Reduced CO2 Impact

Reducing energy use saves more than just energy and money. Energy reduction also reduces your CO2 emissions, and thus your global warming impact. Energy efficiency gets you the most carbon emissions for your dollar, by far. For example, purchasing renewable energy credits, installing renewable energy or offsetting through carbon emissions credits all carry costs. Because energy efficiency reduces costs, it is like paying yourself to reduce your carbon emissions.

Simply put, if your goal is to reduce carbon dioxide emissions, then investing in energy efficiency will have the greatest impact, and is thus the best thing to do first. Moreover, savings from energy efficiency can help finance later projects in renewable energy.

It's not going to reduce itself, the atmosphere needs your help.