The growing ranges of our food supply will change as the temperatures rise.
“When climate change is added to population growth, only the extent of future food shortage is unknown.”
By Dr.John J. Hidore
August 3, 2014—In the early 21st Century global food production is able to meet the global demand. However, the availability of food varies greatly from place to place. Approximately 870 million people living on Earth today are facing food shortages. These shortages result in nearly 15% of the population being malnourished to some extent, with many facing health problems. In Africa, a third or more children under the age of five undergo growth stunting due to malnutrition. The most extreme health problem is, of course, starvation. It is clear that food production is not keeping up with demand regionally, if not globally.
The Impact of Temperature Changes
Changes in climate are now having a major impact on food production, and certainly will have in the future. The biggest factor in climate change is the rapid rise in global temperatures. For instance, the mean temperature for May and June of 2014 were globally the highest on record. Nearly every forecast of global temperature increases, issued in recent decades, has been an underestimate of what has actually occurred. Since the 2007, IPCC (Intergovernmental Panel on Climate Change) report, the new estimate has placed the range of temperature increase as much as 14 degrees F (8°C) by 2100. This increase in temperature will greatly affect life on our planet, including agricultural production.
This may be a rare picture at the supermarket in years to come.
The Decline of Crop Yields
Because most plants evolved during cooler conditions associated with the ice ages, many plants are now growing near the upper limit of their range. Crop yields start to decline when temperatures reach or exceed the optimal temperature range. This is the case in the tropics as well as mid-latitudes. If the temperatures continue to increase, the result will be major changes in the regional growth ranges causing some species to decline in numbers.
Presently, the warmer conditions are now reducing some grass lands to desert conditions, due to greater evaporation and transpiration. It is possible that in the 21st century warming will be sufficient to make many plants extinct. Changes in the plant species growing ranges may become great enough to make some ecosystems non-functional.
Extreme heat waves can devastate crops. In the year 2003 summer temperatures in Europe averaged more than 10°F above normal. In Italy, corn yields dropped 36% below average. In France, yields of fruit fell 25% and wine production fell 10%. Heat also affects the rate of plant pollination. A 3 degree Fahrenheit raise in temperature, in rice producing areas, would cut rice pollination in half. Rising temperatures also increase the frequency and extent of plant diseases and pests.
Water Related Stress of Agriculture
Rising temperatures will, also, result in greater water related stress in agriculture. Agriculture is now the largest user of water on a global basis. Crop production uses some 70 percent of fresh water on a global basis, and about 80 percent in the developing countries. Evaporation rates will increase and, inevitably, less of the global fresh water will be available for irrigation. Over a third of the global human population now lives in water stressed regions. The ratio of population living with water related stress may increase to 50% by 2100.
The transformation of ecosystems will, in all likelihood, result in massive human migrations with the resultant political and economic problems. The possibility of such changes occurring with further warming is very real. Depending on how rapidly warming occurs, the problems will occur sooner than currently anticipated.
The global population is now growing at a rate of about a quarter million each day. In all likelihood, this growth will continue for some time. Unless food production can increase fast enough to feed the additional growth, the number of people suffering from food shortages will increase. That climate change will take place in coming years, is certain. It should be apparent that it will be impossible to return the planet to the temperature it was in 1900 any time in the near future. When climate change is added to population growth, only the extent of future food shortage is unknown. The impact on food production will vary greatly depending on the degree of the climate change, the geographical extent of the change, and the duration of the change!