Climate change: Soot's role 'underestimated' says study "Scientists say that particles from diesel engines and wood burning could be having twice as much warming effect as assessed in past estimates. They say it ranks second only to carbon dioxide as the most important climate warming agent .... This new study concludes the dark particles are having a warming effect approximately two thirds that of carbon dioxide, and greater than methane." "Reducing emissions from diesel engines and domestic wood and coal fires is a no-brainer as there are tandem health and climate benefits," said Professor Piers Forster from the University of Leeds. "If we did everything we could to reduce these emissions we could buy ourselves up to half a degree less warming, or a couple of decades of respite," he added. Prof Piers Forster is Coordinating lead author of the IPCC report chapter Changes in Atmospheric Constituents and in Radiative Forcing (which sets out the scientific evidence on the changes in the atmosphere that are causing global warming).
UN report recommends phasing out wood-burning stoves
in wealthy countries and banning open burning of
agricultural waste to reduce global warming.
Importance of reducing methane, ground-level ozone and black carbon
Because of current warming (half of which is due to methane, ground-level ozone and black carbon) the Arctic is melting and emitting methane, which is 'certain to trigger further warming'. Prof Carlos Duarte, director of the Oceans Institute at the University of Western Australia, warned that the Arctic summer sea ice was melting at a rate faster than predicted by conventional climate models, and could be ice free as early as 2015. Prof Duarte's article in 'The Conversation' explains why methane hydrates are a volatile time bomb in the Arctic "The major risk is that the relatively modest human perturbation will unleash much greater forces." The amount of greenhouse gas stored in the methane hydrates is several times the total CO₂ release since the industrial revolution. NASA is investigating if a Sleeping Climate Giant is Stirring in the Arctic? the Similar sentimes are echoed by Climate Spectator: " We’ve known for a while that ‘permafrost’ was a misnomer (see Thawing permafrost feedback will turn Arctic from carbon sink to source in the 2020s). The defrosting permamelt will likely add up to 1.5 degrees Fahrenheit to total global warming by 2100."
The immediate increase in global warming from the methane, carbon monoxide and black carbon emissions of wood heaters contribute disproportionately to current warming - in the first 20 years as much as heating 20 similar houses with gas or an electric heat pump, adding to the relatively modest perturbations that could unleash much greater forces if a tipping point is reached.
The graph from the latest UNEP report (November 2011) shows the effect of the measures to reduce methane (CH4) and black carbon (BC) on global temperatures. Compared the purple Reference line (business as usual) the dark blue line shows a rapid reduction in global temperatures of about 0.4 degrees by 2040, complementing the measures to reduce CO2 emissions. Measures to reduce CO2 result in benefits from about 2040. By about 2070, half the reduction is due to the reductions in methane and black carbon emissions and about half due to the reduction in CO2 emissions.
A peer-reviewed paper in Atmospheric Pollution Research shows that, based on the latest estimates of Global Warming Potentials, over a 20 year horizon the average Australian wood heater causes more warming than heating 12 similar homes with gas (see Table 1).
Ross Garnaut recommends credits for growing trees, taxes for chopping them down
On April 14, 2011: Professor Ross Garnaut, distinguished Australian economist and author of a review on Climate Change and Policy Response to Climate Change for the Federal, State and Territory governments of Australia, gave a lecture on Climate Change in Armidale, NSW. When asked about how to account for biomass climate change policy, he argued that people who grow trees, should get credits for the carbon sequestered every year. But people who chop them down (and burn them) should pay tax on the carbon released into the atmosphere.
This sensible accounting system (which relates directly to the impact on
the atmosphere - sequester carbon and get credit; pay the tax when it
is burned) Methane should still be counted, as it
is now, but the release of the CO2 dominates. Under this accounting system, a comprehensive peer-reviewed paper, published in Atmospheric Pollution Research shows that the average Australian wood heater causes more global warming than heating up to 5 similar homes with gas or a reverse cycle airconditioner.
The Kyoto protol used a different accounting system, in which, rather than being counted directly, CO2 emissions from wood burning were accounted for by the change in biomass in the forests and other stored carbon. This works well for an entire country. However, if used by individuals, it leads to wasteful and inefficient use of a valuable resource
Example: If the owner of a forest gets a credit for the amount of carbon sequestered every year, but pays a tax when the wood it burned, it may become economic to use thinnings to make wood pellets for power stations, instead of burning coal. Without this incentive, forest owners are likely to simply burn waste wood on site, leading to much higher total greenhouse gas emissions than by using the wood as a replacement for burning coal. The same applies to domestic wood heaters. The average Australian wood heater burns 2.7 tonnes of wood, emitting about 6.7 tonnes of CO2-equivalent, compared to 1.3 tonnes of CO2 for centrally heating an entire house with floor area of 160 square metres. Australia’s annual contribution to global warming would be reduced by at least 8.7 million tonnes of CO2-equivalent (the same as removing about 21% of Australian passenger cars from the roads, or generating electricity from 5.8 million household 1 kW rooftop photovoltaic systems) if the 4.5 to 5 million tonnes of firewood currently burned in domestic wood heaters were instead used to replace coal in power stations and domestic wood heaters replaced by gas or reverse cycle air-conditioning.
Global warming from methane (CH4) emissions from domestic wood heaters
Even if CO2 emissions from are not counted, incomplete burning in enclosed heaters creates methane (CH4), carbon monoxide (CO, about 15% of carbon emissions) and black carbon smoke. According to the IPPC Fourth Assessment report (AR4), one kilogram of CH4 causes as much global warming as 25 kg CO2. CO (not covered by the Kyoto protocol) causes 1.9 times as much.
A Swedish study of enclosed wood burners used to heat water found that methane emissions can cause up to twice as much global warming as generating the same heat from an oil-fired burner.
Lab tests: new Australian heaters on low burn as bad as the Swedish model causing twice as much global warming as an oil heater
Environment Progress: Australian wood heaters currently increase global warming and health costs
Greenpeace - Fuelling a Biomess
• "Burning natural forest biomass – whether for electricity, heat or biofuels – is not carbon-neutral as governments and companies claim.
"Burning trees contributes to climate change for decades, as shown by the most up-to-date science, until replacement trees fully grow back
• "Compared to current coal-fired electricity plants in North America, current woody biomass power plants can emit at the smokestack up to 150% more climate disrupting CO2, 400%more lung irritating carbon monoxide, and 200% more asthma causing particulate matter to produce the same amount of energy. The CO2 emited will harm climate for decades before being captured by regrowing trees.
• "Burning boreal biomass contributes to climate change through a long carbon payback
time due to the slow regrowth of forests and the fragility of existing carbon stocks."
Atmospheric Pollution Research - Australian wood heaters currently increase global warming and health costsJohn Gras's study (mainly of correctly-operated heaters) measured particle emissions from of emissions from Australian woodheaters burning both eucalype hardwoods and softwoods.
The results for eucyalypt hardwoods (see graph) were used by consultant Prof John Todd to derive an equation (CH4 = 1.495 x praticle emissions) which is used by the Australian Greenhouse Office to estimate methane from particle emissions.
For pine, the graph shows a combination of Australian and overseas results. In John Gras's Australian study the AS4103 heater burning pine had average particle emissions of 15.8 g/kg and methane emissions of 30 g/kg, equivalent to the global warming of 0.75 kg of carbon dioxide. Even a correctly-operated heater burning Amidale's average of 4 tonnes of pine per year would be expected to emit 3 tonnes of CO2-equivalent anc cause more global warming from its methane emissions than heating a similar house with gas or a reverse cycle electric heat pump.