The future of microclimate in Southeast Asia

Southeast Asia, an important biodiversity hotspot, hosts approximately 15% of the world’s tropical forests. Deforestation and forest degradation, driven by human activities and natural disasters, have led to significant changes in landscape structure and composition, impacting the thermal regime within forests. One of the consequences of forest disturbances is the changes in the thermal regime, affecting local temperatures experienced inside the forest. Alterations in forest microclimate from forest disturbances are likely to be amplified by global warming, but the magnitude and spatial patterns of these changes have not yet been quantified. In this study, the daily maximum microclimate temperatures (Tmicromax) at 15 cm above the surface was estimated for the historical baseline (last 30 years) and compared to change under two future scenarios that account for both global climate and forest cover changes by 2050 in forested areas for Southeast Asia. The baseline Tmicromax across Southeast Asia varies from 8.4 °C to 25.1 °C, with most of this variability being explained by topographic features, macroclimate temperature and vegetation structure. Future scenarios indicate that the average Tmicromax is likely to increase by 1.7 °C and 2.3 °C under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. By 2050, it is expected that an area between 224,369 (5%) to 598,445 (13%) km2 of forests will experience a Tmicromax warmer than the baseline, thus creating microclimate conditions that have never been experienced before in the region. Although temperature increases are expected throughout the entire region, some countries are predicted to be disproportionally affected, with particularly high forest temperatures in Brunei and Cambodia. This anticipated increase in microclimate temperatures poses a significant threat to species distribution, potentially impacting migration patterns or even leading to extinctions. Consequently, understanding where and to what extent these temperature shifts will occur by 2050 becomes imperative for informed biodiversity conservation strategies.