One of the most talked-about ways to combat climate change is planting trees. Big organizations, like the United Nations Environment Programme and the Trillion Tree Campaign, aim to absorb huge amounts of carbon dioxide by restoring forests worldwide.
But a recent study reveals that the location of these trees may matter more than the sheer number planted. While some say we could reforest a staggering 1,000 million hectares to absorb around 750 gigatonnes of carbon, others suggest much smaller figures. Many previous studies relied on simplified models that don’t accurately reflect real-world conditions.
Scientists from ETH Zurich conducted more realistic simulations to test this idea. Their findings showed that tree planting in specific regions could offer similar climate benefits while requiring significantly less land. They used one of the university’s powerful supercomputers to run detailed climate models and gathered an impressive 300 terabytes of data to support their conclusions.
Using a sophisticated climate model, the team evaluated three reforestation strategies. They didn’t just look at how well trees absorb carbon but also how forests influence the Earth’s surface by altering sunlight reflection and water evaporation, which in turn affects local climates. They discovered that reforestation efforts in tropical areas yield the best cooling effects.
Regions like the Amazon Basin, West Africa, and Southeast Asia are prime locations for planting trees. Here, trees not only store carbon effectively but also cool the nearby air through a process called evapotranspiration, where water from leaves lowers the temperature. In contrast, in northern areas like Siberia and Canada, too many trees can actually warm the climate by capturing sunlight that would otherwise reflect off snow-covered landscapes.
Nora Fahrenbach, the lead author of the study, emphasized the importance of choosing the right locations: “Avoiding reforestation in northern areas and focusing on the tropics makes the efforts more effective for climate protection.”
Interestingly, the team found that new forests can influence climates far away from where they are planted. Changes in one area can alter weather patterns thousands of kilometers away. This highlights the idea of “climate-smart reforestation,” which suggests focusing on the most effective locations for planting rather than just the number of trees.
However, experts caution that reforestation alone won’t solve climate change. According to this new research, even the most optimistic reforesting efforts may only reduce global temperatures by about 0.25°C by 2100. This underscores the essential need to cut fossil fuel emissions alongside tree planting efforts.
Recent data from the Global Forest Watch shows that while tree cover is increasing in some regions, deforestation continues at alarming rates in others, particularly in the tropics. A unified approach that includes both reducing emissions and strategic reforestation will be key to effectively combating climate change.
The findings serve as a valuable reminder that thoughtful planning is crucial in our fight against climate change. Trees are important, but where we plant them can make all the difference.
Reference:
- Fahrenbach NLS, De Hertog SJ, Jäger F, Lawrence PJ, Jnglin Wills RC: Reforestation scenarios shape global and regional temperature outcomes. Communications Earth & Environment 2026, 7: 204, DOI: 10.1038/s43247-026-03331-3
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Carbon Dioxide,Climate Change,Earth
