Geoscience and Public Policy

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The Great Lisbon Earthquake of 1755:

Major Change in a Geological Instant and The Age of Science and Reason

“Civilization exists by geological consent, subject to change without notice.” ― Will Durant

My, how quickly your world can change when you're living on an active planet...

On November 1, 1755 (All Saints' Day), a huge, devastating earthquake occurred off the coast of Lisbon Portugal. It has been argued that this single earthquake led to the decline of the Portuguese empire, and changed the world by bringing about the "Age of Science and Reason." The magnitude of this earthquake has been estimated to be as high as 8.7, but more recent research concludes that it was somewhat lower: in the 7.2 to 8.2 range. But regardless of this uncertainty in estimating its magnitude, this was clearly a very large and tragic earthquake, which led to major changes in society and culture, at least in Portugal and likely more far reaching than that. It has been argued that this earthquake brought about historical changes in worldviews regarding whether earthquakes are punishment by god for the sins of the world versus natural phenomena that can be explained by scientific analysis*.

The sudden changes brought about by this earthquake exemplify the warning of historian Will Durant: "Civilization exists by geological consent, subject to change without notice." Many of the topics covered in this course include examples of how geological (and/or environmental) events, occurring in a "geological instant", resulted in major changes to our lives on personal, global, and/or historical scales.

The Great Lisbon Earthquake seems to have been at least one of the significant factors in bringing about major changes in how humans (at least in the "Western World") think about and relate to science, truth, and reason. This is not the only time that humans have been confronted by long-term Earth processes manifesting themselves as major (world changing) surprises occurring on a human time scale. A few examples of these geological and/or environmental surprises with major unexpected (and often unpredicted) human consequences are:


  • On March 11, 2011 a magnitude 9.1 earthquake (and a tsunami that it generated) occurred off the coast of Japan. This earthquake, which lasted for less than about 10 minutes, generated a tsunami that forced the shutdown of Japan's Fukushima nuclear power plant, and led Japan (and other countries) to reconsider the role of nuclear energy in modern society. Although this earthquake only lasted for a geological instant, it might have very long-lasting consequences for human society.

  • On January 10, 2010 a tragic earthquake struck Haiti. Lasting only about half a minute, it was one of the most deadly earthquakes in history. And now, more than a decade later, we are still not sure of what all the negative effects of this earthquake are (and will continue to be?) on the economy and future of the people of Haiti.

  • The steam engine, and other modern machines that powered the industrial revolution, were invented in the 17 and 1800s. These devices use energy stored in fossil fuels (such as coal, oil, and natural gas) to transform life for humans, improving the quality of life for many of citizens of planet Earth. Even though these changes have been occurring for more than two centuries, that's still just "an instant" relative to the many millions of years of geologic time. Now, just a couple of centuries later, we find that these fossil fuel dependent machines have lead human society into a complex relationship with science and public policy issues associated with global warming, sea-level rise, and other climate change issues.

  • The COVID-19 virus emerged as a worldwide phenomenon while I was teaching this course in March of 2020, and we were all suddenly sent home and told that social distancing, and other COVID-19 safety measures, were necessary. Now almost three years later we are still dealing with major life changes of living in a pandemic of historical proportions. Although not directly a "geoscience" phenomenon, the COVID-19 pandemic fits in with a number of the geoscience and public policy issues discussed in this course: in particular, how our ever-increasing human population living on planet Earth can be so quickly and globally affected by unexpected hazardous events occurring within the Earth's biosphere. There are, of course, many factors affecting the way that people are responding to the science associated with the COVID-19 pandemic. But it seems to me that, consistent with the theme and framework of this course, how the current pandemic situation is unfolding is significantly intertwined with the way that people relate to certainty and uncertainty in science.

And what future, as yet unpredictable, hazardous manifestations of natural Earth processes might be awaiting us? Hopefully, this course will help students prepare for coping with such future challenges at the intersection of Earth systems and public policy.


*Details regarding the fascinating story of the Great Lisbon earthquake and its consequences can be found in these (and other) references: