BRUSSELS What do olives stones shipped from the Mediterranean to Sweden and a wooden bed have in common? They can both count as part of EU efforts to limit the amount of carbon leaking into the atmosphere and, as such, they are hotly contested.
Increasingly, the 27-member bloc, which has sought to lead the fight against global warming, is relying on biomass - covering anything from olive waste to old blackcurrant bushes to trees - to generate heat and power.
For the purposes of the EU Emissions Trading Scheme, biomass used as fuel is counted as carbon-neutral. The underlying assumption is its emissions are offset by the planting of a new tree. Felled wood, until burnt, is a carbon store.
The reality is much more complicated, say environmentalists, who are concerned creative accounting is belying the true state of the world's forests, while EU climate goals slip from grasp.
"You're assuming the whole world has started reducing emissions from its own use and is improving its land management and that's a total fantasy," Pieter de Pous, policy director at the European Environmental Bureau, said.
Demand for biomass, most commonly in the form of wood pellets that can easily be transported, has leapt since the EU in 2007 set its 2020 climate goals, which include cutting carbon emissions by 20 percent and increasing the share of renewables in the energy mix to 20 percent.
National renewable energy action plans drawn up by EU states show around 50 percent of green fuel will come from biomass.
Officially, the EU is meeting its carbon cutting and renewable goals. The first danger is that shipping wood pellets and then burning them adds to, rather than lowers emissions.
"The point to remember is that the smoke that directly comes out of the chimney burning biomass pollutes the same as the emissions from coal," Robbie Blake, biofuels campaigner at Friends of the Earth, said.
Another consequence, the wood industry says, is that the demand for wood pellets is distorting the market.
The European Panel Federation, which represents makers of wood board, says costs for its raw materials have been driven up in nations, such as Germany, while use of wood for biomass is subsidized under policies to encourage renewables.
It wants the carbon life-cycle of wood to be taken into account and more wood to be used in construction and furniture.
The body quotes an industry estimate that a 4 percent rise in Europe's use of wood as a material, rather than a fuel, would sequester an extra 150 million tons of CO2 per year.
A CARBON STORE CUPBOARD?
Whether treating furniture as a carbon store can help to save the planet is a moot point if it is shipped from countries where it is not accounted for at the point of harvesting.
Beyond the EU rules, the United Nations' Kyoto framework does not cover all nations. The United States never ratified the 1997 Kyoto pact, while Canada and Russia have said they will not set new Kyoto targets.
These countries are likely to be the leading suppliers of wood, especially Russia, home to a fifth of all forests.
"One way or another, an awful lot of emissions from forests look like being completely overlooked," John Lanchbery, principal climate change advisor for the Royal Society for the Protection of the Birds, said.
He cautiously welcomed European Commission proposals to tighten its accounting, published earlier this year and up for further debate in the final quarter.
Although they don't close every loophole, they go further than U.N. rules because they aim to map the carbon consequences of changes to agricultural as well as to forestry land.
But they don't set any targets for emissions or change the ETS assumption biomass-use for power is carbon-neutral.
Efforts to over-rule that would be likely to meet stiff resistance from the woodiest EU nations, as well as the big utilities, which would be required to offset far more emissions through the Emissions Trading Scheme.
For all the vagaries in the current accounting, there are lobbyists on both sides who do not propose abandoning biomass.
Energy companies are experimenting with all energy forms. They say co-firing power stations to generate from biomass as well as coal is an easy conversion and they say it is better than just using carbon-intensive coal.
The Paris-based International Energy Agency says counting up the trees will become more scientific through trial and error.
"Rather than focusing on these uncertainties that are not straightforward to eliminate, we think that a bottom-up approach is needed that identifies those feedstock sources and production methods with clear CO2 benefits compared to fossil resources," Anselm Eisentraut, bioenergy analyst at the IEA, said.
"We recommend setting up intermediate targets for bioenergy, such as doubling global bioenergy supply by 2030 in a sustainable manner. Such targets are needed to gain experience," he said. "These real-life results will be extremely valuable."
(Additional reporting by Stephanie Ebbs)