Greenland　Stadial　1　(GS-1)　was　the　last　of　a　long　series　of　severe　cooling　episodes　in　the　Northern　Hemisphere　during　the　last　glacial　period.　Numerous　North　Atlantic　and　European　records　reveal　the　intense　environmental　impact　of　that　stadial,　whose　origin　is　attributed　to　an　intense　weakening　of　the　Atlantic　Meridional　Overturning　Circulation　in　response　to　freshening　of　the　North　Atlantic.　Recent　high-resolution　studies　of　European　lakes　revealed　a　mid-GS-1　transition　in　the　climatic　regimes.　The　geographical　extension　of　such　atmospheric　changes　and　their　potential　coupling　with　ocean　dynamics　still　remains　unclear.　Here　we　use　a　subdecadally　resolved　stalagmite　record　from　the　Northern　Iberian　Peninsula　to　further　investigate　the　timing　and　forcing　of　this　transition.　A　solid　interpretation　of　the　environmental　changes　detected　in　this　new,　accurately　dated,　stalagmite　record　is　based　on　a　parallel　cave　monitoring　exercise.　This　record　reveals　a　gradual　transition　from　dry　to　wet　conditions　starting　at　12,500　y　before　2000　A.　D.　in　parallel　to　a　progressive　warming　of　the　subtropical　Atlantic　Ocean.　The　observed　atmospheric　changes　are　proposed　to　be　led　by　a　progressive　resumption　of　the　North　Atlantic　convection　and　highlight　the　complex　regional　signature　of　GS-1,　very　distinctive　from　previous　stadial　events.