Modeling the Future

2014 was a big year for climate change discussions with both the UN Climate Summit and the Lima Climate Change Conference. While not the ultimate focus of either of these conferences, talk of the effect of climate change on agricultural production was greatly highlighted. 2015 is gearing up for another big year of climate change discussion, though related actions taken by governments are yet to be determined. Nevertheless, in March the Global Science Conference for Climate Smart Agriculture is taking place in France. The focus of this conference is evaluating which agricultural practices could potentially 1) mitigate climate change, 2) reduce food security, 3) and adapt agricultural systems to the effects of climate change. International organizations, scientists, and governments alike are taking this conference very seriously as it will provide the basis for policy recommendations related to agriculture at many high-level international meetings this year.

These meetings include the 3rd International Conference on Financing for Development (FfD) in July and the United Nations Framework Convention on Climate Change Conference of Parties (COP21) this December in Paris. The FfD meeting will focus on setting international agendas for the financing of development projects and is expected to especially highlight financing adaptation to climate change. COP21 is set to put actionable plans into place in regards to combating climate change, but will also have a strong focus on insuring food security through resilient agricultural systems globally.

These actionable plans are extremely important, as climate change is expected to cause major disruptions to food supply. In 2050, compared to 2010, rain fed wheat yields are expected to decrease by 1.4%, rain fed maize yields decrease by 2.9%, and rain fed rice yields decrease by 1.5% in developing countries under the National Center Atmospheric Research (NCAR) model. Irrigated rice in developing countries is expected to decrease by a staggering 18.5%. Of course, these projections are based on global circulation models (GCM’s) that depend on projections of future CO2 emissions. For example, these decreases in crop yields previously mentioned are under a business-as-usual basis, meaning that we as a global society do nothing to curb greenhouse gas concentrations in the atmosphere. However, if actionable plans are put into place at events such as the COP21, this could ultimately curtail the amount of greenhouse gases emitted into the atmosphere and thus change the impact on crop yields.

While this information is absolutely important for policy makers moving forward, where does it even come from? Do agricultural scientists simply make educated guesses for this information, or alternatively, is this information gleaned from historical records of some sort? The answer is actually very interesting. This information is derived using many different types of crop simulation models that interact with future climate predictions based on a single, multiple, or a suite of GCM’s.

Crop simulation models (CSM) are mathematical and/or statistical representations of agricultural phenomena. They begin with mathematically describing the most basic processes in plants through rigorous experimentation. This is then combined with mathematical descriptions of how these processes are affected by environmental conditions such as amount of soil nutrients, solar radiation, soil water, and planting density. Specifically for studies involving the impact of climate change, these models will include mathematical descriptions of the concentration of CO2 in the atmosphere, daily solar radiation, daily temperature, and daily precipitation amounts.

While these models are complex to develop, scientists have been developing and fine-tuning these crop models for decades. This has allowed the incorporation of all this information into user-friendly software that allows scientist and policymakers to use modeling without having to recreate the mathematical algorithms each time. Crop modeling has many applications ranging from scientific inquiry, to policy making, to actual farm management. They also allow for the evaluation of more than just crop yields. Various crop models can also determine the effect that agricultural practices will have on soil properties, erosion rates, and greenhouse gas emissions.

In regards to climate change, these crop models can be used in tandem with GCM’s to determine the effect that a changing climate will have on crop production. This can be done for a single field, a landscape, a country, a region, or even globally. Various research programs then use this information to determine which agricultural practices can be suitable in future climates and also compare the trade-offs between all practices potentially viable in the same area.

Climate change is strongly influencing many countries’ ability to remain food secure. The use of crop models is an essential aspect of identifying the best options currently available to move forward. However, it is still important to remember a great quote by an influential mathematician:

“Essentially, all models are wrong, but some are useful.” – George E.P. Box, Mathematician

It is easy to realize the usefulness of crop models, however, it is still important to approach discussions of the future impact of climate change with great precaution. Missing the mark on investments in agricultural adaptation could mean a more food insecure world. Nevertheless, 2015 will see much more discussion on the impact of climate change on agriculture. Many crop models have proved to be extremely useful in various projects and will contribute much to the discussions we will hear this year.

Image Credit: Robbiegiles via Wikimedia Commons


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