Advice Request: My wife and I are currently in Paris. Where else in the world should we go next in order to minimize the amount of CO2 emissions that we are currently responsible for?

My wife and I are both in Paris, both with one checked bag and one carry on. We are currently planning on flying to Southern Spain in about 5 days but we haven't booked anything yet. We have no work commitments or any other constraints until Jan 1.<br><br>Should we go to Madrid? Should we go to Lisbon? Should we go to London? Should we go back to the United States and drive somewhere? Where can we get to within 5 days in order to minimize our carbon footprint in the next 30 days?<br><br>Or should we just go to Madrid/Seville and then Barcelona?