COPENHAGEN - Researchers in Denmark have calculated the environmental 'cost' of producing a basic cotton T-shirt to be around US $3.75. The work, carried out in collaboration with Danish clothing company IC Group - which is behind brands like Tiger of Sweden and Peak Performance - suggests that Danish consumption of clothing costs nature and the environment around US $514 million annually. This natural accounting cost of a clothing item takes into accounts issues such as the use of water, fertilizer for cotton and energy consumption throughout the production chain.