What uses more energy, reading this book online or acquiring and reading a physical copy?

It definitely takes less energy to read it online. I'll try to explain this intuitively rather than just through calculations. The only significant energy cost if you read the book online is the operation of your computer.

The power this uses is dependent on the size of your computer and the type of monitor you use. I have a 500W power supply and a 19" CRT monitor, so I draw about 650W maximum (this is very approximate). The national average for electricity costs is $0.058/kWh, so it costs me about 3.75 cents to run my computer for an hour.

The energy involved in producing a physical copy of the book and getting it to you is much higher. - Logs must be cut and transported to a paper mill. Logging equipment uses large amounts of gasoline, and paper mills are notorious for their consumption of fresh water.

- Finished paper must be transported to the publishing company. - Ink must be produced separately and transported from its factory as well. - The book must be printed, trimmed and bound (whether it's a small printshop or a large factory, it's still another step in the process).

- The book is shipped to a bookstore, and then you need to buy gas to go buy it and bring it home. The bookstore (like every building in the chain of production) has utility bills and other overhead. When you look at how many different stages there are in making a book, and how much energy is used at each stage, it's amazing that a physical book doesn't cost $100 or more (I realize textbooks do, but that's not because of the energy costs).

The good news is that once you get the book home, you can read it by the light of a 60W bulb, which uses 1/10 the energy of a computer. Edit: Silverhammer has a very good answer, and I'm giving him a "helpful" vote. I encourage you to do the same.

By "energy" you don't mean calories I take it. To put (and consequently read) a book online the infrastructure (cable lines, webhosting companies, computers, devices) has to be manufactured, shipped and installed. Not to mention the electricity used to run them and the impact on the environment when machines break down, batteries die, and are thrown away/recycled (yes, recycling consumes more energy than recovered resources).

Most of what we experience today started years ago but daily improvements and changes are being made worldwide (presuming a global reading audience). A lot of heavy metals and petroleum products (including plastics and oil for gasoline and other non-renewable resources) are consumed in the making of these infrastructures Including the computer you're using to read this now. While a single book run uses materials that are renewable.

The shipping of said books leans a little more onto the non-renewable side (gas, vehicles to move them). But overall a physical copy consumes less energy unless you then incorporate online advertising and sales into the energy costs. Yet the same could be true if you printed information about your online book - then the lines begin to blur.

But if you restrict the numbers to "reading" alone, a printed book always wins. No matter how hard you try to limit the energy impact of an online book you can only go so far. Someone who prints a book can go so retro that the impact on the environment is practically non-existent.

Even to the point of hand delivering copies, using pulp from downed trees, hemp for binding made by hand, natural inks and reading them using sunlight. I've even seen flower seeds pressed into the printed page so that when a book is lost, nature reclaims the resources and plants a garden in the process. That would actually put energy back into the environment, leaving an inverse impact on the Earth!

:) NOTE: I chose not to read the resources you provided so that my answer wasn't influenced. Only personal reasoning and without fancy calculations.

I guess reading online would be spend less enegry , since you are sitting there and ...stuff...

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.