Forests are most effective for climate regulation when conserved or restored in their natural or native locations, according to a new study.
The importance of natural forests is becoming more apparent, say the researchers, not only for global climate change mitigation, but for local climate adaptation of people and biodiversity. The study, led by a group at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, brought together research from more than 20 organizations, and used it to analyse how natural forests affect local temperatures across regions worldwide. The result is a unifying perspective on when and where natural forests deliver the greatest benefits to people and ecosystems.
In recent years, there has been considerable academic discussion about the role of forests in global climate mitigation. The analysis revealed that when balancing the cooling effects of carbon storage and the warming of albedo change, forests generally have net global cooling effects in areas where dense tree cover would naturally exist. However, the local climate effects of forests may be considerably more important for the wellbeing and livelihoods of rural communities across the globe, particularly in the face of global climate change. By buffering against the effects of extreme temperatures, forests have warming effects in freezing areas and cooling effects in warm regions, both of which can be important for local people and biodiversity.
“Protecting and restoring natural ecosystems is not just about carbon,” said Prof. Thomas W. Crowther – the senior author of the study. “It is about safeguarding the living systems and providing climate adaptation to protect billions of people across the globe.”
The research also provides useful context to address the controversies around the role of forests in shaping the climate. Some studies have shown that forests can increase local temperatures under specific conditions, raising concerns that conservation and restoration efforts could have unintended effects. This new analysis shows that these outcomes are closely linked to context. When forests are introduced into environments where they would not naturally occur, their impacts on temperature and water systems can become less predictable.
Forests also shape the global water cycle. They are vital for intercepting rainfall, enhancing infiltration, and reducing peak flows which lowers flood risk. Yet in some dry climates, where moisture is particularly limiting the tendency of forests to slow runoff can mean that they can limit water availability in downstream regions.
The findings highlight the importance of regional scientific evidence in guiding land-use and restoration decisions, ensuring that nature-based solutions are effective, appropriate, and sustainable over the long term.
