The mortality cost of carbon

Abstract

Many studies project that climate change can cause a significant number of excess deaths. Yet, in integrated assessment models (IAMs) that determine the social cost of carbon (SCC) and prescribe optimal climate policy, human mortality impacts are limited and not updated to the latest scientific understanding. This study extends the DICE-2016 IAM to explicitly include temperature-related mortality impacts by estimating a climate-mortality damage function. We introduce a metric, the mortality cost of carbon (MCC), that estimates the number of deaths caused by the emissions of one additional metric ton of CO2. In the baseline emissions scenario, the 2020 MCC is 2.26 × 10‒4 [low to high estimate −1.71× 10‒4 to 6.78 × 10‒4] excess deaths per metric ton of 2020 emissions. This implies that adding 4,434 metric tons of carbon dioxide in 2020—equivalent to the lifetime emissions of 3.5 average Americans—causes one excess death globally in expectation between 2020-2100. Incorporating mortality costs increases the 2020 SCC from $37 to $258 [−$69 to $545] per metric ton in the baseline emissions scenario. Optimal climate policy changes from gradual emissions reductions starting in 2050 to full decarbonization by 2050 when mortality is considered.

Estimates of country level temperature-related mortality damage functions

“…Here, our implied global mortality damage function projects that in RCP 8.5 end of century (2080–2099), there will be a projected 4.2% increase in the global mortality rate due to temperature-related mortality when the protective effects of rising incomes are accounted for. This global average is quantitatively similar to a global mortality damage function reported recently in Bressler 7 based on a meta-analysis of published studies, which projects 4.4% increase in mortality by RCP 8.5 in 2090 as well as the working paper by Carleton et al 13 , which reports a 5.1% increase in temperature-related mortality by 2090 under RCP 8.5.…”

“…In particular, climate change impacts on human health and mortality are both a critical aspect of climate change costs and not well represented in current SCC estimates. For example, the Climate Framework for Uncertainty, Negotiation and Decision (FUND) model accounts for mortality through a number of different pathways, but its estimates are based off of studies from the 1990s and 2000s 6 while the scientific evidence base for mortality impacts in the Dynamic Integrated Climate and Economy (DICE) model is also dated 7 . A 2017 National Academy of Sciences (NAS) report specifically mentioned mortality as an impact sector that could be readily updated in IAMs 8 .…”

“…A Lancet report concluded that “Climate change is the biggest global health threat of the twenty-first century” 19 while a recent study estimated that anthropogenic warming over the 1991–2018 period is responsible for 37% of warm-season heat-related deaths 20 . Incorporating this literature into SCC estimates can have important implications for estimated damages: A recent study found that revising global mortality estimates increased the SCC by a factor of 7 in the single-region DICE model 7 .…”

“…Our approach is fully consistent with recommendations by the NAS for calculating the SCC, which recommended that damage functions should be based on the current, peer-reviewed literature on climate impacts, have uncertainties that are characterized and quantified where possible, and be transparent, well-documented, and reproducible 8 . The NAS also recommended that damages should be given in natural/physical units which, for mortality costs, is the number of excess deaths associated with carbon dioxide emissions 7 . Finally, we also discuss climate change effects on mortality other than direct temperature effects.…”

Carbon Neutrality Policies and Technologies: A Scientometric Analysis of Social Science Disciplines

“…By informing decision-makers and collective actions, such knowledge will help researchers and policy-makers design and implement policies and technologies that work in initiating and implementing individual, organizational, and social changes. This explains the rationales behind global initiatives such as bringing transparency and rigor to the voluntary carbon market (Twidale, 2021) and research that connects mortality with carbon emissions under the notion of "the mortality cost of carbon" (Bressler, 2021;Schwartz, 2021). Social science knowledge matters.…”