of certain meteorologists in a certain meteorological society in the United States, and even then shows a clear majority (78% of climate experts) who believe that humans are the primary cause of global warming. In addition, the 97% figure was found in a study conducted three years prior to the aforementioned one, finding:

97–98% of the climate researchers most actively publishing in the field surveyed here support the tenets of ACC outlined by the Intergovernmental Panel on Climate Change.

This demonstrates that there has been nothing in the years between 2010-2013 which has undermined the credibility of the theory of anthropogenic global warming.

The Evidence

The first line of evidence which may demonstrate that humans are causing global warming is the correlation between the CO2 levels and global temperatures – as one has risen, so has the other. It is widely known that humans are contributing largely to the rise in CO2 levels through combustion and deforestation. But, correlation does not equal causation. To find out whether something is causing something, we need a mechanism, and the mechanism by which CO2 traps heat was discovered as early as the 19th Century by Joseph Fourier, and expanded upon by John Tyndall and others: the greenhouse effect.

Thus, we have established that humans are contributing to a rise in carbon dioxide which can and does plausibly raise temperature levels. Nevertheless, the extent to which humans are causing temperature levels could still be limited by other factors. However, there is ample evidence which suggests that other factors are not playing a major role in global warming. The first reason to doubt the major role of other factors is that ice cores in Greenland show that non-artificial climate change has, in the past, taken place over thousands and millions of years, whereas global warming that is occurring today is taking place in tens of years.

One specific factor which many global warming skeptics and deniers state may be driving the warming trend is the sun. Nevertheless, since 1975, the sun has shown a slight cooling trend, which continued through the 2000s and resulted in an extremely deep solar minimum from 2007-2009. Taking into account pre-1975 and post-1975 data, Benestad and Schmidt concluded, in their 2009 study:

[T]he most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980.

Additionally, cosmic rays have been hypothesized to be contributing to global warming, but numerous papers have discredited this hypothesis. A September 2013 paper, for instance, concluded:

…there is little empirical evidence that links GCR [Galactic Cosmic Rays] to the recent global warming.

The predicted effects of global warming are also being observed. For example, according to the National Oceanic and Atmospheric Administration in the United States, global sea levels rose by 1.7mm per year in the last century, corresponding to an increase of 17cm overall. Overall glacier and ice sheet volume is also declining rapidly. Specifically, Arctic sea ice has been steadily declining by 3 to 4% per decade due to climate change. While, in the Antarctic, the surface has been warming at a rate of 0.1C per decade, meaning that the Antarctic Ice Sheets, overall, lost approximately 1350 Gt between 1992 and 2011 at an average rate of 70 Gt per year. Indeed, Antarctica is losing ice mass at an accelerating rate, despite the claim often made by deniers that Antarctica is experiencing in ‘increase in ice extent’, because what they’re actually referring to is the temporary winter sea ice extent, the increase in which was explained in this 2009 study, which found:

The autumn increase in the Ross Sea sector is primarily a result of stronger cyclonic atmospheric flow over the Amundsen Sea.

Essentially, the hole in the ozone layer above the South Pole has caused stratospheric cooling, creating cyclonic winds which push sea ice around, which in turn creates polynyas, areas of open water which contribute to increased sea ice production.

The global warming ‘pause’ is largely a myth

A typical claim from a global warming denier that one will hear today is that Earth has not warmed since 1998. This is a typical anti-scientific claim, as it involves cherry-picking specific periods of time to prove a point. What’s more, using data from 1998 onwards is particularly egregious because the period between 1997-98 included an El Nino event, which caused temperatures to soar in 1998: it was the warmest year on record at the time. After such an unusually warm year in which temperatures were far above the mean, regression to the mean invariably occurred, causing it to superficially appear as if there was a ‘pause’ or ‘cooling’.

Despite this regression to the mean, recent data have even shown that 2010 and 2005 were warmer than 1998, and that 9 out of the 10 warmest years on record have occurred in the 2000s. Therefore, the decade of 2000-2010 was the warmest full decade on record, and 2011-2020 is, at the moment, looking as if it will be even warmer. I also say ‘recent data’ because the UK Met Office’s HadCRUT3 dataset was updated in 2012 to HadCRUT4, which took into account more measurements around the Arctic area, resulting in higher temperatures for 2010 and 2005 relative to 1998, a finding corroborated by NASA’s GISS dataset. Therefore, warming hasn’t even paused.

Nevertheless, it is true that the rate of warming has slowed. The most likely explanation for this is that more than 90% of the Earth’s heat goes into the oceans. Indeed, when we factor in ocean temperatures, global average temperatures are actually accelerating, with this 2013 study stating:

In the last decade, about 30% of the warming has occurred below 700 m, contributing significantly to an acceleration of the warming trend.

The available empirical evidence therefore points to the likely possibility that the strengthening of ocean heat uptake efficiency is a significant cause of the slowing down of the warming of the Earth’s surface. As Masahiro Watanabe and his colleagues put it in this study, the so-called ‘pause’ likely has

…an internal origin… associated with active heat uptake by the oceans.

While ocean heat content seems to be a significant factor in the so-called ‘pause’, as confirmed even more recently by another study looking specifically at the Atlantic Ocean, it has also been suggested in one study that if we had today’s modelling technology in the 1990s, the slowdown in the rate of surface temperature warming could have been predicted, implying that the slowdown may have partly been due to natural variability.

In light of the evidence, the UK Met Office makes three conclusions:

First, periods of slowing down and pauses in surface warming are not unusual in the instrumental temperature record. Second, climate model simulations suggest that we can expect such a period of a decade or more to occur at least twice per century, due to internal variability alone. Third, recent research suggests that ocean heat re-arrangements, with a contribution from changes in top of the atmosphere radiation, could be important for explaining the recent pause in global surface warming.

Conclusions

Across the world, extreme weather conditions are becoming more prevalent. The National Oceanic and Atmospheric Administration has detailed records of this for the United States. Meanwhile, the UK witnessed its wettest winter on record in 2013, in line with the prediction of global warming that increased convection and evaporation will result in more instances of extreme rainfall events. And, in Australia, 2013 was the warmest year on record.

Ideological concerns that action on global warming may undermine a particular economic or political system never justifies denial of the evidence in support of the theory of AGW. In fact, studies are beginning to show that action on global warming doesn’t have to slow down economic growth at all. In essence, there are plenty of potential solutions from across the political spectrum, which should each be put forward and evaluated on their merits, but denial of the problem itself should never be resorted to.

Ending the evolution “controversy” once and for all

Evolution by natural selection is as close to a fact as you can possibly get. It’s a scientific theory; that is, it’s backed up by objective, falsifiable, empirical evidence – it’s not simply a ‘guess’ or an ‘idea’ or ‘just a theory’ – scientific theories aren’t colloquial ‘theories’. This is why every national academy of science and scientific organisation which has made a statement on the evolution-creation “controversy” has been fully supportive of the theory of evolution. The InterAcademy Panel, for instance, consisting of more than 100 national science academies, endorsed the following statement:

Since its first appearance on Earth, life has taken many forms, all of which continue to evolve, in ways which palaeontology and the modern biological and biochemical sciences are describing and independently confirming with increasing precision. Commonalities in the structure of the genetic code of all organisms living today, including humans, clearly indicate their common primordial origin.

Meanwhile, in 2005, the National Science Teachers Association, a professional association made up of 55,000 science teachers, said of Intelligent Design – the only alternative “hypothesis” there is to evolution:

intelligent design is not science… it is simply unfair to present pseudoscience to children in the science classroom

In the same year, 38 Nobel Laureates issued a statement stating the following:

intelligent design is fundamentally unscientific; it cannot be tested as a scientific theory

Finally, it’s worth noting that at least 47 of the Nobel Prize winning bodies of work for medicine or physiology have depended on evolutionary theory, demonstrating its importance within science. (1)

In a nutshell, this shows that there is no debate in the scientific community over evolution by natural selection, and this is because of the evidence coming from at least 6 different independent scientific fields in support of evolution. Firstly, we’ll start off with the fossil evidence. Fossils are valuable, although not necessarily essential, in learning about the tree of life and they demonstrate that, over time, organisms have changed and become more complex, and are related to each other. To take a specific example, we can look at the fossil record of the horse – we start with Eohippus, or Hyracotherium, which was a small animal, the size of a fox, and we can then look at all of the intermediate species that existed between Eohippus and the modern horse – equus, and find that various features have changed – a 45 inch increase in size, the lengthening of the limbs and feet and the reduction of lateral digits, for example. (2) The earliest of these changes occurred during the transition of eohippus to orohippus, approximately 50 million years ago, which evolved an elongated head, slimmer forelimbs and longer hind legs, which increased its proficiency in jumping. (3) In sum, with this example, we can see that over millions of years, eohippus has gradually, going through at least 12 different transitional species in the process, evolved into the modern horse.

When it comes to fossils, a common complaint that one might hear from religious people who deny evolution is that “missing links” have not been found; that is, the exact common ancestor of two certain groups or species. Firstly, this is axiomatically incorrect because a number of “missing links” or intermediate forms have been found. But, secondly, their insistence upon this demonstrates their misunderstanding of evolution. The fact of the matter is that as long as we find transitional forms that fit with the predictions of evolution, we will know that the prediction is correct. For example, biologists do not think they have yet found the exact common ancestor of birds and reptiles, but they have found fossils of a number of birds who have reptilian features, and vice-versa, which demonstrates that birds do share a common ancestor with reptiles. One of the earliest known birds which also had reptilian features was archaeopteryx, which lived around 150 million years ago. (4) This, and many other fossils like it, demonstrates that birds share a common ancestor with reptiles and that groups of animals were different in the past. There is also an abundance of fossils in support of human evolution, specifically common ancestry with chimpanzees, for example the famous Homo erectus and Homo habilis, as well as Australopithecus afarensis, a species which lived between 3 and 4 million years ago and had a number of human characteristics, including arches in the foot (5) but also many characteristics of a chimpanzee, including the smaller sized brain.

Evidence also comes from molecular biology and genetics. All living organisms have been found to share DNA in common and the genetic record corroborates the fossil record in that we see the same tree of life – the fossils, for example, suggest that apes are the closest cousins to humans, and that is exactly what we see in the DNA record, with chimpanzees being our closest cousins sharing 98.8% of DNA with us. (6) This shows that humans and chimpanzees are related and share a common ancestor. Not only that, but pseudo genes also rule out design as an explanation for the genetic observations – we share non-functional DNA with other organisms as well as functional DNA (7), but seeing as this DNA has no use, why would an intelligent designer even insert it into our genetic code in the first place, especially as some estimates have it as making up 99% of our genetic code. A specific chromosome illustrates nicely our common lineage with chimpanzees and other hominids, namely chromosome 2. This is because hominids, including chimpanzees, have 24 pairs of chromosomes, yet humans only have 23 pairs of chromosomes. The cause of the missing chromosome is that human chromosome 2 is a fusion of two ancestral chromosomes, and this is supported by the fact that chromosome 2 in humans has a near identical DNA sequence to that of two separate chromosomes in chimpanzees (8), demonstrating that those two separate chromosomes fused together to form human chromosome 2. Of course, those in the intelligent design community might argue that the intelligent designer simply used the same DNA that was in the two chimpanzee chromosomes but decided to put it in only one chromosome in humans instead. Not only does this seem incredibly far-fetched and have no evidence whatsoever to support it, but the presence of vestigial telomeres also supports the ancestral fusion model – telomeres are usually found at the ends of chromosomes, yet in chromosome 2, they’re also found in the middle, showing that two ends of our ancestral chromosomes fused together to form human chromosome 2. (9) This is why the biologist J.W. Ijdo concludes:

the locus cloned in cosmids c8.1 and c29B is the relic of an ancient telomere-telomere fusion and marks the point at which two ancestral ape chromosomes fused to give rise to human chromosome 2

Would an intelligent designer literally fuse together two chromosomes? Again, it seems unlikely, but I’m sure creationists could concoct some kind of scenario in which an intelligent designer would do this. This is exactly why scientists regard intelligent design as pseudoscience – it’s unfalsifiable. Chromosome fusion, by contrast, is an observed phenomenon in biology.

More evidence from molecular biology in support of evolution by natural selection comes from cytochrome C, which is a ubiquitous protein which exists in all living cells of every organism and performs very basic life functions. It is made up of 100-104 different amino acids, in a sequence, and as expected, similar organisms have similar or identical sequences of cytochrome C: for instance, humans and chimpanzees have identical sequences as do chicken and turkeys, as do pigs cows and sheep. Meanwhile, rhesus monkeys’ sequences are identical to humans and chimpanzees’ except for one amino acid. (10) This is, of course, strong evidence, but it’s even stronger evidence for common ancestry because the protein cytochrome C has a high degree of functional redundancy; that is, changing the amino acid sequence barely affects the functionality of the protein, meaning that it’s far more likely that humans and chimpanzees, for example, share an identical sequence due to random mutation and common ancestry rather than due to an intelligent designer, because an intelligent designer could have made the sequence identical in every single organism and it wouldn’t have affected how it worked! Only random mutation would, for no reason, alter the sequence when no alteration was needed.

Moving into comparative anatomy, there is a plethora of evidence that supports evolution by natural selection. To take a specific example, the recurrent laryngeal nerve in, especially, giraffes, provides evidence that giraffes’ ancestry lies in the ocean and that intelligent design is, again, false. The recurrent laryngeal nerve, rather than travel an optimal route of just several inches, takes almost a 15 ft detour by passing from the brain down into the neck, past the heart, round the aorta and through the neck again to the larynx. Natural selection explains this perfectly – the nerve’s route would have been direct in the fish-like ancestors of modern tetrapods, traveling from the brain, past the heart, to the gills (as it does in modern fish). Over the course of evolution, as the neck extended and the heart became lower in the body, the laryngeal nerve was caught on the wrong side of the heart. Natural selection gradually lengthened the nerve by tiny increments to accommodate, resulting in the circuitous route now observed. (11) However, there’s no reason at all to suggest a reason as to why an intelligent designer would create such a professedly illogical route for a nerve.

Perhaps the most obvious evidence for evolution by natural selection is the fact that it has been observed. One of many examples is Dr. Richard E. Lenski’s long-term experiment with e.coli. He started off with 12 identical populations of asexual e.coli, and by changing the environments in which the populations were living, induced many evolutionary adaptations in them due to beneficial random mutations. Other observations include the evolution of elephants – ivory hunters obviously kill elephants with larger tusks, which means that smaller-tusked individuals may be at an evolutionary advantage. And, that’s exactly what we see – the Uganda Game Department, for example, published data showing that, over just 3 decades, the average tusk size of the elephants, most likely due to ivory hunting, decreased, as elephants who had smaller tusks had a larger chance of reproducing. Another observation of evolution before our very eyes is the case of Italian wall lizards – in 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. Decades later, Duncan Irschick, a professor of biology at the University of Massachusetts Amherst says that “striking differences in head size and shape, increased bite strength and the development of new structures in the lizard’s digestive tracts were noted after only 36 years, which is an extremely short time scale.” This was directly because of the change in the environment that the lizards were living in – observed changes in head morphology were caused by adaptation to a different food source. (12) According to Irschick, lizards on the barren island of Pod Kopiste were well-suited to catching mobile prey, feasting mainly on insects. Life on Pod Mrcaru, where they had never lived before, offered them an abundant supply of plant foods, including the leaves and stems from native shrubs. As a result, Professor Irschick observed that “individuals on Pod Mrcaru have heads that are longer, wider and taller than those on Pod Kopiste, which translates into a big increase in bite force… Because plants are tough and fibrous, high bite forces allow the lizards to crop smaller pieces from plants, which can help them break down the indigestible cell walls.”

The geographical distribution of animals also illustrates how much better the explanatory power of evolution by natural selection is compared to creationism or ID. For instance, kangaroos and other marsupials are only found in Australia, an observation that can easily be explained by evolution by natural selection. By contrast, according to creationism, there was a massive flood 4000 years ago which wiped out every organism on the planet bar two of each kind. After the flood was over, the animals disembarked from the Ark in the Middle East. So, why did all the kangaroos go to Australia? And, why do we not find a single fossil of a kangaroo anywhere between the Middle East and Australia?

Notes

1. James McCarter, “Evolution is a Winner – for Breakthroughs and Prizes”, National Center for Science Education, originally published in the St. Louis Post-Dispatch, 2005-10-09.
2. MacFadden, B. J. (1999), Fossil Horses: Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge & New York: Cambridge University Press. ISBN 0-521-47708-5
3. MacFadden, B. J. (1976). “Cladistic analysis of primitive equids with notes on other perissodactyls”, Syst. Zool 25 (1): 1–14. Doi: 10.2307/2412774. JSTOR 2412774
4. Alan Hamilton Turner, Peter J. Makovicky and Mark Norell (2012). “A review of dromaeosaurid systematics and paravian phylogeny”, Bulletin of the American Museum of Natural History 371: 1–206 doi:10.1206/748.1
5. Ward, C. V.; Kimbel, W. H.; Johanson, D. C. (2011). “Complete Fourth Metatarsal and Arches in the Foot of Australopithecus afarensis”. Science 331 (6018): 750.
6. Chen FC, Li WH (2001). “Genomic Divergences between Humans and Other Hominoids and the Effective Population Size of the Common Ancestor of Humans and Chimpanzees”, American Journal of Human Genetics 68 (2): 444–56.
7. Petrov DA, Hartl DL (2000). “Pseudogene evolution and natural selection for a compact genome”, J Hered, 91 (3): 221–7.
8. Yunis and Prakash; Prakash, O (1982). “The origin of man: a chromosomal pictorial legacy”. Science 215 (4539): 1525–1530
9. Ijdo, J. W.; Baldini, A; Ward, DC; Reeders, ST; Wells, RA (1991). “Origin of human chromosome 2: an ancestral telomere-telomere fusion”. Proceedings of the National Academy of Sciences 88 (20): 9051–5.
10. Lurquin PF, Stone L (2006). Genes, Culture, and Human Evolution: A Synthesis. Blackwell Publishing Incorporated. p. 79, ISBN 1-4051-5089-0
11. Dawkins, Richard (2009). The Greatest Show on Earth: The Evidence for Evolution. Bantam Press, pp. 364–365. ISBN 978-1-4165-9478-9.
12. Dawkins, Richard (2009). The Greatest Show on Earth: The Evidence for Evolution. Bantam Press, pp. 113-114. ISBN 978-1-4165-9478-9; see also Johnson, K, “Lizards Rapidly Evolve after Introduction to Island”, National Geographic, April 21st 2009.