Energy Access and Climate Mitigation and Adaptation
Facts and Figures
- The number of people relying on unsustainable cooking energy has increased from 2.6 billion (2013) to 3 billion (2015).[1][2]
- Cookstoves generate the most black carbon emissions in the developing regions. Black Carbon (BC) is a major constituent of particulate matter (PM) from biomass combustion.[3]
- Black Carbon is the 2nd largest contributor to global warming after CO2. The warming effect is expected to be about 2/3 of CO2. [3]
- 60-80% of black carbon emissions in the developing regions are from biomass cookstoves.[3]
- Almost 8.5 billion tons of atmospheric carbon dioxide – or about 18 percent of all anthropogenic carbon dioxide emissions – comes from biomass burning, according to Prof. Mark Jacobson from Stanford university [4]
Effect of Black Carbon on Climate
Burning of biomass generates carbon dioxide, other forms of carbon such as methane, tiny bits of soot called black carbon and motes of associated substances caleld brown carbon.
Black Carbon is generated by the incomplete combustion of fossil fuels, biofuels and biomass. It is a strongly light-absorbing particulate matter that absorbs solar radiation at all wavelength.[5]
Brown carbon (BrC) is also a carbon based particulate matter that absorbs solar radiation within the visible and ultraviolet wavelength. [5]
Black and brown carbon particles causes atmostpheric warming in three ways:
Direct effects
Black carbon absorbs both the incoming and outcoming solar radiation at all wavelength and thus lead to the atmosphere warming. the green house gases (GHG) only trap the ougoing infrared radition from the earth's surface.[5]
Warming of clouds
Black and brown carbon, in the atmospheric surface enter the miniscule water droplets that form clouds. During day time, the sunlight penetrates the water droplet and is absorbed by the carbon particles, creating heat and acceleraing the evaportation of the water droplets. Similarly, the carbon particles floating inbetween the water droplets spaces also absorb the sunlight resulting in additional heating. Heating the cloud reduces its relative humidity and casues the clouds to dissipate. Cloud acts as a buffer between the earth and the sun, reflecting the sunlight back to the atmosphere. with increased dissipation of the cloud, less sunlight will be refelcted and more will be absorbed, resulting in the warming of the earth.[6]
Snow/albedo Effect
White surface result more light as compared to darker surfaces. Therefore, snow and ice effectively reflect sunlight and are vital in balancing the atmosphering temperature. Black carbon deposited on snow and ice darkens the surface and decrease the refelectivity of the surface (albedo effect). Black carbon can also absorb solar radiation in all wavelength and thus, the BC deposited on the snow accelerates the melting of the snow,exposing the dark soil and the dark seas underneath. Since these surfaces are dark, they contribute to further warming.[6]
Net Effect of Black Carbon
To understand the net effect of black carbon on atmospheric warming, it is important to take into account the following points:
- Black carbon is not emitted alone but rather with other particles such as sulfur dioxide (SO2) , nitrogen oxides (NOx) and organic carbon. Some of these particles have a cooling effect on the climate. Therefore to calculate the net effect of black carbon, the cooling effect of co-emiited pollutants has to be offset.[5]
According to Jacobson, in some carbon particles – specifically white and gray carbon, the variants associated with some types of ash – can exert a cooling effect because they reflect sunlight. That must be weighed against the warming qualities of the black and brown carbon particles and CO2 emissions generated by biomass combustion to derive a net effect.[6]
According to a computer simulated model by Prof Jacobson, the director of Stanford’s Atmosphere/Energy Program and a senior fellow at the Stanford Woods Institute for the Environment and the Precourt Institute for Energy, " The sum of warming caused by all anthropogenic greenhouse gases – CO2, methane, nitrous oxide, chlorofluorocarbons and some others – plus the warming caused by black and brown carbon will yield a planetary warming effect of 2 degrees Celsius over the 20-year period. But light-colored particles – white and gray particles primarily – reflect sunlight and enhance cloudiness, causing more light to reflect.The cooling effect of these light-colored particles amounts to slightly more than 1 degree celcisu and thus the total net warming gain is 0.9 C or so and biomass accounts for about 0.4 degree celcius. [6]
Jacobson’s model also tracks the impact of the direct heat produced by combusting biomass. According to the model, the direct heat generated by burning biomass is significant and contributes to cloud evaporation by decreasing relative humidity,”“e and determined that 7 percent of the total net warming is caused by biomass burning – that is, 7 percent of the 0.4 C net warming gain – can be attributed to the direct heat caused by the fires.”[6]
Biomass Burning
Biomass burning also includes the combustion of agricultural and lumber waste for energy production. Such power generation often is promoted as a “sustainable” alternative to burning fossil fuels. And that’s partly true as far as it goes. It is sustainable, in the sense that the fuel can be grown, processed and converted to energy on a cyclic basis. But the thermal and pollution effects of its combustion – in any form – can’t be discounted, Jacobson said.[6]
“The bottom line is that biomass burning is neither clean nor climate-neutral,” he said. “If you’re serious about addressing global warming, you have to deal with biomass burning as well.”[6]
Exposure to biomass burning particles is strongly associated with cardiovascular disease, respiratory illness, lung cancer, asthma and low birth weights. As the rate of biomass burning increases, so do the impacts to human health.
The global middle and upper class which are largely responsible for GHG emissions currently are the major beneficiaries in the climate mitigation approach whereas the poor and disadvantaged are left out! The poor are only served by climate financing through climate adaptation measures (risk mitigation, disaster management, etc.). This approach however might lead to sharpen inequalities as the funds are rather beneficial to the better-off and not to the poor and hence distort many development approaches.
For Black Carbon there is no internationally standardized methodology available. The Golden Standard Quantification Methodology has not been approved by UNFCCC by now. WB however applies it in a few pilot projects and has come out with first figures. Hence the question still remains which methodology to apply to monitor Black Carbon.
Non-Kyoto particles such as black carbon and short-lived climate pollutants are not mentioned in the current draft of the climate treaty but are important for INDC under UNFCCC. In developing countries, more than 1 billion tons of CO₂ are emitted into the atmosphere from burning biomass for cooking.
Other products of incomplete combustion and climate forcers (non-Kyoto particles) such as black carbon further exacerbate the problem. 21% of black carbon emissions is thought to be from residential solid fuel use for cooking and heating in the developing world (US EPA, 2012).
In terms of climate change, woody resources are generally regarded as “renewable” and “carbon neutral” if sustainably produced; however, while CO₂ to a degree could be sequestered if biomass regrows, the level of regrowth is likely to vary geographically. There is evidence that biomass used for household cooking is thus a net contributor to global warming since not all biomass harvested is renewable. When short-lived climate pollutants (SLCPs) such as black carbon are taken into consideration, the burning of solid fuels is decidedly not “climate neutral”.
Potential Measures
To combat this situation, following potential measures/solutions could be applied:
- Promotion of clean cookstoves - it is estimated that some modern biomass stove models can reduce CO₂ emissions by 25-50%.
- Transitioning to agricultural waste briquettes - such as those made from sawdust, and crop residues and pellets (from compressed woodwaste, invasive plants, etc.) that can be burned in highly efficient residential gasifier stoves.
- More efficient production of charcoal or reducing overall production of charcoal.
- Switching to alternative fuels such as LPG, biogas, and bioethanol.
Further Information
- Household Cookstoves, Environment, Health and Climate Change – A New Look at an Old Problem (WB 2010)
- On thin Ice: How Cutting Pollution Can Slow Warming and Save Lives (WB 2013)
- Black Carbon Finance Study Group Report (CCAC 2015)
- Black Carbon Finance Study Group Report 2015
- M. Jacobsen: Journal of Geophysical research: Atmosphere, July 30, 2014
References
- ↑ Worldbank, SE4All 2015
- ↑ WHO: http://www.who.int/mediacentre/factsheets/fs292/en/
- ↑ 3.0 3.1 3.2 T. Bond, et al., Journal of Geophysical Research: Atmospheres, 2013 Cite error: Invalid
<ref>tag; name "T. Bond, et al., Journal of Geophysical Research: Atmospheres, 2013" defined multiple times with different content - ↑ https://engineering.stanford.edu/print/node/38216 https://engineering.stanford.edu/print/node/38216
- ↑ 5.0 5.1 5.2 5.3 http://www3.epa.gov/blackcarbon/2012report/Chapter2.pdf
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 https://engineering.stanford.edu/print/node/38216
