Exploring the risk of savanna expansion in Tropical South America under climate ch...
| Full text | |
| Author(s): |
Boers, Niklas
;
Marwan, Norbert
;
Barbosa, Henrique M. J.
;
Kurths, Juergen
Total Authors: 4
|
| Document type: | Journal article |
| Source: | SCIENTIFIC REPORTS; v. 7, JAN 25 2017. |
| Web of Science Citations: | 23 |
| Abstract | |
The Amazon rainforest has been proposed as a tipping element of the earth system, with the possibility of a dieback of the entire ecosystem due to deforestation only of parts of the rainforest. Possible physical mechanisms behind such a transition are still subject to ongoing debates. Here, we use a specifically designed model to analyse the nonlinear couplings between the Amazon rainforest and the atmospheric moisture transport from the Atlantic to the South American continent. These couplings are associated with a westward cascade of precipitation and evapotranspiration across the Amazon. We investigate impacts of deforestation on the South American monsoonal circulation with particular focus on a previously neglected positive feedback related to condensational latent heating over the rainforest, which strongly enhances atmospheric moisture inflow from the Atlantic. Our results indicate the existence of a tipping point. In our model setup, crossing the tipping point causes precipitation reductions of up to 40% in non-deforested parts of the western Amazon and regions further downstream. The responsible mechanism is the breakdown of the aforementioned feedback, which occurs when deforestation reduces transpiration to a point where the available atmospheric moisture does not suffice anymore to release the latent heat needed to maintain the feedback. (AU) | |
| FAPESP's process: | 11/50151-0 - Dynamical phenomena in complex networks: fundamentals and applications |
| Grantee: | Elbert Einstein Nehrer Macau |
| Support type: | Research Projects - Thematic Grants |
| FAPESP's process: | 13/50510-5 - Brazil-USA collaborative research: modifications by anthropogenic pollution of the natural atmospheric chemistry and particle microphysics of the tropical rain forest during GoAmazon intensive operating periods |
| Grantee: | Henrique de Melo Jorge Barbosa |
| Support type: | Research Program on Global Climate Change - Regular Grants |