In recent years, scientists have made numerous attempts to determine how much vegetation, or "biomass," is appropriated by humans. Past estimates have varied widely, however, according to the models used and the data available to plug into them. A team led by Helmut Haberl, an ecologist at the University of Klagenfurt in Klagenfurt, Austria, has taken another crack at the question using a larger number of updated databases and taking into account the effects of land use by humans on overall plant growth. Haberl and his co-workers took the latest available statistics on agricultural production, forestry, and human-caused soil degradation, and mapped them.I am glad to see this research as I have tried to find the amount of biomass production that humans use before and was unable.
The analysis showed that in 2000, humans used up to 23.8% of that year's biomass production, the team reports online this week in the Proceedings of the National Academy of Sciences. Of this total impact, the researchers found, 78% was due to agriculture and 22% to forestry, human-caused fires, and other activities. The team also found marked variations in human use of plant life around the world. Southern Asians topped the charts, appropriating about 63% of their area's vegetation, mostly due to more intense agricultural practices. North Americans used 22% and central Asians only about 12%. The authors warn that measures to increase the consumption of biofuels produced from agricultural and forestry products "need to be considered carefully," because they could double the amount of biomass used by humans and put even more pressure on other species trying to get their share of the Earth's plants.
By comparing carbon consumption through human activity with the amount of carbon consumed overall, Haberl’s team found that humans use 15.6 trillion kilograms of carbon annually.
I can't wait for the actual journal article to be released online to understand how he went about calculating this figure.
via Science Now, Scientific American and New Scientist Environment