The Four Horsemen of Near Term Extinction

Guy McPherson is a well known climate change scientist and blogger at Nature Bats Last. On September 9, 2014 he did an interview of Jennifer Hynnes and he asked her, not on its face unreasonably, so when do you think Near Term Human Extinction (NTHE) will occur. Jennifer, who has done a superb recitation of the evidence for catastrophic methane release which has gone viral on Youtube – called  The Arctic Methane Monsters Rapid Rise – was understandably coy about the answer. Many other people who have looked deeply into climate catastrophe and realize that we are facing near term extinction find it difficult to talk about timing. It is hard for us to discuss what we would consider as “signposts” to look for in future news reports. In this essay I will try to look at the systemic couplings and consequences that we need to keep in mind to approach this fairly.

Signposts to NTHE

Now we think that the problem is a rather straightforward systems question – for those with the intestinal fortitude to think about mortality on the grand scale. At one end we expect Near Term Human Extinction (due to our science and ideology, as an honest caveat) at some point within a short period (20-40 years). This implies large scale human die-off – gigadeaths, billions of humans; potentially all 7-plus billions of us will die. The proximate causes of death I name the Four Horsemen – an obvious reference, I hope. And at the causal end of the the system we have global climate change. In order to think about this we need to stop looking at the current climate as an effect of human activity and start to look at the climate disruptions as causes of  large scale deaths. The question we need to think through is “What linkages are necessary and sufficient for global climate change to lead to Near Term Human Extinction?”

The second part of this is to set what we may think of as signposts, or future events which will confirm (or disconfirm) the track that we think we are going on. This is a clear tactic from future strategy development seminars that I have participated in in the past. A key to realizing if we are correct in our assumption of NTHE is an obvious, radical upturn in what the actuarial science calls “excess mortality,” those above the normal death rate. Since we have currently an estimated 7.2 billion people on the planet let’s do a quick back of the envelope calculation. There are 16 years, as I write this to 2030, say 192 months – let’s round up to 200 months. For extinction (7.2 billion excess deaths – ignoring birth rate for now) to happen in 200 months we need 36 million deaths per month to go straight line to extinction. No we all know that we won’t be doing a straight line. We will have a hyperbolic growth curve, low at the beginning and then the classic hockey stick up. But even with that caveat we can expect certain events to occur in our NTHE future scenario.

So if we are to think about this and scan the news for our signposts, they will be things that we can verify, with our own eyes in a news report (at least until it is impossible to see any news anymore from outside our local community.) So I will put the signposts into a format of What, Where and When. If my ideas are off, in good scientific fashion, let us debate the causes and new effect systems, adjust the hypothesis and move on to a new signpost scenario.

The Four Horsemen

Auguste Dore - The Four Horsemen of the Apocalypse

Auguste Doré: The Four Horsemen of the Apocalypse

The Four Horsemen of the Apocalypse are War, Famine, Pestilence and Death. The ultimate is obviously death, as all the others lead to that dark horseman.

Death is from three proximate causes: the modern equivalent of the other three horsemen. Natural causes, human causes, and  disasters. Natural causes such as heart disease and cancer are already prodigious harvesters of human life – these may be equivalent to what the author of Revelation termed: Pestilence. Death from human causes is most often caused by a recognizable horseman: War. Famine is also clear and death from famines in our recent past have seized our collective memory as well: e.g. Biafra. But there is one cause of direct human death which is not captured in the horsemen of Revelation, the deaths cause by natural events such as flood, earthquake and fire.

Recent natural and human produced disasters have not yet gotten us to the threshold of gigadeaths. According to Wikipedia the largest man-made loss of life, World War II was responsible for between 40 and 85 million deaths. The Chinese famine associated with the Great Leap Forward were between 15 and 55 million. In the area of natural disasters the Great Chinese flood of 1931 caused 2 to 4 million deaths; the Indian Ocean earthquake and tsunami of December 26, 2004 killed an estimated 260,000.

What is clear from this short history of large scale death is that, if we are correct about the trend, we are about to witness disasters on a scale that we have never seen before. When speaking of near term human extinction (NTHE) we will see – in a very short time frame – deaths at a rate two orders of magnitude greater than World War II. To see a death of 4-7 billion people in the next 20-40 years due to the effects of climate change we need to have extraordinary, even novel linkages of cause and effect.

Systems of mass death

As stated, in order to think about this we need to stop looking at the current climate as an effect of human activity and start to look at the climate disruptions as causes of  large scale deaths. To think about that I developed the following infographic. (As an excuse for its somewhat poor presentation I must note that I am a bad graphic artist.)

Four Horsemen of Near Term Human Extinction

Four Horsemen of Near Term Human Extinction

Although I utilize the Four Horsemen as an image of death they are largely allegorical. The main proximate causes of death will remain much as they are today: direct death caused by natural disaster, direct death cause by man-made disasters such as wars, indirect death caused by natural factors such as disease, and indirect death caused by man-made factors. A caveat here as the delineation of the boundary natural vs. man-made may blur or be indistinguishable.

In order to discuss the linakges I will attempt to go through the four top level causes of death and work downward in the diagram


As stated earlier the greatest level of deaths caused by war has been World War II with about 7-12 million deaths per year. It is difficult to conceive of the level of deaths which will be coming due to basic violent human conflict in the coming decades. The current period of low level conflicts will increase many-fold. Perhaps the best idea of a signpost then is the rate at which violent war related deaths occur. WWII violence was at 7 million a year – not w so that would be the minimum for us to say the War Horseman “signpost” has started to be unleashed.

As a background, the Iraq Body Count effort released its 10 year body count for that conflict on March 19, 2013. The total number of confirmed civilian and combatant deaths was 174,000 – a mere 17,400 per year. In a piece of unusual optimism in 2011 Foreign Policy magazine published an article Think Again: War -World peace could be closer than you think, in which they figured:

Worldwide, deaths caused directly by war-related violence in the new century have averaged about 55,000 per year, just over half of what they were in the 1990s (100,000 a year), a third of what they were during the Cold War (180,000 a year from 1950 to 1989), and a hundredth of what they were in World War II.

So if we are looking for the unleashing of the War Horseman we should expect much more violence and very soon. Low level conflicts will very probably escalate both in number around the world and in intensity of violence. Within the progressive crumbling of what Henry Kissinger called the World Order (here for a NY Times review) it is possible to imagine nuclear confrontation in the Middle East or Asia which would raise the violent mortality rate to millions a day.

It is difficult for citizens of the USA, Canada or Europe to imagine war on their territories killing 1 million or more in the near term. But it may occur. Within our life time we should expect small to medium scale armed conflict even to invade the peaceful areas of North America and Europe. Later I will go into the netowrk destabilization effects of multiple scenarios playing out in a single geographic area. It may be that city collapse, supply chain collapse, lead to famine which leads to conflict in even developed areas.

Many commentators have noted that the US Department of Defense has issued its Quadriennial Defense Review which makes mention of many of the trends which can escalate conflict: resource scarcity in the Middle East, proliferation of WMD, warlord-like behavior in many places such as Africa, Western Asia. I would quote it on the impact of climate change but the pdf that it is in doesn’t allow me to copy-paste.

So this is my first signpost for the Horseman of War

What: War deaths exceed 7 million in 1 year

Where: Any continent (except Antarctica) 😉

When: 2020


The Famine Horseman is historically one of the most prevalent. Wikipedia notes that from the period of 108 BC to 1911 AD there were 1,828 famines in China alone, of varying severity nearly one a year in one province or another. Which leads us to the major difference with famines all the way up to the 21st century. Famines have been largely often and local. One province, one area of a continent.

The mortality rates of famine directly are also low relative to population. In July 2013 the UN estimated the famine deaths in Somalia at “258,000 people died in the Somalia famine between October 2010 and April 2012. The number of deaths caused widespread shock and the percent of the population – 4.6% – was shockingly high.” The greatest amount of deaths in a famine was China’s Great Leap Forward of 1958-1962, which caused famine deaths of over 30 million.

There are several competing causes of famine, many, if not most of which, are man-made. Political decisions in China’s case led to inability of farms to support the population thrust back into the rural economy. In Somalia a civil war led to disruption both of farming and distribution of what stocks were available.

If we expect famine to be a major contributor to extinction then death rates and geographic spread will have to rise. A signpost must be at least continent-wide food crisis with death rates greater than 7 million per year (the rate of the Great Leap famine). This will inevitably be difficult to quantify separate from the violent conflicts over food resources which will break out if famine happens again e.g. in China or India.

So the Horseman of Famine signpost is:

What: 7 million deaths by famine

Where: on any continent (OK, still excluding Antarctica)

When: This could start early so I say 2016


I have been following, at the time of writing this (September 2014), the developing crisis with Ebola in West Africa. So this one seems very present.  It is clear that we are seeing disease increase rapidly in infectiousness, virulence and morbidity. Ebola has a perfect transmission profile for a global contagion. A virus that takes a long time to develop symptoms, in Ebola’s case 21 days, but with an ability to infect others prior to symptoms (after perhaps as little as 7 days). And as a extra level of infectiousness, persistence even in male patients who survive the sickness (i.e. do not die) for up to 60 days in their semen. My current signpost for Ebola is ABOVE the current WHO and CDC ideas. I see West Africa with 100,000 to 200,000 cases, by December 31, 2014 with a 50% or more death rate. I also see isolated (I hope) outbreaks in non African countries in the Middle East or Asia.

But let’s just look at what are the thresholds for this level of NTHE signpost. The most recent worst case of virulent disease is the 1917 Flu Outbreak. In that outbreak in 2 years it infect 500 million people and the recent data shows that it killed around 100 million. As commenters have pointed out the flu was an instigator and many people died of secondary complications. In considering a scenario we prefer to keep it as clear as possible. In the cast of pestilence then the signpost is some at least as virulent as the flu.

The thought I have in my own mind is that there are so many variants of really virulent flu know right now: H1N1, H2n2, H5N9. All of which are able to transmit in air. Every year approximately 500,000 people die worldwide from the flu. So a sign post is equal to the worst cast so far and two orders of magnitude over normal.

What I an NOT saying here is that this NTHE signpost disease will be a flu. I don’t think it will be Ebola – but Ebola evolves to be transmissible by air the it is possible. It will be something at least as bad as the worst flu ever experienced (and probably much worse and probably unknown at this time – 2014.)

What: 50 million deaths per year

Where: Worldwide

When: 2020

Birth Rates

I want to say one last thing about the other side of the population equation. I believe that we will see global birth rates decline very quickly as people realize that there is very little (good) future left to give to their children. This is a hard thing to say, and to realize in your gut. Also large scale migrations, refugees, wars, low level conflicts, famines or food insecurity will lead to birth rate dropping. Many societies like Japan and some in Europe already have birth rates below replacements levels. Wikipedia again shows the world birth rate on a long decline. I found this graphic of global birth and death rates.

A signpost for population declines will be that birth rates drop below death rates per 1,000 people. No population experts expect this in their models, which all show population continuing to rise to near 10 billion people in 2050 – an outcome I find implausible.

Pew Global Birth and Death Rates

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