The Long Plague Era Seen Through a Grand Historical Lens
As the climate warms, scientists have observed some animals migrating toward cooler regions. Continued temperature rises are forcing animals in tropical forests to seek new homes, and their first contact with other species will greatly raise the risk that humans contract new viruses and that another pandemic is triggered.
According to a study just published in Nature, at least 10,000 viruses could potentially jump across species to humans. The study also predicts that by 2070 the cumulative number of new cross-species viral transmission events will reach at least 15,000. The researchers observed 3,139 mammal species over five years, modeling their migration under different climatic conditions and analyzing the impact on viral spread. The scientists involved believe climate warming will place some densely populated population centers at higher risk of plague; once an outbreak appears in these centers, it will spread rapidly around the globe.
Another study, recently published in Science, shows that by 2300, due to excessive greenhouse-gas emissions, marine life will die off on a massive scale. If warming continues at its current rate, global temperatures will rise by 4.9 degrees Celsius by the end of the century and keep rising, and the world's marine ecosystems will undergo a mass extinction comparable to the “Great Dying” at the end of the Permian.
If we view humanity on Earth today through a grand historical lens, we will understand that we are entering a long plague era. This means plagues will come wave after wave, appearing every few years or every decade, or one wave not yet settled while another rises. History has seen several such long plague eras; for example, from the late Ming dynasty to the early Qing, plagues raged continuously for more than a hundred years.
The usual pattern is that after humanity enters an era of prosperity and development, the population surges. As the population booms, the distance between humans and wild animals grows ever shorter, cross-species transmission of pathogens becomes increasingly frequent, and plagues therefore break out often. After a plague has raged for a while, mortality soars because of the disease itself and the wars and chaos it triggers. Under such a disaster pattern, people's willingness to bear children declines—today through medical contraception or abortion; in the past, there was not only abortion but also infanticide (Su Shi himself recorded that people in Huangzhou at the time killed infants because they could not feed so many mouths)—and the total population is greatly reduced, after which a new ecological balance between humanity and nature is struck.
The wheel of civilization does not always roll forward; sometimes our path of development is rough, history often reverses, and the same disasters recur in cycles. At root, the genes of all living things are selfish; in order to survive and reproduce, organisms constantly struggle over limited resources. Sometimes all beings are in relative balance, sometimes in serious imbalance, and nature constantly adjusts this imbalance with an invisible hand. As early as more than two thousand years ago, the Chinese philosopher Laozi sighed: “Heaven and earth are ruthless; they regard all creatures as straw dogs.”
A considerable part of our fate is not in our own hands. Things reach an extreme and reverse; joy reaches its peak and sorrow is born; prosperous ages do not last, nor do favorable circumstances. What kind of living condition we find ourselves in depends on the broad historical trend and on our position on the curve of history. Whether as our ancestors, as people today, or as humans in the future, we who live on this planet will continually face challenges.
What differs from the age of ignorance is that today our technology is far more advanced, and we are no longer as clueless about plagues as our ancestors were. Although conspiracy theorists are always manufacturing all sorts of misleading fallacies, most people with sound minds and basic scientific common sense still understand the causes of plagues.
The present can also be said to be the first long plague era humankind has experienced in an age of scientific enlightenment, and we have many more tools for dealing with plagues than the ancients did.
Virologists can monitor epidemic trends; through surveillance of sentinel populations, humanity can detect early signs of a plague and nip it in the bud. Regrettably, however, humans have not taken scientists' warnings especially seriously, nor have we paid due attention to disease prevention and control, and investment in this area has been quite limited. Because development across the world's nations is uneven, for a long time to come some impoverished, backward population centers will still lack corresponding epidemic-surveillance systems.
Advances in pathogens and immunology have also given humankind more and more tools for coping with pandemics, such as vaccines and antibody drugs, so once a plague strikes we will not be as helpless as the ancients. Our public-health methods are also more advanced than in the past, enabling rapid quarantine and isolation of infected populations through modern technology to contain the plague's rapid spread.
But in the end, these very measures may prolong the length of a long plague era. Yet humans, unwilling to sit passively and die, will certainly not surrender meekly before the plague; rather, in the struggle they will fumble out better methods and experience for fighting it. I hold an inclusive attitude toward both “dynamic zero-COVID” and “coexisting with the virus”; I feel that everything we are going through now is merely the prelude to this long plague era, and that we have a long road ahead in it. Whatever anti-epidemic approach is being groped for now will come in handy in the long plague era to follow, and time will render a fairer verdict on everything.
Chinese physicians, historians, and writers have recorded the long plague era in great detail. The literary works of the Seven Masters of Jian'an, and the writings of physicians of the Jin-Yuan and Ming-Qing periods, contain abundant descriptions of the social phenomena of long plague eras. Even the poetry of Qiu Chuji, the famous Daoist priest of the Quanzhen School, bears the marks of the long plague era. From those sorrowful and harrowing passages, we can see how wretched the long plague eras of every dynasty were. Zhang Zhongjing, the Medical Sage of the late Han, said that two-thirds of his clan died in a great plague; the poems of the Jian'an Masters are full of scenes of corpses strewn across the fields, and a great plague in the 22nd year of Jian'an directly killed off more than half of them. The ceaseless great plagues of the Jin-Yuan period forced Genghis Khan to halt his wars; the plagues that lasted over a century in the Ming dynasty left nine out of ten houses empty and even gave rise to cannibalism.
The long plague era can be called the trough of human civilization; every kind of animal goes through such long plague eras, known in biology as good years and bad years. But only humans are a species with thought and emotion, able to record our own sufferings in language; our joys and sorrows carry a collective memory.
Some of our compatriots will be culled in the long plague era; wave after wave of plagues is like wave after wave of the tide, always washing away a part of the people. Different human communities bound by kinship and region will explore different survival strategies, which will not necessarily be welcomed by every member of the group, but each strategy will draw the support of many people with shared needs. Conflicts of interest are everywhere, and in a long plague era they may be fiercer than ever; the conflicts themselves will spawn new tragedies. Tragedy is a word we hear all too often in a long plague era, because tragedy occurs almost every day.
I do not think there is an optimal solution to the long plague era; any anti-epidemic plan should fully take its own shortcomings into account, reduce harm to people's livelihood, and reduce the trampling of human emotion, so as to ease humanity's suffering in this era. Ultimately, nature will find an optimal solution for us in a way that transcends human emotion. Nature does not care about our joys and sorrows; nature is ruthless, and merely executes its inner rules—it must reduce the population to achieve balance of resources and environment, and to that end it will stop at nothing.
Born into such a long plague era, we should also recognize that we are powerless before the great historical trend; we can only adjust our life expectations to adapt to it. The gentlest way to get through this long plague era is for humanity as a whole to adopt a low-fertility strategy, gradually reducing the size of our species over the coming hundred years so that the tragedies do not come too cruelly.
I believe most people have already made this choice instinctively, which is why births are declining in most countries around the world. If we look at this downward demographic trend from the perspective of grand history rather than the impatient, utilitarian mindset of economists, it is not hard to see that this is the best choice for reducing tragedy—rather than letting our descendants be slaughtered by plagues and wars, we should voluntarily have fewer children.
Sometimes I am awestruck by religious monuments as magnificent as the Mogao Grottoes at Dunhuang and the Longmen Grottoes at Luoyang, and I wonder what kind of force drove humans to overcome enormous hardships and persevere in completing such colossal works. I think the most likely answer is that in certain special historical periods, human death was so horrific that people's need for religion reached an unprecedented height, which gave the public immense enthusiasm for completing such grand projects.
Today we may no longer need such religious monuments to soothe our hearts, because science has vanquished religion and become the consensus of most people. But our need for inner peace is no different from that of the ancients—so what do we rely on today to soothe our hearts? That is the question.