A ship’s greenhouse gas footprint may shrink, although only on paper, with one step: figuring out what its emissions truly are.

Technology companies that measure or calculate emissions with more precision have found that vessels’ actual carbon output is often smaller than the estimates traditionally used to report their carbon footprint to European Union and international regulators.

And shipping industry experts said the act of figuring out what a vessel’s emissions truly is then allows its owner or operator to test operational measures that might shrink them further.