New Research in The Lancet Planetary Health – Part 1 – CO2 is more than just a greenhouse gas

It’s been an exciting couple of weeks, with the recent publication of a couple articles in the latest issue of The Lancet Planetary Health, so I thought I’d put together a couple blog posts about the articles.

The first, “Combining the effects of increased atmospheric carbon dioxide on protein, iron, and zinc availability and projected climate change on global diets: a modelling study“, is the product of more than a year of collaborative research across multiple institutions (IFPRI, Harvard, USDA, EPA, RTI, and CSIRO). In this study we tried to look at a wide range of climate change induced impacts on crop growth.

A lot of work that I’ve contributed to has looked at the impacts of shifting temperature and precipitation patterns on crop yields, and how changes in crop productivity can lead to changes in commodity prices, agricultural trade flows, consumer demand and food security. For example, Ignaciuk and Mason-D’Croz (2014), Nelson et al. (2014), and Wiebe et al. (2015) all of which focused primarily on assessing the impacts of changes in mean temperature and precipitation on crop productivity. In another recent study we looked at how changes in economic growth and climate change could impact the supply of nutrients. In this latest article, we tried to expand on this previous work to consider the role of atmospheric CO2 on crop growth and nutrient supply.

Changing CO2 concentration levels can have multiple effects on the environment, beyond its impact as a greenhouse gas. Varying levels of CO2 in the atmosphere has multiple effects on plant chemistry.

  • CO2 Fertilization CO2 is a critical input into plant photosynthesis, the biochemical process which plants use to convert sunlight into carbohydrates that serve as food for the plant, with Oxygen another key by-product. More CO2 (assuming there aren’t water and nutrient constraints), should lead to more photosynthesis, and more plant biomass. In theory, CO2 fertilization could help offset some of the negative yield impacts of changes in temperature and precipitation.
  • Shifting nutrient balance Greater availability of carbon can also change the nutrient balance in crops. More carbohydrates from photosynthesis dilutes the concentration of many micronutrients like iron and zinc. Changes in the carbon cycle can also impact the chemistry of building protein and vitamins, often contributing to a decline in the nutrient content of many crops.

Adding these additional impact pathways on crop productivity and nutritional quality, continues to show the climate change will have a negative impact on our food supply, not only by reducing crop yields, but also by reducing the nutritional quality of the foods we grow. Perversely, the regions most likely to be negatively impacted by these changes are also those regions least responsible for higher CO2 levels. These findings suggest that while we cannot ignore the productivity losses climate change may cause, the situation is more complicated than just a food supply (quantity) question. We need to also consider more broadly issues of food quality and nutrition.

New journal article in The Lancet: Global and regional health effects of future food production under climate change: a modelling study

Kind of crazy to think that I have had the opportunity to work on a project that got published in The Lancet. I knew the journal had extremely high visibility and impact, but intellectually knowing this and actually experiencing it are 2 different things. The journal article was released by Lancet last night and it is already getting major attention, with an article in the Guardian, an article on GIZMODO, and requests from several newspapers to talk about our findings.

While it took a lot of work and time to get the article through through the peer review process, it was a fun experience on the whole. It was great getting to collaborate with colleagues, such as Marco Springmann, at the University of Oxford to explore the effects of climate change on diets, and health. Hopefully, this is just the start of several future collaborations, which will allow us to explore the intersections of agriculture, trade, diet, and health. It is kind of crazy to think that this whole endeavor started almost 2 years ago when I met Marco in an IMPACT model training workshop I led in Cali, Colombia.

The abstract of the article is available for free at The Lancet:

Unfortunately, it looks like the full article requires a subscription to read. I am looking at what options we have for sharing the article. In the mean time, you can check out this blog post I made on the IFPRI Research blog summarizing some of the work, as well as the press release written by my colleagues at Oxford.

 

Weekly Development Links – March 15

Decided that the easiest way to summarize a bunch of the stuff that I read during the week is to start a weekly summary and review of some of the articles and papers I found interesting.

So on to the links:

  • Undernutrition: the invisible killer of 3 million children a year – A nice summary of many of the effects of malnutrition in children. There isn’t anything particularly new in the article. Nevertheless, I think it is important to keep highlighting the topic due to the enormous value to society of tackling and correcting child malnutrition.
  • 45-Year Trends in Women’s Use of Time and Household Management Energy Expenditure – Seemed to attract some controversy on the NY Times website, because people interpreted it as sexist and that the report was suggesting that women’s greater participation in the labor force was leading to their obesity. This is an incorrect interpretation. The report is the second part of an overall study looking at levels of activity today vs. 50 years ago. The first report looked primarily at office activity, which showed less physical activity today compared to 50 years. This second report was needed because women were underrepresented in the first report because of the lower level of labor participation by women 50 years ago. Therefore, this paper looked at the activity level of doing household chores 50 years ago as compared to doing the same chores today or activity in the office. The overall take away from both of these studies is that people are significantly less active today then they were 50 years ago, in large part due to greater automation and use of new technologies. Not sure what is controversial about this conclusion. It seems like it is a good first step in testing the anecdotal hypothesis of less physical activity contributing to increasing obesity in the U.S.A.
  • How USAID Could Score a Double-Win for Learning and Transparency – Greater sharing of data in development would be a huge plus. This article covers some excellent benefits that could be achieved by sharing the raw data of development interventions. Sarah Rose (author) points to improvements in transparency, and ensuring the quality of reported development results. However, Rose didn’t mention another major benefit, which is the power of cloud sourcing analysis. Development practitioners use their data for their own specific objectives. They collect all of their data usually with a very specific task in mind. However, all this information maybe very valuable for a wide array of other uses. By freely sharing it, who knows what independent data users and analysts might be able to make of data. There are undoubtedly thousands of interesting side-effects of development interventions that may be missed by the development agency. Or entirely new connections observable in the data that the data collectors may never have found.
  • Measuring impact: Keep it clear and simple – Article from Stanford Social Innovation Review. Makes the point of the importance of measurement in development. I do agree on the importance of measurement, I am not as much of a fan of  the KISS (keep it simple stupid) principle. Yes having clear objectives that we can measure progress toward is critical. However, I am less enthusiastic about focusing only on simple metrics. I am concerned only trying to influence things we can easily measure. Entire fields of development could be ignored, especially in areas like institution and political reform. Economic development isn’t easy. Communities are complex systems, looking for simple changes can encourage a sort of checklist mentality that implies development is just a long to-do list. We should instead be thinking about the complex interactions between people and institutions and the incentives that drive both. Certainly there can be simple changes that dramatically change systems, but we shouldn’t just get involved on easily measurable goals. This should instead encourage us to find ways to measure progress on more complex objectives. I have no doubts that simple goals make fund raising much easier, and that it is a lot easier to show that you are achieving your limited objectives. It is less clear if this would lead to overall better development outcomes if applied widely. While I am skeptical on simplicity in development, I wholeheartedly agree with one of the other points made in the article – the need to use longer term budgets in development. Far too many projects are designed around annual and biannual budgets. This isn’t realistic. Change takes time, we need to have development budgets that take this into account and allow for greater stability, such that development agencies can plan long term interventions with the necessary follow up with the knowledge that the funding will be there in the later stages of the project.