The use of fossil fuels comes with a wide variety of externalized costs. The big focus tends to be on the carbon dioxide fossil fuel produces and its role in warming the climate. But fossil fuels also cause environmental damage when they’re extracted, and burning them produces particulate pollution and ozone. Those substances have downstream effects on human health and agriculture. If all of these costs were included in the price of fossil fuels, then alternatives would be far more competitive.
There have been numerous attempts over the years to quantify these externalized costs. Some look at the issue from a purely economic perspective, and others look at efforts to inform policy. These efforts tend to be based on our best understanding at the time; however, as our knowledge improves, the figures can be worth revisiting. That’s exactly what’s been done by a team of researchers at Columbia and Duke Universities who use current climate scenarios and updated health data.
The researchers’ results say that, even if you ignore the climate benefits, moving away from fossil fuels rapidly would lead to benefits that, in the US alone, can add up to trillions of dollars before the century is over.
The big changes in the work involve a shift over to model version six of the Coupled Model Intercomparison Projects (CMIP), which was accompanied by new emissions scenarios. These scenarios include everything from emissions growing at their prepandemic pace through to near the end of the century, down to a net-zero-by-2050 scenario. The ones that are considered most often are two high-end scenarios (growth to 2080 and a slower pace of growth to the end of the century), and two that are consistent with limiting warming to either 1.5º or 2.0º C.
These scenarios obviously produce impacts via climate change. But the researchers also converted them into emissions of other pollutants, such as particulates and nitrogen oxides, based on the current US energy mix. Those pollutants have a variety of effects on the US population, such as exacerbating asthma and raising the risk of heart problems. Ozone, which is produced by some of the combustion products, can also damage crops.
A second major change compared to past analyses was the consideration of medical impacts. The authors state that we now have an “improved understanding of the human health impacts of exposure to both heat and air pollution.” This turns out to be critical, since health impacts are far and away the most costly of those considered.
Before diving into some of the specific numbers, it’s worth looking at the general principles that dominate the results. The first is that the impact of changing carbon emissions is relatively slow. The Earth takes a while to adjust its temperature to match the energy added by additional carbon dioxide. As a result, we have a fair amount of upcoming warming already baked into the system due to our past emissions, which even aggressive fossil fuel cuts can’t avoid. The result is that the climate impacts of changes we make don’t typically become significant until late in the century.
By contrast, things like ozone and particulate pollution change almost instantly when changes to the energy mix are made. As a result, going on the path to 2º C warming produces statistically significant changes by 2030 in many cases. And, critically, those differences are largely local—we’d see well over half the benefits even if the entire rest of the planet continues using fossil fuels at current levels.
It’s (almost) all bad
In either of the trajectories consistent with climate goals (1.5º or 2.0º warming), emission of nitrogen oxides is dropped by about half, while ozone production responds almost instantly. Particulate pollution is similar. These combine to produce a significant drop in premature deaths as early as 2030. By contrast, heat exposure continues to rise for a while, and reductions in heat-associated deaths don’t show up until after 2050.
The benefits aren’t evenly distributed, however. California, New York, and the northern Midwest see most of the benefits of the drop in pollution. By 2030, California sees over 5,000 fewer deaths per year compared to high-emissions scenarios. For particulates, both California and New York see over 5,000 fewer deaths per year by 2070. (Both of those numbers are in comparison with higher emissions scenarios.)
In parallel with deaths, there’s a relative drop in hospitalizations for asthma, heart disease, and lung problems. Since these conditions often lead to blood circulation issues in the brain, there’s also an associated drop in the cases of dementia.
Overall, if you compare a 1.5º C emissions scenario to a prepandemic growth scenario, by 2070, you’d see 23,000 fewer deaths due to heat, 41,000 fewer deaths per year due to ozone, and 81,000 deaths per year due to particulates.
Finally, the increased heat has an impact on labor productivity. This mostly shows up in Southern states (which are hot already) and agricultural states (where a larger percentage of the workforce has to be outdoors). For agriculture itself, reducing the amount of carbon dioxide in the atmosphere cuts plant productivity slightly. But it’s more than offset by the reduced ozone damage that the crops experience.