Researchers from Canada, the United States, and India measured the indoor air quality impacts of providing modern “clean cook stoves” to families in southern India. The Kyoto Protocol’s Clean Development Mechanism (CDM) subsidizes the distribution of such devices.
The effectiveness (or lack thereof) of CDM-supported cook stoves to reduce indoor air pollution is a big deal. As the researchers explain:
Burning solid fuel (wood, dung, agricultural residues, and coal) in traditional stoves for cooking and heating negatively affects the health and welfare of nearly 3 billion people, mostly in low and middle-income countries. Household air pollution (HAP) emitted from solid fuel combustion contributed to an estimated 2.9 million premature deaths and 81.1 million disability adjusted life-years in 2013.
The researchers examined indoor air pollution concentrations and fuel use in 187 households in a village in Karnataka, India. About half the households received “clean” stoves, and half–the control group–did not.
The study, published in Environmental Science & Technology, is paywall protected. The online journal Phys.Org accurately summarizes the results: “Actual indoor concentrations measured in the field were only moderately lower for the new stoves than for traditional stoves.”
Part of the reason was that “40 percent of families who used a more efficient wood stove as part of the intervention also elected to continue using traditional stoves, which they preferred for making staple dishes such as roti bread. That duplication erased many of the hoped-for efficiency and pollution improvements.” Those households “stacked” new and old stoves instead of replacing the old with the new. See the image at the top right corner of the page.
The climate benefit of the CDM-financed “intervention” was also nil. As Phys.Org reports:
Laboratory studies suggested that the more efficient, cleaner-burning stoves could reduce a family’s fuelwood consumption by up to 67 percent, thereby reducing household air pollution and deforestation. In practice, there was no statistically significant difference in fuel consumption between families who used the new stoves and families who continued to cook over open fires or traditional stoves.
Moreover, the “clean” cook stoves actually “increased the proportion” of household emissions composed of black carbon, a strong warming agent that darkens and melts Arctic ice.
Weirdly, whether households used the new stoves or traditional stoves, indoor air pollution concentrations increased during the course of the study: “Across all households, average indoor concentrations of particulate matter, an unhealthy component of cooking smoke that can contribute to lung and heart disease, increased after the intervention stoves were introduced—likely because of seasonal weather patterns or food rituals that required more cooking.”
Here’s the most shocking thing, which Phys.Org does not report. It is well known that CDM-subsidized cook stoves do not reduce household concentrations of fine particulate matter (PM2.5) to safe levels, especially in households that lack “chimney ventilation.”
More advanced stoves that use modern fuel (liquid or gas) rather than wood emit far less PM2.5 and black carbon. However, though such stoves are “ideal” for achieving “ambitious health and environmental goals,” the CDM program does not support those technologies “because they use fossil fuels, which are not considered renewable.”
So the CDM promotes stoves with negligible health and climate benefits rather than stoves with far greater potential to avert disease, limit deforestation, and reduce black carbon emissions.
Of course, nothing would cure indoor air pollution faster than allowing grid-based fossil-fuel technologies to provide heat and power to peoples who presently have little or no access to modern energy services. But the climate agenda, especially as ramped up by the Paris Agreement, demands that developing countries dramatically reduce their current consumption of fossil fuels.
The Paris Agreement aims to limit global warming to “well below 2°C above pre-industrial levels” and pursue “efforts to limit the temperature increase to 1.5°C above pre-industrial levels.” Stephen Eule of the U.S. Chamber Institute for 21st Century Energy has calculated how much developing country emissions must decline if the world is to achieve the 1.5ºC target.
If we assume “consensus” climate sensitivity estimates are correct, holding the increase in average global temperature to 1.5ºC would require global emissions to decrease 70 percent to 95 percent below 2010 levels by 2050. For convenience, Eule uses 83 percent, the mid-point of the range, as the global emission-reduction target required to limit warming to 1.5ºC.
If industrial countries miraculously reduce their emissions to zero, developing countries would still have to cut their current emissions by a whopping 72 percent for the world to meet the 83-by-50 target. If, a bit less implausibly, industrial countries reduce their emissions by 95 percent, developing countries would have to cut their current emissions by 75 percent.
Figure explanation: Industrial country (Annex I) emissions in 2010 totaled 18.8 billion tons and are projected to reach 24.2 billion tons in 2050. Developing country (Non-Annex I) emissions in 2010 totaled 29.6 billion tons and are projected to reach 56.6 billion in 2050. If Annex I emissions drop to zero, Annex II emissions must decline to 8.2 billion tons to meet the 83-by-50 (1.5ºC) target. If Annex I emissions drop to 0.9 billion tons, Annex II emissions must decline to 7.3 billion tons. Emissions data and projections are from the OECD Environmental Outlook to 2050.
Absent breakthroughs that make renewables genuinely cheaper than fossil fuels, achieving the Paris Agreement’s 1.5°C goal would require low-income countries to intensify the fuel poverty that already holds back development and exposes billions of their inhabitants to harmful levels of indoor air pollution.