Articles | Volume 7, issue 1
Earth Syst. Dynam., 7, 167–181, 2016
Earth Syst. Dynam., 7, 167–181, 2016

Research article 07 Mar 2016

Research article | 07 Mar 2016

The role of spatial scale and background climate in the latitudinal temperature response to deforestation

Yan Li1,2,3,4, Nathalie De Noblet-Ducoudré5, Edouard L. Davin6, Safa Motesharrei4,7,8, Ning Zeng2, Shuangcheng Li1,3, and Eugenia Kalnay2,4 Yan Li et al.
  • 1College of Urban and Environmental Sciences, Peking University, 100871 Beijing, China
  • 2Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland 20742, USA
  • 3Key Laboratory for Earth Surface Processes of The Ministry of Education, Peking University, 100871 Beijing, China
  • 4The Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742, USA
  • 5Laboratoire des Sciences du Climat et de l'Environnement, Institut Unité Mixte CEA-CNRS-UVSQ, Université Paris-Saclay, Orme des Merisiers, Bât. 712, 91191 Gif-sur-Yvette, France
  • 6Institute for Atmospheric and Climate Science, Eidgenössiche Technische Hochschule (ETH) Zurich, 8092 Zurich, Switzerland
  • 7Department of Physics, University of Maryland, College Park, Maryland 20742, USA
  • 8National Socio-Environmental Synthesis Center (SESYNC), Annapolis, Maryland 21401, USA

Abstract. Previous modeling and empirical studies have shown that the biophysical impact of deforestation is to warm the tropics and cool the extratropics. In this study, we use an earth system model of intermediate complexity to investigate how deforestation on various spatial scales affects ground temperature, with an emphasis on the latitudinal temperature response and its underlying mechanisms. Results show that the latitudinal pattern of temperature response depends nonlinearly on the spatial extent of deforestation and the fraction of vegetation change. Compared with regional deforestation, temperature change in global deforestation is greatly amplified in temperate and boreal regions but is dampened in tropical regions. Incremental forest removal leads to increasingly larger cooling in temperate and boreal regions, while the temperature increase saturates in tropical regions. The latitudinal and spatial patterns of the temperature response are driven by two processes with competing temperature effects: decrease in absorbed shortwave radiation due to increased albedo and decrease in evapotranspiration. These changes in the surface energy balance reflect the importance of the background climate in modifying the deforestation impact. Shortwave radiation and precipitation have an intrinsic geographical distribution that constrains the effects of biophysical changes and therefore leads to temperature changes that are spatially varying. For example, wet (dry) climate favors larger (smaller) evapotranspiration change; thus, warming (cooling) is more likely to occur. Our analysis reveals that the latitudinal temperature change largely results from the climate conditions in which deforestation occurs and is less influenced by the magnitude of individual biophysical changes such as albedo, roughness, and evapotranspiration efficiency.

Short summary
The impact of deforestation is to warm the tropics and cool the extratropics, and the magnitude of the impact depends on the spatial extent and the degree of forest loss. That also means location matters for the impact of deforestation on temperature because such an impact is largely determined by the climate condition of that region. For example, under dry and wet conditions, deforestation can have quite different climate impacts.
Final-revised paper