Climate change threatens future food security due to the probable increase in temperature and changes in precipitation patterns which could affect the distribution of where different crops may be viably grown [2, 3]. Land suitability and capability classifications are used to evaluate the best growing areas for specific crops and to identify factors that might limit their growth (FAO, 1976, 2007). Key factors in determining these classifications include fluctuations in moisture availability and temperature regimes. Land suitability and capability classifications for particular crops in a given region with or without irrigation need recalculating to take account of future climate change scenarios. In addition to such classifications that are based on the optimum growing conditions for a given crop, increased susceptibility to diseases from bacteria or fungal pathogens are limiting factors which need to be considered. Of particular importance in corn is infection by members of the Aspergillus section Flavi during the silking period and concomitant contamination of the cobs with AFs [4, 5, 6, 7].
AFs, especially aflatoxin B1 (AFB1) are class 1a carcinogens which cause liver cancer in humans and animals [8, 9, 10]. The key species responsible for AFs contamination in corn are Aspergillus flavus and sometimes A. parasiticus, which are able to colonize ripening cobs, especially via pest damage at 30–35°C during the milky ripe to dough ripeness stages of the kernels. This is especially prevalent when the corn plants are under drought stress [7, 11, 12, 13]. Thus, interacting climatic conditions in some years of higher than normal maximum temperatures and lower than normal rainfall represent conditions conducive to AFs contamination [1, 14]. Because of the extreme toxicity of AFB1 and AFs generally, many countries have strict legislative limits on the maximum permitted concentrations of these two categories of toxins in cereals and other foodstuffs for human or animal consumption [15, 16]. The United States Food and Drug Administration (FDA) has a limit of 20 ppb total AFs in corn, peanuts, cottonseed and other feed/feed ingredients intended for animal consumption, particularly for immature animals. The limit is higher (100 ppb) for use of corn and peanut products for beef cattle, pigs and mature poultry . The European Union (EU) generally has the strictest limits of permissible total aflatoxins in various foodstuffs with a maximum of 4–15 ppb [18, 19].
Thus, all batches of grain are sampled for AFs by taking numerous samples from throughout the batch, then mixing the grain and determining the ‘average’ AFs concentration of the batch based on one bulked sample . If the average contamination level of this one sample is above the legislative limits then the whole batch of grain is rejected. The impact of climate-related abiotic factors may result in more stress on corn production in a particular region thus increasing the potential for rejection impacting the viability of growing corn in a specific area.
Several studies of ripening corn and stored corn have investigated the impact of climate-related abiotic factors on AFs or AFB1 contamination [7, 20, 21, 22]. These suggest that elevated temperatures (+ 4–5°C above optimum), drought stress and exposure to increased CO2 levels (400 vs 1000 ppm) resulted in an increase in contamination with AFB1. Summer corn crops are very prone to AFs contamination in the Southern USA  due to high temperatures, rainfall variability, light textured soils and lack of irrigation infrastructure . All these factors compound crop water stress and subsequent remedial actions often do not alleviate the impacts on yield or contamination with these toxins. In Southern GA, the temperature and rainfall conditions in the critical month of June, which corresponds to the key mid-silk growth stage of corn growth, have been linked to the risk of AFs contamination [24, 25].
Kerry et al. developed a spatio-temporal model for estimating the risk of AFs exceeding the FDA legislative levels in corn crops in southern GA, based on a > 20-year county-level AFs survey. Based on their approach Navarro et al.  developed a decision support tool that could be useful to extension services to help determine the counties at greatest risk of AFs contamination during a given growing season. Information on the potential contamination risk in a given area could enable farmers to employ various management strategies before the season, during crop development and at harvest. Such strategies include (1) planting resistant varieties or varying seeding rates in high risk zones at the start of the season, (2) varying irrigation and fungicide applications during the season and (3) at harvest separating grain from zones with different contamination risk prior to storage . In addition, knowing the characteristics of years with different levels of risk could reduce spending on expensive aflatoxin testing surveys in low risk years and in individual counties. Kerry et al. found a strong relationship (r = 0.802) between the percentage of counties exceeding 2 weather risk factor thresholds (June rainfall (June RF) less than, and June average maximum temperatures (June TMax) greater than 30-year normals) and the percentage of counties with > 20 ppb AFS. This relationship was used to identify high and low risk years for toxin contamination for the 1977–2004 period.
Battilani et al. looked at the impacts of temperature changes of 2°C and 5°C on model simulated AFs contamination of maize in Europe but they did not investigate the combined probable impact of temperature and rainfall changes. Future climate projections (temperatures and rainfall) can be estimated based on the IPCC (Inter-governmental Panel on Climate Change) greenhouse gas models (IPCC, 2019): RCP 4.5 (Representative Concentration Pathway) is an intermediate emissions scenario and RCP 8.5 is a high emissions scenario. The IPCC climate change summary  suggests that under the RCP 4.5 scenario mean changes in mean global surface temperature compared with the 1986–2005 reference period would be 1.4°C and 1.8°C for the 2046–2065 and 2081–2100 periods, respectively. Under the RCP 8.5 scenario mean changes in mean global surface temperature compared with the 1986–2005 reference period would be 2.0°C and 3.7°C for the 2046–2065 and 2081–2100 periods, respectively. The range of temperature increases could, however, be as high as 4.8°C for the RCP 8.5 scenario . The RCP 4.5 and RCP 8.5 emissions scenarios were used to predict June TMax and June RF for each county in southern GA for 30-year periods from 2000 to 2100. The aim of this study was to explore how climate change abiotic factors could affect patterns of AFs risk, both spatially and temporally in southern GA, USA under the RCP 4.5 and RCP 8.5 scenarios compared to the 1977–2004 county level AFs and weather survey. The thresholds for June RF and June TMax developed by Kerry et al. to define high and low risk years and counties were used in this process. The purpose of this investigation of future AFs contamination risk was to help inform whether the location of zones where corn is grown in southern GA will need to be changed due to climate change or if management practices need to be adjusted to minimise the levels of these toxins in corn.