Scientists have come up with a way to determine the influence of humans on the planet. It turned out that the first changes were made by human activity about 4 thousand years ago.
To do this, researchers extract “mud cores” from the depths of lakes and swamps. These long, tightly compacted clumps of earth contain information about what and when has grown in this soil over the past millennia. The analysis of these mud cores, the study of the pollen deposited in each layer, made it possible to determine when human activity began to change the structure of the planet.
Scientists expected to see the first “signal” of human intervention in the evolution of the planet several centuries ago, when landscapes began to transform during the Industrial Revolution. The pollen records obtained as a result of the study of cores made it possible to change this assumption and trace the first impact of our species on nature, which occurred 4 thousand years ago.
The researchers noted that this allows them to study in more detail the consequences of changes and their impact on forests and other natural landscapes.
Proof of these theories comes from tiny pollen grains that have fallen and settled in layers of mud over the centuries. By carefully removing this mud and analyzing the “fossil pollen” at different depths, the researchers were able to determine the carbon date of each layer of the mud to figure out what was growing and when.
The team found an increase in the rate of change in soil composition in the mud. They found that each layer began to differ from the other in terms of the pollen contained in it. Scientists decided to look 18 thousand years ago to cover the era when the planet began to emerge from the last ice age. The earth was thawing, so almost the entire environment changed.
“The climate has been relatively stable for the past 10,000 years, so [that’s when] we can sense human influences,” said Suzette Flantois, an ecologist at the University of Bergen. “This influence began as soon as humans began to destroy wild vegetation to make way for themselves, their crops and livestock.”