Need another good reason to plant more trees in pastureland? It’s cool…

Farmers struggling to adapt to rising temperatures in tropical regions can unleash the benefits of natural cooling alongside a host of other wins simply by dotting more trees across their pasturelands, according to a new study – published today in the journal Nature Communications – that puts tangible numbers to the cooling effects of this practice for the first time.

Led by scientists from the University of Washington (UW), in collaboration with The Nature Conservancy (TNC), Duke University, University of California San Diego, and Stony Brook University Hospital, the paper finds that depending on density of trees, this practice – technically known as silvopasture – can reduce localised temperatures up to 2.4°C for every 10 metric tons of woody carbon added per hectare, while also delivering a range of other benefits for humans and wildlife.

Commenting on the significance of this study, senior author Yuta Masuda from TNC’s global science team said: “We already have plenty of peer-reviewed evidence for the multiple socio-economic and ecological benefits agroforestry systems like silvopasture can provide – from increased food security and farmer incomes, to greater biodiversity, and better access to traditional (and affordable) medicines in remote rural communities.

“Adding our findings on the localised cooling potential of silvopasture to the mix only serves to underline the huge spectrum of advantages that come from trees in pastureland, ultimately benefitting not only vulnerable rural communities in tropical hotspots, but people and wildlife in general,” he adds.  

Based on analysis of pasturelands in Latin America and Africa, the study also maps those regions of the world where rural communities stand to gain most from this approach – noting that because this local cooling effect isn’t exclusive to large-scale silvopastural settings, even smallholder farmers can access these benefits by intensifying tree-planting on their own pasturelands.

Highlighting another important implication of the study, lead author Lucas Vargas Zeppetello from UW’s Department of Atmospheric Sciences said: “The way in which lands are used has implications for human health and safety. Our past studies demonstrated how deforestation can increase local temperatures to unsafe levels. Here we show that deliberately incorporating trees on low latitude pasturelands can provide additional cooling benefits, highlighting one pathway for adding further resilience to the rising heat being experienced in these settings.”

A number of the study’s co-authors also collaborated on another recent paper that revealed the extent to which localised temperature rises, driven by a deadly combination of global warming and tropical deforestation, are making outdoor work increasingly perilous for vulnerable communities across the tropics.

To learn more about TNC’s pioneering scientific work on nature-based solutions for climate change, please visit: https://www.nature.org/en-us/what-we-do/our-insights/perspectives/natural-climate-solutions/

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Notes for Editors

Vargas Zeppetello L.R., Cook-Patton S.C., Parsons L.A., Wolff N.H., Kroeger T., Battisti D.S., Bettles J., Spector J.T., Balakumar A., Masuda Y.J. Consistent cooling benefits of silvopasture in the tropics. Nature Communications.

https://doi.org/10.1038/s41467-022-28388-4

NB: Lucas R. Vargas Zeppetello is now a James S. McDonnell Foundation postdoctoral fellow at Harvard University's Department of Earth and Planetary Sciences.