At approximately 1:00 pm on August 24th, 79 CE, Mount Vesuvius erupted, killing nearly all the people in the nearby Roman seaside resort of Pompeii. Tremors were common in the area so little notice was given to the particularly strong ones that occurred the previous day. The same indifference greeted the strange cloud that appeared over the mountain the following afternoon. The eruption, witnessed by Pliny — known later as “the Younger” to distinguish him from his famous uncle, “the Elder” — described the cloud from where his family was living at Misenum, 32 km to the west. It resembled “a pine tree,” he wrote, “for it shot up into a trunk of great height, and then spread out into several branches. Sometimes it looked white, sometimes spotted, as though it had drawn up earth and cinders.”

Pliny’s uncle, a known naturalist and commander of the local Roman fleet, was fascinated by the cloud. So, on the pretence of conducting a rescue mission, he ordered large boats to carry him from Misenum to Pompeii for closer inspection. In reconstructing the event 27 years later, Pliny the Younger wrote that his uncle “dictated and noted down all the motions and shapes of that terrible portent as he went along.” Soon, however, the eruption and tremors became more intense. “Already,” the nephew wrote from his uncle’s notes, “ashes were falling on the ships, and the nearer they drew the hotter and thicker grew the showers; then came pumice-stones and other stones, blackened and scorched and cracked by fire, while the sea ebbed suddenly and the shore was blocked by landslides.”

By evening, in Pliny the Younger’s recounting, “broad sheets of flame broke out over Mount Vesuvius, rising high in the air and lighting up the sky, their brightness silhouetted against the darkness of the night.” His uncle, now in Pompeii, continued to document the eruption until morning. By then violent earthquakes were shaking the buildings as ashes engulfed them. Sulphurous gases and “thick fumes” eventually suffocated the uncle. Three days later his body and notes were found on the Pompeii waterfront.

Back in Misenum, the 17-year-old Pliny helped his mother and family escape the Vesuvius eruption. He described tottering buildings, heaving roads, smothering ashes, and being nearly trampled by the throngs of frantic people trying to flee the catastrophe.

The writings of Pliny the Elder and Pliny the Younger are now a part of history, a personal and vivid account of a tragedy they both witnessed and recorded with the objectivity of a modern scientist. Pompeii remained entombed in ashes for 1,900 years until archeologists exposed the buildings, bodies, frescoes, food and minutiae of daily life that died that August day.

In a sad and tragic parallel, many scientists and environmentalists feel they are observing and documenting a corresponding disaster today, witnesses to an ecological catastrophe that may not be as immediate and lethal as the one that befell Pompeii but which may be even more significant because it is global rather than local. This parallel invites exploration.

For decades climatologists have been documenting a warming planet, the tremors that are dismissed as nothing unusual. As greenhouse gas emissions ominously rise, so do temperatures. Meanwhile, governments ineptly fiddle with ineffective regulations, earnest promises are regularly broken, reduction targets are routinely lowered, and corrective legal agreements are abandoned as being too onerous to implement. Rising levels of atmospheric carbon dioxide are creating a plethora of problems, from extreme weather and ocean acidification to species loss, political instability, food insecurity, property damage and human suffering. All these problems are slated to get worse on a warmer planet.

While we cannot stop a Vesuvius from erupting, we do know how to arrest climate change — and we could if we had the political will to do so. Instead, we note that average global temperatures are rising, Arctic ice is melting, glaciers are destabilizing, ocean levels are creeping higher, and more fires, droughts, floods and storms are ravaging more and more places. Those who know and care are bearing witness.

The struggle for survival of 7 billion people — with 2 or 3 more to come — presents incomparable challenges as so many try to live and flourish in ecosystems that are already stretched beyond their carrying capacity. The political, economic, social, religious and cultural turmoil that keeps erupting in both rich and poor countries is the predictable outcome of too many people crowded on an Earth that is now too small.

We do co-exist remarkably well considering our circumstances. But stress is the normal product of overpopulation and overconsumption of resources. Conflicts develop over shortages of energy, food, territory and wealth. Ideologies collide and weapons proliferate. The homogenizing process that allows people to live together in harmony also generates differences which then lead to separation, factions, rebellion and violence. Those who know and care are bearing witness to this, too.

Helplessness is debilitating. Some wither under the weight of it. Some refuse to acknowledge the warning tremors. Some become cynics and misanthropes. But some heroic others harken to an inner calling, muster their energies, rush to the rescue and struggle toward solutions, ever hopeful that their dedicated effort will avert an ominous outcome. As the metaphorical ashes and stones rain from the sky, many others merely note the unfolding circumstances and bear witness, profoundly saddened by the realization that perhaps nothing can stop the impending loss of something treasured and beautiful.