The impact of anthropogenic land use and land cover change on regional climate extremes

Kirsten L Findell,Alexis Berg,John P Krasting,Sergey Malyshev,Benjamin R Lintner,Joseph A Santanello,Elena Shevliakova,Pierre Gentine

doi:10.1038/s41467-017-01038-w

Abstract

Land surface processes modulate the severity of heat waves, droughts, and other extreme events. However, models show contrasting effects of land surface changes on extreme temperatures. Here, we use an earth system model from the Geophysical Fluid Dynamics Laboratory to investigate regional impacts of land use and land cover change on combined extremes of temperature and humidity, namely aridity and moist enthalpy, quantities central to human physiological experience of near-surface climate. The model’s near-surface temperature response to deforestation is consistent with recent observations, and conversion of mid-latitude natural forests to cropland and pastures is accompanied by an increase in the occurrence of hot-dry summers from once-in-a-decade to every 2–3 years. In the tropics, long time-scale oceanic variability precludes determination of how much of a small, but significant, increase in moist enthalpy throughout the year stems from the model’s novel representation of historical patterns of wood harvesting, shifting cultivation, and regrowth of secondary vegetation and how much is forced by internal variability within the tropical oceans.

Highlights

Land surface processes modulate the severity of heat waves, droughts, and other extreme events
The LUCID (Land Use and Climate: IDentification of robust impacts) intercomparison project[15] demonstrated that six out of the seven contributing climate models show summertime cooling in the mid-latitudes as a result of historical land use and land cover change (LULCC), with little temperature response in the tropics
This study lends a new perspective on the role of anthropogenic LULCC on regional climate extremes, both through the novel consideration of the joint temperature–humidity response to LULCC and through the use of an ESM, which captures effects of sub-grid-scale deforestation and accounts for critical processes such as wood harvesting, shifting cultivation, and secondary vegetation growth

Summary

Introduction

Land surface processes modulate the severity of heat waves, droughts, and other extreme events. The LUCID (Land Use and Climate: IDentification of robust impacts) intercomparison project[15] demonstrated that six out of the seven contributing climate models show summertime cooling in the mid-latitudes as a result of historical LULCC, with little temperature response in the tropics Plant physiological stress and ecosystem function are heavily impacted by the vapor pressure deficit of near-surface air[39] Including both humidity and temperature in this analysis allows us to consider aridity and moist enthalpy: quantities that are closely related to vapor pressure deficit and wet bulb temperature, respectively, and are central to ecosystem health and human physiological perception and experience of near-surface climate conditions[35]

Methods

Results

Conclusion