Deliberate enhancement of rainfall using desert plantations

[Andrew Lockley]

Poster's note: Cross posting due to weather effects 
https://www.pnas.org/content/116/38/18841

Deliberate enhancement of rainfall using desert plantations

Oliver Branch and Volker Wulfmeyer

PNAS September 17, 2019 116 (38) 18841-18847; first published September 3, 2019 https://doi.org/10.1073/pnas.1904754116

Edited by Ignacio Rodriguez-Iturbe, Texas A&M University, College Station, TX, and approved July 25, 2019 (received for review March 19, 2019)

This article has a correction. Please see:

Correction for Branch and Wulfmeyer, Deliberate enhancement of rainfall using desert plantations

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Significance

Our desert plantation concept aligns closely with research into biological carbon sequestration solutions but uniquely extends into the purview of deliberate rainfall enhancement. With this synergy of carbon sequestration and regional weather modification, we can counteract water scarcity and desertification while minimizing conflicts with food croplands. We have demonstrated that large plantations do enhance rainfall in arid regions and identified the underlying process chain. By using this knowledge we have developed a global index to assess which deserts are most favorable for weather modification and discuss how rainfall impacts can be intensified using agricultural methods. This potential for rainfall enhancement and carbon sequestration makes the research extremely interesting for the scientific community and for society.

Abstract

Large-scale afforestation is increasingly being considered as a negative emissions method for sequestering large quantities of atmospheric CO2. At the same time, regional weather modification methods, like cloud seeding, are being used to counteract increasing water scarcity in arid regions. Large-scale sustainable desert agroforestry plantations can contribute to climate change mitigation and can also be used to modify regional climate, particularly rainfall. Climate impacts from plantations need to be well understood before considering implementation. Typically, impact studies are attempted at continental or global scales and use coarse-resolution models, which suffer from severe systematic errors. This is highly problematic because decision makers should only countenance geoengineering schemes like global afforestation if impacts are understood on the regional scale. We posit the necessity of using high-resolution regional models with sophisticated representations of land–atmosphere feedback and vegetation. This approach allows for studying desert plantations and the process chain leading to climate modification. We demonstrate that large-scale plantations enhance regional clouds and rainfall and derive an index for predicting plantation impacts. Thus, desert plantations represent a unique environmental solution via predictable regional weather modification and carbon storage.

desert plantationsweather modificationrainfall enhancement