We estimate the causal effect of external debt (ED) on greenhouse gas (GHG) emissions in a panel of 78 emerging market and developing economies (EMDEs) over the 1990-2015 period. Unlike previous literature, we use external instruments to address the potential endogeneity in the relationship between ED and GHG emissions. Specifically, we use international liquidity shocks as instrumental variables for ED. We find that dealing with the potential endogeneity problem brings about a positive and statistically significant effect of ED on GHG emissions: a 1 percentage point (pp.) rise in ED causes, on average, a 0.7% increase in GHG emissions. Moreover, when disaggregating ED between public and private indebtedness, instrumental variable estimates allow us to find a positive and statistically significant effect of external public debt on GHG emissions. Finally, disaggregation by type of creditor reveals that the external public debt from bilateral (private) creditors causes, on average, a 1.8% (1.2%) increase in GHG emissions. On the contrary, the instrument used is not relevant in the case of multilateral lending so we have not found any significant effect of external public debt from IMF creditors or other multilateral creditors on environmental damage.