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According to new research, relying heavily on land to combat climate change could slow down the decline of global hunger. Nature Food.
Researchers examine how three different types of land-based mitigation strategies – tree planting, growing bioenergy crops and reducing non-CO2 agricultural emissions – could affect prices of agricultural commodities in the coming decades. The researchers then calculated how many people could be affected by rising food prices.
Although global hunger is projected to continue to decline, they find that all three mitigation methods have the potential to increase the global population at risk of hunger, compared to a baseline scenario matching the world’s current trajectory. The study suggests that more than 40 million people could be at risk from widespread tree-planting policies.
One researcher, however, points out that the model doesn’t account for the potential effects of climate changes on future food security. Climate variability and extremes are already a significant contributor to food security. Global food insecurity is increasing.
The lead author of the study stresses that their model is “quite simplified”, but notes that the findings suggest caution and thoughtfulness in how mitigation strategies are implemented.
Mitigation methods
The agriculture, forestry and land-use sector is a major component of humanity’s greenhouse gas emissions. For example, food systems – a term which encompasses the production, processing, transportation and consumption of food – are About one-third of annual greenhouse gas emissions are believed to be caused by them.
However, many climate mitigation measures require significant land use. This can increase agriculturally productive land competition and drive up farmer costs. Many types of climate change mitigation measures require significant land use. Nature-based solutionsTo combat climate change, ecosystems must be preserved from human use or restored to their natural state.
Three land-based mitigation strategies are the focus of the researchers’ research: afforestation, bioenergy crops and cutting non-CO2 greenhouse gas emissions – such as methaneAnd Nitrous oxides. They use a mitigation strategy that is consistent with RCP2.6 – an emissions scenario in which global warming stays below 2C above pre-industrial levels.
Afforestation – or tree-planting – has been a key component of many countries’ plans to reach “net-zero” emissions by mid-century, but will require large amounts of land in order to sequester carbon – By 2050, there will be around 1 million hectares of land in the UK alone. In the study, afforestation is represented by imposing a carbon tax on carbon stored within forests.
Planting bioenergy crops will directly challenge agriculture for productive land, just like afforestation. But bioenergy, in particular, is an important part of the overall picture. Combination with carbon capture, storage(BECCS) is often referred to as A key pathway to decarbonisation. The study calculates the bioenergy requirement of decarbonisation.
Non-CO2 emissions can directly impact food price by increasing production costs, if new technologies have been adopted. Carbon pricing schemes can also drive up food prices since carbon emissions from agriculture can be reduced. It cannot be eliminated completely. These are included in the study as a tax for non-CO2 emissions.
Output and emissions
Six agroeconomic models were used to create the following: Integrated assessment models(IAMs), where researchers analyze how combined mitigation actions will affect agricultural output, emissions, and the distribution of land use among agriculture, bioenergy, and afforestation.
Glossary
The models not only provide information on land-use distribution and agricultural output, but also provide a national agricultural price index and calorie intake per capita. These outputs are combined by the researchers to create a model that calculates how much of a population is at risk of starvation in any given year.
By “turning off” each mitigation method in turn, the researchers also determine how much of an influence each individual strategy has on the final result.
Global hunger has been The past five decades have seen a general decline in the number of people who own homes.. It has been increasing in recent years partly due to the Covid-19 epidemic, but it is expected to continue to decrease in the coming decades as per-capita global income continues to rise.
However, the study finds that if these land-based mitigation policies were implemented, hunger would decline less than it is currently projected to under a baseline scenario matching the world’s current trajectory – putting an extra 79.4 million people at risk of hunger in the year 2050.
The majority of this risk – 41.9 million people – is due to the knock-on effects of afforestation, with 26.7 million people at increased risk due to non-CO2 abatement measures and 10.8 million people due to increased bioenergy production. The price increases resulting from each mitigation measure are also modeled by the researchers. They found increases of 17.2% due to afforestation and 7.8% due to non-CO2 abatement. And 1.4% from bioenergy generation.
The following charts show how combined mitigation strategies will affect calorie availability, at risk population and agricultural prices. They are also compared to a baseline policy (top row), and how each policy affects these three quantities (bottom). The blue lines represent the full mitigation strategy. The pink lines depict the baseline scenario. The lower panels show the contribution to afforestation, bioenergy production, and the tax on non-CO2 emissions.
Bioenergy and Afforestation compete with each other for suitable land. However, afforestation has a greater impact on future food prices and calorie availability. Dr Shinichiro Fujimori, an environmental engineer at MIT and a climate scientist at. Kyoto UniversityCarbon Brief:
“I was really shocked by the result.”
Fujimori, the lead of the new work, stated that he initially thought BECCS would be a major driver of declining food safety. It had the least impact of the three mitigation strategies they studied. He says this could be because of the different mechanisms through which afforestation, BECCS and prices in their models. Carbon pricing is responsible for the afforestation effects. It incentivizes tree planting and raises land rents. However, bioenergy is driven by energy demand. This is limited by population growth as well as societal development.
Addressing the impacts of mitigation approaches on food security is a “very unique” approach, says Dr Luis Peña-LévanoAn agricultural economist at The University of Wisconsin River Falls. He says that previous work in this field had focused on the effects of mitigation on agricultural markets but not taken the extra step to analyze how these changes will impact hunger.
Peña-Lévano, who was not involved in the study, tells Carbon Brief that the study is “very holistic” in trying to understand the interplay between the agroeconomic models and models of food security.
‘Careful interpretation’ required
Researchers were also able to use the IAMs to determine how climate change mitigation efforts might affect specific regions or countries.
Sub-Saharan Africa is expected to experience an increase in hunger risk up to 2030, even in the baseline scenario. Land-based mitigation would have the greatest impact on this region. Researchers found that the mitigation measures would increase the risk of hunger in the region by more than 35 millions people by 2050.
The three studied mitigation measures have different effects on agricultural prices around the world. This is due to differences in diet, food supply, land rent, and other factors. Asia is known for its high intake of a variety. Higher rice contentThere are more people in these regions than in other areas. Rice production is associated with high levels of methane emissions. Therefore, taxation on non-CO2 emissions would be more detrimental to rice-producing countries than it would in other regions.
The following charts show how the potential for hunger would change in response to climate mitigation strategies. Each strategy would also have an impact on the country’s vulnerability to hunger.
The top panels display a comparison between the baseline scenario (pink), as well as the full mitigation scenario (blue), for 2010-50. The middle panel displays the number of people at high risk in different regions by 2050. The lower panels link the changes in agricultural prices and at-risk people to afforestation (pink), non-CO2 taxes (blue) and bioenergy (green).
The researchers also compared the results in three different scenarios. Shared socioeconomic pathways(SSPs), which are a description of different ways that societies and economies could evolve over the course of a century.
The bulk of the study focuses on SSP2, the “middle of the road” scenario. They also considered SSP1, which has low global populations growth and high economic growth, and SSP3, with high population growth but low economic development.
SSP1’s higher economic growth means that baseline hunger falls faster than SSP2’s; however, SSP3 simulations show that baseline hunger will remain relatively constant until 2050. SSP1 projects an increase in the number of people at high risk of hunger by midcentury by 61.1 millions compared to the baseline. SSP3 predicts this number to rise to nearly 360 million.
The three SSPs examined show similar trends in terms the which measures would have a greatest impact on food prices and caloric intake. Afforestation is followed by taxes on non CO2 emissions with bioenergy production coming in a distant third.
Overall, the results of the study are “both consistent with the literature and are very logical”, Peña-Lévano says. However, he adds, “they did not take into account climate change impacts on the system” – for example, how unmitigated climate change will impact future crop yields. Numerous studies have shown the impact of climate change on crop yields. Impact suitable areas for growing, Increase the danger of plant diseases, Degrade cropland qualityAnd Food insecurity increases.
In Similar research that Peña-Lévano has carried out looking specifically at mitigation by afforestation strategies, implementing climate change impacts into the models causes major shifts in the viability of the strategy, he says. Once climate-related food price shocks – such as those caused by extreme weather events – were incorporated into Peña-Lévano’s model, it was no longer economically or socially viable to dedicate so much land to afforestation, he says.
Fujimori believes that they are justified in excluding climate change impacts. Fujimori and his colleagues published a 2018 paper in which they discussed the topic. Nature Climate ChangeThey found that the effects of climate change on crops was much less than the mitigation effects under RCP2.6. He also says that they were able better assess the effects of individual mitigation measures after taking into account climate change impacts.
The authors stress that the relationships between hunger and poverty are “complex”, and thus it is difficult to determine exactly how changes in agricultural prices will affect global hunger. They note that their results “require careful interpretation” but say that it is worth considering how mitigation measures might impact food security.
Fujimori tells Carbon Brief:
“How we represent the climate change mitigation actions is quite simplified in our modelling exercise. Therefore, I would not like the readers of my paper to interpret this study as ‘we shouldn’t do climate actions in agriculture or in land-use sectors’. Definitely, those sectors are important…However, we need to be very careful in how we implement the climate mitigation measures in those areas.”
People “do not like to see the adverse side effects of climate change mitigation”, Fujimori says. Carbon Brief is told by Fujimori:
“There are many, many studies supporting climate action. Climate change impacts will be large and mitigation will definitely be needed.”
However, he adds, it is important to give “careful consideration” to the ways that mitigation measures, too, can impact vulnerable populations.
Fujimori, S. et al. (2022). Land-based climate change mitigation strategies can affect agricultural markets, food security, Nature Food. doi. 10.1038/s43016-022-00464-4.
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