Climate Change (Part 2 of 2)

Satellite photo of the Sundarbans, low-lying mangrove swamps in Bangladesh under threat from rising sea levels (Jesse Allen / NASA / Public Domain)

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Notice about research

Giving What We Can no longer conducts our own research into charities and cause areas. Instead, we're relying on the work of organisations including J-PAL, GiveWell, and the Open Philanthropy Project, which are in a better position to provide more comprehensive research coverage.

These research reports represent our thinking as of late 2016, and much of the information will be relevant for making decisions about how to donate as effectively as possible. However we are not updating them and the information may therefore be out of date.

This report is a continuation of our report on climate change interventions. Part 1 is available here.

1. Tractability

The impacts of climate change may be prevented or reduced through charitable interventions, although the effectiveness of these varies greatly. Political advocacy for highly effective emission reduction policies (see below)may potentially have the greatest effect, though the probability of success or of producing additional impact through individual contributions is small and extremely uncertain. Direct actions which reduce emissions have an effect which is a great deal more certain but smaller in scale.

1.1. Political Advocacy

When conducted by governments and large institutions, it seems that climate change mitigation would be extremely tractable.[1] It is estimated, for instance, that a national ‘cap-and-trade’ emissions trading or taxation scheme could greatly reduce emissions at a negligible or net-negative cost, given that funds raised through such a scheme could be used for other purposes.[2][3][4][5][6] So far, such schemes have proven quite effective in reducing emissions without large negative effects on economic growth, for instance in Australia, the European Union, British Columbia, and elsewhere.[7][8][9][10][11][12] Despite minor reductions in growth in some instances, these schemes have generally resulted in rapid and significant reductions in greenhouse gas emissions in the areas in which they are implemented (although some energy-intensive industries may simply be shifted offshore).[13] It has also been argued that such schemes only produce incremental change and are unlikely to provoke technological innovation sufficient to prevent temperature rises beyond 2°C. Therefore, while useful, such schemes will likely need to be complemented by increased spending on R&D.

It has also been estimated that the total cost of restricting temperature rises to roughly 2°C would cost approximately 1% of Gross World Product (GWP) by 2050.[14] The IPCC has estimated this cost as being higher, at 1.5-3.9% of consumption by 2050 and roughly 4.8% by 2100.[15] Modelling as recent as 2016 has confirmed that this is fairly accurate, with a central estimate of 2.2% by 2050.[16] This modelling also indicates that the cost will be lower the sooner the necessary policies are implemented - delaying the start of sizeable emission reductions until 2030, for instance, would result in the cost increasing by 14%.[17] Furthermore, the economic costs of not doing so at all, and allowing unmitigated climate change, have been estimated to be far greater than the modest costs of mitigation, at roughly 20% of Gross World Product by 2050.[18][19] This does not include the health costs of air pollution attributable to high-emission industries, which could be equivalent to preventing 175,000 deaths per year in 2030, and various other additional impacts on health.[20]

Likewise, the harms of incremental carbon emissions are also greater than the cost of mitigation. This is captured in studies which try to quantify the “Social Cost of Carbon” (SCC), which is a measure “… of  the incremental aggregate economic impact of emitting one more tonne of carbon dioxide…” at present,[21] in dollars. Developed from computational models, estimates of the SCC vary enormously, with some as low as $11 and others above $200.[22][23][24][25] Some of the more robust estimates have placed a lower bound for the SCC at $125, and recognised that the actual figure could be in the tens of thousands.[26] The degree of variance is due largely to the exact model used, the discount rate applied, the monetary values assigned to various forms of harm, and a variety of initial inputs.[27] The selection of model, inputs and, hence, SCC is quite subjective and has been widely debated among policy-makers. Nonetheless, even at the very lowest estimates, the economic harm of one tonne of CO2 being emitted exceeds the cost of preventing its emission - even private donors can do so at a cost of $1.34 per tonne (see below) which, although being an uncertain estimate, is probably an order of magnitude lower than the price. This is without the legislative instruments of government and without the ability to implement wide-ranging tax measures. Thus, climate change mitigation policies are indeed quite worthwhile and sufficiently cost-effective for governments to implement, particularly over the longer-term (although governments may still not implement such policies due to collective action problems among different governments, special interests, and the prioritisation of short-term welfare).[28]

However, for private donors without the resources and legislative tools of government at their disposal, such policies and governmental action can only be brought about through advocacy and lobbying. This is problematic as research into the effectiveness of climate advocacy and of environmental lobbying in general is quite sparse and unhelpful in giving clear estimates of cost-effectiveness. It is unclear, in general, whether such advocacy is particularly tractable. We have looked into various climate advocacy organisations and there have been some minor successes and some promising applications of best practices in lobbying, such as the charity Sandbag  operating in the EU and Citizens’ Climate Lobby in the United States (see below for more information). There is some evidence that such organisations may have some non-negligible probability of success and hence may provide promising opportunities to have a large expected impact through private donations. However, as with advocacy in general, the tractability, cost-effectiveness and expected impact of such charities’ work will be dependent on the organisation in question, as well as highly uncertain, and we cannot attribute any fixed level of tractability to climate change advocacy overall. It is also largely dependent on the resistance which such organisations experience from organisations with opposing interests - these include a number of large energy companies which have previously made considerable financial contributions to major political parties and to lobbying efforts.[29][30][31][32]

1.2. Direct Action - Mitigation

Direct action to reduce emissions, however, may be more promising.

Studies by the World Health Organisation had previously indicated that the average cost to human health incurred by greenhouse gas emissions is roughly 1 DALY per 5,000 metric tonnes of CO2-equivalent,[33][34] but this figure is subject to an enormous degree of uncertainty and may be considerably outdated. Our own more recent modelling, based on the WHO’s 2014 report, has produced an estimate that it would require a reduction of, on average, 258,200t in CO2-equivalent emissions to prevent one human death due to climate change (for more details about our model, see our separate report). This figure is still subject to a high degree of uncertainty but, based on the limited relevant research to date and a number of generous assumptions, we are moderately confident that the per-tonne health impacts of climate change are not likely to be worse than this.

Even if 258,200tCO2eq/death seems very high, it does not necessarily imply that direct action to mitigate emissions is not cost-effective. If charitable organisations and carbon offset providers are able to reduce emissions at a very low cost per tonne, and if they have the capacity to effectively scale up their operations, then reducing emissions through direct action could be extremely tractable. For the organisations which work on this, however, cost-effectiveness is a major problem. For instance, the most cost-effective mitigation opportunity we are currently aware of is through Cool Earth (see below), which can reduce CO2 emissions for approximately $1.34 per tonne (or $0.38 including indirect effects, though these are less certain). Using the older estimate of tonnes per DALY, this equates to approximately $6,700 per DALY averted. Or, purely in terms of temperature, it would be equivalent to $893 billion per degree less of warming[35] (although there are diminishing returns in Cool Earth’s work and it is unlikely that $893 billion could be productively used to protect rainforests, particularly given that forestry accounts for only 11% of global emissions).[36] By our own modelling, which suggests that a future life is saved for every 258,200tCO2eq less which is emitted, this equates to at least $97,300 per human life saved.This is much less than what the Value of a Statistical Life (VSL) in developed nations, i.e. what countries will spend to prevent one death, which has been estimated to be around $10 million in the United States[37]. However, the figure is roughly 24 to 90 times more expensive than those of our top recommended charities per DALY averted and 34 times more expensive per life saved - the Against Malaria Foundation, for instance, averts a DALY for roughly every $100 spent and prevents the death of a child under 5 for every $3,461.[38] This indicates that mitigation efforts such as this are not sufficiently cost-effective, and hence tractable, for improving human health and well being. Of course, this does not include its effects on preserving biodiversity and the natural environment (see Importance above) and so donors particularly concerned with these outcomes may still consider it sufficiently tractable, but thoroughly examining this possibility is beyond the scope of this report.

1.3. Adaptation

Direct interventions on the effects of climate change may therefore be a great deal more tractable. Of the 250,000 annual deaths predicted by the WHO to result from climate change, additional deaths due to malaria, diarrhoeal diseases and undernutrition accounted for 60,000, 48,000 and 95,000, respectively.[39] For malaria specifically, these future effects of climate change on disease burden are smaller in magnitude than the reduction between 1900 and present (by one order of magnitude) and also far smaller than the reduction that could be achieved by scaling up existing control measures such as bed nets (by up to two orders of magnitude).[40] Given this, rather than deal with these mortality figures indirectly through mitigation efforts at a cost of roughly $97,300 per life saved or $6,700 per DALY averted, it may potentially be far more cost-effective and hence tractable to simply deal with these conditions directly. This approach may be particularly effective due to the opportunity to completely eliminate problems such as malaria in some areas before temperature increases can exacerbate them further (vaccination campaigns might also be extremely useful for achieving this goal).[41][42][43] For instance, the burden of malaria can quite reliably be reduced at a cost of $3,461 per life saved and roughly $100 per DALY by the Against Malaria Foundation.[44] Likewise, micronutrient deficiencies can be alleviated at a cost of as low as $0.07 per person reached through Project Healthy Children,[45] and there is evidence that mortality due to diarrhoeal diseases can be cost-effectively reduced by Living Goods.[46] Although it may seem, in a sense, to be treating the symptoms rather than the cause, the high cost per tonne of CO2eq and per DALY averted through mitigation indicates that the more cost-effective and tractable method of improving human health and wellbeing may be to instead deal with these conditions directly. Of course, once again, this excludes the impacts on climate change on animal welfare, biodiversity and environmental preservation so may not apply to donors who place a great deal more weight on these factors. For donors who place much greater value on human well being, it is likely that these basic health interventions may be the more tractable method of maximising that value.

1.4. Geoengineering

Another potential means of reducing the harm brought about by climate change is geoengineering. This refers to “…a broad set of methods and technologies operating on a large scale that aim to deliberately alter the climate system in order to alleviate the impacts of climate change…”.[47] Among the more promising forms of geoengineering are Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR).[48]

Solar Radiation Management aims to reduce solar energy absorbed within the Earth’s atmosphere by reflecting a greater proportion of radiation away from the planet.[49] The two most popular proposals for this are to spray seawater into the air to increase the reflectivity of clouds (marine cloud whitening) or to increase the concentration of highly reflective sulphate aerosols in the upper atmosphere (stratospheric aerosol injection).[50][51] While both these interventions promise to be extremely cost-effective in reducing or averting global warming, they are quite high-risk as it is very difficult to predict other impacts such action could have on the Earth's climate, and these may cause damage to human life comparable to that of the warming which would have happened otherwise. Furthermore, such interventions require maintained action, and should this be interrupted the results could be catastrophic.[52][53] Thus, while such interventions might be highly cost-effective in averting the impacts of climate change, the difficulty in fully understanding their effects mean such an approach is risky. In addition, SRM would not prevent the effects of increased CO2eq other than temperature increase - for instance, it would not prevent ocean acidificationdroughts, ecosystem damage and so on.[54] This may mean that it would be useful as a ‘last resort’ response if mitigation fails or if warming greatly exceeds predictions and poses a catastrophic risk (see Tail Risks above). These approaches are also generally considered very unpopular and might not be politically viable, because in the absence of global coordination and international enforcement of controls on geoengineering technologies, the unilateral use of geoengineering by one nation or organisation may adversely affect the climate globally.[51:1] Indeed, such unilateral action has already been observed for other forms of geoengineering.

Carbon dioxide removal involves the development and deployment of technologies capable of extracting and storing carbon dioxide from the atmosphere.[55][56] While such interventions involve far less risk than SRM, current estimates put the average cost of removing one tonne of carbon dioxide at about $500,[57] and this still far exceeds the cost of abatement through direct mitigation work as described above. It is uncertain how far down this cost can potentially be brought in future.

At this stage, SRM and CDR methods are still in the early stages of development and testing.[58][59] They are also quite underfunded compared to other climate change research - annual funding for geoengineering research projects stands at roughly $11 million.[60][61] Thus, geoengineering research may present an opportunity for donations to have a large impact and, in particular, reduce the risk of catastrophe if climate sensitivity greatly exceeds predictions. It has even been estimated that the benefits of geoengineering research exceed the costs by a factor of 1,000, although this estimate is subject to an enormous degree of uncertainty.[62] It also doesn’t consider the potential harms incurred by SRM, whether it is misused or used correctly with unforeseen consequences. However, we have not yet identified any funding opportunities which we are highly confident will have a large impact, but there has been some research done into the area by GiveWell and the Open Philanthropy Project.

2. Charities working in this area

Mitigation of climate change through direct action is an area that already receives a great deal of funding in the form of carbon offsets. Such offsets are widely available for approximately US$10.[63],[64] Based on the findings of a 2013 investigation by Giving What We Can into 50 different climate change charities, the most cost-effective charity working on mitigation specifically through direct action was Cool Earth.[65] Cool Earth safeguards rainforest by using donated money to help develop rainforest communities economically to a point where they do better by not selling their land to loggers. We estimate that, through these activities, Cool Earth is able to prevent 1t of CO2 emissions for every $1.34 in donations it receives by directly protecting areas of forest. This is more than 7 times more cost-effective than the typical carbon offset scheme. Including the areas of forest indirectly shielded by these protected communities, the cost drops to roughly $0.38 per tonne (though this figure is more uncertain), which is more than 26 times more cost-effective than carbon offset schemes. Still, as mentioned above, this equates to roughly $97,300 per future human death prevented so may not be cost-effective for donors focussed on human well being.

Political advocacy, typically, is an activity which has a comparatively high uncertainty and low chance of success, and for which it is particularly difficult to evaluate the effectiveness.[66] With this in mind, it is nevertheless possible that advocacy initiatives with even a low chance of success may have quite a high value if the scale of the problem they seek to address is sufficiently large. In the case of climate change, given the enormous scale of the problem, it is possible that organisations which work on advocacy might be more effective than those working on direct action. So too, it is entirely possible that they are not, and the extreme level of uncertainty in evaluating this prevents us from firmly recommending any such organisations as more effective than those engaging in direct action.

One charity which has had success through advocacy is Sandbag , which campaigns to improve the EU Emissions Trading Scheme and facilitates the purchase and destruction of permits in this scheme. Prior to 2013, Sandbag had lobbied to have 900 million permits removed from the scheme - the equivalent of 225 million tonnes of CO2 emissions removed from the permit system.[67] During the time this lobbying took place, Sandbag’s budget was $315,000.[68] This suggests that, on average, Sandbag may be able to avert a tonne of CO2eq for $0.0014 through advocacy. However, it is not at all clear how much Sandbag’s lobbying efforts contributed to the removal of those credits. It is also extremely unclear how many more credits Sandbag might be able to remove from the scheme and whether additional donations will improve its ability to achieve this, as this was simply the average value of donations at the time rather than the marginal value. In particular,it does not appear that Sandbag currently has a sizeable funding gap so it is extremely unlikely that further donations will result in additional reductions at such a low cost.

Another charity which appears promising is the Citizens’ Climate Lobby, which campaigns to have carbon pricing legislation introduced and enacted in the United States by organising volunteers to lobby their congressional representatives.[69] Like Sandbag, it is unclear how effective their lobbying efforts are and whether additional donations will increase their chances of success. Despite extreme uncertainty, however, it does seem plausible that the Citizens’ Climate Lobby may be able to achieve significant change at a low cost, as the United States is currently the 2nd highest emitter of greenhouse gases,[70] carbon pricing is considered an effective method of mitigating emissions (see above),[71],[72] and it seems likely that only political action in the United States could provoke large-scale action from many other nations.[73] Indeed, experts have claimed that “…action in the US is necessary but not sufficient for alleviating the threat of climate change. Doing something in the United States would be likely to have a ripple effect on other countries…, and that “…Money spent on climate change might have the highest incremental effect if put towards helping Republicans form a positive agenda on the issue…”.[74] The Citizens’ Climate Lobby attempts to achieve exactly this and, in addition, is doing so at a time when it is becoming increasingly tractable to garner Republican support for climate action.[75] Thus, donations to the Citizens’ Climate Lobby may, in expectation, have large positive impacts at low cost.

Also, while not considered to be climate change charities specifically, the Against Malaria Foundation,[76] Project Healthy Children (PHC),[77] Living Goods,[78] and Development Media International[79] all work on reducing the burden of diseases which are expected to be greatly exacerbated by climatic warming (see above). Work done in the present to reduce the prevalence of malaria and nutritional deficiencies may greatly reduce disease prevalence in future, as anti-malarial bed nets may be expected to reduce the prevalence of the malaria parasite and PHC’s micronutrient fortification programmes might quite reliably remain in place for many years after implementation. By producing such future reductions in disease prevalence, these organisations are able to reduce the adverse impacts of climate change on health and thereby constitute quite cost-effective forms of climate adaptation.

3. Footnotes

  1. Watts, Nick et al. "Health and climate change: policy responses to protect public health." The Lancet 386.10006 (2015): 1861-1914. ↩︎

  2. Baylis, Kathy, Don Fullerton, and Daniel H Karney. "Leakage, welfare, and cost-effectiveness of carbon policy." 21 Mar. 2013. ↩︎

  3. Avi-Yonah, Reuven S, and David M Uhlmann. "Combating global climate change: Why a carbon tax is a better response to global warming than cap and trade." Stanford Environmental Law Journal 28.3 (2009). ↩︎

  4. "A conversation with Adele Morris on June 24, 2013 - GiveWell." 2014. 8 Apr. 2016 < > ↩︎

  5. Nordhaus, William D. "Optimal greenhouse-gas reductions and tax policy in the" DICE" model." The American Economic Review 83.2 (1993): 313-317. ↩︎

  6. Revelle, Eleanor. "Cap-And-Trade Versus Carbon Tax Two Approaches To Curbing Greenhouse Gas Emissions." League of women voters of the United States: Climate change task force (2009). ↩︎

  7. Meng, Sam, Mahinda Siriwardana, and Judith McNeill. "The environmental and economic impact of the carbon tax in Australia." Environmental and Resource Economics 54.3 (2013): 313-332. ↩︎

  8. Jotzo, Frank. "Australia's carbon price." Nature Climate Change 2.7 (2012): 475-476. ↩︎

  9. Martin, Ralf, Mirabelle Muûls, and Ulrich J Wagner. "The Impact of the EU ETS on Regulated Firms: What is the Evidence after Nine Years?." Available at SSRN 2344376 (2014). ↩︎

  10. Pradhan, Basanta K, and Joydeep Ghosh. "The impact of carbon taxes on growth emissions and welfare in India: a CGE analysis." India: Institute of Economic Growth, University Enclave, University of Delhi (2012). ↩︎

  11. "Does a Carbon Tax Work? Ask British Columbia - The New …" 2016. 8 Apr. 2016 <> ↩︎

  12. Fang, Guochang et al. "The impacts of carbon tax on energy intensity and economic growth–A dynamic evolution analysis on the case of China." Applied Energy 110 (2013): 17-28. ↩︎

  13. Revelle, Eleanor. "Cap-And-Trade Versus Carbon Tax Two Approaches To Curbing Greenhouse Gas Emissions." League of women voters of the United States: Climate change task force (2009). ↩︎

  14. Stern, Nicholas. "The economics of climate change." The American Economic Review 98.2 (2008): 1-37. ↩︎

  15. "IPCC Fifth Assessment Report." 2014. 8 Apr. 2016 <> ↩︎

  16. Chen, Y-H Henry et al. "Costs of Climate Mitigation Policies." (2016). ↩︎

  17. ibid. ↩︎

  18. "100% clean and renewable wind, water, and sunlight (WWS …" 2015. 19 Apr. 2016 < > ↩︎

  19. Stern, Nicholas. "The economics of climate change." The American Economic Review 98.2 (2008): 1-37. ↩︎

  20. Shindell, Drew T, Yunha Lee, and Greg Faluvegi. "Climate and health impacts of US emissions reductions consistent with 2 [thinsp][deg] C." Nature Climate Change (2016). ↩︎

  21. "AR5 Synthesis Report - Climate Change 2014 - IPCC." 2015. 8 Apr. 2016 < > ↩︎

  22. ibid. ↩︎

  23. Pindyck, Robert S. "The use and misuse of models for climate policy." 17 Apr. 2015. ↩︎

  24. Nordhaus, William D. A question of balance: Weighing the options on global warming policies. Yale University Press, 2014. ↩︎

  25. Stern, Nicholas. "The economics of climate change." The American Economic Review 98.2 (2008): 1-37. ↩︎

  26. Van den Bergh, JCJM, and WJW Botzen. "A lower bound to the social cost of CO2 emissions." Nature climate change 4.4 (2014): 253-258. ↩︎

  27. ibid. ↩︎

  28. "AR5 Synthesis Report - Climate Change 2014 - IPCC." 2015. 8 Apr. 2016 < > ↩︎

  29. "Electric Utilities -" 2009. 19 Apr. 2016 <> ↩︎

  30. "Oil & Gas -" 2008. 19 Apr. 2016 <> ↩︎

  31. "Oil and Gas Companies Make Statement in Support of U.N.…" 2015. 19 Apr. 2016 <> ↩︎

  32. "Fossil Fuel Industry Opens Wallet to Defeat Obama - The …" 2012. 19 Apr. 2016 <> ↩︎

  33. This is calculated over the next 200 years and at a discount rate of 3% per year. ↩︎

  34. Gasper, Des, and S Rocca. "Is an individual’s impact on health harm via climate change ethically negligible?." (2014). ↩︎

  35. Concordia University. "Carbon Emissions Linked To Global Warming In Simple Linear Relationship." ScienceDaily. ScienceDaily, 11 June 2009. <>. ↩︎

  36. "Global Emissions | Climate Change | US EPA." 2016. 6 Jun. 2016 ↩︎

  37. Rohlfs, Chris, Ryan Sullivan, and Thomas Kniesner. "New Estimates of the Value of a Statistical Life Using Air Bag Regulations as a Quasi-Experiment." American Economic Journal: Economic Policy 7.1 (2015): 331-359. ↩︎

  38. "Against Malaria Foundation (AMF) | GiveWell." 2010. 18 Mar. 2016 <> ↩︎

  39. World Health Organization. Quantitative risk assessment of the effects of climate change on selected causes of death, 2030s and 2050s. World Health Organization, 2014. ↩︎

  40. Gething, Peter W et al. "Climate change and the global malaria recession." Nature 465.7296 (2010): 342-345. ↩︎

  41. Bizimana, Jean Pierre et al. "Modelling homogeneous regions of social vulnerability to malaria in Rwanda." Geospatial Health 11.1s (2016). ↩︎

  42. Tanner, Marcel, and Don de Savigny. "Malaria eradication back on the table." Bulletin of the World Health Organization 86.2 (2008): 82-82. ↩︎

  43. Feachem, Richard GA, and Allison A Phillips. "Shrinking the malaria map: a prospectus on malaria elimination." (2009). ↩︎

  44. "Against Malaria Foundation (AMF) | GiveWell." 2010. 18 Mar. 2016 <> ↩︎

  45. "An Update on Project Healthy Children - Giving What We Can." 2015. 18 Mar. 2016 <> ↩︎

  46. "Living Goods | GiveWell." 2014. 18 Mar. 2016 <> ↩︎

  47. "AR5 Synthesis Report - Climate Change 2014 - IPCC." 2015. 7 Apr. 2016 < > p.89. ↩︎

  48. ibid. ↩︎

  49. ibid. ↩︎

  50. ibid. ↩︎

  51. "Geoengineering research | GiveWell." 2014. 7 Apr. 2016 <> ↩︎ ↩︎

  52. ibid. ↩︎

  53. "AR5 Synthesis Report - Climate Change 2014 - IPCC." 2015. 7 Apr. 2016 < > p.89. ↩︎

  54. ibid. ↩︎

  55. "GAO-10-903 - US Government Accountability Office." 2010. 7 Apr. 2016 < > ↩︎

  56. "Geoengineering research | GiveWell." 2014. 7 Apr. 2016 <> ↩︎

  57. Socolow, Robert et al. "Direct air capture of CO2 with chemicals: a technology assessment for the APS Panel on Public Affairs." 2011. ↩︎

  58. Bickel, J Eric, and Lee Lane. "An analysis of climate engineering as a response to climate change." Smart Climate Solutions (2009): 40. ↩︎

  59. "Geoengineering research | GiveWell." 2014. 7 Apr. 2016 <> ↩︎

  60. Bickel, J Eric, and Lee Lane. "An analysis of climate engineering as a response to climate change." Smart Climate Solutions (2009): 40. ↩︎

  61. See GiveWell’s assessment of geoengineering research funding as of 2013 - <> ↩︎

  62. Bickel, J Eric, and Lee Lane. "An analysis of climate engineering as a response to climate change." Smart Climate Solutions (2009): 40. ↩︎

  63. "ClimateCare." 2006. 12 Jan. 2016 <> ↩︎

  64. "Carbon Footprint Ltd - Carbon Management Services …" 2003. 12 Jan. 2016 <> ↩︎

  65. Mogensen, A. "Cool Earth - Giving What We Can." 12 Jan. 2016 <> ↩︎

  66. "Political change | Giving What We Can." 2014. 13 Jan. 2016 <> ↩︎

  67. "Sandbag Report - Giving What We Can." 13 Jan. 2016 < > ↩︎

  68. ibid. ↩︎

  69. "About CCL - Citizens' Climate Lobby." 2014. 13 Jan. 2016 <> ↩︎

  70. Olivier, Jos GJ, Greet Janssens-Maenhout, and Jeroen AHW Peters. Trends in global CO2 emissions: 2012 Report. Hague: PBL Netherlands Environmental Assessment Agency, 2012. ↩︎

  71. "Effective Carbon Prices - Books - OECD iLibrary." 2013. 13 Jan. 2016 <> ↩︎

  72. Calderón, Silvia et al. "Achieving CO 2 reductions in Colombia: Effects of carbon taxes and abatement targets." Energy economics (2015). ↩︎

  73. Meinshausen, Malte et al. "National post-2020 greenhouse gas targets and diversity-aware leadership." Nature Climate Change (2015). ↩︎

  74. "A conversation with Adele Morris on June 24, 2013 - GiveWell." 2014. 8 Apr. 2016 < > ↩︎

  75. "11 Republicans vow to fight climate change - The Hill." 2015. 8 Apr. 2016 <> ↩︎

  76. "Against Malaria Foundation (AMF) | GiveWell." 2010. 18 Mar. 2016 <> ↩︎

  77. "An Update on Project Healthy Children - Giving What We Can." 2015. 18 Mar. 2016 <> ↩︎

  78. "Living Goods | GiveWell." 2014. 18 Mar. 2016 <> ↩︎

  79. "Development Media International | GiveWell." 2014. 18 Mar. 2016 <> ↩︎