diff --git a/probabilistic-analysis/probabilistic_assessment.py b/probabilistic-analysis/probabilistic_assessment.py
index 59ae0cd..c52fb91 100644
--- a/probabilistic-analysis/probabilistic_assessment.py
+++ b/probabilistic-analysis/probabilistic_assessment.py
@@ -222,10 +222,10 @@ def get_ongoing_recession(n_runs, start_year, end_year, sea_level_rise,
             slr[i, :] = np.ones([1, n_runs]) * slr_mode[i]
 
     # Sort each row, so SLR follows a smooth trajectory for each model run
-    slr.sort(axis=1)
+    slr = np.sort(slr, axis=1)
 
     # Shuffle columns, so the order of model runs is randomised
-    np.random.shuffle(slr.T)
+    slr = np.random.permutation(slr.T).T
 
     # Shift sea level so it is zero in the start year
     slr -= slr[0, :].mean(axis=0)