diff --git a/agenda/trip.py b/agenda/trip.py
index 90e9997..b1cf69f 100644
--- a/agenda/trip.py
+++ b/agenda/trip.py
@@ -50,8 +50,14 @@ def load_trains(
             if route_distances:
                 travel.add_leg_route_distance(leg, route_distances)
 
+            # Calculate CO2 emissions for train leg (0.037 kg CO2e per passenger per km)
+            if "distance" in leg:
+                leg["co2_kg"] = leg["distance"] * 0.037
+
         if all("distance" in leg for leg in train["legs"]):
             train["distance"] = sum(leg["distance"] for leg in train["legs"])
+            # Calculate total CO2 for entire train journey
+            train["co2_kg"] = sum(leg["co2_kg"] for leg in train["legs"])
 
     return trains
 
@@ -73,6 +79,10 @@ def load_ferries(
         if route_distances:
             travel.add_leg_route_distance(item, route_distances)
 
+            # Calculate CO2 emissions for ferry (0.02254 kg CO2e per passenger per km)
+            if "distance" in item:
+                item["co2_kg"] = item["distance"] * 0.02254
+
         geojson = from_terminal["routes"].get(item["to"])
         if geojson:
             item["geojson_filename"] = geojson