We live in the centre of town, and were receiving 2-3 pieces of junk mail a day. I never read them, they would just get binned. I felt guilty, as the local businesses were paying for this advertising for no reason.
In the UK, 2% of our waste going to landfill is mail. The paper and pulp industry is responsible for 5% of global industrial energy use, and is the fourth worst sector for releasing toxic chemicals to water and air. Recycling helps, but not using it in the first place would help more.
Assuming 17.9 g/letter received, the total carbon emissions reduced by stopping my junk mail is approximately 13 kg CO2/ year. Not a huge impact on my personal carbon emissions, but the volume of waste reduced is substantial, and it keeps my hall tidier, so I’d still highly recommend it, (particularly if you don’t read the adverts).
For further advice about reducing the volume of junk mail you are receiving, visit the Stop Junk Mail website, for some great advice and helpful links, including stopping the junk mail sent through Royal Mail, which will not be stopped by a sign.
See The Environmental Impact of Mail for further detailed calculations about the environmental impact the paper and pulp industry has.