I have done quite a bit of research on climate change and its impacts on Iowa agriculture in the past couple of weeks. This post is to summarize what I have learned, discovered, and still have questions about.
The information sources I used were unanimous in a few things, including the fact that our climate naturally changes over time, humans (urban and rural) are speeding up the climate change process, and the effects that climate change will have on our beloved Earth are detrimental.
According to the National Academy of Sciences, “it is unequivocal that the climate is changing, and it is very likely that this is prominently caused by increased human interferences with the atmosphere. These changes will transform the environmental conditions on Earth unless counter-measures are taken. Our present energy course is not sustainable.” Scientists have identified the culprit as emissions of carbon dioxide (CO2), nitrous oxides (N2O), methane (CH4), and other “greenhouse gases” that build up in the atmosphere, and trap more of the sun’s energy close to the Earth’s surface. So, human activity is moving these elements around from “sinks” to other forms, all of which are building up in the atmosphere and causing this warming effect on our planet. A sink is a reservoir that takes up a chemical element or compound from another part of its natural cycle.
Effects on our planet:
The direct effects of climate change will be heat stress, flooding, drought, late spring freezes, which will be multiplied by changes in pests and disease prevalence, increased competition from non-native species, ecosystem disturbances, land-use change, landscape fragmentation, atmospheric pollutants, and economic shocks such as crop failures or reduced yields due to extreme weather events. According to the Intergovernmental Panel of Climate Change, if we did nothing to curb our emissions of greenhouse gases, we would get an approximately one meter rise in sea level by 2100. While the Earth has experienced fast rates of sea-level rise before, humans have never had to experience such rapid rates of sea-level rise.
The indirect effects are somewhat of a mystery at this point, but we do know that there will be alterations of our ecosystems and socioeconomic patterns and processes in ways that most people in the region would consider detrimental.
According to the National Climate Assessment, from 1900-2010, Midwest average air temperatures rose more than 1.5°F. Within that time period, from 1950-2010, average air temperatures rose twice as quickly and from 1980-2010, average air temperatures rose three-times as quickly. With the increase in temperatures, the growing season has lengthened by almost 2 weeks since 1950. Exposure to extreme temperature events during the critical pollination (reproduction) phase can be particularly detrimental to corn yields because pollen doesn’t survive well in extremely hot conditions. The fewer pollen grains that survive and complete fertilization, the few number of kernels per ear of corn.
Extreme Weather Events
A recent study done by scientists at Purdue University and Stanford suggests that corn prices in the U.S. will become extremely volatile in the near term because of more frequent severe heat conditions. The volatility of U.S. corn prices is more sensitive to near-term climate change than to energy policy influences or the use of agricultural products for energy production (ex. Biofuels). This will, in turn, translate to fluctuating prices on store shelves. So, while policies set a minimum amount of corn-based biofuels for the national fuel supply affects the prices of corn, climate change will be upping the odds for years with low yields due to extreme weather events.
While scientists cannot attribute any single storm to climate change, more heavy precipitation can be attributed to climate change that has already occurred over the past 50 years. Precipitation is more likely to come in the form of heavy rains, which could be damaging to crops and soil.
Upcoming seasons of winter, spring, and fall will be wetter, but summers will be drier. Global climate models project that the average winter and spring precipitation will increase 10-20% relative to 1971-2000, while summer and fall are not expected to be larger than natural fluctuations. The average number of days without precipitation is going to increase, which could lead to short-term agricultural droughts throughout the summer, which will suppress crop yields.
A wetter spring and fall season will bring flash flooding or flooding problems to the Midwest. Flooding affects the integrity and diversity of aquatic ecosystems. It also causes yields to potentially be severely reduced, depending on what time of the growing season the flooding occurs. Flooding causes runoff to occur, which results in soil erosion and diminished soil moisture. According to CGIAR (a research program on climate change, agriculture, and food security), there is a potential for flooding to impact the spread and incidence of malaria, cholera, and dengue fever. This is a serious health threat for millions of people. Along with the human/animal disease increase and costly damage to cities and infrastructure, flooding will increase the pests and weeds that cause stress and disease in crops like corn and soybeans.
Effects on Midwest Agriculture:
Agriculture dominates the land use in the U.S. Midwest. Using over 2/3 of the land in the Midwest, row crop production here accounts for 65% of the total U.S. corn and soybean production.
What does climate change mean for future production? According to my research, the climate change effects on corn in the future have varying predictions. Some research indicates that the corn will thrive on the increase in CO2 available in the atmosphere, increasing our corn yields. Other research indicates that even with the increase in CO2, the increase in average temperatures will shorten the duration of reproduction development stage, as well as the increase in extreme weather events, will have a negative impact on the corn yields.
According to the National Climate Assessment, soybeans yields will have a 66% chance of increasing early in the century due to CO2 fertilization, but will be offset later by the stress of higher temperatures.
There will be an increase of stressors on both corn and soybeans. Wetter springs will cause flooding and runoff; drier summers will cause an increase in short-term drought periods; flooding brings new pests, weeds, and diseases to the crops. There will be potential for decrease in crop yields related to the weather that comes with climate change.
Overall, future crop yields will be strongly influenced by anomalous weather events rather than by average temperatures or annual precipitation.
Agriculture is responsible for about 8% of U.S. heat-trapping gas emissions, and there is tremendous potential for farming practices to reduce emissions or store more carbon in the soil. Techniques like planting cover crops, perennials, and no-till soil management can further increase CO2 uptake in the soil (example of a “sink) and reduce energy use.
There are also many non-agricultural ways to reduce your impact on climate change. Reducing energy use or switching to a green energy source is another way to decrease your “carbon footprint.”
AGRICULTURE. (n.d.). Retrieved April 04, 2016, from http://www.climate.org/topics/agriculture.html
CCAFS: CGIAR research program on Climate Change, Agriculture and Food Security. (n.d.). Retrieved April 04, 2016, from https://ccafs.cgiar.org/
Climate Models. (n.d.). Retrieved April 04, 2016, from https://www.wmo.int/pages/themes/climate/climate_models.php
FAQ 5.1 Is Sea Level Rising?. (n.d.). Retrieved April 04, 2016, from https://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-5-1.html
Midwest. (n.d.). Retrieved April 04, 2016, from https://www3.epa.gov/climatechange/impacts/midwest.html
National Climate Assessment. (n.d.). Retrieved April 04, 2016, from http://nca2014.globalchange.gov/report/regions/Midwest
Shaping our food – an overview of crop and livestock breeding. Edited by A. Lehrman. Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden. Published in 2014, pp. 176. ISBN 978- 91-637-5757-0 Available at http://tr.anpdm.com/track? t=c&mid=11856281&uid=603295709&&&http://www.slu.se/shapin gourfood/en. (2014). Animal Genetic Resources/Ressources Génétiques Animales/Recursos Genetics Animales Anim. Genet. Resour., 55, 143. Retrieved from http://www.nasonline.org/about- nas/leadership/president/academies-statement-on- energy.pdf
Sources & Sinks – The Environmental Literacy Council. (n.d.). Retrieved March 20, 2016, from http://enviroliteracy.org/air-climate-weather/climate