I have several times now sounded warnings about the impact of climate change on health and the re-emergence of some infectious diseases.

Today I’d like to tell you about a remarkable theory that could have profound implications for how we see ourselves and our place in the world.

Dr. Nick Brooks from the Tyndall Centre for Climate Change Research at the University of East Anglia has recently proposed a remarkable hypothesis. It has long been assumed that civilization started where is did because conditions had become very hospitable, but people banded together for mutual protection and for hunting and agriculture.

By contrast, Nick Brooks proposes that severe climate change was the primary driver in the development of civilization. He proposes that without climate changes thousands of years ago, we might have remained farmers, herders and hunter-gatherers.

The early civilizations of Egypt, Mesopotamia, South Asia, China and northern South America were founded between 6000 and 4000 years ago when global climate changes, driven by natural fluctuations in the Earth’s orbit, caused a weakening of monsoon systems resulting in increasingly arid conditions. These first large urban, state-level societies and monumental architecture such as the pyramids, emerged because diminishing resources forced previously transient people into close proximity, in areas where water, pasture and productive land was still available.

It is certainly remarkable that all of these places where the first urban civilizations developed, arose in once humid and productive environments that are now largely covered by desert. One theory has been that many of these deserts, as well as the Sahara desert, were the result of over-grazing by goats.

In a presentation to the British Association Festival of Science earlier this month, Dr. Brooks said, “Civilization did not arise as the result of a benign environment which allowed humanity to indulge a preference for living in complex, urban, ‘civilized’ societies. On the contrary, what we tend to think of today as ‘civilization’ was in large part an accidental by-product of unplanned adaptation to catastrophic climate change. Civilization was a last resort - a means of organizing society and food production and distribution, in the face of deteriorating environmental conditions.”

He added something that we now see all over the world: for many, if not most people, the development of civilization meant a harder life, less freedom, and more inequality. The transition to urban living meant that most people had to work harder in order to survive, and suffered increased exposure to communicable diseases. Health and nutrition are likely to have deteriorated rather than improved for many.

The new research challenges the widely held belief that the development of civilization was simply the result of a transition from harsh, unpredictable climatic conditions during the last ice age, to more benign and stable conditions at the beginning of the Holocene epoch some 10,000 years ago.

This work also presents some profound philosophical implications, because it challenges deeply held beliefs about human progress, the nature of civilization and the origins of political and religious systems that have persisted to this day. It suggests that civilization may not be our natural state, but the unintended consequence of adaptation to climatic deterioration - a condition of humanity “in extremis.”

Dr Brooks said: “Having been forced into civilized communities as a last resort, people found themselves faced with increased social inequality, greater violence in the form of organized conflict, and at the mercy of self-appointed elites who used religious authority and political ideology to bolster their position. These models of government are still with us today, and we may understand them better by understanding how civilization arose by accident as a result of the last great global climatic upheaval.”

This is an extraordinary throwback to the ideas of romantic philosophers like Jean-Jacques Rousseau who contended that Man is good by nature, but it corrupted by society and civilization.

Though we need to continue to be very alert to the dangers inherent in climate change, could it be that it is actually an invitation to evolve?

I’m sure that you’ve heard the Robin Williams joke, “See, the problem is that God gives men a brain and a penis, and only enough blood to run one at a time.”

Well it may turn out that Robin was right for the wrong reason.

Typically thought of as the “male hormone,” testosterone plays key roles in maintaining health and wellness in both men and women. It is true that most men produce about twenty ties as much testosterone as women, but in both sexes, it is involved in energy, libido, and immune function and helps protect against osteoporosis. It is also essential for the normal development, growth and functioning of the brain. In small amounts it may also be neuroprotective.

However, too much of a good thing can quickly turn bad. Researchers from the Departments of Pharmacology and Cellular and Molecular Physiology at Yale University in New Haven, Connecticut have just published an important study of apoptosis or programmed cell death in neurons exposed to excessive amounts of testosterone. Apoptosis is a process for disposing of un-needed or unwanted cells, but if it gets out of control, it can begin to remove cells that should have been left alone. Apoptosis is thought to pay a role in illnesses including Alzheimer’s disease and schizophrenia.

While too much testosterone destroyed nerve cells, estrogen appeared to be neuroprotective: there was less cell death in the presence of the hormone.

This new finding has a number of important practical implications.

Testosterone is one of the hormones abused by some athletes. It certainly can enable them to pump up their muscles, but it may also make them aggressive. Now we know that the practice may also kill neurons. And loss of brain cells is associated with a loss of brain function. This is yet another reason why people should think long and hard before they try to use testosterone supplements. The concentrations used in the experiments were very close to what we might expect to see in someone supplementing with the hormone.

These effects of testosterone on neurons will likely have long term effects on brain function. Though you do generate new connections and some new neurons throughout life, there is a limit to how many you can put back, once they’ve been tainted by testosterone.

And since this is election year here in the United States, I’m sure that we’re now going to have to have a string of off-color jokes about the esteemed Governor of California….

“Not to have control over the senses is like sailing in a rudderless ship, bound to break to pieces on coming in contact with the very first rock.”
–Mahatma Gandhi (Indian Nationalist and World Teacher, 1869-1948)

The Mahatma’s statement could apply to most people stuggling with attention deficit disorder.

There is an important idea in neurology and psychology called “Executive functioning.” This refers to our ability to be able to make and carry out plans, direct our attention, focus and also to control our internal states: our impulses and emotions and to be able to switch from one task to another. In other words it is a key part of our ability to self-regulate our behavior, mind and emotions.

Most evidence now indicates that executive function is mediated by the regions of the dorsolateral prefrontal cortex. It happens that these same regions are amongst those that seem to undergo beneficial changes in people who practice meditation.

For people interested in attention deficit disorder, I’d like to recommend a book, “Attention Deficit Disorder: The Unfocused Mind in Children and Adults,” by Thomas E. Brown. In the book he encapsulates some up-to-date research indicating that one way of conceptualizing some of the difficulties faced by people with attention deficit disorder, is to break them down into the six major “domains” of executive functioning:

1. Activation: Organizing, prioritizing and getting to school or work
2. Focus: Tuning in, maintaining focus and shifting attention
3. Effort: Sustaining effort, regulating alertness and adjusting processing speed
4. Emotions: Modulating emotions and managing frustration
5. Memory: Holding and manipulating information and retrieving memories
6. Action: Monitoring and regulating actions

It can be very helpful for people to understand why they face the problems that they do, and how each may be amenable to a different type of help.

What we have done below is to re-draw and slightly simplify an extremely helpful diagram from Dr. Brown’s book, that will make it easier for you to see that kind of problems you or a loved one may be facing, and how treatment and coping strategies will be directed toward whichever of these is causing the most trouble in a person’s life.

(You can click on the diagram to see a large version of it.)

“Those who cannot remember the past are condemned to repeat it.”
–George Santayana (Spanish-born American Philosopher, Humanist and Poet, 1863-1952

I’m a bit of a history buff, and like most armchair historians who know something about medicine, it’s always interesting to try and work out why some civilizations underwent rapid collapse. Was the decline of Rome really due to malaria, lead pipes or societal malaise? Why did the huge Khmer Empire in Southeast Asia vanish in just a few years? Was it ecological failure, disease or pollution? The list goes on.

The map shows some of the major empires in Eurasia around A.D.1200. See how few still exist.

One of these historical puzzles seems to be close to solution, and provides important lessons for us today. In the second year of the Peloponnesian war, the city state of Athens was devastated by an epidemic known as the Plague of Athens. Historians and scientists have been debating the cause of the Plague for years. When I was a young schoolboy, the debate was already a century old.

According to historical records, the plague began in Ethiopia and passed through Egypt and Libya to Greece in 430-426 B.C.E. It forever changed the balance of power between Athens and Sparta, effectively ending the Golden Age of Athenian dominance in the ancient world. It is thought that up to one third of the Athenians, including their leader, Pericles, dies in the epidemic. Most of our knowledge about the Plague came from the fifth century B.C.E. Greek historian Thucydides, who himself was taken ill with the plague but recovered. Though Thucydides gave a detailed description, researchers have not managed to agree on the identity of the plague. Several diseases have been suggested, including bubonic plague, smallpox, anthrax and measles.

Now a study in the International Journal of Infectious Diseases helps answer this question that has puzzled historians for decades: What destroyed ancient Athens, the cradle of democracy? Analysis carried out by Manolis Papagrigorakis and colleagues from the University of Athens, using DNA collected from teeth obtained from an ancient Greek burial pit points to typhoid fever as the disease responsible for this devastating epidemic. Typhoid fever (or enteric fever) is an illness caused by the bacterium Salmonella Typhi. It is common throughout the world, more so in tropical and semitropical climates. It is transmitted by ingestion of food or water contaminated with feces from an infected person.

There are some classic physical symptoms of typhoid: In the first phase there is coughing, a fever, sweating and a rash of “rose spots,” particularly on the abdomen. Typhoid has a unique feature: normally when you get a fever your pulse rate increases. In typhoid the pulse slows. In the second phase of the illness people get severe headaches muscle pain and diarrhea. And it is the diarrhea that usually dehydrates and kills people. You may have heard about typhoid in the last few days after publication that a well-known terrorist was supposed to have died from it.

It is humbling to realize that entire civilizations have been put to the sword, not by force of arms, but by microbes. Climate change or a breakdown in sanitation of food inspection can all lead to a reappearance of typhoid: within the last hundred year there have been outbreaks all over the Western world, and it is endemic in many less developed countries.

I mention in Healing, Meaning and Purpose that one of the reasons for the persistence of the gene for cystic fibrosis is thought to be that carriers of the gene are resistant to typhoid.

We must never forget the power of micro-organisms and how rapidly they can re-appear if we let down our guard or if we neglect the impact of climate change on their growth and viability.

It is no coincidence that H.G. Wells vanquished the Martians not with guns, but with microbes.

There’s been a longstanding puzzle in medicine. Well actually there are lots of them, but here’s one that may be a puzzle no more.

For many years now, it’s been known that asthma is more common in women, and also that psychological stress can cause flare ups of asthma.

Many women experience “menstrual flaring:” a worsening of asthma around the time of their menstrual period. There is also a strange paradox: some women with asthma wheeze less if they take an oral contraceptive, while some non-asthmatic women begin to wheeze when they take it. In some women pregnancy makes asthma worse, and in others it affords months of relief of symptoms. Women who are obese are more likely to get asthma, presumably because their intra-abdominal fat stores are churning out inflammatory mediators.

Researchers from the University of Wisconsin have shed  some important light on this link between asthma and the brain. In research published in the Proceedings of the National Academy of Sciences. In the study, six patients with mild asthma were exposed to ragweed or dust-mite extracts. The subjects were shown three different categories of words: asthma-related (e.g., "wheeze"), non-asthma negative ("loneliness") or neutral ("curtains").

Using functional magnetic resonance imaging, they showed that activity in two regions, known as the anterior cingulate cortex and the insula showed increased activity when the asthma-related words were heard compared with the other types. What is more, this enhanced activity was specifically linked to physiologic signals from the ragweed and dust-mite extracts. So being exposed to asthma-relevant emotional stimuli is associated with markers of inflammation and airway obstruction in asthmatic people exposed to an asthma-producing antigen.

In people with asthma and other stress-related conditions, these brain regions may be hyper-responsive to disease-specific emotional and physiologic signals. Taken together, these could contribute to problems that worsen the asthma, such as inflammation.

And one of the ways of making these regions of the brain hyper-responsive? Bathe them in estrogen.

That still does not explain why pregnancy and the oral contraceptive makes some women’s asthma better, and does the opposite in others. But it may just have to do with the “set point” of the cells in these regions of the brain. In the same way that we might set the thermostat in out house. An already hyper-responsive brain might be normalized and an under-active one stimulated to be over-active.

We need to do some more experiments, but these are a great start.

If you ever wheeze, have a look to see if there are stressors or hormonal events that trigger you. Whether you are being treated with homeopathy, herbals or conventional therapy, knowing when to expect trouble gives you the power to adapt you treatment when you are entering a risky time in your life.