Vegetation influences climate by altering water and energy budgets. With intensifying threats from anthropogenic activities, both terrestrial biomes and climate are expected to change, and the need to understand land–atmosphere interactions will become increasingly crucial. We ran a climate model coupled with a Dynamic Global Vegetation Model (DGVM) to investigate the establishment of terrestrial biomes starting from a bareground scenario and how these biomes influence the climate throughout their evolution. Vegetation reaches quasi-equilibrium after ~350 years, and the vegetation establishment results in global increases in temperature (~2.5 °C), precipitation (~5.5%) and evapotranspiration as well as declines in albedo and sea ice volumes. In high latitude regions, vegetation establishment decreases albedo, causing an increase in global temperatures as well as a northward shift of the Intertropical Convergence Zone (ITCZ). Low latitude tropical afforestation results in greater evapotranspiration and precipitation, and an initial decrease in temperatures due to evaporative cooling.
This content will become publicly available on January 1, 2025
Abstract. Large-scale reforestation, afforestation, and forest restoration schemes have gained global support as climate change mitigation strategies due to their significant carbon dioxide removal (CDR) potential. However, there has been limited research into the unintended consequences of forestation from a biophysical perspective. In the Community Earth System Model version 2 (CESM2), we apply a global forestation scenario, within a Paris Agreement-compatible warming scenario, to investigate the land surface and hydroclimate response. Compared to a control scenario where land use is fixed to present-day levels, the forestation scenario is up to 2 °C cooler at low latitudes by 2100, driven by a 10 % increase in evaporative cooling in forested areas. However, afforested areas where grassland or shrubland are replaced lead to a doubling of plant water demand in some tropical regions, causing significant decreases in soil moisture (∼ 5 % globally, 5 %–10 % regionally) and water availability (∼ 10 % globally, 10 %–15 % regionally) in regions with increased forest cover. While there are some increases in low cloud and seasonal precipitation over the expanded tropical forests, with enhanced negative cloud radiative forcing, the impacts on large-scale precipitation and atmospheric circulation are limited. This contrasts with the precipitation response to simulated large-scale deforestation found in previous studies. The forestation scenario demonstrates local cooling benefits without major disruption to global hydrodynamics beyond those already projected to result from climate change, in addition to the cooling associated with CDR. However, the water demands of extensive forestation, especially afforestation, have implications for its viability, given the uncertainty in future precipitation changes.
more » « less- Award ID(s):
- 2218758
- PAR ID:
- 10546106
- Publisher / Repository:
- European Geosciences Union
- Date Published:
- Journal Name:
- Biogeosciences
- Volume:
- 21
- Issue:
- 17
- ISSN:
- 1726-4189
- Page Range / eLocation ID:
- 3883 to 3902
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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