The COVID-19 Pandemic: Human Health and Earth Systems

In March 2020, estimates of global emissions of CO2 began to show a decrease, but for an unexpected reason: Planet Earth experienced an unusual decrease in human activity as the COVID-19 pandemic spread around the world. Lockdown measures limiting many human activities and forced confinement resulted in decreases in activities such as road and air traffic, electricity demand, and industrial activity. Many people changed from commuting to offices to working from home.

Studies of these decreases in human activity reported that global CO2 emissions also dropped. For example, Liu, et al. (2020) concluded that CO2 emissions decreased by about 9% in the first half of 2020, with the timing of the decrease corresponding to the timing of lockdown measures. But that decrease in CO2 emissions did not last long, as the world population struggled to "return to normal" when the pandemic continued for more than two years, and is now in its third year. And by 2021, global greenhouse emissions rose to a new high point, almost as high as pre-pandemic levels of 2019 and 2018. The lockdown response to this unexpected pandemic provided some hope that it is possible for humans to significantly slow down the emissions of CO2 (and other greenhouse gases) by changing their behavior and thus reducing the levels of fossil-fuel consuming activities. But it took a huge, global health crisis to make that happen. Could this turn out to “wake us up” and encourage society to change its ways regarding our dependence on fossil fuels? Or, will we continue to just return to “normal” after the pandemic is over?

These are questions that will likely be debated for a long time as the story unfolds regarding the science and politics of the COVID-19 pandemic. But for students taking this course in the spring semester of 2020, it was a more immediate, personal experience. We were faced with a very abrupt and stressful situation, but also a “teachable moment” regarding how humans interact with global Earth processes in ways that can have a direct effect on our lives. Because of increasing concerns about the pandemic, students were abruptly forced to leave campus, and we had to instantaneously switch this course (and all other BC courses) to online teaching. Although this experience was very stressful for all involved, it motivated the addition of a new section of this course on the intersection of global Earth systems, human population growth, and the spread of COVID-19.

Understanding how human population growth and human use of resources affect Earth systems is an important aspect of the global climate change story and of the more general intersection of Earth systems and public policy explored in this course. That topic was not adequately covered in previous versions of this course, and I had wanted to add that topic into the course for quite a while. The COVID-19 lockdown provided an opportunity to do that, and it also provided a very direct connection between the course concepts and what the students were dramatically experiencing in their lives. And, although personally challenging, it provided one of the best examples of uncertainty and of why the topics for this course are a moving target. Also, some students commented in online class discussions that learning about the science underlying these issues provided at least some comfort during these stressful times.

Thus, the course now has a section on human population, mathematical modeling of human population and pandemics, and the so-called “flattening the curve” that was being discussed in COVID-19 news headlines. We start this topic with human population modeling, which forms a good basis for modeling the spread of diseases and why we were hearing so much about “flattening the curve” to help society deal with the effects of the pandemic.

Reference:

Liu, Z., P. Ciais, Z. Deng, et al., Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic. Nat Commun 11, 5172 (2020). https://doi.org/10.1038/s41467-020-18922-7