Collaborative Research: Ecoclimate Teleconnections between Amazonia and Temperate North America: Cross-Region Feedbacks among Tree Mortality, Land Use Change, and the Atmosphere

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Many recent cases of large scale tree death over the earth have raised concerns that warming temperatures may alone, or when combined with droughts and natural enemies like bark beetles, be reducing or degrading forests as never before. The area of forests is also being greatly reduced in the Amazon basin by deforestation. Because trees play such an important role in regulating the climate near the ground, losing trees to massive die offs or deforestation also means changes in that microclimate. With enough tree die off and large enough reductions in the area forested, the effects of tree loss on microclimates may add together and begin to affect the climate at much larger scales (or macro-climate). Recent results from computer models that link climate and forest cover have shown that a large increase in the area of forests in North America actually led to locally warmer conditions and also caused three global scale climate effects: it increased the amount of energy exchanged between the northern and southern hemispheres, it shifted the band of tropical rainfall (known as the Inter-tropical Convergence Zone), and it increased drought in the Amazon basin of South America. This raises the concern that decreases in the area forested, which could be caused by either die off or deforestation, could also have important effects both globally as well as locally. In particular, this could link the fates of forests in North America and South America through a so-called climate teleconnection. To address this, this project will use a model that predicts how forests respond to climate to evaluate the effects of large scale decreases in forest area from die off and deforestation in North and South America. To do this, measurements related to how decreases in forested area affects the microclimate near the ground will be made at a series of field sites in both regions. This project will provide important information about how decreases in forest area in one hemisphere could affect climate conditions not only locally but also in the other hemisphere. To find and explore the boundaries of the potential range of responses that could occur in the future, the assessment will evaluate extreme conditions where all forests are removed and then the consequences of actual recent decreases in forested area. The project will also provide key information on which factors in the models are the most important to accurately measure in order to improve predictions. Because scientists are uncertain about what conditions massive trigger tree die offs, the project will also provide important information about the reasons for tree death and the expected in climate that might result. Overall, the project will provide science results that can aide in developing policy. It will also build a strong collaboration between U.S. and Brazilian scientists. Finally, the project will train postdoctoral scholars and inform the public and teachers through use of the Biosphere 2 facility in Tucson, where more than 100,000 members of the public visit each year.