In climate change discussions, energy intensity is the amount of energy required to produce a dollars worth of GDP.  While there are big differences in energy intensity around the world.  Generally poor countries are more energy intensive than rich, and the US, Canada and Australia are more energy intensive than Europe and Japan.  A recent graph from the Economist illustrates how energy intensities are falling and converging, unfortunately at a slower rate than economic growth, meaning that energy use, and hence CO2 emissions, continue to grow.

From the Economist: