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Weather and climate have both short-term and long-term impacts on livestock development and management. This talk will focus on longer-term trends in climate and drought over time across the United States and the impacts of changes in these factors on animal agriculture. We will start by examining the trends in temperature and precipitation that have occurred over different regions of the US over the past century and how they have varied from one area to another. Then we will look at how future climate is predicted and problems in making useful predictions. We will follow that by looking at some of the most reliable predictions of future climate and discuss the potential impacts on livestock health, forage and feed supply, and farm management practices and the importance of resilience in farm practices. We will conclude by identifying both the challenges and the opportunities for future livestock producers in a changing climate. http://www.extension.org/pages/67615/impacts-of-a-changing-cimate-on-animal-agriculture
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A n i m a l A g r i c u l t u r e & C l i m a t e C h a n g eDeveloping National Extension Capacity to Address Issues Related to Animal Agriculture and Climate Change
Livestock And Poultry Environmental Learning Center
This project was supported by Agricultural and Food Research Initiative Competitive Grant No. 2011-67003-
30206 from the USDA National Institute of Food and Agriculture.
Impacts of a Changing Climate on Animal Agriculture
Pam Knox, University of GeorgiaAgricultural Climatologist
Outline
1. Trends in temperature and precipitation across the US
2. Predicting future climate: possibilities and problems
3. Most reliable predictions of future climate
4. Impacts of future climate on livestock and farm management
5. Challenges and opportunities for livestock farmers in the future
What is Climate?
Review of Present Climate Trends:
Regional Temperature Trends
Review of Present Climate Trends:US Temperature
http://www.ncdc.noaa.gov/cag/time-series/us
WA
CO
TX
NY
GA
Review of Present Climate Trends:Global Temperature
Review of Present Climate Trends:
Review of Present Climate Trends:Precipitation
WA
CO
NY
GA
TX
Seasonal Precipitation Trends
Review of Present Climate Trends:Global Precipitation
How to Predict Future Climate
• Continuation of present trends
• Oscillations
• General circulation model (GCM) uses energy balance to calculate future climate
How to Predict Climate
You can predict climate by predicting trends, but that depends on things continuing the same way they have in the past. Not always a good assumption!
Instead, climatologists use climate models to simulate the future climate based on physics and predictions of future CO2 and other emissions.
Climate 101: Energy Balance
Energy in – Energy out = Change in temperature
Energy in > Energy out Increasing temperature
Energy in > Energy out Decreasing temperature
Climate 101: Energy Balance
Climate Models
Increasing Model Complexity
Global Climate Models
A model has to have a way to account for all the process in the atmosphere-ocean system To use a computer, the information has to be divided into individual boxes or grids which are all connected.
Problems with Models
• Coarse resolution leaves out mountains, Great Lakes, alters local conditions like coastlines
• Simplification processes make rainfall less believable since most of it happens in sub-gridscale processes like thunderstorms
• They are not very good at predicting current climate, making them less believable
• No El Niño, hurricanes
Weather vs. Climate Models
Weather models are designed to predict detailed hourly weather information for up to 7 days across a continent.
Emphasis: short term, individual storm evolution
Climate models are designed to predict multi-year climate conditions across the entire globe.
Emphasis: long-term, seasonal to multi-year average climate conditions
Changes in Atmospheric Composition
Models can separate out CO2 Effects
Models can be used to separate out the effects of individual factors to see what effect each factor has on the temperature trend.
Scenario ModelingModelers use scenarios of various projections of changing CO2, changing energy efficiency, etc. to produce a series of graphs giving a range of expected outcomes.
Observations don’t always agree with predictions. So which is right?
Predicted Trends in Temperature
Across the United States, temperatures are predicted to increase over the next 100 years, but the amount of warming predicted depends on the particular model used.
http://www.usgcrp.gov/usgcrp/nacc/education/
http://www.usgcrp.gov/usgcrp/nacc/education/default.htm
Predicted Trends in Precipitation
http://www.usgcrp.gov/usgcrp/nacc/education/
Precipitation across the US is harder for the models to predict, and some models show increased precipitation while others show drying or no trend. Some datasets indicate that rainfall has become more intense with longer dry spells in between.
http://www.usgcrp.gov/usgcrp/nacc/education/default.htm
Projected Change in Precipitation over next 100 Years
Impacts of Changing Climate on Livestock and Poultry
• Warmer temperatures would increase growing degree days for forage and crops but also weeds and insect pests and diseases.
• Warmer temperatures, both daytime and nighttime, would increase heat stress on livestock and increase the need for and the costs of cooling.
• Warmer temperatures will decrease heating costs in winter.
Impacts of Changing Climate on Livestock and Poultry
• Warmer temperatures will increase evaporation from farm ponds, lakes and reservoirs, which could affect water availability and affect the ability to irrigate.
• Power generation from coal-burning and nuclear plants as well as hydropower from dams all depend on availability of water and power prices could be negatively affected by warmer temperatures.
Impacts of Changing Climate on Livestock and Poultry
• Uncertainty of rainfall predictions makes it hard to determine what to expect in the future, especially since there is already a lot of natural variability in rainfall patterns by location and season.
• Higher intensity rainfall will increase erosion and runoff from farm fields and could increase localized flash flooding in storms.
Impacts of Changing Climate on Livestock and Poultry
• Longer dry spells, coupled with warmer temperatures, will increase the likelihood of drought and will reduce average stream flows.
• Seasonal changes in precipitation could affect pollination and harvesting of cereal crops.
What does the Future Hold?
Challenges
• Warmer temperatures increase diseases and pests
• More stress on livestock• More potential for drought• More extremes• Market uncertainty• Economic costs of becoming
resilient (for example, irrigation or power sources)
• Changing tastes and demographics
Opportunities
• Population growth means potential for market growth
• Parts of the US will see increased growing season and more rainfall
• Other parts of the world will also undergo climate change, leading to expanded markets
• Smart management can improve budget while also taking advantage of market incentives
Livestock And Poultry Environmental Learning Center
For a full list of references cited in this presentation, please visit:
www.animalagclimatechange.org
This project was supported by Agricultural and Food Research Initiative Competitive Grant No. 2011-67003-
30206 from the USDA National Institute of Food and Agriculture.
Developing National Extension Capacity to Address Issues Related to Animal Agriculture and Climate Change
A n i m a l A g r i c u l t u r e & C l i m a t e C h a n g eDeveloping National Extension Capacity to Address Issues Related to Animal Agriculture and Climate Change
