Often, there is an "out of sight, out of mind" attitude when it comes to greenhouse gasses that cause climate change and impact human health. We can't see carbon dioxide in the air, so we tend to forget about it or ignore its effects. But a new computer application from the folks at Google could change that.

The program uses Google Earth to show a bird's eye view of US carbon emissions. The interactive map lets users see emissions from factories, cars on roads - even their own neighborhoods-to compare with other parts of the country.

The US contributes nearly a quarter of the world's CO2 emissions. Scientists have identified CO2 as the most important human-produced gas contributing to global climate change. And the EPA has labeled it a pollutant that endangers the public's health and welfare.

The Google map breaks down emissions by sector - like aircraft, electricity production, industrial and so on.

Seeing is believing. And it may help provide the spark for policy changes that clean up the air.