Laptop or desktop? Which is the least environmentally harmful?

Until recently, power consumption in use has received most attention and laptops have been judged the greenest. A more balanced appreciation of life-cycle costs is growing, especially of the very high environmental costs of manufacturing and distribution. Perhaps long life is environmentally more important than low power consumption in use.

Without dependable data on the non-financial life cycle cost of computers, both laptop and desktop, it is hard for consumers to choose the least harmful. Meanwhile how about this list of discriminators?

• • Laptops are smaller and lighter so probably cost less but most of the cost is in manufacturing and most of the manufacturing cost is in the chips and these are similar for laptops and desktops so there may not be much difference.
• • Laptops have shorter lives (more fragile, parts more costly and harder to find, uneconomic to replace batteries, impractical to upgrade).
• • Laptops have batteries (particularly toxic, waste energy in charge/discharge cycle, waste energy when degraded).
• • Laptop components are hard to re-use at end of computer life
• • Wherever possible we can buy for longer life and lower power to encourage the industry to change. That's more of an option when buying desktops and desktop components than when buying laptops.
• • Laptops use less power.

Regards "Laptops use less power", desktops don't have to consume a lot more power than laptops; they could be designed for similar power consumption.