In the past few years, there have been many wildfire incidents. This year, the horrifying scenes of wildfires burning down towns on Maui, Hawaii, and the evacuation of many small towns on the edge of the Arctic Circle due to wildfires in Canada, have made everyone on the planet have a real sense of the approaching disaster. In fact, there are traces of these events. The late Ice Age, that is, the Pleistocene Era, was an era of profound ecological changes. At that time, a large number of large mammals in different parts of the world disappeared. Now scientists have discovered that this event occurred 13,000 years ago. The world’s largest mammal extinction was also caused by wildfires and human activities.
Scientists often refer to the past 66 million years of Earth’s history as the age of mammals, when the dinosaurs became the dominant animal on Earth. During the Pleistocene Epoch, Eurasia and America were filled with huge beasts like mammoths, giant bears and dire wolves, but suddenly, they disappeared.
At the end of the Pleistocene, the last major extinction event of the Ice Age, about 10,000 to 50,000 years ago, wiped out most of the large mammals on the earth. The mammals weighing more than 44 kg in North America decreased by more than 70%, and South America lost more than 80% %, Australia lost nearly 90%. Today, only Africa, Antarctica and some remote islands retain so-called natural fauna.
Scientists only know that it was an era of dramatic climate change and rapid population expansion, but it has been difficult to determine whether it was caused by habitat loss, resource scarcity, natural disasters, human hunting, or a combination of these factors.
The La Brea Tar Pits in Los Angeles are the richest Ice Age fossil site in the world, where naturally occurring asphalt seeps trapped and preserved 50,000-year-old bones of large Ice Age mammals, most of which contained primitive collagen . In a recent study published in the journal Nature, scientists in California used radiocarbon to precisely date skeletal proteins in the La Brea tar pits to discover when and why species collapsed.
Herbivores plummeted, wildfires came, and species collapsed
The study found evidence of a dramatic event 13,000 years ago, when the end of the Ice Age and a warmer climate, accompanied by prolonged drought and rapid population growth, pushed Southern California’s ecosystems to a tipping point where herbivores declined , species related to trees, such as camels, have completely disappeared, but the catalyst for the extinction appears to be an unprecedented increase in human-caused wildfires.
The study found that in the millennium before the species went extinct, the average annual temperature in the region rose by 5.5 degrees Celsius and the lake began to evaporate. Then, 13,200 years ago, the ecosystem entered a 200-year drought, half of the remaining trees died, and dead vegetation piled up on the ground as fewer large herbivores ate it.
At the same time, the population of North America began to expand, bringing with it a powerful new tool, fire. Humans have used fire for hundreds of thousands of years, but it has not caused destructive effects, because in the 20,000 years before the extinction of species, even in similar dry periods, the incidence of fire was very low, but after the arrival of humans, fire Only then did it begin to become an ecological threat. Fires in the region increased by an order of magnitude as population increased between 13,200 and 13,000 years ago, the study found.
Today’s warming is ten times faster
Today’s combination of warming, population growth, biodiversity loss, and man-made fires is eerily similar to the extinction conditions of the time. Even more frightening is that today’s temperatures are rising ten times faster than at the end of the Ice Age. This human-caused climate change has resulted in the frequency and intensity of fires, and the area burned.
Most fires are human-caused. Current evidence points to Hawaiian wildfires being caused by faulty electrical equipment. Studies have found that more than 90 percent of wildfires in coastal California are started by downed power lines, campfires and other human activities. The ecosystems we depend on are vulnerable to collapse when subjected to multiple cross-cutting pressures. Scientists call for redoubled efforts to eliminate greenhouse gas emissions, prevent fires, and protect the planet’s last remaining megafauna. Otherwise, human beings will witness another disaster with their own eyes. sexual extinction event.
(Source of the first image:Wikipedia)
