Warming's Global effect on Agriculture
By Briana Bowers and Alena Courtney
Global Warming
The graph on the right shows that the global average surface temperature is increasing as well as the global average sea level while the northern hemisphere snow cover is melting. This gives proof that global warming is occurring which greatly impacts agriculture.
Notes
By seeing these graphs it shows that global warming is taking place. As you can see on the top graph there has been a significant rise in global surface temperature relative to the last hundred years. The middle graph represents the increase of global average sea level. According to the graph there has been a steady increase. The bottom graph shows the northern hemisphere's snow cover has recently been melting at a faster rate than we have ever seen before. SOURCES: IPCC, "IPCC FOURTH ASSESSMENT REPORT, CLIMATE CHANGE 2007 (AR4) ." IPCC AR4 Synthesis Report chapter 12007 20 Feb 2009 <http://www.ipcc.ch/graphics/graphics/syr/fig1-1.jpg>.
Impacts of Increased Temperature
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Many believe that global warming could be positive for agriculture due to the fact that carbon dioxide plays an important role in photosynthesis and prevents photorespiration; which can destroy many important types of crops. However, an overall increase in temperature would result in longer droughts and higher levels of ground level ozone gases, which would most likely cause a great decrease of crop yields in the future. A surface temperature increase would most likely benefit agriculture in areas such as America and Siberia. An increased temperature would reduced yield of wheat, rice, maize, and soybeans in the tropics and subtropics. These crops are their main source of nutrition. There would also be an increase in water stress and a reduced amount of nutritional content in crops. In Iceland an increased temperature has allowed for an increased sowing and barley .
NOTES
The previous picture shows that there has been an increase in temperature in the last 50 years. We are showing that it is true that there has been an increase in temperature and what some of the impacts are. Although there are some benefits due to the temperature increase the overall impact of the temperature increasing will not be good. Most areas that can't grow these crops are doing fine right now and will only benefit from the temperature increase. But in the areas that will not be able to grow their crops like usual they will suffer resulting in loss of food, income, nutrition etc. SOURCES: http://www.noaanews.noaa.gov/stories2009/20090126_climate.html and The Independent, April 27, 2005, "Climate change poses threat to food supply, scientists say". IPCC, "IPCC FOURTH ASSESSMENT REPORT, CLIMATE CHANGE 2007 (AR4) ." IPCC AR4 Synthesis Report chapter 12007 20 Feb 2009 <http://www.ipcc.ch/graphics/graphics/syr/fig1-1.jpg
Decrease in Crop Yields
NOTES: Temperature increase and Decrease in Crop Yields
According to the graph there has been a significant decrease in wheat yields in Egypt and Mongolia. The graph also shows an overall decrease in Maize in Egypt, Romania, and the USA as well as a decrease in rice yields in Egypt and parts of temperate Asia. The overall message of the graph is that agriculture will be negatively affected. It is predicted that by 2090 the average temperature will be the same as the record hottest temperature In 2003. By the end of the 21st century the average temperature everywhere will be much hotter . The tropics and subtropics seasonal average will be warmer than the hottest record which will lead to desertification. In next 50 years this increased temperature will ultimately lead to -a decrease in grain -a filling decrease in spikelet fertility -an increase in water stress -an increase in respiration *this is important for all crops but especially for wheat, rice, maize, and soybeans. With an increased temperature there will be a reduced nutritional content, especially in third world countries, of approximately 10% per 1 degree C of warming. SOURCES: In class notes from Professor Wallace, lecture 01/28/2009. Graph: IPCC, "Climate change 2001 - Working group II - Impacts, adaptation, and vulnerability." Ranges of percentage changes in crop yields spanning selected climate change scenarios Working Group II2001 20 Feb 2009 <http://www.ipcc.ch/graphics/graphics/2001wg2/small/08.01.jpg>.
Agriculture Impacts Humans
800 million people are malnourished 95% of these people are in the tropic/subtropics Food insecure people are poor: they depend on agriculture for both food and income These people mostly eat rice, wheat, sugar cane, maize, nuts, casava, etc.
NOTES
As you can see the lack of agriculture (crops) will be devastating to humans (mostly in the tropics/ subtropics areas). From previous slides we know that crops have been decreasing because of global warming. The temperture in the tropics/subtropics will increase due to global warming which results in a decrease in agriculture. *This increase in temperature in the tropics/subtropics will decrease the agriculture in tropics/subtropics resulting in a lack of food and income to the people living in the tropics/subtropics. This is going to be devastating to this area and other areas like it.
Sources: In class notes from Professor Wallace, lecture 01/28/2009 IPCC, "IPCC FOURTH ASSESSMENT REPORT, CLIMATE CHANGE 2007 (AR4) ." IPCC AR4 Synthesis Report chapter 12007 20 Feb 2009 <http://www.ipcc.ch/graphics/graphics/syr/fig1-1.jpg
Precipitation Changes
The graph to the right shows an example of one of the drier areas in the world, southern Australia, becoming drier with less precipitation. Other wetter areas are experiencing an increase of rainfall.
Source of graph: http://www.nytimes.com/imagepages/2007/07/29/opinion/29weather3_CHART.ready.html
NOTES: Drought and Precipitation
Just like some areas are getting warmer there are areas that are...