Climate change
Climate change is a serious problem with worldwide impact that will be felt most by the poorest and most vulnerable members of society. But it is very difficult to measure the cost-effectiveness of interventions on climate change because of the global reach of the impact. Below, we discuss the three key approaches to reducing the harms of climate change: mitigation, geoengineering, and adaptation. While we do not rule out the possibility that climate change interventions may be more effective than our current recommended charities, given their enormous potential rewards, at this time we are unable to recommend any climate change charity as one of our ‘top rated charities’. We are continuing to do research into this area, though our initial estimates suggest that interventions focusing on climate change are several times less effective than those carried out by our current top-recommended charities.
What is Climate Change?
Climate change—specifically human-caused global warming—is often cited as one of the greatest dangers facing mankind in the 21st Century. In short, we are referring to the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth’s mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980. Warming of the climate system is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation. Climate change is seen by many as having the potential to undo all of the gains made in poverty reduction over the past three or four decades.
How cost-effective are Climate Change interventions?
The Copenhagen Consensus 2012 panel, made up of five economists (including four Nobel prize winners), ranked research and development efforts on green energy and geoengineering among the top 20 most cost-effective interventions globally, but ranked them below the interventions that our top recommended charities carry out.
Our own initial estimates agree, suggesting that the most cost-effective climate change interventions are still several times less effective than the most cost-effective health interventions. These estimates are highly uncertain, however, and we do not rule out the possibility that climate change interventions may actually be more effective than our current recommended charities. The uncertainty in our estimates results from a lack of clarity in our understanding of the relationships between our actions, climate, and global health, as well as vagueness about the future actions that humanity will take to avert the negative consequences of climate change.
In calculating our initial cost-effectiveness estimates, we relied on a World Health Organisation (WHO) estimate of the disability-adjusted life years (DALYs) lost to what are thought to be the dominant health risks created by the predicted effects of climate change: exposure to thermal extremes and weather disasters, and increased incidence of malaria, diarrhoea, and malnutrition. 1 Their research shows that we may consider 5,000 tonnes of carbon dioxide emitted to be equivalent to the loss of one disability-adjusted life year (DALY). Therefore, for an intervention to be in the same range of effectiveness to our recommended health charities, it must abate carbon dioxide emission, or the emission of an equivalent amount of other greenhouse gases, at very roughly $0.02 per tonne 2 . Our calculations for AMF, for example, say that for each $30-50 donated, a DALY is saved. Current estimates of the cost of preventing a tonne of carbon dioxide or equivalent from being emitted are many times $0.02. However, independent experts have suggested that this estimate has an uncertainty so large that it could easily be 10 or more times smaller or larger than the numbers presented above. This method of assessing cost-effectiveness also does not capture all the potential negative side-effects of climate change, neglecting reduced economic productivity, damage to culture, forced migration, and biodiversity loss, among others.
Reference:
Anthony J. McMichael A, Campbell-Lendrum D, Kovats S, Edwards S, et al. Global Climate Change. In: Ezzati M, Lopez A, Roders A et al. Comparative Quantification of Health Risks, Global and Regional Burden of Disease Attributable to Selected Major Risk Factors, Geneva, World Health Organization, 2004, pp. 1543-1650. (Close footnote)
The economic costs of climate change mitigation have been estimated, for example, in the Stern Review, which was conducted for the UK treasury. The report estimated that climate change could reduce global GDP by 5%, and up to 20% if a wider range of impacts was considered and if climate change was worse than expected. On the other hand, the cost of mitigating climate change was estimated to be only about 1% of global GDP annually. But uncertainty in how these economic benefits transfer to the least well off in society makes it difficult to apply these benefits to our analysis.
The three key categories of climate change interventions are: mitigation (reducing greenhouse gas emissions), geoengineering (manipulating the climate system to reduce the impacts caused by a given injection of CO2), and adaptation (reducing the loss of welfare caused by the impacts of climate change).
For a more detailed analysis of different responses see our individual pages on:
