What is meant by human activity

Not because of nature children in the Stone Age: humans had a considerable influence on the environment much earlier than previously assumed

Usually the middle of the 20th century is considered to be the point in time when humans began to change the environment on a large scale. An evaluation of archaeological data from all over the world now suggests a completely different dating.

Everything wasn't better in the past. But at least people were better for their environment, according to the common assumption: It was only with industrialization and especially in the 20th century that he began to change the environment on a large scale for the negative. It seems logical that hunters and gatherers, and later a few small farmers, burden nature less than factory farming, cheap flights and fracking. By and large, that's probably the case. But with a study for which they collected data from colleagues around the world, scientists have now found that humans had a significant impact on the environment much earlier than previously assumed: the earth was already due to human activities 3,000 years ago has been substantially changed, they write in the journal “Science”.1 This realization stands in clear contrast to the year that is often traded for the beginning of the Anthropocene, i.e. the geological age in which humans changed the planet: 1950.

3000 years ago, around 1000 BC BC, the people of Europe, the Middle East, China and Central America had been sedentary farmers for several millennia. They practiced agriculture, for which they first had to cut down forests in many regions to make room for their fields, animals and housing. In some areas they made objects out of bronze, which required a lot of fuel in the form of wood. It is obvious that these activities affect the environment. But according to the authors of the study, the negative effects of human activity began even earlier: “The globally widespread evidence of land use by hunters and gatherers shows that ecological conditions in most of the terrestrial biosphere were influenced by human activities across the board, even before domestication of plants and animals. "

Hunters and gatherers make fire

Already the nomadic people of the late Pleistocene (the epoch preceding the Holocene, which lasted from about 2.6 million to 11,700 years ago), archaeologically the Palaeolithic and Mesolithic, have accordingly begun the transformation. Even at that time, the changes were "dramatic and sometimes irreversible". For example, they would have changed communities of living beings by “transporting and spreading” preferred species - whether intentionally or unintentionally, it remains open, as well as which species could be meant. Above all, however, they might have used fire to make their hunt more successful - with ecological consequences: the greenhouse gas emissions that occur influenced the global carbon cycle, just as they do today. The changes in the vegetation and thus the evaporation had an effect on the water cycle. And because burned land is black, the albedo, i.e. the reflectivity of the earth's surface, changes, which increases the temperature.

Incidentally, “Vor heute” is the translation of the English term “before present”, or “BP” for short, which has become common mainly in scientific contexts. The “today” is not 2019, but the year 1950, which has to do with the introduction of the radiocarbon dating method (C14) at that time. For many, geological, for example, almost 2000 years are more or less irrelevant. In the case of more recent archaeological finds, these two millennia are calculated out in order to obtain a year "before Christ".

For their investigation of human impact on the environment, the scientists sent questionnaires to archaeologists with land use expertise around the world. 255 archaeologists took part and provided information on 711 regions on all continents except Antarctica for the period between 10,000 before today and 1850. The result is not equally detailed for all regions and not all periods of time: The best data are therefore for the period around 2000 before today, after which they decrease sharply - which, according to the authors, is likely to be due to the fact that environmental archeology is mainly carried out then when there are few material legacies or text sources.

The results are consistent with other studies

In the same issue of "Science" there was also a classification of the article by Neil Roberts, Professor Emeritus of Geography at the University of Plymouth, England. In it he writes that the result that humans changed the earth as early as 3,000 years ago coincides with that of other studies: Studies on the disappearance of forests in central European latitudes have also come to this number. And the findings also matched a publication published in 2015: using archaeological and palaeoecological data, it even makes people responsible for warming the climate through greenhouse gas emissions long before industrialization.

As a point of criticism, Roberts mentions that archaeological data are selective. They came mainly from areas where people had lived - which is why, writes Roberts, it is not surprising that land was also used there. Further studies are now necessary based on other empirical data, for example on pollen or insects. This is the only way to find out whether the wilderness, remote high mountains or polar deserts had already been influenced back then - or whether at least everything was better there earlier.

1 Science 365: 897-902 (2019).