Thursday, January 25, 2024

As a carbon offset, cookstove emission credits are greatly overestimated

Study finds that global carbon markets overcredit cookstove GHG reductions by a factor of 10

UNIVERSITY OF CALIFORNIA - BERKELEY

Women gathering firewood — IMAGE:
AFRICAN WOMEN GATHERING FIREWOOD FOR COOKING. MORE EFFICIENT COOKSTOVES LESSEN THE NEED TO GATHER FIREWOOD AS WELL AS REDUCE CARBON EMISSIONS AND IMPROVE HEALTH.
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CREDIT: ANNELISE GILL-WIEHL, UC BERKELEY

The fastest growing type of offset on the global carbon market subsidizes the distribution of efficient cookstoves in developing countries to reduce greenhouse gas emissions, but a new study finds that the credits overestimate the stoves’ carbon savings by a factor of 10.

The overestimation undermines efforts to counteract carbon emissions to slow climate change, since companies use these offsets to meet climate targets and to sell products labeled as “carbon neutral” instead of making real reductions in greenhouse gas emissions. It also undermines trust in the carbon market, and therefore the market’s ability to support the longterm financing of efficient stoves.

The conclusions come from the first comprehensive, quantitative quality assessment of any type of offset project, in which researchers from the University of California, Berkeley, compared five methodologies for evaluating the emission reductions of cookstoves to published studies and their own independent analysis. The study will be published on Jan. 23 in the journal Nature Sustainability.

“Clean cooking now figures very centrally on national decarbonization and sustainable development goal strategies, global funding cycles and the political agenda of national leaders," said Daniel Kammen, the James and Katherine Lau Distinguished Professor of Sustainability at UC Berkeley. "Integrating the science, human rights and economics of clean cooking is now critically linked to both social justice and climate strategies around the planet.”

This study, which was shared in preprint form last year, has received substantial attention from the cooking-health, carbon market, sustainable development and national climate action communities, he noted.

“Cookstove offset methodologies are currently being revised and if our recommendations are adopted could become a rare project type that offset buyers can trust,” said Barbara Haya, an expert on offset quality and director of the Berkeley Carbon Trading Project in UC Berkeley's Goldman School of Public Policy.

Cookstove offsets have become popular because roughly 2.4 billion people around the world cook with smoky solid fuels or kerosene, contributing to 2 to 3 million premature deaths annually and approximately 2% of global greenhouse gas (GHG) emissions. Providing efficient cookstoves now represents the fastest growing project type on the voluntary carbon market, with the second largest share of issued credits in the first ten months of 2023.

Estimated correctly, carbon offsets have the potential to support the free or subsidized distribution of efficient stoves that reduce time spent collecting firewood or the cost of purchasing fuel, said first author Annelise Gill-Wiehl, a UC Berkeley Ph.D. candidate in the Energy and Resources Group who has conducted extensive household energy fieldwork in East Africa. Furthermore, certain stoves can reduce smoke enough to save lives.

The UC Berkeley study not only documents the extent of the quality issues on the offset market, but also offers specific recommendations to align cookstove methodologies with current science and Sustainable Development Goal progress. A companion website provides guidance for buyers and developers on how to trade in quality credits that can substantially improve health.

The researchers specifically advise buyers to prioritize projects that distribute stoves that meet the World Health Organization’s health standards. The majority of stoves on the market do not, they found. The rigorous method the team developed for assessing offset quality could be used by offset program developers, program regulators and credit assessors to comprehensively assess offset quality and prevent over-crediting from all project types.

“Our results support a paradigm shift away from the majority of today’s improved stoves, which do not reduce smoke enough to see health benefits, towards clean fuels and stoves that can substantially support health and climate benefits with their transparent monitoring and low emission profiles," Gill-Wiehl said. "We find that low quality carbon produces low quality solutions."

The studies key findings include:

● Based on the project's sample, which covered 40% of cookstoves credits, cookstoves were over-credited 9.2 times. Extrapolating to all cookstove offset credits from the five methodologies studied, the group found over-crediting by approximately 10.6 times.

● Over-crediting is mostly from exaggerated estimates of stove adoption and use, underestimates of the continued use of the original stove and high estimates of the impact of fuel collection on forest biomass.

● Gold Standard’s Metered methodology, which directly monitors fuel use and credits the cleanest stoves, is most aligned with the study's estimates — it is only overvalued by a factor of 1.5 — and has the largest potential for emissions abatement and for health benefit.

● The assessment methods we develop and demonstrate in this study can be used to comprehensively assess offset quality across all project types on the offset market.

Kammen holds parallel appointments in the Energy and Resources Group, the Goldman School of Public Policy and the Department of Nuclear Engineering. The project was funded by UC Berkeley's Center for African Studies, Carbon Direct, Google.org, the Katherine Lau Family Foundation, the National Science Foundation, the Mulago Foundation/Better Cooking Company and the Zaffaroni Family Foundation.

In many countries, food is prepared over a wood or charcoal fire, often indoors. The smoke causes serious respiratory disease and contributes to global carbon emissions. While more efficient cookstoves can improve both health and the environment, most cookstoves carbon credits sold on the global market vastly overestimate their emission reductions.

CREDIT

Annelise Gill-Wiehl, UC Berkeley)

JOURNAL

Nature Sustainability

DOI

10.1038/s41893-023-01259-6

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Pervasive over-crediting from cookstove offset methodologies”

ARTICLE PUBLICATION DATE

23-Jan-2024

A new perspective on the temperature inside tropical forests

New worldwide maps of temperatures inside tropical forests

Peer-Reviewed Publication

UNIVERSITY OF HELSINKI

The map shows the variation in temperature differences on the South American continent. — IMAGE:
*THE MAP SHOWS THE VARIATION IN TEMPERATURE DIFFERENCES* BETWEEN GROUND LEVEL AND ABOVE CANOPY LEVEL (GROUND LEVEL ALWAYS COOLER) *ON THE SOUTH AMERICAN CONTINENT.* THE MAP IS BASED ON ACTUAL DATA COLLECTED BY RESEARCHERS.
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CREDIT: ISMAEEL ET AL., 2024 GRAPHIC DESIGN JANI NÄRHI/UNIVERSITY OF HELSINKI

New worldwide maps of temperatures inside tropical forests show that global warming affect different way in different parts of the forests. Undergrowth level temperature of the tropical forests can be even 4 degrees less than average temperature of the area.

Tropical forests host up to half of the planet’s biodiversity but up to now, ecological studies over tropical forests often relied on large scale datasets depicting open-air temperatures – that is, the temperature outside the forests, which can be several degrees different from the temperatures inside the forest. This limitation imposed a large barrier in our understanding on how species will respond to climate change.

The research coordinated at the University of Helsinki and the Finnish Meteorological Institute by associate professor Eduardo Maeda, has now achieved a major step to overcome this limitation. The results have been published in the scientific journal Nature communication.

Hotspots of microclimate refugia

Temperature is a fundamental factor defining the survival, growth, and reproduction rate of species living inside tropical forests.

New study provides maps of temperature inside forests that can be used by ecologists to massively improve the reliability of species distribution models.

“The maps will help to predict with higher confidence how species will respond to climate change, such as to where species are more likely to migrate”, says Maeda.

Furthermore, we are able to identify hotspots of microclimate refugia (i.e., areas that can maintain stable and cool microclimates). These areas are likely to be more and more important in a warming future – with highly detailed maps provided by this study, we can now indicate to policy makers where these areas are, so they can be more efficiently preserved.

Building on an extensive international collaboration effort, the researchers compiled data from hundreds of temperature sensors installed inside tropical forests across the world. The study also used satellite data that provided information on different characteristics of the forests, such as the height of the trees and the leaf density. All this information were combined in a machine learning algorithm that was able to estimate temperatures inside tropical forests throughout the entire planet.

The result of this study demonstrates an amazing variability in the temperatures experienced inside forests, which were not visible from other available datasets. For example, the differences between temperatures inside and outside forests are larger in regions with a distinct dry season (e.g., in southern Amazon forest). Areas with lower rainfall are usually associated with higher temperatures, but this study demonstrate that the deep roots of tropical trees can still access water reserves, thus maintaining their 'airconditioning' function in the ecosystem.

“We already knew that temperatures inside forest differ substantially from those outside forests. Our study shows that those differences are evident not only in terms of magnitude (ie., the absolute difference between temperature inside and outside forest) but also in terms of spatial and temporal heterogeneity”, says Maeda.

Along the same lines, temperatures inside the forests can be affected by many other anthropogenic disturbances, such as selective logging or fires. Without having a baseline of the expected temperatures, we would not know how these disturbances are impacting the climate conditions inside forests.

Reference:

Patterns of tropical forest understory temperatures, Ismaeel et al., 2024 Nature Communication https://www.nature.com/articles/s41467-024-44734-0.

Researchers compiled data from hundreds of temperature sensors installed inside tropical forests across the world.

CREDIT

Eduardo Maeda