[last update: 2009/08/13]
Deforestation: The hidden cause of global warming
The “environmental” movement is pushing biomass burning to reduce global warming – burn the trees and they re-grow: theoretically a CO2-neutral approach to energy (but theory and reality are often two different things).
Biomass Burning: Another hidden cause of global warming
Tropical Forests are Increasingly Used for Fuel Wood
Tropical forests are increasingly used as fuel wood – without being replaced – i.e. not CO2 neutral. The following figures are from the UN FAO 2007 report on Africa’s forests [ftp://ftp.fao.org/docrep/fao/009/a0773e/a0773e02.pdf]. The left figure shows the extent of forest burning (as detected from satellite data). The right figure shows the increasing cutting of forests for fuel wood.
The UN FAO 2007 forest report [ftp://ftp.fao.org/docrep/fao/009/a0773e/a0773e09.pdf] states:
These are very telling statements: “new energy and environmental policies are making woodfuel an essential ingredient of energy policy in both developed and developing countries”… and “increasing concern for climate change will result in increased use of wood as fuel in both developed and developing countries”. The environmental policies that are referred to are the anti-fossil-fuel policies, wherein the burning of wood is deemed preferable because it is “renewable biomass”. The fact that burning wood releases more greenhouse gases per unit of energy released than burning oil or natural gas does, is simply overlooked. The assumption is that the wood will be re-grown and absorb as much CO2 from the atmosphere as released in the burning.
The following figure from the same report shows the expected increase in biomass burning as a source of energy. The U.S. can curb CO2 emissions all it wants – globally it will achieve nothing while other countries increase their biomass burning.
Biomass Burning Promotion
The environmental movement is now promoting increased wood burning to reduce greenhouse gas emissions. [http://www.guardian.co.uk/environment/2009/jan/25/eco-wood-burning-fires]
The assumption is the wood is re-grown thus re-absorbing all the CO2 from the atmosphere released in burning the wood – and voila, no CO2 emissions from burning wood! But what an assumption. In addition to erroneous assumptions we need to ignore all the particulate pollution from wood burning that causes actual health problems (which is why burning is banned in most cities). But with the modern green movement, the CO2 bogey-man now trumps all actual health-related pollution issues.
“At least five wood-burning power plants are being proposed or built in New England, encouraged by government incentives and environmentalists who tout wood as an ecofriendly substitute for fossil fuels. A state law (MA) to encourage new sources of renewable energy favors the plants by creating financial incentives for their operators. Russell Biomass's expected emissions of nitrogen oxides, a key component of smog, are one concern, according to the American Lung Association of Massachusetts. The town is in a valley, where air pollutants could be trapped and aggravate health problems such as asthma and pulmonary inflammation” [http://www.boston.com/news/local/massachusetts/articles/2006/08/05/wood_burning_plants_gain_power/]
A few years ago environmentalists still remembered the problem with wood burning: actual health-related pollution problems [http://www.usatoday.com/news/nation/2005-11-13-woodburning-pollution_x.htm]
From the above article: “Scientists have long known that wood smoke contains carbon monoxide and cancer-causing chemicals. But research shows that wood smoke's major ingredient — tiny particles of soot and liquid pollution — worsens heart disease and triggers asthma attacks.”
Biomass Burning Causes Black Carbon Emissions
Biomass and wood burning result in another type of emission – black carbon. “While carbon dioxide may be the No. 1 contributor to rising global temperatures, scientists say, black carbon has emerged as an important No. 2, with recent studies estimating that it is responsible for 18 percent of the planet’s warming, compared with 40 percent for carbon dioxide.” [http://www.nytimes.com/2009/04/16/science/earth/16degrees.html?_r=1] (An implication here is that climate models are overestimating the effects of CO2.)
From the above article: “In Asia and Africa, cookstoves produce the bulk of black carbon, although it also emanates from diesel engines and coal plants there. In the United States and Europe, black carbon emissions have already been reduced significantly by filters and scrubbers. … In the United States, black carbon emissions are indirectly monitored and minimized through federal and state programs that limit small particulate emissions, a category of particles damaging to human health that includes black carbon. But in March, a bill was introduced in Congress that would require the Environmental Protection Agency to specifically regulate black carbon and direct aid to black carbon reduction projects abroad, including introducing cookstoves in 20 million homes. The new stoves cost about $20 and use solar power or are more efficient. Soot is reduced by more than 90 percent. The solar stoves do not use wood or dung. Other new stoves simply burn fuel more cleanly, generally by pulverizing the fuel first and adding a small fan that improves combustion.” (A small fan will do no good when there is no electricity).
The following figure is from the above article showing the Asian emissions of black carbon comparing the inclusion of cooking with biomass (top) or without the cooking emissions (bottom).
The following figure shows the atmospheric solar heating due to black carbon, indicating the regional areas of major black carbon emissions [http://www.nature.com/ngeo/journal/v1/n4/full/ngeo156.html].
“In their frantic search for a solution to the global warming crisis, climatologists and policy makers have managed to overlook one of the leading causes of rising world temperatures - soot, the familiar black residue that coats fireplaces and darkens truck exhaust. ``Soot - or black carbon - may be responsible for 15 to 30 percent of global warming, yet it`s not even considered in any of the discussions about controlling climate change,`` says Stanford Professor Mark Z. Jacobson” [http://www.sciencedaily.com/releases/2001/02/010208075206.htm]
“Widespread use of wood as a household fuel in sub-Saharan Africa will cause ten million premature deaths by 2030 and make a significant contribution to climate change … unless African households adopt cleaner, more efficient fuels, the equivalent of 6.7 billion tonnes of the greenhouse gas carbon dioxide will be released into the atmosphere by 2050
Switching to fossil fuels such as kerosene and liquid petroleum gas would reduce the amount of greenhouse gases emitted by African households … However, high costs put such fuels beyond the reach of many people in sub-Saharan Africa. The other alternative is to use more charcoal instead of wood. This would also reduce the number of predicted deaths but it could nearly double greenhouse gas emissions.” [http://www.scidev.net/en/climate-change-and-energy/news/burning-wood-for-fuel-could-kill-10-million-africa.html]
See also the article “Why Wood Burning is Not ‘Carbon Neutral’” [http://burningissues.org/car-www/science/Climate/climate-ilan-koren.html] which states: “certain types of aerosols – those containing black carbon – can also decrease cloud cover, ultimately leading to a warming effect. This occurs as black carbon absorbs part of the sun's radiation, warming the surrounding atmosphere and reducing the difference in temperature between the Earth's surface and the upper atmosphere. This combination prevents atmospheric instability – the condition needed to form clouds and rain. A stable atmosphere means fewer clouds; fewer clouds mean less reflection of sunlight; less reflection of sunlight and absorption of radiation lead to warming.”
Researchers involved in a 2005 NASA study stated: “black carbon, generated through the process of incomplete combustion, may have a significant warming impact on the Arctic," Koch said. "Further, it means there may be immediate consequences for Arctic ecosystems, and potentially long-term implications on climate patterns for much of the globe. … They found the timing and location of Arctic warming and sea ice loss in the late 20th century are consistent with a significant contribution from man-made tiny particles of pollution” [http://www.sciencedaily.com/releases/2005/04/050411135517.htm]
While some states (like Maine) are pushing wood burning as part of their global warming “solutions”, other states (like Connecticut and New Jersey) are trying to ban wood burning (Connecticut Legislature concerning proposed bill HB. 6616, An Act Establishing Wood Smoke to be a Public Nuisance. [http://www.cga.ct.gov/asp/menu/CommDocTmyBill.asp?comm_code=PH&bill=HB-06616&doc_year=2009])
The following figure shows particulate emissions from various heating sources [http://burningissues.org/car-www/index.html]. In most US cities wood burning is controlled due to the fact that the particulate pollution is a health hazard.
So-called “environmentalists” would do well to remember the health effects of particulates from wood burning. See the following for more info: http://ehs.sph.berkeley.edu/krsmith/publications/HC%20woodsmoke%20report%20Mar%2031%2005(rev).pdf
The following figure is from the above source.
The same source states regarding indoor smoke exposure in developing countries: “In more than a dozen studies each, two important diseases, chronic obstructive lung diseases and acute lower respiratory infections have been strongly associated with these household exposures, leading to an estimate by WHO of some 1.3 million premature deaths per year globally. Multiple studies have also shown relationships with tuberculosis, cataracts, adverse birth outcomes, and asthma. Biomass smoke is also an important part of outdoor air pollution in many developing-country cities, although no studies seem to have been done to separate out their impacts from other particles.”
The U.S. Is The World’s Leader in Positive Land Use Change
The following figure shows the net flux of carbon to the atmosphere due to land use change (which results mainly due to deforestation for agriculture and fuel-wood in the tropics and reforestation in the US). The United States has the largest land use change carbon sink in the world – i.e. while much of the world is burning its forests, the US is absorbing the carbon from the atmosphere. This figure shows: “Cumulative Emissions of C02 From Land-Use Change measures the total mass of carbon absorbed or emitted into the atmosphere between 1950 and 2000 as a result of man-made land use changes (e.g.- deforestation, shifting cultivation, vegetation re-growth on abandoned croplands and pastures). Positive values indicate a positive net flux ("source") of CO2; for these countries, carbon dioxide has been released into the atmosphere as a result of land-use change. Negative values indicate a negative net flux ("sink") of CO2; in these countries, carbon has been absorbed as a result of the re-growth of previously removed vegetation.” [http://earthtrends.wri.org/pdf_library/maps/co2_landuse.pdf].
The same report also states: “While the majority of global CO2 emissions are from the burning of fossil fuels, roughly a quarter of the carbon entering the atmosphere is from land-use change.”
Wood Burning Carbon Emissions
The following figures show the carbon based emissions from
the burning of wood, either directly or via conversion to charcoal and then
burning. (“Emissions from the Combustion of Biofuels in Western Africa”,
Broucard, Lacaux, Kouadio and Yoboue [http://books.google.com/books?id=kYr5FYNFtq0C&pg=PA350&lpg=PA350&dq=
(The actual emissions CO2 / CO depend on the efficiency of the burner used).
See also, Deforestation the Leading Cause of CO2 Emissions: http://www.appinsys.com/GlobalWarming/Deforestation.htm