Numerous countries have fixed carbon neutrality as a policy goal, but according to new research by an international group of scientists from IIASA, Japan, and the United States, there are a number of risks related to the reduction of greenhouse gases, particularly in the forestry, agriculture, and land-use sectors, that need to be taken into consideration when developing mitigation policies.
While removing emissions from the energy industry is certainly a move in the right direction to attain the goals of the Paris Agreement, forestry, agriculture and other land use were responsible for 20-25% of greenhouse gas emissions worldwide in 2010.
According to the researchers, both the magnitude of baseline emissions and the effect on other Sustainable Development Goals when attempting to alleviate these emissions means that this sector cannot be overlooked in the framework of meeting ambitious long-term climate change mitigation goals. Details of the study have been published in Nature Food.
The strategies required to decarbonize the forestry, agriculture and other land-use sectors, however, may cause food prices to rise, which may have a potentially negative effect on food security. The researchers propose three key reasons for this. The first of these is increased costs related to methane and nitrous oxide reduction.
Secondly, existing decarbonization strategies could cause an escalation of competition for land owing to the expansion of bioenergy crops; and lastly, they could result in a higher value being put on forest carbon to sequester more carbon and stop large-scale plantations and bioenergy crops from intruding on forestland.
Although these factors are believed to impact agricultural markets through various mechanisms, it is still ambiguous to what extent they could influence future agricultural prices and food security.
Previous studies have pointed out that decarbonization strategies in the agriculture and land use sectors could lead to higher food prices and potential negative impacts on food security, but it has not been clear which of the three main factors would have the greatest impact. In this study, we used six global agricultural economic models to show the extent to which these three factors would change the agricultural market and food security situation under a decarbonization scenario.
Shinichiro Fujimori, Study Lead Author and Guest Researcher, Energy, Climate, and Environment Program, IIASA
Taking into consideration only the socioeconomic conditions, such as economic level improvement and future population growth, the findings specify a population at risk of hunger in 2050 of approximately 420 million people.
If all three of the abovementioned greenhouse gas reduction actions for agriculture and land use are executed, the international food price will rise by nearly 27%. This would cause a decline in food consumption among the poor in developing nations, which would consecutively lead to a projected additional 120 million people at risk of hunger.
Of the above additional hunger risk, it was projected that around 50% would probably be because of large-scale afforestation, and 33% to increased costs of methane and nitrous oxide reduction, while 14% could be attributed to the expansion of bioenergy crops.
The study also projects that mass afforestation could be responsible for approximately 60% of the increase in global food prices, followed by the rise in the cost of methane and nitrous oxide reduction, which makes for approximately another 33%.
From a regional standpoint, the effect is not uniform, with methane and nitrous oxide reduction costs having a bigger effect in Asia, and mass afforestation having a bigger effect in Africa.
According to the researchers, this can be ascribed to the fact that methane emissions from rice cultivation make up for a large proportion of the breakdown of greenhouse gas emissions ascribable to the agricultural industry in Asia.
Traditionally, the expansion of bioenergy to achieve negative emissions has been discussed as a food security concern. However, it turns out that other factors are rather more significant, particularly in general equilibrium models.
Stefan Frank, Study Author and Researcher, Integrated Biosphere Futures Research Group, IIASA
The scientists warn that, since all emission reduction strategies in their study are expressed by supposing a uniform international carbon tax, the findings should be used with caution. For example, afforestation and forest protection are signified by supposing that carbon stocks in forests will be taxed by carbon taxes.
The model approximates that this would significantly increase the potential value of land, increase the cost of agricultural production and raise food prices. However, it needs to be examined if such a measure will even be taken.
On the other hand, earlier studies have pinpointed that bioenergy crops can eat away at forests on a large scale if the carbon stored in forests is not appropriately valued. It is also assumed that nitrous oxide and methane will be exposed to the same carbon taxes as carbon dioxide.
Unlike carbon dioxide from fossil fuels, it is not so easy to measure these emissions, so we need to be careful about generalizing our model assumptions. Similarly, the actual risk of hunger in response to agricultural price increases or mean food consumption decreases is difficult to elucidate due to the complex nature of hunger and poverty.
Petr Havlik, Study Co-Author and Leader of Integrated Biosphere Futures Research Group, IIASA
Having said that, the results of the study are significant in that they emphasize the complexity and challenges in the execution of decarbonization strategies in forestry management, agriculture and other land use from numerous angles.
This could be useful to ensure proper coordination in emissions reduction and agricultural market management strategies, as well as improved representation of land use and related greenhouse gas emissions in modeling.
Fujimori, S., et al. (2022) Land-based climate change mitigation measures can affect agricultural markets and food security. Nature Food . doi.org/10.1038/s43016-022-00464-4.