Reporting on a recent poll, the Pew Research Center revealed, "44% of the public now says China is the world’s leading economic power." The overall results indicated a sharp decline in US confidence in its position (see the whole report here).
The degree of ignorance this reflects is somewhat staggering. The US's economy is by far the world's largest in absolute terms, as illustrated by this graph of GDP by year for several countries.
The Spaceship Earth image so popular following the moon missions focused much creative thought on the importance of preserving our living space, with discussions ranging from adequacy of food, preservation activities and Malthusian discussions of population growth vs. resources. Recently, however, the focus has turned to climate change and the impact of fossil fuel usage on rising temperatures.