Non-state actors deliberately using powerful new technologies to cause harm could be bad in a number of ways:[1]

  • By directly causing the deaths of millions of people
  • By creating instability and thus compromising humanity’s ability to combat other existential risks
  • In worst case scenarios, by directly posing an existential risk, via irreparable civilizational collapse or human extinction

But how plausible is it really that non-state actors would cause this much harm?

Crudely, this breaks down into two questions:

  1. How many actors will be capable of committing harm in this way?
  2. How many actors will be willing to commit harm in this way?

Question 1 is about future technologies: how cheap they will be, how easy it will be to access the relevant information, what human and natural resources will be necessary to create them, and how much harm they will be capable of. I don’t have the expertise to say sensible things about this.

Question 2 is about people. I think that to form an overall answer to the question there are a number of different approaches to consider:

  • Historical approaches: base rates for things like terrorist attacks, mass murders with omnicidal intent, genocides etc; qualitative histories of past omnicidal actors and past uses of dangerous technologies
  • Security approach: identifying and monitoring actors in the present who seem most worrying from this perspective
  • Psychological approach: base rates for things like dark triad traits, omnicidal wishes etc
  • Structural approach: factors which influence the rates of things like terrorist attacks, instability, political violence; and how these factors might change in future

This post doesn’t attempt an overall answer. Instead, it offers one concrete piece of the puzzle: some data on the base rates of terrorist attacks. 

For a range of different groups, I’ve pulled together data on the number of attacks per million group members over roughly the last decade. This gives a sense of how common terrorist attacks are, and of how much the rates vary between groups. 

In the main post, I discuss a summary table of the main findings. For each of the groups I look at, there’s also a more detailed appendix.

I think information like this helps us think about what rates of terrorism might be like in future, and contributes to getting a better sense of how big the risks from non-state actors are.

Summary table

The table below shows an annual rate of terrorist attacks for various different groups.

  • The data for terrorist attacks is an average of attacks from 2010-2019 from the Global Terrorism Database.
  • The data for groups comes from various years and sources. Follow the links for more detailed tables. Hover over the footnotes to see the data source for the group.
GroupAttacks per millionDefinition of group
Northern Irish nationalists[2]

57

Self-reported
Northern Irish unionists[2]

8

Self-reported
US Muslims[3]

1.7

-
US radical Muslims[4]

23

US Muslims who think that suicide bombing is sometimes justified in defense of Islam
UK Muslims[5]

0.5

-
UK radical Muslims[6]

12

UK Muslims who have sympathy with suicide bombers
US radical right (see definition)[7]

0.21

Republicans who think political violence is sometimes justified
US pro-lifers[8]

0.01

Self-reported pro-lifers
UK right[9]

0.6

Self-reported right wing people
US radical left (see definition)[7]

0.04

Democrats who think political violence is sometimes justified
UK left[9]

0.3

Self-reported left wing people
US environmentalists[10]

0.01

Self-reported active participants in the environmentalist movement
US vegans[11]

0.1

-
UK environmentalists[12]

0.016

People who think the environment is one of the three most important issues facing the country
UK vegans[13]

0.1

-
The World[14]

1.45

-
The West[15]

0.3

Countries included: the EU, UK, Norway, Iceland, Switzerland, US, Canada, Australia, New Zealand.

Discussion

There are some salient problems with these numbers:

  • The groups aren’t directly comparable to one another. Are Muslims in the UK who think suicide bombings are sometimes justified comparable to vegans in the UK? Or to environmentalists? Are Republicans who think that political violence is sometimes justified comparable to people in the UK who say they are right wing? I would caution against reading this table as a straightforward indication of relative rates of attacks. The tables in the appendices often contain additional categories for each group (e.g. UK vegans but also UK vegetarians, UK green voters etc). If you’re interested, you can play around with these numbers to see how they change the comparative rates.
  • The selection of groups isn’t random. I picked the groups that were most available to me, in terms of data and prior knowledge.
  • Often the data sources I’m using for group size aren’t great. Sometimes I couldn’t get data for the right years, and used the closest I could get (earliest 2007). Sometimes the sources are self-reports from a single survey. Sometimes I used a secondary source and didn’t bother to find a more authoritative one.
  • The Global Terrorism Database (GTD) doesn’t contain all terrorist attacks.[16]
  • Terrorism is a social rather than a natural category, and calling someone a terrorist is a political act. The activities involved in terrorism blur into other categories like mass murder, state sponsored violence, guerrilla warfare etc.

But the table does give a rough indication of the base rates for terrorist attacks.

Taking the worldwide average as a starting point, you’re looking at roughly one attack per 700,000 people

However, it’s unlikely that access to the most dangerous emerging technologies will be uniformly distributed around the world. Exactly how it will be distributed is complicated, but if you think access will be concentrated in richer, more stable countries, then you might want to use the Western base rates instead: that’s roughly one attack per 3,000,000 people. So a bit lower.

I think looking at the rates by smaller groups is also interesting: it gives you a sense of how much the rates vary in subpopulations, which could be useful if you wanted to think about risks from specific future groups. To really understand these numbers, I think you need to have a deeper qualitative understanding of the contexts than I do, and I expect this means that some of the numbers are misleading in ways that I can’t see. That said, I think there are still some minimalist things to note

Among the groups I looked at and according to the numbers I found, ​​the groups with the most attacks were self-reported Northern Irish nationalists, with rates of ~60 per million.[17] Then came Northern Irish unionists and radical Muslims in the UK and US,[18] with rates in the low 10s per million. UK Muslims, the US radical right, the UK right, UK and US vegans, and the UK left all had rates below 1 per million. (US Muslims were a bit higher at 1.7.) The US radical left, US pro-lifers and UK and US environmentalists[19] had rates below 0.1 per million. So the rates among the different groups I looked at vary by around two orders of magnitude.

Another thing worth noting is that terrorist attacks are reasonably rare in all of these groups, even where part of the group definition includes thinking that political/religious violence is sometimes justified. It’s cheaper to talk than to act, and we should expect many, many talkers to every act of terrorism (and millions of innocent bystanders whose ideas have been radicalised in ways they would never condone).

Even when it comes to the actual attacks, most of them are clearly not committed with omnicidal intent. Most terrorist attacks have no fatalities, and it’s plausible that terrorism in general isn’t really about causing lots of deaths.[20] Groups like al-Qaeda or the IRA have political goals which couldn’t be met if everyone died, and ideologies which genuinely support human extinction are mercifully rare. The  rate of terrorist attacks with omnicidal intent must be far lower than the rate of terrorist attacks in general.

But given that there are 8 billion people in the world, the rough rates of terrorist attacks I’ve presented here aren’t exactly reassuring when it comes to risks from non-state actors.

Appendices

There’s a more readable version of these tables here.

Appendix 1: Northern Irish nationalists

CategoryNumberYearNumber per million nationalistsSource
Nationalist voters

757,000

Average 2010, 2015, 2017, 2019

1,740,000

Wikipedia [a]
Sympathy with republican violence

566,000

2007

1,300,000

NILT [a]
Nationalists

434,000

Average 2010-2019

1,000,000

NILT [b]
Tomorrow would vote to join ROI

415,000

2016

956,000

Ipsos MORI, p. 6
Pro reunifying with Ireland

331,000

Average 2010-2019

763,000

NILT survey via Wikipedia
A lot of sympathy with republican violence

94,300

2007

217,000

NILT [a]
Republican attacks

24.7

Average 2010-2019

57

GTD

Appendix 2: Northern Irish unionists

CategoryNumberYearNumber per million unionistsSourceNotes
Pro remaining in the UK, devolution/direct rule

1,230,000

Average 2010-2019

2,130,000

NILT survey via Wikipedia 
Tomorrow would vote to stay in the UK

1,190,000

2016

2,060,000

Ipsos MORI, p. 6 
Unionist voters

910,000

Average 2010, 2015, 2017, 2019

1,570,000

Wikipedia [a] 
Unionists

578,000

Average 2010-2019

1,000,000

NILT [b] 
Sympathy with loyalist violence

547,000

2007

946,000

NILT [a] 
Pro remaining in the UK, direct rule

287,000

Average 2010-2019

497,000

NILT survey via Wikipedia 
A lot of sympathy with loyalist violence

56,600

2007

97,900

NILT [a] 
Marching band members

30,000

2013

51,900

Wikipedia [b]NB this is 'an all-time high'
Loyalist paramilitaries

12,500

2020

21,600

BBCNB CFR thinks it's only several hundred
Loyalist attacks

4.6

Average 2010-2019

8

GTD 

Appendix 3: US Muslims

CategoryNumberYearNumber per million MuslimsSources
Muslims

2,550,000

Average 2007, 2011

1,000,000

Pew Research (a)
Suicide bombing and other forms of violence to defend Islam is sometimes justified

179,000

Average 2007, 2011

70,000

Pew Research (b), p. 2
Suicide bombing and other forms of violence to defend Islam is often justified

25,500

10,000

Charged with jihadi terrorism

40

Average 2007, 2011

16

Statista
Attempted to join ISIS

60

One fifth of the cumulative total in 2018

24

NPR
Terrorist incidents

4.2

Average 2010-2019

1.7

GTD
Groups involved

0.2

0.1

Appendix 4: UK Muslims

CategoryNumberYearNumber per million MuslimsSourcesNotes
Muslims

3,230,000

Average 2015-2016

1,000,000

ONS

Wikipedia

Slight underestimate because the Scottish data is from 2011.

Sympathy with violence organised by groups to protect their own religion

762,000

2015

236,000

Ipsos MORI, p. 69 
Support for establishing a Caliphate

222,000

68,800

The survey emphasised that this was ISIS' goal.
Sympathy for suicide bombing

127,000

39,300

Ipsos MORI, p. 70 
Sympathy with people organising radical groups/making threats of terrorist actions/committing terrorist actions

65,700

2016

20,300

Sympathy for all three statements came out at 2%.
In custody for terrorism

151

Average 2015-2016

47

UK government 
British nationals who have fought in Syria or Iraq

150

One sixth of the cumulative 2019 figure

46

Parliament 
Islamist terrorist attacks

1.5

Average 2010-2019

0.5

GTD 
Groups involved

0.2

0.1

 

Appendix 5: US right

CategoryNumberYearNumber per million on the right*SourcesNotes
Republicans who think political violence is sometimes justified [a]

77,400,000

Average 2017-2021

1,000,000

Washington Post

PRRI

Statista

Some of the numbers from eyeballing.
Faith and flag conservatives plus populist right [b]

69,700,000

2021

901,000

Pew research 
Faith and flag conservatives [c]

33,200,000

2021

429,000

Pew research 
Devoted conservatives [d]

20,000,000

2018

258,000

Hidden Tribes 
Hate groups

938

Average 2017-2020

12.1

SPLC (a) 
Extreme antigovernment groups

571

Average 2019-2020

7.4

SPLC (b) 
Militias

175

Average 2019-2020

2.3

SPLC (b) 
Terrorist plots

45

Average 2015-2020

0.6

Washington Post 
Terrorist attacks and plots

42

Average 2017-2019

0.5

CSISNumbers from eyeballing.
Right wing terrorist attacks

16.4

Average 2010-2019

0.2

GTD 

* See [a].

[a] The average responses to a few different questions over a few different years:

  • Do you think it is ever justified for citizens to take violent action against the government, or is it never justified?
  • True American patriots might have to resort to violence in order to save our country
  • "feel somewhat justified in using varying levels of violence to achieve their political goals" (my source isn't reasoning transparent about the questions that build this up)

[b] “Populist Right, who have less formal education than most other typology groups and are among the most likely to live in rural areas, are highly critical of both immigrants and major U.S. corporations.” 11% of the population. Plus [c].

[c] “Faith and Flag Conservatives are intensely conservative in all realms; they are far more likely than all other typology groups to say government policies should support religious values and that compromise in politics is just “selling out on what you believe in.”” 10% of the population.

[d] “Devoted Conservatives (6 percent of the population) are deeply engaged with politics and hold strident, uncompromising views. They feel that America is embattled, and they perceive themselves as the last defenders of traditional values that are under threat.”

Appendix 6: US pro-lifers

CategoryNumber (average 2010-2019)Number per million pro-lifersSourcesNotes
Pro lifers

150,000,000

1,000,000

GallupUS only.
All violence excluding threats

536

3.6

NAF

Includes things like trespassing, stalking, vandalism, burglary.

US and Canada to 2013, then US, Canada and Colombia.

Arson/bombing and attempted

2

0.01

US and Canada to 2013, then US, Canada and Colombia.
Arrests at clinical blockades

1.8

0.01

US and Canada to 2013, then US, Canada and Colombia.
Murders and attempted

1.2

0.01

US only.
Terrorist incidents

1.3

0.01

GTDUS and Canada to 2013, then US, Canada and Colombia.

Appendix 7: UK right 

CategoryNumberYearNumber per million far right peopleSource
Voters for right wing parties [a]

14,400,000

Average 2010, 2015, 2017, 2019

2,500,000

BBC 2010, 2015, 2017, 2019

Wikipedia 2010, 2015, 2017, 2019

Voters for far right parties, inc Brexit parties [b]

1,690,000

Average 2010, 2015, 2017, 2019

292,000

Voters for far right parties, exc Brexit parties [c]

171,000

Average 2010, 2015, 2017, 2019

29,600

Right wing people

5,770,000

2013

1,000,000

Ipsos MORI
Terrorist related convictions

12

Average 2019-2020

2.1

Hope not Hate 2018, 2020, 2021
Terrorist attacks [d]

3.6

Average 2010-2019

0.6

GTD

[a] Voters for the following parties: Conservative, Democratic Unionist Party, Ulster Unionist Party, Ulster Conservatives and Unionists - New Force, Traditional Unionist Voice, Christian Peoples Alliance, UKIP, The Brexit Party, Independence from Europe, English Independence Party, Democratic Nationalist Party, Christian Party, English Democrats, Libertarian, National Front, BNP

[b] Voters for the following parties: UKIP, The Brexit Party, Independence from Europe, English Independence Party, Democratic Nationalist Party, Christian Party, English Democrats, Libertarian, National Front, BNP

[c] Voters for the following parties: English Independence Party, Democratic Nationalist Party, Christian Party, English Democrats, Libertarian, National Front, BNP

[d] I included attacks by: Anti-Muslim extremists (and suspected), Anti-Semitic extremists, English Defense League (EDL), Neo-Nazi extremists, Right-wing extremists, White supremacists/nationalists

Appendix 8: US left

CategoryNumberYearNumber per million on the left*Sources
Democrats who think political violence is sometimes justified [a]

57,500,000

Average 2017-2021

1,000,000

Washington Post

PRRI

Statista

Progressive left plus outsider left [b]

53,100,000

2021

923,000

Pew research
Progressive left [c]

19,900,000

2021

346,000

Pew research
Progressive activists [d]

26,600,000

2021

463,000

Hidden Tribes
Left wing terrorist attacks [e]

2.2

Average 2010-2019

0.04

GTD

* See [a].

[a] The average responses to a few different questions over a few different years:

  • Do you think it is ever justified for citizens to take violent action against the government, or is it never justified?
  • True American patriots might have to resort to violence in order to save our country
  • "feel somewhat justified in using varying levels of violence to achieve their political goals" (my source isn't reasoning transparent about the questions that build this up)

[b] “Outsider Left, the youngest typology group, voted overwhelmingly for Joe Biden a year ago and are very liberal in most of their views, but they are deeply frustrated with the political system – including the Democratic Party and its leaders.” 10% of the population. Plus below.

[c] “Progressive Left, the only majority White, non-Hispanic group of Democrats, have very liberal views on virtually every issue and support far-reaching changes to address racial injustice and expand the social safety net.” 6% of the population.

[d] “Progressive Activists (8 percent of the population) are deeply concerned with issues concerning equity, fairness, and America's direction today. They tend to be more secular, cosmopolitan, and highly engaged with social media.”

[e] I included attacks by the following groups: Anarchists, Anti-Fascist Activists, Anti-Police extremists, Anti-Republican extremists, Anti-Trump extremists (and suspected), Left-wing extremists, Students For Insurrection.

Appendix 9: UK left 

CategoryNumberYearNumber per million left wing peopleSource
Left wing people

5,770,000

2013

1,000,000

Ipsos MORI
Voters for leftist parties [a]

26,800

Average 2010, 2015, 2017, 2019

4640

BBC 2010, 2015, 2017, 2019

Wikipedia 2010, 2015, 2017, 2019

Terrorist attacks [b]

1.8

Average 2010-2019

0.3

GTD

[a] Voters for: Respect-Unity Coalition, Trade Unionist and Socialist Coalition, Scottish Socialist Party, Respect Party, Socialist Labour Party, Workers Party, Class War, Workers Revolutionary Party, Workers Party, Socialist Party, Communist, Socialist Alternative, People before profit

[b] Attacks by: All Coppers Are Bastards (ACAB),Angry Foxes Cell, Anarchists (and suspected), Borderless Solidarity Cell (BSC), Informal Anarchist Federation, Random Anarchists

Appendix 10: US environmentalists

CategoryNumberYearNumber per million active environmentalists*SourceNotes
Protecting the environment should be a top priority for the president and Congress

213,000,000

2020

3,640,000

Pew Research 
Environmentalists

136,000,000

2021

2,330,000

GallupSelf reported
Make an effort to live in ways that protect the environment all the time

62,500,000

2019

1,070,000

Pew Research [b] 
Active participant in the environmental movement

58,500,000

Average 2010-2017

1,000,000

Gallup [b] 
Vegetarian

9,700,000

2021


 

166,000

The Vou 
Vegan

1,000,000

17,100

 
Ecoterrorism indictments

7.5

Average 2005-2008

0.1

FBI 
Terrorist attacks

0.8

Average 2010-2019

0.01

GTDIncluding animal rights related attacks.
Groups involved

0.3

0.01

* Defined as ‘active participants in the environmental movement’, self-reported. 

Appendix 11: UK environmentalists

CategoryNumberYearNumber per million environmentalistsSourceNotes
Environment affects purchase decisions

28,500,000

Average 2019-2021

1,510,000

YouGov (a)Self reported
Environment affects donation decisions

23,800,000

1,260,000

YouGov (b)
Environment most important issue

18,900,000

1,000,000

YouGov (c) 
Environment affects career decisions

15,300,000

808,000

YouGov (d)Self reported
People who would vote green tomorrow in general election

4,270,000

Average 2019-2021

226,000

YouGov (e)

YouGov (f)

 
Green voters general election

850,000

2019

45,000

Wikipedia 
Said they'd go meat free

5,670,000

Average 2019-2021

300,000

Finder (a)

Finder (b)

 
Did go meat free

270,000

14,300

 
Vegetarians

4,350,000

Average 2019-2021

231,000

Finder (b) 
Pescatarians

2,900,000

154,000

 
Vegans

1,440,000

76,300

 
XR mailing list

168,000

Average 2019-2021

8,900

XR 
Read XR emails

50,400

2022

2,670

Extrapolating their current open rate
XR protestors

7,000

Average 2019-2021

371

James Ozden, correspondenceThis is a rough number of people per year attending an in-person protest. James was an XR member at the time.
XR arrests

1,380

73

Independent

Guardian

Standard

Huffington post

Probably doesn’t include all arrests. James thinks these constitute most of the relevant arrests.
Animal Rebellion arrests

115

Average 2020-2021

6

James Ozden, correspondenceJames ran Animal Rebellion at the time, and thinks Animal Rebellion arrests constitute the vast majority of animal rights arrests in the period.
Terrorist incidents

0.3

Average 2010-2019

0.016

GTDIncluding animal rights related attacks.
Groups involved

0.4

0.021

Appendix 12: Worldwide terrorist attacks

CategoryAverage number 2010-2019Number per millionSource
Global population

7,340,000,000

1,000,000

Wikipedia
Terrorist attacks

10,600

1.45

GTD

Appendix 13: Western terrorist attacks

CategoryNumberYearNumber per millionSources
Population

906,000,000

Average 2010-2019

1,000,000

World Bank
Terrorist attacks

274

0.30

GTD

Countries included: Australia; Austria; Belgium; Bulgaria; Canada; Croatia; Cyprus; Czech Republic; Denmark; Estonia; Finland; France; Germany; Greece; Hungary; Iceland; Ireland; Italy; Latvia; Lithuania; Luxembourg; Malta; Netherlands; New Zealand; Norway; Poland; Portugal; Romania; Slovak Republic; Slovenia; Spain; Sweden; Switzerland; United States; United Kingdom.

Group/SubgroupOffence typeNumber of offences per million group membersNotes
US Muslims who think suicide bombing and other forms of violence to defend Islam is sometimes justifiedCharged with jihadi terrorism

223

 
US Muslims who think suicide bombing and other forms of violence to defend Islam is often justified

1569

 
UK Muslims with sympathy with violence organised by groups to protect their own religionIn custody for terrorism

198

 
UK Muslims with sympathy for establishing a Caliphate

680

 
US devoted conservativesTerrorist plots

2

 
UK far right votersTerrorist related convictions

7

 
US vegetariansEcoterrorism indictments

1

 
US vegans

8

 
UK vegetariansXR arrests

317

These aren’t really terrorism related, but give an indication of rates of commitment.

UK vegans

958

UK green voters, 2019 general election

1624

UK vegetariansAnimal Rebellion arrests

26

UK vegans

80

UK green voters, 2019 general election

135

Appendix 15: rates of attacks for Northern Irish unionists and nationalists

CategoryAttacks per millionSource
Nationalists

57

NILT [b]
Sympathy with republican violence

44

NILT [a]
A lot of sympathy with republican violence

262

Unionists

8

NILT [b]
Sympathy with loyalist violence

8

NILT [a]
A lot of sympathy with loyalist violence

81

The data used for this table is from various years between 2007 and 2019.
 

  1. ^

     State actors deliberately causing harm in this way could be bad too, but this post doesn’t address those risks.

  2. ^
  3. ^
  4. ^
  5. ^
  6. ^

    Ipsos MORI, p. 70.

  7. ^
  8. ^
  9. ^
  10. ^
  11. ^
  12. ^
  13. ^
  14. ^
  15. ^
  16. ^

    Though it probably does contain most of them for this time period. See Our World in Data: “ A valuable resource which also provides impressive accounts of terrorist incidents across the world is the many detailed entries in Wikipedia by year, by region or by country. Using this as a cross-reference with the GTD, we have high confidence in the completeness of global data in recent years.”

  17. ^

    Maybe this is higher than it should be: you could argue that the correct denominator should actually be Irish nationalists, not Northern Irish nationalists.

  18. ^

    The numbers for radical US and UK Muslims may also be higher than they should be. As Islamist terrorism is so politicised, it seems likely to me that moderate Muslims are less likely to say that suicide bombing is sometimes justified, than moderate Democrats to say that political violence is sometimes justified, for example. So maybe I’m selecting for a more extreme denominator, which inflates the rates.

  19. ^

    The rates for environmentalists are drawing on terrorist attacks by animal rights groups as well as environmentalist groups, so arguably the real rates should be even lower. Then again, if I could get numbers for environmentalists who think violence is sometimes justified, that might increase the rates quite a lot.

  20. ^

    See these posts by Gwern. I’m told Bruce Hoffman’s Inside Terrorism also has good discussion of the motivations and aims of terrorist groups, though I haven’t read it myself.

52

3 comments, sorted by Click to highlight new comments since: Today at 7:49 PM
New Comment

Handy reference! Apart from the average rate, it seems also interesting to notice the variance in the table, spread over 4 orders of magnitude. This may point to something like 'global sanity' being an important existential risk factor. 

 

I only read the intro and summary, but:

  • Seems like a useful resource!
  • I appreciated the clarity of the intro, and that it made it very clear what was in vs out of scope and how to situate this evidence in relation to other lines of evidence and the higher-level questions that are ultimately of interest
  • It seems quite weird - and probably misleading - to use the terms US right and US left for Republicans/Democrats who think political violence is sometimes justified
    • "right" and "left" have widely understood meanings here. But what this is pointing to is just a specific subset of those things (well, a specific subset of Republicans/Democrats, which I guess is a separate & smaller label-category mismatch issue), and the subset presumably differs from the whole set in a way that's directly relevant to the question at hand?
    • I don't know what alternative short term I'd recommend, but one idea would just be to add anything to make it clear that this is specific jargon and not just the whole group. E.g., "US right PVSJ"

Thanks for this Michael, I think that's a good point. I've changed those labels to 'US radical right (see definition)' and 'US radical left (see definition)'. Not perfect, but less misleading.