Tropical deforestation drives strong dry-season precipitation reductions at large spatial scales
Authors: Smith Callum , Baker Jessica , Spracklen Dominick 
Published: March 2022

&lt;p&gt;&lt;span xml:lang=&quot;EN-US&quot;&gt;&lt;span&gt;Tropical forests play a critical role in the hydrological cycle and can&lt;/span&gt;&lt;span&gt; impact&lt;/span&gt;&lt;span&gt; local and regional precipitation. T&lt;/span&gt;&lt;span&gt;o date, t&lt;/span&gt;&lt;span&gt;he &lt;/span&gt;&lt;span&gt;effects &lt;/span&gt;&lt;span&gt;of tropical &lt;/span&gt;&lt;span&gt;deforestation&lt;/span&gt;&lt;span&gt; on precipitation &lt;/span&gt;&lt;span&gt;have&lt;/span&gt;&lt;span&gt; largely been assessed &lt;/span&gt;&lt;span&gt;based on &lt;/span&gt;&lt;span&gt;case studies focused on a specific region, with the broader impacts being poorly constrained. Here, we make the first pan-tropical assessment of &lt;/span&gt;&lt;span&gt;how &lt;/span&gt;&lt;span&gt;tropical forest loss between 2003 and 201&lt;/span&gt;&lt;span&gt;7&lt;/span&gt; &lt;span&gt;impacts &lt;/span&gt;&lt;span&gt;precipitation &lt;/span&gt;&lt;span&gt;at a range of spatial scales, &lt;/span&gt;&lt;span&gt;using satellite&lt;/span&gt;&lt;span&gt;, station-based and &lt;/span&gt;&lt;span&gt;reanalysis &lt;/span&gt;&lt;span&gt;datasets.&lt;/span&gt;&lt;/span&gt;&lt;span xml:lang=&quot;EN-US&quot;&gt;&lt;span&gt;&amp;#160;We find the impact of forest loss on precipitation increases at larger spatial scales, with &lt;/span&gt;&lt;span&gt;satellite&lt;/span&gt;&lt;span&gt; datasets (n=9) showing robust reductions in precipitation &lt;/span&gt;&lt;span&gt;at scales greater than&lt;/span&gt;&lt;/span&gt; &lt;span xml:lang=&quot;EN-US&quot;&gt;&lt;span&gt;~50&lt;/span&gt;&lt;/span&gt; &lt;span xml:lang=&quot;EN-US&quot;&gt;&lt;span&gt;km&lt;/span&gt;&lt;span&gt;.&lt;/span&gt;&lt;/span&gt;&lt;span xml:lang=&quot;EN-US&quot;&gt; &lt;span&gt;The greatest relative declines in precipitation were observed &lt;/span&gt;&lt;span&gt;at ~200 km, where &lt;/span&gt;&lt;span&gt;reduction&lt;/span&gt;&lt;span&gt;s&lt;/span&gt;&lt;span&gt; in canopy cover caused a &lt;/span&gt;&lt;span&gt;30&lt;/span&gt;&lt;span&gt;%&lt;/span&gt;&lt;span&gt; decrease in &lt;/span&gt;&lt;span&gt;dry season &lt;/span&gt;&lt;span&gt;precipitation&lt;/span&gt;&lt;span&gt; (satellite data).&lt;/span&gt; &lt;span&gt;Station-based and r&lt;/span&gt;&lt;span&gt;eanalysis&lt;/span&gt; &lt;span&gt;datasets &lt;/span&gt;&lt;span&gt;were &lt;/span&gt;&lt;span&gt;unable to capture the precipitation response to defores&lt;/span&gt;&lt;span&gt;tation&lt;/span&gt;&lt;span&gt; shown by satellite datasets&lt;/span&gt;&lt;span&gt;,&lt;/span&gt;&lt;span&gt; likely due to limited tropical in situ data and poor representation of surface changes i&lt;/span&gt;&lt;span&gt;n land-surface &lt;/span&gt;&lt;span&gt;schemes&lt;/span&gt;&lt;span&gt;.&lt;/span&gt; &lt;span&gt;Our analysis provides&lt;/span&gt;&lt;span&gt; further evidence that &lt;/span&gt;&lt;span&gt;tropical &lt;/span&gt;&lt;span&gt;deforestation &lt;/span&gt;&lt;span&gt;disrupts the forest-ra&lt;/span&gt;&lt;span&gt;infall cascade&lt;/span&gt;&lt;span&gt;, with consequences for&lt;/span&gt;&lt;span&gt; forest&lt;/span&gt; &lt;span&gt;ecosystems&lt;/span&gt;&lt;span&gt;, human settlements and agriculture&lt;/span&gt;&lt;span&gt; downwind &lt;/span&gt;&lt;span&gt;that are &lt;/span&gt;&lt;span&gt;reliant on &lt;/span&gt;&lt;span&gt;mois&lt;/span&gt;&lt;span&gt;ture &lt;/span&gt;&lt;span&gt;propagated inland through&lt;/span&gt;&lt;span&gt; recycling over forests.&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;