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).
• 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.
• Black Carbon is the 2nd largest contributor to global warming after CO2. The warming effect is expected to be about 2/3 of CO2.
• 60-80% of black carbon emissions in the developing regions are from biomass cookstoves.
• 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

Effect of Black Carbon on Climate

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.​ 

Brown carbon (BrC) is also a carbon based particulate matter that absorbs solar radiation within the visible and ultraviolet wavelength. 

Black and brown carbon particles causes atmostpheric warming in three ways:

• Direct effect

Black and brown carbon, in the atmosphere enter the miniscule water droplets that form clouds. The sunlight penetrates the water droplet and is absorbed by the carbon particles, creating heat and acceleratign the evaportation of the water droplets. Similarly, the carbon particles floating inbetween the water droplets spaces also absorb the sunlight resulteing in additional heating and evaportion of the cloud. Cloud acts as a buffer between the earth and the sun, reflecting the sunlight back to the atmosphere. with increased evaporation of the cloud, less sunlight will be refelcted and more will be absorbed, resulting in warming of the earth.

• Snow/albedo Effect

Black and brown carbon particles increase atmospheric warming in three ways. First, they enter the minuscule water droplets that form clouds. Sunlight scatters around the clouds, bathing them in luminescence. According to Jacobson, when sunlight penetrates a water droplet containing black or brown carbon particles, the carbon absorbs the light energy creating heat and accelerating the evaporation of the droplet. Carbon particles floating around in the spaces between the droplets also absorb scattered sunlight, converting it to heat.

“Heating the cloud reduces the relative humidity in the cloud,” - Jacobson

This causes the cloud to dissipate. And because clouds reflect sunlight, cloud dissipation causes more sunlight to transfer to the ground and seas, ultimately resulting in warmer ground and air temperature. Finally, carbon particles released from burning biomass settle on snow and ice, contributing to further warming.

“Ice and snow are white, and reflect sunlight very effectively,” - Jacobson. “But because carbon is dark it absorbs sunlight, causing snow and ice to melt at accelerated rates. That exposes dark soil and dark seas. And again, because those surfaces are dark, they absorb even more thermal energy from the sunlight, establishing an ongoing amplification process.”

Jacobson also noted that 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.

Jacobson further states that 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 simulated by the computer. 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 C,” Jacobson said, “so you end up with a total net warming gain of 0.9 C or so. Of that net gain, we’ve calculated that biomass burning accounts for about 0.4 C.”

Jacobson’s model also tracks the impact of the direct heat produced by combusting biomass.“The direct heat generated by burning biomass is significant and contributes to cloud evaporation by decreasing relative humidity,” Jacobson said. “We’ve determined that 7 percent of the total net warming 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.”

►Go to Top

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.

“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.”

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”.

►Go to Top

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.

►Go to Top

Further Information

• Household Cookstoves, Environment, Health and Climate Change – A New Look at an Old Problem (WB 2010)

http://documents.worldbank.org/curated/en/2010/03/14600224/household-cook-stoves-environment-health-climate-change-new-look-old-problem

• On thin Ice: How Cutting Pollution Can Slow Warming and Save Lives (WB 2013)

http://www.worldbank.org/en/news/feature/2013/11/03/protecting-snow-ice-critical-for-development-climate

• 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
  

►Go to Top