Climate change and forest hydrology in future forests

Abstract

About one-third (or 4.06 billion hectares) of the Earth’s land surface is covered by forests, with the majority in the tropics and subtropics (56%), followed by boreal (27%) and temperate (16%) zones (FAO UN, 2020). These forests provide vital ecosystem services, including carbon sequestration (2.460.4 pg C yr21 or 2.4 billion tons per year) (Pan et al., 2011), which is critical for mitigating climate change in the 21st century. Forests provide 75% of the world’s accessible freshwater resources, and more than half the human population is dependent on these water resources for domestic, agricultural, industrial, and environmental uses (Millennium Ecosystem Assessment, 2005) (Fig. 6.1). However, forests depend on the appropriate climate for their existence, and climate is a major control of forest hydrology (Zhang et al., 2022). The recently released Intergovernmental Panel on Climate Change Sixth Assessment Report (IPCC AR6, 2021) concludes with high confidence that climate change dramatically affects many terrestrial ecosystem functions (Fig. 6.2). Thus climate change will significantly affect water availability to future forests and people. Climate change also interacts with land use and land cover change. Overall, the Earth’s surface has been greening up over the past 20 years because of both human activity (e.g., agricultural expansion in India and forest gains in China, the United States, Sweden, and Finland) and climate change (Chen et al., 2019; Convention on Biological Diversity, Secretariat, 2009; Zhang, Song, Band, Sun, & Li, 2017a). However, along with the loss of boreal forests (Hansen, Stehman, & Potapov, 2010), global forest coverage in the tropics continues to decline due to pressures from cropland expansion and livestock grazing (FAO UN, 2020; Kumagai, Kanamori, & Chappell, 2016), especially in low-income countries. Climate change and human population rise are likely to aggravate this trend of global forest loss in some regions.

Citation

Sun, Ge; Tiwari, Krishna Raj;  Hao, Lu;  Amatya, Devendra;  Liu, Ning;  Song, Conghe. 2024.  Climate change and forest hydrology in future forests. Future Forests Mitigation and Adaptation to Climate Change. Elsevier Inc.: 95-124. Chapter 6. 30 p.