The short answer is yes. The bulk calculator shows how you can buy fewer tonnes without losing paper thickness. The long answer is, well, long ... Read the whole thing below.
There are lots of factors to take into consideration if you want to minimize the environmental impact of your printed matter. The impact from the paper depends heavily on how the paper is sourced, produced, transported, and used. As a paper supplier, we follow up and report all emissions that cause environmental impact, and we constantly work to improve all the factors under our control.
All these different aspects are measured and reported in a Carbon footprint declaration, showing the CO2 and greenhouse gas emissions (GHG) from each step in the process.
The Carbon footprint declaration follows the framework for carbon footprints for paper and board products by CEPI. It lets you compare different papers to see which one has the lowest emissions, stated in kilos of fossil CO2 per tonne of paper.
For a more detailed view of parameters outside of Carbon footprint, it's a good idea to look at another type of paper industry product declarations called Paper profiles.
TAPPI
http://www.tappi.org/