Impact of Human Activities on Forest Ecosystems: Carbon Cycling and Energy Balance

According to the Intergovernmental Panel on Climate Change (IPCC) sixth report in 2021, global warming caused by human activities has become an undeniable fact. Global temperatures have increased by 1.09  ﾰC between 2011-2020 compared to the period of 1850-1900. The main cause of this temperature rise is the emission of greenhouse gases, primarily carbon dioxide (CO2). In 2015, 196 countries and regions signed the Paris Agreement, which aims to limit the global average temperature increase to within 2  ﾰC above pre-industrial levels, and to strive for a limit of 1.5  ﾰC. Forest ecosystems play a crucial role in achieving this goal (Grassi et al., 2017).\n\nThe global forest area is approximately 4 billion hectares, covering about 30% of the Earth's land surface. Forests play an important role in land carbon cycling and energy balance (Bonan, 2008). Firstly, forests have a large carbon storage capacity and act as carbon sinks. About one-third of carbon emissions caused by human activities are absorbed by land, with forests contributing the most as land carbon sinks, significantly slowing down the growth rate of atmospheric CO2 concentration (Friedlingstein et al., 2022). Secondly, forests can alter surface latent and sensible heat fluxes, as well as surface albedo, thereby significantly changing surface temperatures (Bright et al., 2015). This article provides an overview of the impact of human activities on the land carbon cycling (biogeochemical effects) and energy balance (biogeophysical effects) of forest ecosystems.