Afforestation in larger forest blocks could affect climate on a regional scale and may reduce the projected climate change in a drought-threatened study region, so say researchers from Germany and Hungary, who report their climate simulation work in Environmental Research Letters.

Increased forest cover affects the climate to a very different extent, depending on the region. In some areas, half of the projected precipitation decrease can be offset and the total number of drought events may be reduced, assuming complete afforestation of the areas in question. Modelling studies can help to identify regions where forest-cover increase should most effectively alleviate climate-change effects.

The experts selected Hungary as their study area because of the significant increase in the probability and severity of summer droughts predicted for the end of the 21st century, the large-scale land-use changes envisaged, and the high climate sensitivity of the zonal forest belts of the lowlands.

Using REMO (regional climate model at the Max Planck Institute for Meteorology, Hamburg) they prepared a case study to analyse whether the climate-change signal for summer precipitation and the probability of droughts could be reduced, assuming afforestation for the entire country.

We conclude that, although even practically unrealistic increases in forest cover did not offset the projected climate change, the ecological significance of the indicated effects of land-cover changes – as well as certain services and local-scale benefits of forests – should not be underestimated.”

Their results emphasise the need for regional-scale studies of future land cover and land use to assess climate-change-mitigating effects and to develop future adaptation strategies in agriculture, forestry and water management.

The analysis has been extended to Europe under the framework of the EC-FP7 project Climate Change – Terrestrial Adaptation and Mitigation in Europe (CC-TAME).