How have human activities altered Earth’s climate and biogeochemical cycles during the Holocene?

Human activities have profoundly altered Earth’s climate and biogeochemical cycles, particularly since the Industrial Revolution. While the Holocene Epoch has served as the stable framework for human history, the scale of human influence has led some scientists to propose the Anthropocene Epoch to describe this era of human domination over Earth's systems.123

Climate Alterations

Human activities have driven significant climate changes, primarily through the emission of carbon dioxide from fossil fuel combustion and industrial processes. This buildup has contributed to a global rise in average surface temperatures, the loss of sea ice, and more frequent extreme weather events. Additionally, land-use change, such as deforestation and the conversion of land to agriculture, alters Earth’s albedo and disrupts evapotranspiration, further influencing regional and global climates.14

Biogeochemical Cycles

Humans have fundamentally reshaped biogeochemical cycles, most notably through the Haber-Bosch process, which increased usable nitrogen by 150 percent. Furthermore, the oceans absorb significant amounts of anthropogenic CO2, leading to ocean acidification, which threatens marine biodiversity and coral reefs. Other impacts include the damming of rivers and the creation of oxygen-depleted zones in the hydrosphere.1