Business Green: Senders of junk mail in the US are causing carbon emissions equal to nine million cars, according to a forest preservation group. Pressure group ForestEthics released the report, Climate Change Enclosed: Junk Mail’s Effect on Global Warming, last week to support its new campaign for a “do not mail” registry. The study, which is based on figures from the Environmental Defense Fund, the Environmental Paper Network, and industry data, found that half the carbon expenditure relating from …