Climate change will shift the patterns of circulation in some ways, but there is no strong reason to believe that it will lead them to seize up more often.
Given the international nature of many supply chains, the process of working out products' carbon footprints is also helping to change the way carbon emissions are reckoned.
During the past generation, the American middle-class family that once could count on hard work and fair play to keep itself financially secure has been transformed by economic risk and new realities.
Changing the type of lighting wouldn't have much impact, the scientists suspect, unless cities would use red lights, which don't interfere with nitrate radical formation.