Food and Greenhouse Gases: Climate change, agricultural production and food demand.

Post written by C.Will

Our recent blogs have been discussing food security, and the role agricultural production has to play in ensuring a sustainable future. Below are two recently published papers that incorporate the effects of climate change into this discussion.

“Climate change effects on agriculture: Economic responses to biophysical shocks”. By Nelson et al. 2013. Published in Proceedings of the National Academy of Sciences (PNAS).

Abstract:

“Agricultural production is sensitive to weather and thus directly affected by climate change. Plausible estimates of these climate change impacts require combined use of climate, crop, and economic models. Results from previous studies vary substantially due to differences in models, scenarios, and data. This paper is part of a collective effort to systematically integrate these three types of models. We focus on the economic component of the assessment, investigating how nine global economic models of agriculture represent endogenous responses to seven standardized climate change scenarios produced by two climate and five crop models. These responses include adjustments in yields, area, consumption, and international trade. We apply biophysical shocks derived from the Intergovernmental Panel on Climate Change’s representative concentration pathway with end-of-century radiative forcing of 8.5 W/m2. The mean biophysical yield effect with no incremental CO2 fertilization is a 17% reduction globally by 2050 relative to a scenario with unchanging climate. Endogenous economic responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce consumption by 3%. Agricultural production, cropland area, trade, and prices show the greatest degree of variability in response to climate change, and consumption the lowest. The sources of these differences include model structure and specification; in particular, model assumptions about ease of land use conversion, intensification, and trade. This study identifies where models disagree on the relative responses to climate shocks and highlights research activities needed to improve the representation of agricultural adaptation responses to climate change.”

“The future of food demand: understanding differences in global economic models”. By Valin et al. 2013. Published in Agricultural Economics.

Abstract:

“Understanding the capacity of agricultural systems to feed the world population under climate change requires projecting future food demand. This article reviews demand modeling approaches from 10 global economic models participating in the Agricultural Model Intercomparison and Improvement Project (AgMIP). We compare food demand projections in 2050 for various regions and agricultural products under harmonized scenarios of socioeconomic development, climate change, and bioenergy expansion. In the reference scenario (SSP2), food demand increases by 59–98% between 2005 and 2050, slightly higher than the most recent FAO projection of 54% from 2005/2007. The range of results is large, in particular for animal calories (between 61% and 144%), caused by differences in demand systems specifications, and in income and price elasticities. The results are more sensitive to socioeconomic assumptions than to climate change or bio-energy scenarios. When considering a world with higher population and lower economic growth (SSP3), consumption per capita drops on average by 9% for crops and 18% for livestock. The maximum effect of climate change on calorie availability is −6% at the global level, and the effect of bio-fuel production on calorie availability is even smaller.”

Food and Greenhouse Gases: Emissions Intensity of Nutrition Sources

Post written by C.Will

New research published in Nature Climate Change argues that reducing the number of ruminant livestock, especially cattle, could significantly reduce greenhouse gas (GHG) emissions.  They find the GHG emissions from ruminants are 19-48 times higher than emissions from high protein foods obtained from plants. This comparison is based on full life cycle analysis including both direct and indirect environmental effects from ‘farm to fork’ (enteric fermentation, manure, feed, fertilizer, processing, transportation and land-use change are considered).

This offers a compelling argument for significantly reducing our consumption of animal protein to reduce our GHG emissions. However, it is important to consider the nutritional differences between animal protein and high protein foods obtained from plants.

A previous blog of ours discussed studies that look into the debate about GHG emissions from animal protein products and the nutritional difference between animal protein and other high protein sources. To get a comparable amount of energy from fruit and vegetables, larger portions are needed because animal protein products are a rich source of energy. Therefore, when comparing animal protein products and fruit and vegetables on a measure of GHG emissions per unit of energy (in kilocalories), the difference is much smaller.

The problem is complicated and the solution is not clear, but it is important to understand that the food choices we make as individuals do have an impact on the environment. Together we can improve the food security problem by making better informed decisions about our consumption.

Food and Greenhouse Gases: An Ominous Future?

Post written by C. Will

In a world increasing in population and wealth, food production needs to be steadily increasing to meet the growing demand. However, a recent study in Nature Communications (discussed here) argues the rate of yield gains in wheat and rice production have plateaued, despite increased investment in R&D and education. Other studies (for example Ray et al. (2013)) have also found evidence that the current yield gain in major crops is insufficient to reach the estimated 60% increase in production required by 2050. If wheat and rice production have approached a yield ceiling it provides an ominous future for food security.

Previous increases in yield gain have been driven by investment in technologies that were largely one-time innovations and cannot be repeated. For example, innovations in genetically modified grains, major investment in irrigation infrastructure and increased use of fertilisers and pesticides saw steady increases in grain production.

Is livestock agriculture also at risk of approaching a yield ceiling?

New Zealand has experienced significant annual increases in livestock productivity for more than 20 years.  As we discussed in a previous post even with existing technology there is room for significant ongoing improvement as less efficient farmers catch up with those who are more efficient. In the short term, constraints on yield per hectare (intensity) are likely to be environmental (water quantity and quality) rather than technological (as noted by the Parliamentary Commissioner for the Environment’s report on water quality). Internationally, the enormous differences in livestock productivity suggested by differences in emissions per unit of output suggest space for considerable yield gains.  

Globally we need to be making all the efficiency gains that we can to resolve the food security problem and New Zealand has an important role to play in this through the livestock sector.

An Economist’s Perspective on Value

Post written by C. Will

Motu has just released a Note on “Value and Natural Capital: Examining the Economist’s Perspective” written by Josh Pemberton and Suzi Kerr. The paper considers what economics brings to a conversation about environmental value, and what the limits of its contribution might be.

Many of you will have experienced how different people can view the same problem or issue in various ways. With this in mind, this paper seeks to highlight and examine the assumptions and implicit goals that underpin the way in which economists think about value in general, and environmental value in particular. 

FAO Report

Post written by C. Will

New Zealand (NZ) has relatively low emissions per unit of dairy production. So can NZ farmers share the skills and technologies that allow such low emissions to help lower global greenhouse gas (GHG) emissions?

The Food and Agricultural Organization (FAO) released a report in 2010 that looked into GHG emissions from the global dairy sector. Although the report is from 2010, it has some interesting findings worth discussing. In particular, a comparison of GHG emissions per kg of Fat and Protein Corrected Milk (FPCM) across different regions (see graph below).

Source: Gerber, P., Vellinga, T., Opio, C., Henderson, B., & Steinfeld, H. (2010). Greenhouse Gas Emissions from the Dairy Sector, A Life Cycle Assessment. FAO Food and Agriculture Organisation of the United Nations. Animal Production and Health Division, Rome. Page 34.

FPCM is a way of comparing milk produced from different dairy animals on a common basis by equating the level of fat and protein in the milk. The graph highlights where milk production is the most GHG emissions intensive and therefore the least efficient. There is a clear trend showing developing regions (Africa and Asia) having higher emissions than more industrialized regions (Europe and North America). 

We have been told that NZ emissions are even lower than the rest of Oceania; approximately 0.9 per kg of FPCM. This gives an idea how efficient NZ farming is and supports a comment in a previous blog that touched on the difference in efficiency between NZ farmers and farming in Africa. 

Thin Ice

Post Written by C. Will

Thin Ice is a New Zealand created movie that follows Simon Lamb (Victoria University of Wellington) as he travels around the world meeting the scientists behind climate change. The film is intended to help people develop a better understanding of climate change. The film also gives an introduction to the most recent Intergovernmental Panel on Climate Change (IPCC) Assessment Report.

Livestock: The answer, not the problem?

Post written by C. Will

Seth Itzkan of Planet-TECH discusses how holistic management can restore grass lands and reverse the effects of climate change in his TEDx talk; “How global warming can be mitigated through holistic management”.

In the video, Seth discusses his experiences in Zimbabwe and how the village herders have changed the way they manage their livestock. Using holistic management, they have replenished grasslands and during the dry season surface water is occurring further upstream than before. Increased availability of surface water has made farming easier and removed the need for water pumps, saving money. Regenerating grasslands also increases soil sequestration, reducing the amount of carbon in the atmosphere.

Holistic management uses livestock in a way that mimics wild herds which were a key component in the ecosystem when grasslands thrived. The wild herds would graze, naturally process the grass, fertilise the ground and then move onto a new area. The villagers are now replicating this process by running livestock in dense packs and moving them regularly just as a wild herd would. They also stick to grazing plans to prevent over grazing.         

Although his focus is on environments that have suffered desertification (the transformation of habitable land to desert), parallels can be made between the framework of holistic management and the way farmers in New Zealand manage their stock. Relative to farmers in Africa though, New Zealand farmers have lower emissions per unit of production and are more efficient. However, even in New Zealand many farmers can apply management strategies other farmers are already using to reduce their environmental impact. A recent Motu working paper, looks at such mitigation possibilities.

Holistic management was a way of managing resources originally developed by Allan Savory. Here Allan offers further discussion on holistic management and “how to fight desertification and reverse climate change”.