Why we have over-rated Cool Earth

0. Exec summary

Cool Earth is a non-profit that tack­les cli­mate change; it has been en­thu­si­as­ti­cally sup­ported by many in the Effec­tive Altru­ism com­mu­nity. In this post, I will say the fol­low­ing:

1. How Cool Earth works

2. Ac­cord­ing to ear­lier anal­y­sis by Giv­ing What We Can (GWWC), Cool Earth is a high-im­pact charity

3. How­ever this anal­y­sis omits cer­tain as­pects/​risks

4. Once you take these into ac­count, Cool Earth’s work is ei­ther fairly low im­pact, or there is (cur­rently) not enough ev­i­dence available to say; this de­pends on which pro­ject (i.e. coun­try) you’re look­ing at

5. Some other op­tions that cli­mate-in­ter­ested donors may wish to consider

6. At this stage the in­for­ma­tion gath­ered doesn’t al­low me to give a strong opinion on Cool Earth, but I would recom­mend that we now con­sider the ear­lier GWWC anal­y­sis out of date

As for the omit­ted as­pects/​risks (item 3), these in­clude the dis­place­ment effect—i.e. when log­gers are un­able to log the trees pro­tected by one com­mu­nity, they will sim­ply go el­se­where. A sec­ondary con­cern is risks post-exit. (read on for more ex­pla­na­tion of these)

Many thanks to Cool Earth for their in­put, and note that Cool Earth do not agree with all that has been said in this piece. I will try to rep­re­sent their views as well.

I would have preferred to in­ves­ti­gate these is­sues more fully be­fore shar­ing this piece, given that some of the in­for­ma­tion gaps are quite ma­te­rial, how­ever that has not been pos­si­ble, largely be­cause of time con­straints on the part of Cool Earth. I would also like to thank Cool Earth for the time they have given me for this anal­y­sis.

As for whether to donate to Cool Earth or not, I would sug­gest not to based on the cur­rent ev­i­dence, al­though as more ev­i­dence arises, this opinion could change.

Donors in­ter­ested in cli­mate change may be in­ter­ested in the re­cent anal­y­sis con­ducted by Founders Pledge. I will also list be­low some other op­tions that donors in­ter­ested in sup­port­ing cli­mate change might con­sider, i.e. pro­vid­ing con­tra­cep­tion and fe­male ed­u­ca­tion.

1. How Cool Earth works—intro

Cool Earth is a non-profit that tack­les cli­mate change by work­ing with rain­for­est com­mu­ni­ties to avoid de­foresta­tion. They do this by sup­port­ing the liveli­hoods of the peo­ple in the rain­for­est.

The logic is that lo­cal com­mu­ni­ties in the rain­for­est will be less likely to per­mit log­ging if they are not in need of money, since they fun­da­men­tally want to pre­serve the rain­for­est as well.

This re­sults in rain­for­est be­ing pre­served, which is pos­i­tive from a cli­mate change per­spec­tive.

2. Why is it con­sid­ered a high-im­pact choice of char­ity to donate to?

Ac­cord­ing to anal­y­sis by Giv­ing What We Can (an Effec­tive Altru­ist or­gani­sa­tion which used to do re­search into char­i­ties) Cool Earth was con­sid­ered a high-im­pact choice.

The ra­tio­nale is that the Cost per tonne of CO2 is low com­pared to other op­por­tu­ni­ties, i.e.

  • Cost per tonne of CO2 for Cool Earth is ~ $1

  • Cost per tonne of CO2 for other op­por­tu­ni­ties is typ­i­cally more ex­pen­sive, e.g. ~ $10 (esp di­rect work, not cam­paign­ing)

See Ap­pendix 2 for more about GWWC’s anal­y­sis.

My main claim is that GWWC’s claim of c. $1 per tonne of CO2 claim is op­ti­mistic. In­deed Cool Earth’s over­all im­pact from a cli­mate change per­spec­tive may be neg­ligible, al­though this de­pends on var­i­ous fac­tors.

The GWWC anal­y­sis was last up­dated in 2016, and GWWC no longer con­ducts anal­y­sis of char­i­ties, so GWWC were not available to com­ment on this piece.

3. Rea­sons to doubt Cool Earth’s impact

  • 3a Rea­son to doubt 1: Dis­place­ment risk

  • 3b Rea­son to doubt 2: Risks post-exit

  • 3c Po­lari­sa­tion: how calcs lead to all-or-noth­ing views

3a Rea­sons to doubt 1: Dis­place­ment risk

- Lo­cal com­mu­ni­ties (e.g. the Ashan­inka in Peru) will be less likely to per­mit log­ging if they are not des­per­ate for money

- Cool Earth helps them to be not des­per­ate for money

- So the log­gers will be un­likely to perform log­ging in *those com­mu­ni­ties*

- How­ever they would prob­a­bly just go some­where else and log there in­stead.

If we were to model this as say­ing that log­gers would *definitely* go and log some­where else, then the model should as­sume that Cool Earth has achieved noth­ing from a cli­mate change per­spec­tive. While it’s un­likely that 100% of log­gers would “be dis­placed” (i.e. just log el­se­where) I sus­pect it ap­plies to most log­gers.

In the ap­pen­dices, I have con­sid­ered fac­tors which I thought might miti­gate this con­cern, which I call:

  • ex­oge­nous-log­ger-gives-up scenario

  • long-term-broad-cov­er­age sce­nario and the

  • en­doge­nous-log­ger-would-be-ma­te­rial sce­nario.

Hav­ing looked into each of those sce­nar­ios (see ap­pen­dices for more), it seems that their effect is small in Peru and Pa­pua New Guinea, so the dis­place­ment effect is likely to dom­i­nate. I.e. the dis­place­ment effect is likely to mean that Cool Earth is hav­ing a small amount of im­pact on cli­mate change. (See ap­pendix A3(ii) for more on this)

This might not be the case for all the coun­tries where Cool Earth op­er­ates—more on this in the next sec­tion (sec­tion 4).

I have been in touch with Cool Earth, and they have been kind enough to give me some time to dis­cuss these con­cerns. They dis­agree with this as­sess­ment, es­pe­cially around the en­doge­nous-log­ger-is-ma­te­rial sce­nario. More info in the ap­pen­dices, es­pe­cially ap­pendix A3(iii), in­clud­ing why I’m not con­vinced by their ar­gu­ments.

3b Rea­sons to doubt 2: Risks post-exit

Cool Earth’s model in­volves sup­port­ing a com­mu­nity for some years and then leav­ing and mov­ing on. Once that’s hap­pened, will the sup­port that Cool Earth pro­vides still per­sist?

By in­clud­ing a prob­a­bil­ity of log­ging of only 0.5% with Cool Earth’s in­ter­ven­tion (see the sum­mary of GWWC’s anal­y­sis), we are es­sen­tially plac­ing a high prob­a­bil­ity that the in­ter­ven­tion will work *not only now but in the fu­ture*. If in fact the effects are not per­ma­nent, then the cost-effec­tive­ness model should be differ­ent from the one used by GWWC. In­stead it should take into ac­count the ex­pec­ta­tion that log­ging will restart, but model it as hap­pen­ing at some point in the fu­ture, and dis­count that back to the pre­sent day. Alter­na­tively we could ad­just the model by in­creas­ing the costs to re­flect the fact that Cool Earth will be re­quired to work with those in­definitely, rather than just for a limited pe­riod of time as origi­nally as­sumed.

There are ac­tu­ally not very many part­ner­ships that Cool Earth has ex­ited from (only 4) and even those are not good ex­am­ples be­cause they were im­posed by ex­ter­nal cir­cum­stances. Although the lit­tle data we have about those seem pos­i­tive, we don’t have enough ev­i­dence to know whether the pre­ven­ta­tive effects will per­sist af­ter Cool Earth’s work has finished.

Quote from Cool Earth on this topic:

“At the very be­gin­ning of Cool Earth’s ex­is­tence ten year’s (sic) ago we worked in Ecuador and Brazil briefly but had to end these early due to poli­ti­cal is­sues be­yond our con­trol. For one of the Brazilian com­mu­ni­ties we worked with for two years, back in 2007, we have satel­lite images that show the for­est to still be in­tact. This is a good sign that the com­mu­ni­ties re­mained re­silient but of course we need many more data points from cur­rent and fu­ture part­ner­ships to be able to provide re­ally strong ev­i­dence for the long-term effec­tive­ness. This is some­thing we are putting to­gether now by build­ing a port­fo­lio of part­ner­ships globally which will test how much our sup­port cre­ates re­silient com­mu­ni­ties and how this needs tweak­ing un­der differ­ent cir­cum­stances and slightly differ­ent meth­ods (eg di­rect fund­ing to house­holds in­stead of to com­mu­nity as­so­ci­a­tions) to im­prove its effec­tive­ness. ”

In or­der to get to a clearer pic­ture on this, I would need to bet­ter un­der­stand the as­sump­tions be­hind the cost­ings. I have re­quested this Cool Earth; they have not been able to provide this in­for­ma­tion.

3c Po­lari­sa­tion: how the calcs lead to all-or-noth­ing views

One of the quirks of the way the calcu­la­tions work is that we are likely to be­lieve ei­ther that Cool Earth’s work is com­fortably more cost-effec­tive than tree-plant­ing or that it has min­i­mal im­pact. There is only a very small range of in­put as­sump­tions which lead to con­clu­sions in be­tween. This point is slightly tech­ni­cal, so I have ex­panded on it in an ap­pendix (see ap­pendix 5).

4 Im­pact­ful­ness varies by country

The de­tails differ be­tween the differ­ent coun­tries where Cool Earth op­er­ates. Cool Earth have been kind enough to dis­cuss this with me, al­though we have not had time to cover ev­ery­thing.

Dis­place­ment risk is a key driver of whether Cool Earth has some im­pact.

(More notes on the “marginal im­pact of the next pound” in Ap­pendix 6.)

Pa­pua New Guinea: I think it’s un­likely that a palm oil com­pany would be put off from do­ing their work just be­cause an area can no longer be logged, so it seems the dis­place­ment risk is high. Note that Cool Earth ar­gue that there is a po­ten­tial sys­temic im­pact, how­ever I don’t find this con­vinc­ing. More on this in Ap­pendix 4

Mozam­bique/​Cameroon: Th­ese are new coun­tries that Cool Earth is ex­pand­ing into. Cool Earth has in­formed me that the log­ging that they are tack­ling is mostly en­doge­nous—if true, this would sug­gest that the cost-effec­tive­ness is good. I would have liked to have in­ves­ti­gated this fur­ther, how­ever our con­ver­sa­tions ran out of time and I was un­able to dig into this deeper, which is un­for­tu­nate.

Peru: Cool Earth has sug­gested that the log­ging would be en­doge­nous to a ma­te­rial de­gree. This seems un­likely to be the case, in my view. See Ap­pendix 3(iii) for more de­tail.

Demo­cratic Repub­lic of Congo: Cool Earth has in­formed me that the log­ging that they are tack­ling is mostly en­doge­nous—if true, this would sug­gest that the cost-effec­tive­ness is good. I would have liked to have in­ves­ti­gated this fur­ther, how­ever our con­ver­sa­tions ran out of time and I was un­able to dig into this deeper, which is un­for­tu­nate.

5 Other op­tions for donors to consider

The pur­pose of this piece is not to provide the full an­swer to the ques­tion of how to donate if you are keen on tack­ling cli­mate change. How­ever here are a few (not nec­es­sar­ily thor­oughly re­searched) ideas:

  • Founders Pledge has given this ques­tion plenty of thought and has some recom­men­da­tions (link)

  • Pro­vid­ing con­tra­cep­tion for free to peo­ple who oth­er­wise don’t have ac­cess to it could be com­pet­i­tive with Cool Earth’s cost-effec­tive­ness, even un­der GWWC’s as­sess­ment of Cool Earth. More on this in Ap­pendix 7.

  • Fund­ing ed­u­ca­tion for girls has been pro­posed by draw­down.org as a high-im­pact choice. Some of the ar­gu­ments made in Ap­pendix 7 would ap­ply here too. I don’t know how this would stack up in terms of cost-effec­tive­ness, al­though I’d guess it would likely be on the same or­der of mag­ni­tude as pro­vid­ing con­tra­cep­tion, with similar non-cli­mate-change benefits.

The main pur­pose of men­tion­ing these is to in­di­cate that there *are* other po­ten­tially high-im­pact op­por­tu­ni­ties for cli­mate-in­ter­ested donors (i.e. it’s not that we are look­ing at Cool Earth be­cause there are no other promis­ing dona­tion can­di­dates)


Cool Earth’s work is ei­ther fairly low im­pact, or there is (cur­rently) not enough ev­i­dence available to say; this de­pends on which pro­ject (i.e. coun­try) you’re look­ing at.

For the coun­tries for which we don’t have enough ev­i­dence, it may be that more ev­i­dence would show Cool Earth to be more cost-effec­tive. While Cool Earth staff have been very kind in giv­ing me their time, there has been a limit to how time they have been able to provide—these con­clu­sions may evolve with more in­for­ma­tion.

Based on the in­for­ma­tion as it stands, I would be more in­clined to recom­mend that donors not donate un­til more anal­y­sis is done. I also note that there are sev­eral other promis­ing in­ter­ven­tions that could be at least as cost-effec­tive as Cool Earth’s work.




There now fol­low some ap­pen­dices.

Ap­pendix 1: More back­ground info about log­gers and logging

Cool Earth op­er­ates in 3 lo­ca­tions:

2 part­ner­ships in Peru

2 part­ner­ships in Pa­pua New Guinea

1 part­ner­ship in Demo­cratic Repub­lic of Congo

They plan to ex­pand to Mozam­bique and Cameroon

In Peru, the log­gers are mostly small-scale log­gers, pos­si­bly one-man-bands, not nec­es­sar­ily op­er­at­ing legally.

(Side note: if log­gers are will­ing to op­er­ate out­side of the law, it’s pos­si­ble that they would be will­ing to log even though the lo­cal com­mu­nity doesn’t per­mit it. I have not in­ves­ti­gated this in any de­tail, how­ever I un­der­stand that Cool Earth does care­ful mon­i­tor­ing of the rain­for­est in the ar­eas where they work, which gives some cause for re­as­surance about this risk.)

In Pa­pua New Guinea, the log­gers are more likely to be large multi­na­tional com­pa­nies.

(For DRC I have not checked—it is un­for­tu­nate that I’ve not been able to get more time with Cool Earth)

Ap­pendix 2: Sum­mary of GWWC’s $1 per tonne of CO2 analysis

The be­low table sum­marises the anal­y­sis done by Giv­ing What We Can (GWWC). You can see the full sources for Giv­ing What We Can’s (GWWC’s) anal­y­sis here: https://​​www.giv­ing­whatwe­can.org/​​re­port/​​cool-earth/​​

Ap­pendix 3: Dis­place­ment risk—more details

Dis­place­ment risk is the risk that some­one in­tend­ing to log in a given area is re­buf­fed from that area be­cause of Cool Earth’s work, but then the log­ger sim­ply goes el­se­where.

At first glance, I think that the most likely sce­nario is that most log­gers are not put off (i.e. they are sim­ply dis­placed and perform log­ging el­se­where), largely be­cause they have already trav­el­led a long dis­tance to get there, so to ex­pect them to be put off by the thought of trav­el­ling just a lit­tle fur­ther seems sur­pris­ing.

How­ever I con­sider here some pos­si­ble miti­gat­ing fac­tors:

  • A3(i) Ex­oge­nous-log­ger-gives-up sce­nario: The log­ger may have at­tempted log­ging some­what op­por­tunis­ti­cally, and once the near­est/​eas­iest log­ging op­por­tu­nity has been re­buf­fed, they sim­ply choose to do some­thing else in­stead of log­ging.

  • A3(ii) Long-term broad cov­er­age sce­nario: The im­me­di­ate im­pact of log­ging may be that the log­ger just goes el­se­where. How­ever if Cool Earth were to con­tinue to ex­pand enough, even­tu­ally there would be so few ar­eas left, that the log­ger may be forced to give up on log­ging. If that oc­curs, it seems fair to give some credit now to that fu­ture pos­si­bil­ity.

  • A3(iii) En­doge­nous-log­ger-would-be-ma­te­rial sce­nario: By “en­doge­nous log­gers” I mean peo­ple from within the com­mu­nity that Cool Earth sup­ports. If Cool Earth has ma­te­ri­ally re­duced the num­ber of en­doge­nous log­gers, it would sug­gest that Cool Earth’s in­ter­ven­tion is im­pact­ful, be­cause those peo­ple are less likely to go el­se­where.

A3(i) Log­ger-gives-up scenario

For our anal­y­sis, we need an es­ti­mate of the prob­a­bil­ity of the log­ger-gives-up sce­nario. I have tried dis­cussing this with Cool Earth, how­ever I’m con­scious that they are ex­perts on the com­mu­ni­ties that they sup­port, and not ex­perts on the com­mu­ni­ties who do the log­ging. So they are not best placed to an­swer this ques­tion.

How­ever I’m con­scious that the log­ger has trav­el­led some dis­tance to perform the log­ging. For ex­am­ple, in Peru the log­gers are typ­i­cally small-scale log­gers who may have trav­el­led from the An­dean re­gion—i.e. po­ten­tially a long dis­tance across the width of the coun­try—in or­der to reach the forests. In Pa­pua New Guinea, the log­gers are large, se­ri­ous log­ging com­pa­nies. Nei­ther of these groups are likely to be ca­sual/​op­por­tunis­tic about the in­tent to log.

I would be in­clined to as­sume that this sort of giv­ing up doesn’t hap­pen to any ma­te­rial ex­tent, al­though if there was ev­i­dence that this was an (at least) some­what com­mon oc­cur­rence, it might change the over­all anal­y­sis. Similarly if we be­lieved that log­gers who have trav­el­led a long dis­tance, are forced to travel a bit fur­ther, and are there­fore dis­in­clined to travel again and more in­clined to seek in­come from el­se­where, this would also change the anal­y­sis.

A3(ii) Long-term broad cov­er­age scenario

If Cool Earth were to con­tinue to ex­pand enough, even­tu­ally there would be so few ar­eas left where log­ging was pos­si­ble that the log­ger may be forced to give up on log­ging. How far away are we from that?

The be­low bul­let points in­di­cate why I think that we are very far away from that. Hence con­sid­ers the long-term broad cov­er­age sce­nario to be far away enough that it gives it neg­ligible credit.

  • Peru

  • The log­gers are typ­i­cally com­ing from the An­des and trav­el­ling sev­eral hun­dred km to get to there

  • So the amount of ex­tra travel needed would per­haps need to be sev­eral hun­dred more kilo­me­tres be­fore it de­ters a logger

  • One com­mu­nity will typ­i­cally oc­cupy around 100 acres of land

  • This might re­quire around 600m to tra­verse (or pos­si­bly a bit less)

  • So they would need to add an­other sev­eral hun­dred communities

  • They are cur­rently cov­er­ing 2 com­mu­ni­ties in Peru

  • Pa­pua New Guinea

  • The log­gers are typ­i­cally large multi­na­tional log­ging companies

  • So if it be­came harder to ac­cess for­est in one lo­ca­tion, the com­pany would sim­ply look elsewhere

  • Demo­cratic Repub­lic of Congo

  • Cool Earth has one part­ner­ship in DRC. I have not con­sid­ered DRC closely in this analysis

A3(iii) En­doge­nous log­ger would be ma­te­rial scenario

Cur­rently there is very lit­tle “en­doge­nous” log­ging (i.e. log­ging by peo­ple from within the com­mu­nity which Cool Earth sup­ports) -- it ac­counts for around 3% of the log­ging which oc­curs, ac­cord­ing to Cool Earth.

The key ques­tion is whether en­doge­nous log­ging would be ma­te­rial if Cool Earth weren’t work­ing in those com­mu­ni­ties—if so, then the dis­place­ment risk is less of a con­cern.

From my con­ver­sa­tions with Cool Earth I un­der­stand the fol­low­ing:

  • They be­lieve that en­doge­nous log­ging would be ma­te­rial with­out them

  • They were un­able to provide data about the ex­tent to which en­doge­nous log­ging oc­curs in other nearby communities

  • They were able to give an anec­dote about an­other com­mu­nity who logged 25% of the land around them

This has not been enough to con­vince me that en­doge­nous log­gers are ma­te­rial. In par­tic­u­lar:

  • Cool Earth works with com­mu­ni­ties who are par­tic­u­larly prone to value the rain­for­est, this sug­gests that en­doge­nous log­ging is likely to be low there. In­deed they have ar­gued that the com­mu­nity’s de­sire to pre­serve the rain­for­est is part of the rea­son for their suc­cess.

  • If the com­mu­ni­ties would have logged 25% of the rain­for­est around them with­out Cool Earth’s work, this would be more than enough to push Cool Earth into cost-effec­tive ter­ri­tory; how­ever I don’t be­lieve the com­mu­nity that did this was typ­i­cal.

  • In my con­ver­sa­tions with Cool Earth, they have refer­enced some more data about the de­foresta­tion that’s been oc­cur­ring both within and out­side of Cool-Earth-sup­ported com­mu­ni­ties, and this might help to shed some light on this. At the time of writ­ing, Cool Earth have not had time to share this with me.

Ap­pendix 4: More on Cool Earth’s opinion on Pa­pua New Guinea

Cool Earth have sug­gested that the work in Pa­pua New Guinea is still valuable, even though dis­place­ment risk is high for the log­gers. They have noted that a ma­jor palm oil com­pany—New Bri­tain—has de­cided that they will stop log­ging and only cre­ate palm oil on ex­ist­ing sites rather than per­pe­trate fur­ther de­foresta­tion. They be­lieve that Cool Earth has a valuable role to play in achiev­ing out­comes like these.

I am not so sym­pa­thetic to this claim. Cool Earth is not a cam­paign­ing or­gani­sa­tion, and does not al­lo­cate a ma­te­rial amount of its re­source to in­fluenc­ing gov­ern­ments or cor­po­rates. I sus­pect that New Bri­tain would have made the same de­ci­sion had Cool Earth never ex­isted, and that Cool Earth’s con­tinued ex­is­tence is un­likely to in­fluence other such palm oil com­pa­nies.

Ap­pendix 5: Po­lari­sa­tion—why Cool Earth is likely highly cost-effec­tive or not at all

Ap­pendix 2 sets out the model used by Giv­ing What We Can (GWWC) when they did their anal­y­sis. This post has fo­cused on how much re­duc­tion in over­all prob­a­bil­ity of log­ging is ac­tu­ally gen­er­ated by Cool Earth’s work, in other words:

  • if the prob­a­bil­ity of log­ging with­out Cool Earth is 28% (line (B) from Ap­pendix 2)

  • how much does that prob­a­bil­ity re­duce to with Cool Earth? (line (C) from Ap­pendix 2)

The be­low chart shows how the cost per tonne of CO2 averted varies with as­sump­tion (C) from Ap­pendix 2, while keep­ing all other as­sump­tions fixed.

GWWC’s as­sump­tion was that the prob­a­bil­ity of log­ging *with* Cool Earth do­ing their work was 0.5%. This means that al­most any re­duc­tion in the scale of Cool Earth’s work (e.g. in­stead of bring­ing the prob­a­bil­ity of log­ging down to 0.5%, let’s say you thought it was ac­tu­ally 10%) would still leave Cool Earth more cost-effec­tive than a straight­for­ward tree-plant­ing scheme. In other words, for most of the chart, the green line is lower than (i.e. more cost-effec­tive than) the blue line.

It’s only if Cool Earth’s work is hav­ing very lit­tle im­pact that we get a cost-effec­tive­ness which is much worse than tree-plant­ing.

There is still a zone where Cool Earth’s cost-effec­tive­ness hap­pens to be close to that of tree-plant­ing, how­ever this is a nar­row win­dow.

Note that I’ve in­cluded here a com­par­i­son with tree-plant­ing mostly be­cause this is an easy com­par­i­son to make—it’s not be­cause I ex­pect tree-plant­ing to be the best cli­mate change in­ter­ven­tion out­side of Cool Earth.

Ap­pendix 6: What is the marginal im­pact of the next pound donated?

At the mar­gin, the next pound donated to a char­ity is typ­i­cally likely to sup­port the fol­low­ing types of work:

-- those pro­jects which the char­ity is seek­ing to grow or get off the ground (i.e. which are some­how “ex­pand­ing” be­yond what they are cur­rently do­ing)

-- those pro­jects which are less “core” to the char­ity (and there­fore more likely to be at risk if money were short)

Th­ese are sub­tle things, and of­ten not easy to de­ter­mine. In the case of Cool Earth, be­cause they are ex­pand­ing in cer­tain ar­eas (Pa­pua New Guinea, Mozam­bique and Cameroon) these are likely to be good can­di­dates for the marginal im­pact of the next pound.

If we hap­pened to know that the im­pact of the next pound was to fund work in Pa­pua New Guinea, say, then the im­pact anal­y­sis on (say) Peru would be al­most ir­rele­vant. It would not be en­tirely ir­rele­vant be­cause it says some­thing about the ap­proach of the or­gani­sa­tion be­ing funded. And there is always some chance that the funds could end up sup­port­ing (say) Peru, or in­deed any­thing else Cool Earth does.

Ap­pendix 7: Pro­vid­ing contraception

This is a very shal­low re­view, and needs more work be­fore it could be con­sid­ered defini­tive. How­ever here are some rough and ready calcs to in­di­cate that the cost per tonne of CO2eq averted is prob­a­bly only around $1:

[EDIT: Some com­menters have ar­gued that the post would be bet­ter with­out this sec­tion. They are prob­a­bly right. The spirit of this sec­tion is meant to be: “if we keep on think­ing cre­atively about cli­mate change we will prob­a­bly keep find­ing cre­ative solu­tions—I don’t know if con­tra­cep­tion is re­ally a good idea, but I’m just throw­ing an idea out to illus­trate this.” I’m keep­ing this sec­tion in any­way.]

Cost per preg­nancy averted?

  1. Cost to fully meet the need for mod­ern con­tra­cep­tives: $9.4 billion [A]

  2. Num­ber of un­wanted preg­nan­cies per year: 74 mil­lion [B]

  3. Cost per preg­nancy averted ~ $100 (= (1) /​ (2) with some round­ing)

Aver­age CO2 foot­print per per­son?

  1. To­tal CO2 emis­sions = c 53 billion tonnes of CO2eq per an­num [C]

  2. To­tal world pop­u­la­tion = c 7 billion

  3. Aver­age CO2 foot­print = c 7.5 tonnes per per­son p.a. (= (4)/​(5) with some round­ing)

  4. Aver­age CO2 foot­print for some­one in the de­vel­oped world = 10 tonnes per per­son p.a. [D]

  5. Aver­age CO2 foot­print for some­one in the de­vel­op­ing world ~ 5 tonnes per per­son p.a. (rough es­ti­mate, see [E])

Cost per tonne of CO2eq averted?

  1. Life­time CO2eq foot­print ~ 100 tonnes per per­son (roughly calcu­lated, see [F])

  2. Cost per tonne of CO2eq averted ~ $1 per tonne of CO2eq (= (3)/​(9))

[A] source: Guttmacher In­sti­tute, p5 of https://​​www.guttmacher.org/​​sites/​​de­fault/​​files/​​re­port_pdf/​​addin­gitup2014.pdf . The source did not say that this was a per an­num cost, but I’m guess­ing it prob­a­bly is.

[B] source: Path­fin­der In­ter­na­tional: “In de­vel­op­ing coun­tries, more than half of all women of re­pro­duc­tive age want to avoid preg­nancy. 214 mil­lion women are not us­ing an effec­tive method of con­tra­cep­tion. And mil­lions of women lack the ser­vices they need, lead­ing to 74 mil­lion un­in­tended preg­nan­cies in de­vel­op­ing coun­tries each year.” https://​​www.path­fin­der.org/​​fo­cus-ar­eas/​​con­tra­cep­tion-fam­ily-plan­ning/​​

[C] World bank gives a figure of c 53,526,300,000 tonnes as at 2012 https://​​data.wor­ld­bank.org/​​in­di­ca­tor/​​EN.ATM.GHGT.KT.CE

[D] On­line source says: “The av­er­age per­son’s car­bon foot­print is about 10 tonnes” https://​​www.car­bon­calcu­la­tor.co.uk/​​av­er­ages.php

[E] I didn’t find a source for the av­er­age car­bon foot­print for some­one who is liv­ing in a con­text where con­tra­cep­tion is not read­ily available and needs to be pro­vided by a char­ity. How­ever as a rough guess I just chose 5 tonnes be­cause the av­er­age of 10 tonnes and 5 tonnes comes to the de­sired 7.5 tonnes—this does not weight cor­rectly for pop­u­la­tion sizes, but I think this will prob­a­bly mean I’m un­der­stat­ing the car­bon foot­print.

[F] The sim­plis­tic way to calcu­late the life­time car­bon foot­print is to mul­ti­ply the an­nual car­bon foot­print by the life ex­pec­tancy in years, which would be c. 50 years for coun­tries with the short­est life ex­pec­tan­cies. How­ever we should dis­count the fu­ture years be­cause there is un­cer­tainty about the fu­ture (e.g. maybe we will have solved cli­mate change in 30 years’ time; or maybe we will have caused a cli­mate catas­tro­phe and wiped out hu­man­ity in 30 years’ time). So to ac­count for this I’ve used a dis­count rate of 5%, and to get the right dis­counted pre­sent value would in­volve di­vid­ing by 5% (i.e. mul­ti­ply­ing by 20) as­sum­ing peo­ple live in per­pe­tu­ity, which would give a similar num­ber to as­sum­ing that peo­ple live for 50 years.

Fur­ther notes:

  • This is based on the cost to fully meet the con­tra­cep­tive need—this may in­clude more ex­pen­sive “last mile” con­tra­cep­tive needs and the best use of funds at the mar­gin might be more cost-effec­tive (al­though I haven’t checked how the $9.4 bn figure was calcu­lated, so I don’t know if that’s cor­rect)

  • Calcu­la­tions of this sort of­ten ig­nore an im­por­tant fac­tor: each per­son adds a de­mand on the world’s re­sources, but also brings a small (maybe only 0.00001% or what­ever) chance that the per­son will cre­ate a phe­nom­e­nal break­through which will solve the prob­lem. As an ex­am­ple, many have wor­ried over the years about hav­ing enough food to feed a grow­ing pop­u­la­tion. How­ever if we had limited pop­u­la­tion growth as a re­sult of this, we might have never had Nor­man Bor­laug, and never had the Green Revolu­tion. That said, for peo­ple born in the de­vel­op­ing world, it’s likely that the best way to un­lock their po­ten­tial to help the world is prob­a­bly to have fewer of them and make sure they are well ed­u­cated rather than hav­ing more of them in coun­tries with still-de­vel­op­ing ed­u­ca­tion in­fras­truc­tures.

  • A sep­a­rate study has found that if you met the un­met need for con­tra­cep­tives (no co­er­cion what­so­ever) then you could achieve large scale abate­ment at less than a dol­lar a ton. Source: https://​​www.vox.com/​​en­ergy-and-en­vi­ron­ment/​​2018/​​11/​​16/​​18096352/​​cli­mate-change-clean-en­ergy-poli­cies-guide. Note that I had seen this quote be­fore I put to­gether my num­bers, so I prob­a­bly sub-con­sciously tweaked my choice of dis­count rate to agree to this. (I.e. if you think that two in­de­pen­dent as­sess­ments have come to the same figure, it’s prob­a­bly bet­ter to say that they are not en­tirely in­de­pen­dent)

  • Note that this gives no credit to the many other benefits of the in­ter­ven­tion, no­tably re­duc­ing ma­ter­nal mor­tal­ity, en­abling fe­male em­pow­er­ment, and other sus­tain­abil­ity benefits.

Many thanks to John Halstead and Jo­hannes Ackva who re­viewed ear­lier drafts of this post.