The global response of temperature to high-latitude vegetation greening in a two-dimensional energy balance model

Abstract

The relationship between vegetation greening and climate change remains unclear due to its complexity, especially in drylands. Against the background of global warming, arid and semi-arid areas, including mid-latitude deserts, are most sensitive to climate change. In recent decades, the mechanisms underlying the relationship between vegetation greening and climate change have been widely discussed in the literature. However, the influence of vegetation greening in high latitudes on regional climate has not been fully studied. In this paper, a two-dimensional energy balance model was used to study the influence of greening in high latitudes on mid-latitude deserts. The authors found that when greening occurs in high latitudes, the mid-latitude desert recedes at the south boundary, while the polar ice belt and low-latitude vegetation belt both expand. Simultaneously, greening in high latitudes can induce a negative temperature anomaly in northern latitudes and a positive temperature anomaly in southern latitudes. The mid-latitude desert expands at its north and south boundaries until the CO 2 concentration reaches 600 ppm (saturated state). The greening in high latitudes could result in a lower global-mean temperature in the 'saturated' state, due to the stronger cooling in high latitudes.

Recent changes in global dryland temperature and precipitation

“…Evapotranspiration, however, did not change much at the high latitude, therefore, indicating the limited effect of evaporative cooling on mean temperature at the zone. Additionally, the cooling effect of evapotranspiration may be cancelled out by the dominating effect of albedo changes as studies have shown (Jeong et al, 2011;Pearson et al, 2013;Shen et al, 2015), especially with the recent greening, which has a warming effect through reduced albedo (Forzieri et al, 2017;Bi et al, 2020).…”