I would imagine OP meant in terms of CO2 emitted by those particular planes. I have no sources, but recall hearing that due to the relative inefficiency of the engines at taxi speeds, a large percentage of the fuel required for a flight is consumed driving to/from the runway. However, how much extra emissions were made highly depends on how they did stop the flights and/or announce their presence on the runway - if the planes never left the gates, the extra emissions would be close to 0 for instance.