Forecast for Future of Humanity: Showers Likely 
by Andrew Kerr
January 2008

Dr. Peter Brecke, an associate professor at the Sam Nunn School of International Affairs at Georgia Tech, co-authored an interesting study published in the November 28, 2007 Proceedings of the National Academy of Sciences (PNAS) Journal. The article considers the potential relationship between climate change and human conflict. Do temperature changes result in more war?

Q - This seems like a fun thing to look into. How does a study like this come about?

A - I had been developing a database of wars (my work was on conflict early warning). One of the reasons why we have not been able to do this well is because we were trying to find causes of wars. That was too blunt an approach. What we needed to do was find the causes for particular types of wars. So I said, "Why don't I make an taxonomy of violent conflicts, analogous to what's in biology: kingdom, phylum, class, order, etc.?" To do that I had to make a large dataset of all different kinds of wars so that I could then group them by shared characteristics. So I made this dataset of all recorded violent conflicts in the world since 1400 AD in which 32 or more people were killed.

Q - Why 32?

A - It's 10 to the 1.5 power. This scholar named Lewis Fry Richardson had categorized war by their conflict, or their fatality level, and he did it in powers of 10. A category six war would be from 10 to the 5.5 to 10 to the 6.5 power. A category 7 would be 10 to the 6.5 to 10 to the 7.5. Category two would be 10 to the 1.5 [which is ~32]. So that was why that level.

I received an email from David Zhang, the lead author, a few years ago. He said, "I saw on your web pages what you do and I thought you might be interested in this project I have in mind." He said, "We have all this climate data and I was wondering how it affects warfare. And you have this database of wars. So do you want to work together on this?"

I had got about 4500 conflicts in my dataset, and going back to 1400 there's a long time series, and so it was sort of like hey, this is perfect. You can compare the conflicts over time to the climate over time. I said that sounds like a fun idea and we just started working from there.

Q - What is a war, exactly?

A - I prefer the term "violent conflict," because wars for certain people have certain connotations. For some scholars a war has a very specific definition. It's between two or more countries, it involves armies, and has 1000 or more fatalities. Things like that. For me that's just way too specific. So to not go down that road I just said let's look at violent conflicts and go down to a very low level. But to me a violent conflict is where there is two or more social groups that are contending over something, and it could be territory, it could be resources, it could be control of the government, it could be to create a new separate political entity that the rebel group wants to control. You have a certain point of contention and the sides feel strongly enough about it such that they will start shooting at each other. It's basically that simple.

Q - To put an optimistic spin on your report, one might argue you have described the history of mankind triumphing over nature through an increased talent for better long-range planning.

A - For me it's a matter of that humankind has gotten better at social organization and management. And because of that increased capability it is not as susceptible to serious harm because of climate-related changes. However, I wouldn't go so far as to say that we're so good at it that the future is rosy. In fact my personal inclination is that this century is going to be incredibly challenging for human-kind. When you look at climate change, biodiversity loss, fisheries depletion, deforestation, you realize that humanity has got the creativity to get through these things, but it's not going to be easy. And we don't want to do it through the creation of a police state that tells us exactly what to do in order for us to survive. My concern is can we find a way past these challenges, these big problems, and have a lifestyle for the people that are going to live it, like my son, that is something that I would be happy that's he's living?

Q - So you're suggesting that although we have ultimately gotten over those past challenges, the hugeness of the climate change problem might prove less easily surmountable, and that this could serve as a trigger for future conflict.

A - Let me restate that. I'm not disagreeing with you, but for me it's that we've gotten better at dealing with problems. Our systems of governance have definitely improved. But the challenges I think over the past century or so have been relatively modest compared to what we're going to face this century. So we need to ratchet it up a level in terms of our ability to cope with these problems.

Now let me perhaps anticipate a question that you're going to ask, in terms of well what does your results say about the future?

The conceptual model that drives our research is that crops are most productive in a certain band of temperatures and precipitation. If you get too high temperature or too low a temperature or too much rain or too little rain the crops are harmed.

Our model looks at the aspect of when the temperature gets too cold. And it found that, hmm, what you would expect seems to be the case. As it got colder crop production and productivity went down, food prices consequently went up. Because of the higher food prices you had more starvation and more social unrest. In certain instances this social unrest created more conflicts, which then on top of starvation killed more people, so that you had either a reduction in the population growth or in some instances even population declines.

In the future what we're looking at is that we're going to go off the top side of the band [i.e., the temperatures are getting too warm]. The rest of the model, the rest of the explanation, stays the same. If you go outside the band you're going to have problems.

The report from the IPCC second working group talks about how the higher temperatures are going to cause certain reductions in crop productivity. They've even got graphs showing how much they expect it to go down. So my belief is our model applies to the current and future situation because we're doing a similar thing only from the opposite end [too warm, versus the study's too cold focus].

Q - One thing not mentioned in your report, I suppose because it's a very recent subject of alarum in the news media, is the decline in food supplies due to ethanol demand. The December 8, 2007 Economist's cover story was entitled "The End of Cheap Food."

A - My personal feeling is that that's disaster. The ethanol from corn and stuff like that. You simply have to go towards a better crop if you're going to go that route.

Q - Were temperatures cited in your article world-wide averages or were they localized by hemisphere?

A - Most of the time they're localized by hemisphere—Northern Hemisphere.

Q - How do we get temperature data from the distant past?

A - It's based upon ice cores, tree rings, stalagmites and stuff in caves, pollen in the muck at the bottoms of ponds, all that kind of stuff. David and his colleagues took the leading reports on estimates of what the climate has been in the Northern Hemisphere over the past millennium. They didn't do the actual gathering of that data. They simply took what are well-respected reports, recent reports about what we think the climate was.

Q - And what are some of the factors that led to temperature fluctuations in the past? I recall reading about sunspot cycles, things like that...

A - You've had sort of natural variability in the system. Part of it is related to the tilt of the earth's axis, its procession around the axis in terms of what distance from the sun, do you have the Northern Hemisphere leaned back instead of leaning forward, variation in the sun's radiance, stuff like that. I have no doubt whatsoever that those things have affected the climate.

But the important thing is that the climate scientists have looked really, really hard at those kinds of explanations for the last, let's say decades if you want, and what they find is that if you take all of those factors into account they cannot explain the increase in temperature. And so you're left saying "What could it be?" And the obvious one is, well, humans have been pouring more and more carbon dioxide into the atmosphere.

If you want to sort of see this argument laid out in a form for the lay-audience, and I would argue put this in your article, go to www.realclimate.org. The level of sophistication—yet getting away from the scientific jargon into something that you or I understand—I think these guys are unsurpassed.

Q - Is the source of conflict the sudden temperature change itself or the longer-term prevalence of abnormally high or low temperatures?

A - That's a great question, because the answer is probably both. And the IPCC report focuses primarily on just the sheer temperature, but there are various people that have argued, and it is part of the reports, that the frequency of extreme weather events will go up with climate change, because you have more heat and energy in the system to make bigger storms, to cause wind patterns to shift and things like that. So chances are, you will have more droughts and more deluges that will in a localized area cause crop problems. But if you talk about across the globe or the Northern Hemisphere, those kinds of things will kind of wash out and then the major effect becomes just the sheer increase in temperature.

Q - So just for fun, how might a doomsday scenario play out in our future?

A - That's real pie in the sky—I don't want to say something totally stupid! (Laughs.)

My gut feeling is that with climate change causing tougher times in terms of growing enough crops, we're going to find more instances of people either starving or migrating because of lack of food production. It's this migration that I think will be a major source of conflict. People are just going to be desperate, they're going to start moving, and they'll go to the nearest place they can where they can get something to support them. The locals there most of the time are going to be really unhappy. They'll put up with it for a while, and then some incidents will happen, people will get set-off, and you'll have intercommunal conflict.

I think one of the real things we have to worry about is the creation of garrison states, where local populations in the United States, Europe are going to say, "No way!" and they're going to try and keep outsiders out. They'll end up having surveillance systems at the borders and probably at towns and stuff like that to try and identify non-natives, and that will cause immense social pressure and tension. It won't always, but in certain places it will cause some kind of conflict.

An important point here is that not every conflict is going to be caused by climate change, but it's going to exacerbate situations and sometimes they're going to go off.

Q - It seems cold common sense that if food crops are reduced in quantity due to climate change then there's going to be a fight for what's left of those depleted resources.

A - Here's to me actually the bigger issue. You will read in many places that the world population is going to go up to about 9 billion in about 2050 and then kind of level off and maybe peak out at 10 billion or something like at roughly 2300. Well, the problem is if you go into the reports and look at the assumptions that result in that outcome...I looked at them and said, "That's nonsense." The odds of that happening are near zero because it involves population growth rates that are highly unlikely to occur. They were trying to say, "OK, here's a high-end scenario, here's a low-end scenario, and a just right Goldilocks scenario, and they don't tell you unless you go into the details what were the assumptions to get you that Goldilocks.

So my sense is that there's actually going to be an increase in population. And we can grow more food, but in order to do that we're going to have to be more and more intensively using the land and other resources like fertilizer and stuff like that. So we're kind of winding up the system really tight in order to produce enough a food. That to me is what you want to avoid—having a system that is running right at the limit in order to keep people alive. Because if you make a boo-boo the consequences are large. A much better strategy is to say, "Look, let's back off and not pressure the earth's systems so much, such that there's some flexibility in the system."

Q - It seems that the single largest problem that we face is simply population growth.

A - Population is certainly one of them. And the second thing is the increasing wealthiness of large numbers of people.

The big conundrum with China and India: they want to become rich like us. And who are we to say they can't? But if you have 2 billion people more living like we do, existing earth's biological systems cannot support that. I taught a class last spring where I showed that to my students, and it was pretty sobering to them.

We all want to be wealthy. We all want our iPods. But we've got to figure out a better way.

Nobody wants to get poorer, and so maybe the better way out is to say look, can we change our population trajectory so that we actually go down in population. And I'll just throw out a number: 1 or 2 billion. And then we can all live pretty well.

Q - Kinda reminds me of that Voluntary Human Extinction Movement.

A - I guess I've heard that term. And it's not that I want extinction, although I think if we keep going the way we are we will face the real problem of possible extinction!

We want to control population growth. It's simply a matter of, if you look at the earth's systems and say to yourself do you want to run it screaming or do you want to run it more relaxed, the way to run it more relaxed is to have fewer people.

Q - Why do countries always place such a positive emphasis on population growth and fret so much over population declines considering these issues? It seems in a modern world that reducing the strain on one's resources would be a positive thing.

A - Well I guess there's something about if you have more population you have more power and you have more talent at your disposal. Just assuming that some percentage of your population is going to be really smart, motivated people. So if you have more people born the hope is that you'll have more of those motivated smart people who are going to do great things.

Q - Does reality bear that out?

A - I think that there is some truth to that. No place has any monopoly on talented individuals, and so by having more people more of them will appear.

The problem is, how do you create an environment in which this talented individual that is born actually gets to realize her or his talent? In terms of getting us through this century, to me that's the key. We want to figure out a way to maximize the realization of talent in individuals, because those are the people that are going to find the solutions via technological, organizational, or political means.