Herd immunity to pandemics is a thing – actually, something of a human superpower.
However, herd immunity to other hazards, including weather and climate extremes, is not. No human superpowers here! But perhaps we could emulate the fictional Marvel character Tony Stark – and invent some.
Digging a bit deeper:
Humanity is more-or-less successfully coping with covid-19 in much the same way as it has handled previous pandemics over past millennia – through the buildup of:
Herd immunity (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection that applies only to contagious diseases. It occurs when a sufficient percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby reducing the likelihood of infection for individuals who lack immunity.
Today, we recognize herd immunity as an example of a basic biological process we call natural selection. The idea (and the label) has been around long enough that today it seems ordinary. But when Charles Darwin and Alfred Russel Wallace introduced it in 1858 it was electrifying. To recapture the feel for the early impact of that notion, let’s speak of a human superpower – one built on a three-fold foundation: 1. The pre-existing diversity in people’s immune systems allow some – perhaps many – to survive a pathogen’s initial attack. 2. Human immune systems are trainable. 3. Virtually all human beings share these traits; generally speaking, access is not (directly) restricted to a limited, privileged few. The ultimate result? Successive pathogen onslaughts encounter a more resilient population and fewer pathways for infecting any remaining vulnerable human hosts.
A key point. As the definition notes, innate herd immunity can be augmented by intentional societal action. In the covid-19 instance, researchers quickly mapped the virus genome, and drew inferences on its sources and ways of working. Others developed tests to detect the presence of the virus. The pharmaceutical industry invented vaccines to train and strengthen natural immunity at the individual level (as well as antivirals to constrain the severity of individual infections). The larger society adopted habits such as mask wearing, social distancing, teleworking, and remote learning to protect against disease transmission.
Pandemics, however, are not the only doomsday challenge we face. And when it comes to the others, we lack a built-in physiology that might help us survive. What to do? The answer differs from challenge to challenge, but let’s start with natural hazards – primarily cycles of flood and drought, and severe storms such as hurricanes, but also including climate change, earthquakes, and vulcanism. These matter because our host planet does its business through extreme events. Earth’s ecosystems and the individual plant and animal species they comprise have nearly-perfectly adapted both their structures and their behaviors to the timing and nature of these extremes – capturing their benefits, and minimizing their associated hazards. The global migrations of birds and whales, seasonal births of many species timed to take advantage of plentiful food supplies, and hibernation are just a few examples.
Early on, the human race enjoyed a similar success, through nomadism: hunter-gatherers simply followed the migrations of wild game, and pastoralists moved their herds and flocks to productive grasslands. In this way they kept losses low and at the same time kept food on the table.
But wait! There was no table. No furniture of any kind. No shelter of any permanence. Keeping pace with migrating animals and seasonal changes required traveling light. Shelter and possessions were kept to a minimum. Nomadism had its limits; work was relentless and wealth accumulation not in prospect.
Human creativity and cleverness helped our ancestors see clear opportunities – advantages of truly marvelous consequence and scale – that would be offered by agriculture, by trade, and by built environments, if we would only root ourselves in fixed place. What we saw less clearly was that these advances would be accompanied by novel vulnerabilities to hazards. An earthquake threat is magnified by building collapse. Drought poses a greater hazard to a society dependent on monoculture. And so on.
While the opportunities posed by fixed settlement, economic specialization, and technology advance were evident and immediate, it has taken time for the attendant shortcomings and vulnerabilities to manifest themselves. What’s worse, even as the risks have become more evident, continuing scientific and technical advance and social change have further mutated the vulnerability. Particularly challenging has been the rapidly growing dependence on critical infrastructure – early on, in the form of civilization’s dependence on roads, on water supplies, and waste disposal – and more recently on energy (especially electricity), and on communication; and on soft infrastructure like centralized financial, educational, and healthcare networks.
Enter the (entirely fictional) Marvel character Tony Stark, who:
…is initially depicted as an industrialist, genius inventor, and playboy who is CEO of Stark Industries. Initially the chief weapons manufacturer for the U.S. military, he has a change of heart and redirects his technical knowledge into the creation of mechanized suits of armor which he uses to defend against those that would threaten peace around the world. He becomes a founding member and leader of the Avengers.
Mr. Stark possesses no superpower. But being clever, he conceptualizes and builds some, most notably his Iron Man apparel. As a society, we need to do the same if we want to cope with weather, climate, and other geophysical threats with superpowered effectiveness.
What might that look like? More details to come.
 And disease as well; pathogens have historically found new opportunity in crowded urban environments.