Global warming refers to the upward temperature trend across the entire Earth since the early 20th century, and most notably since the late 1970s, due to the increase in fossil fuel emissions since the industrial revolution. Climate change refers to a broad range of global phenomena created predominantly by burning fossil fuels, which add heat-trapping gases to Earth’s atmosphere.
Climate change threaten our food sustainability, because this phenomena have a major effect on our agriculture field. In addition, scientists can prognosticate about the changes that are likely to occur in agriculture if global climate change causes changes in temperatures and rainfall.
the frequency of rainfall events greater than 2 inches is increasing, leading to longer dry periods between rain events. Crop yields are likely affected by these changes to some extent already, but it is not clear if future changes will be catastrophic or not. For example, climate change is shifting wine grape harvests in France and Switzerland
These shifts were caused by changes in the connection between climate and harvest timing. While earlier harvests from 1600 to 1980 occurred in years with warmer and drier conditions during spring and summer, from 1981 to 2007 warming attributed to climate change resulted in earlier harvests even in years without drought. But, don’t worry Plants are surprisingly resilient, and can withstand a variety of conditions while still being productive. In addition, other factors such as location, soil fertility, crop varieties, and management practices will all affect future yields. There’s two side of everything. Temperatures increases that caused by climate change, can turn a cooler areas of the country to be more habitable for some of the main food crops, expanding the areas in which certain crops could be grown or moving their ranges north.
And the bad side is, In areas where crops are being grown in their warmest productive temperature ranges already, heat stress or increased disease could reduce yields. However, research on new crop varieties and technological advances could improve yields in spite of reductions due to temperature increases. If climate change reduces the global amount of arable land, however, total yields could still decrease. Rising temperature not only effecting crops. increased air temperatures will also cause more stress on livestock. Both humans and livestock are warm-blooded animals, so both are affected by increased heat and humidity. During stifling heat, livestock reproduction declines as well as their appetite. Decreased appetite will lengthen the time needed for the livestock to reach their target weight (most animals only eat about half of normal quantities when they are heat-stressed).
Extreme Weather Events
Some scientists believe that climate change will lead to more extreme weather events. Extreme weather events include heat waves, droughts, strong winds, and heavy rains. Droughts are damaging because of the long-term lack of water available to the plants. The next extreme weather is heat waves
Not only heat waves that treathen our agricultural goods Strong winds also can cause leaf and limb damage, as well as “sandblasting” of the soil against the foliage.Heavy rains that often result in flooding can also be detrimental to crops and to soil structure, not only that heavy rain can also erode topsoil from prime growing areas, resulting in irreversible habitat damage.
Weeds, Pests and Disease
Insect parasites, diseases and weeds could become more prolific as global warming progresses. New diseases may also emerge in the Southeast that were once considered to inhabit only tropical areas. It is expected that in cases of increased heat stress and humidity, most livestock will not be able to fight these diseases without the use of costly medicines.
Irrigation and Rainfall
Changes in climate may also impact the water availability and water needs for agriculture. If temperature increases and more sporadic rainfall events result from global warming, it is possible that irrigation needs could increase in the future. For example, rainfall in parts of the southeastern US states has increased about 10% over the past century. However, part of this increase may be due to changes in the frequency of tropical storms. Tropical storms usually result in rainfall events greater than 2 inches in a day which occur at irregular intervals; these are less useful in an agricultural sense than are rainfall events that occur more frequently, even with lower accumulations. Plants growing in a high carbon dioxide environment may have lower water needs. In addition, widespread increased humidity will slow transpiration, further reducing the need for water. However, these benefits will probably be overshadowed by the lack of available water due to increased droughts and heat waves. The crops will transpire more heavily than when under “normal” growing conditions, and would likely need more water to adjust to these climactic changes. In anticipation of these changes, plant breeders are currently working to develop new varieties of crops that are considered to be drought tolerant, and more adaptable to varying levels of temperature and moisture.While crops could be impacted by climate change, it is likely that farm animals would be even more susceptible to changes in the climate.
Carbon Dioxide Increase
Scientists are in agreement that the levels of atmospheric CO2 (carbon dioxide) have increased in recent years. Prior to the Industrial Revolution, they were measured at 280 parts per million by volume (ppmv); currently the levels are around 380 ppmv. These levels have been steadily increasing by 1.9 ppm yearly since the year 2000, largely as a result of fossil fuel burning. Carbon dioxide is critical to photosynthesis (and thus plant growth). Scientists agree that even small increases in carbon dioxide result in more plant growth. It is likely that higher levels of carbon dioxide will result in higher harvestable crop yields. However, this depends critically on the availability of sufficient water and nutrients necessary for plant growth. Some scientists believe that one drawback to this increased productivity will be crops with lower nutrient and protein levels. If true, this could have a significant, widespread impact on long-term human health if additional fertilizers were not incorporated into crop production.
As indicated above, increased carbon dioxide may result in feed and forage that is less nutritious even if there is more of it. It is likely that growers would be forced to use feed additives in order to see the expected growth gains in livestock, and to avoid illnesses. This increased cost to the grower would result in increased food costs to the consumer. Availability could also decrease if there is not enough water and nutrients in stressed soils to keep up with plant growth.
Insect parasites and diseases could also become more prolific as global warming progresses. New diseases may also emerge in the Southeast that were once considered to inhabit only tropical areas. It is expected that in cases of increased heat stress and humidity, most livestock will not be able to fight these diseases without the use of costly medicines.
Source : http://climate.ncsu.edu/edu/k12/ClimateChange-Ag