Humans are just one of the millions of species on Earth, but we use up almost a quarter of the sun's energy captured by plants - the most of any species. The human dominance of this natural resource is affecting other species, reducing the amount of energy available to them by almost 10 per cent, scientists report.
Researchers said the findings showed humans were using "a remarkable share" of the earth's plant productivity "to meet the needs and wants of one species". They also warned that the increased use of biofuels — such as ethanol and canola — should be viewed cautiously, given the potential for further pressure on ecosystems.
The scientists, from Austria and Germany, who publish their results today in the journal of the Proceedings of the National Academy of Sciences, analysed data on land use, agriculture and forestry from 161 countries, representing 97 per cent of the world's land mass. This showed humans used 24 per cent of the energy that was captured by plants. More than half of this was due to the harvesting of crops or other plants.
The human use of the natural resource varied across the globe, ranging from 11 per cent in Oceania and Australia, to 63 per cent in southern Asia.
An agriculture professor at the University of Melbourne, Snow Barlow, said the paper showed humans were taking up too much of an important natural resource. "Here we are, just one species on the earth, and we're grabbing a quarter of the renewable resources Â… we're probably being a bit greedy."
After all, there are only so many joules in the Sun, and when they're gone, they're gone.