SANTA CLARA, USA: Until now, spam's impact has been measured in time, money, and aggravation. But have you ever thought of the environmental impact of the spam?

According to a recent study conducted by climate-change consultant ICF International and spam expert Richi Jennings for McAfee the energy consumed in transmitting and deleting spam is equivalent to the electricity used in 2.4 million U.S. homes, with greenhouse gas (GHG) emissions equivalent to 3.1 million passenger cars using 2 billion gallons of gasoline!

The 'Carbon Footprint of e-mail Spam Report' released on Wednesday estimated that 62 trillion spam emails are sent globally every year.

“As the world faces the growing problem of climate change, this study highlights that spam has an immense financial, personal and environmental impact on businesses and individuals,” said Jeff Green, senior vice president of product development and McAfee Avert Labs.

“Stopping spam at its source, as well investing in state-of-the-art spam filtering technology, will save time and money, and will pay dividends to the planet by reducing carbon emissions as well,” he said.

In late 2008, McColo, a major source of online spam, was taken offline and global spam volume dropped 70 per cent, the report pointed out.

The energy saved in the ensuing lull before spammers rebuilt their sending capacity, equated to taking 2.2 million cars off the road that day, proving the impact of the 62 trillion spam e-mails that are sent each year.

The “Carbon Footprint of Spam” study looked at global energy expended to create, store, view and filter spam across 11 countries, including Australia, Brazil, Canada, China, France, Germany, Japan, India, Mexico, Spain, the United States and the United Kingdom.

According to the study, the average GHG emission associated with a single spam message is 0.3 grams of CO2. That's like driving one meter; but when multiplied by the yearly volume of spam, it is equivalent to driving around the earth 1.6 million times.

Nearly 80 per cent of the energy consumption associated with spam comes from end-users deleting spam and searching for legitimate e-mail. Spam filtering accounts for just 16 per cent of spam-related energy use.

Spam filtering saves 135 TWh of electricity per year. That is equivalent to taking 13 million cars off the road, the report said.

If every inbox were protected by a state-of-the-art spam filter, organizations and individuals could reduce today’s spam energy by 75 percent or 25 TWh per year, the equivalent of taking 2.3 million cars off the road, it added.

Do you think we are posing threat to our own existence by promoting spam and forwarding unnecessary emails?