The pervasive alteration of global ecosystems is mainly the result of?

The alteration of global ecosystems is primarily driven by human activities, which encompass a wide range of practices such as deforestation, urbanization, industrialization, and agricultural expansion. These actions have profound impacts on natural habitats, leading to biodiversity loss, changes in land use, and alterations in biogeochemical cycles. For instance, the conversion of forests into agricultural land not only reduces habitat for countless species but also changes the carbon storage capacity of the ecosystem, thereby influencing climate feedback systems.

While global climate change does contribute to ecosystem alterations, much of the climate change itself is a direct consequence of human activities, particularly the burning of fossil fuels and land-use changes. The movement of continents by plate tectonics operates over geological time scales and contributes to the formation of new ecosystems, but it does not explain the rapid and extensive changes observed in today's environments. Increased frequency of wildfires has occurred due to various factors, including climate change and land management practices, but it represents only one facet of the broader impact human actions have on ecosystems. Thus, human activities are the overarching driver of extensive changes in global ecosystems.