Now, this day of environmental activism has morphed into one of corporate promotion.

Freakonomics Radio's Stephen Dubner talks about the idea of "conspicuous conservation," where people indulge in certain earth-saving acts as a way to show off that they care about the environment, and in turn, benefit socially.

The Japanese government has expanded the evacuation zone surrounding the Fukushima Daiichi nuclear plant after several explosions. The fires, triggered by the earthquake, have caused a surge in potentially toxic radiation.

After a devastating earthquake last week, Japan is taking steps to prevent an economic collapse in the country. The Bank of Japan has injected a record amount of cash into the financial system to provide liquidity and stabilize the shaky economy.