Fraunhofer calculated the reduction by combining IDC figures for the number of thin clients sold in Europe with research that found that the energy consumption of the thin client devices was 50% lower than that of conventional PCs.
Last year the researchers said British businesses could save £78m in electricity bills and slash carbon emissions by 485,000 tonnes a year by switching from PCs to thin clients.
Hartmut Pflaum, Fraunhofer researcher, said, "While PCs consume 85 watts on average, thin clients and their server get by with 40 to 50 watts. In view of climate change and the need to reduce carbon emissions, this is an important factor."
Fraunhofer said the carbon reduction through the use of thin clients in just one year alone was equivalent to the emissions of more than 540 return flights from London to New York.
Stephen Yeo, director of marketing for IGEL Technology, the world's third largest supplier of thin clients, said, "This analysis proves that businesses are reducing their carbon footprint by simply switching to thin client."
He said Europe could make even bigger carbon savings by increasing the proportion of thin clients from the current level of around 10%.