Historical deforestation locally increased the intensity of hot days in northern mid-latitudes, LeJeune 2018

Deforestation contributes to climate change on a global scale through carbon emissions (biogeochemical effects), and on a local/regional scale through biogeophysical effects related to albedo, evapotranspiration and roughness, affecting surface energy budgets.

Here, we show that historical deforestation has led to a substantial local warming of hot days over the northern mid-latitudes – a finding that contrasts with most previous model results. Based on observation-constrained state-of-the-art climate-model experiments, we estimate that moderate reductions in tree cover in these regions have contributed at least one-third of the local present-day warming of the hottest day of the year since pre-industrial time, and were responsible for most of this warming before 1980 [LeJeune 2018: 1].

The study uses observational data to constrain the outcome of a climate model simulating the effects of deforestation on regional temperatures. The authors found that during most of the 20th century, the biogeophysical effects of deforestation were the main cause of regional temperature increases, and that by 1980 deforestation in northern mid-latitudes had declined. By that time other forcings began to take on a proportionally greater role in regional temperature increases.