Bioenergy Potential and Tradeoffs with Food Production?

As the Intergovernmental Panel on Climate Change concluded in its Fifth Assessment Report’s Working Group III Contribution, “[b]ioenergy coupled CCS (BECCS) has attracted particular attention since AR4 because it offers the prospect of energy supply with negative emissions.” However, as the IPCC report also cautions, BECCS poses serious challenges, among them, the potential threat to food supplies posed by diversion of biomass to energy production. A study published a few years ago in the journal Biomass & Bioenergy (subscription required) provides an excellent overview of the potential interrelations between food and energy production, and the potential for projected climatic change to either ameliorate or exacerbate the tensions between food and energy production. The study employed what it termed a “socioeconomic metabolism approach” to formulate a biomass balance model (to 2050) to link supply and demand of agricultural biomass, excluding forestry.
Among the conclusions of the study:
1.    Climate change could have dramatic impacts on available biomass in 2050. If some projections of the CO2 fertilization effects are correct, bioenergy potential could rise by a whopping 45% to 151.7 EJ y-1, or it could decline to 87.5 EJ if CO2 fertilization is completely ineffective.  To put this in context, humans currently harvest and utilize a total of amount of biomass with an energy value of 205 EJ y-1. “This implies that the global bioenergy potential on cropland and grazing areas is highly dependent on the (uncertain) effect of climate change on future global yields on agricultural areas.”
a.    However, part of the potential benefits of the CO2 fertilization effect could be obviated by potential decreases in protein content and higher susceptibility to insect pests
2.    There is huge uncertainty in potential bioenergy from forests, ranging from zero to 71 EJ y-1 in 2050;
3.    After taking into account projected food needs, primary bioenergy potential is estimated to be between 64-161 EJ y-1 However, this is “only a fraction of current fossil-fuel use.” Moreover, realizing bioenergy potentials on grazing lands of this magnitude would require “massive investments” in agricultural technologies, e.g. irrigation and could also particularly threaten populations practicing low-input agriculture.
This study demonstrates that BECCs remains a highly contested proposition in terms of potential tradeoffs of food and energy production. Moreover, the “wildcard” of the potential impacts of climate change on biomass production are likely to remain unknown for many decades, making it difficult to determine if large-scale BECCS should be pursued as a policy option.

Among the discussion questions this article could generate:

  • How can society determine if potential tradeoffs between food and bioenergy production, if they exist, are acceptable, i.e. what should be the pertinent metrics? How do we take into consideration equitable concerns, e.g. potentially disproportionate on particularly vulnerable groups, e.g. small-scale farmers?
  • What are other pertinent questions to ask about BECCS, including the viability of CCS technologies; concerns about finding adequate storage capacity to effectuate “negative emissions,” and the potential threats associated with carbon dioxide leakage;
  • Should BECCS be considered a form of “geoengineering”? Does it matter?

Green Grabs and Biochar

Biochar (usually classified as a geoengineering option) is charcoal produced through the thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen. The process has been touted by some proponents as a potentially important component of climate policymaking over the course of this century. Because biochar can sequester carbon in soil for hundreds to thousands of years, supporters argue that it constitutes a “carbon negative” process:

Ordinary biomass fuels are carbon neutral — the carbon captured in the biomass by photosynthesis would have eventually returned to the atmosphere through natural processes — burning plants for energy just speeds it up. Sustainable biochar systems can be carbon negative because they hold a substantial portion of the carbon in soil … (International Biochar Institute)

Biochar has been fulsomely characterized by climate activist Bill McKibben as “the key to the New Carbon Economy,” and received prominent coverage in the Working Group III report of the IPCC’s Fifth Assessment Report as one of the technologies that could effectuate negative emissions scenarios that might be critical to avoiding the passing of critical temperature thresholds.  However, an article by Melissa Leach, James Fairhead and James Fraser in 2012 in the Journal of Peasant Studies (subscription required) sounds a cautionary note in terms of potential implications of a full-scale commitment to biochar for farmers, with a focus on Africa. It would be an excellent reading in a module on climate geoengineering, or one discussing equity and human rights issues associated with climate policy responses.

Among the conclusions of the article:

  1. Analyses that contemplate large draw downs of carbon from biochar (e.g. one study projecting a potential sink of 5.5-9.5 GtC/year by 2100) “suppose an enormous growth in the resources and land areas devoted to the production of biochar feedstocks . . .” Some advocates have proposed dedicating somewhere between 200 million-1 billion hectares of forests, savannah and croplands to biochar projects. Such opponents have invoked the specter of large-scale “land grabbing” that they contend could threaten agricultural, pastoralist, collecting and other livelihoods;
  2. Foreign deals for biochar feedstock land could ultimately result in competition between biofuels and biochar projects;
  3. While some have argued that small farmers in developing countries could develop a substantial new income stream from sequestering carbon in biochar systems, many proponents of biochar as a climate solution are advocating development of new technologies to produce “clean char” that are different than indigenous practices in this context. Moreover, in contrast to REDD+, very little attention has been devoted to ascertaining how farmers could financially benefit from biochar projects;
  4. “The logic of the market” is likely to gravitate against small-scale projects that conducive to local priorities and livelihoods;” the need for verification and standardization protocols are likely to lead to large-scale industrialized biochar projects.

In contrast to the rather dry rendition of the potential socio-economic threats posed by biochar projects in the IPCC’s Fifth Assessment Report, this article is a stark reminder of how such projects pose the threat of exacerbation of existing inequalities associated with climate change.  Moreover, while some proponents of carbon dioxide removal approaches argue that they are more benign than solar radiation management approaches because they allegedly don’t threaten transboundary impacts, this article is a palpable reminder that this is not necessarily the case.