Our Crops are Changing
Temperature
It’s getting warmer, but some changes in temperatures are surprising. Nighttime temperatures have increased faster than daytime temperatures, and this affects crops. For example, rice yields decline with higher nighttime temperatures.
Scientists expect heat waves to intensify, occur more often, and last longer in the coming decades. In fact, experts think high temperature stress will slash global corn, spring wheat, and soybean yields late in the century.
Because winters are warmer, farmers can now grow crops further north than previously. An additional shift of 13.3 miles is expected per decade, with huge implications for producing, transporting, and processing many major crops.
Another surprise: winter temperatures have increased twice as fast as summer temperatures, which means fruit and nut trees won’t experience enough winter chill. Without this chill, yields can drop dramatically. Warming winters do not bode well for California, and researchers predict it will become marginal for walnuts, peaches, and other important crops by the end of the century.
Warming Oceans
The oceans are also warming and becoming more stratified (layered), which prevents the upwelling of nutrients from the depths that are needed by tiny floating plants known as phytoplankton. These exquisite creatures produce over half the oxygen on which we depend, absorb carbon dioxide, and form the basis for the ocean’s food chain, from little fish to the larger fish that we eat. In some areas, phytoplankton have declined 20%.
Photo Credit:
Water
Warming conditions are causing glaciers to retreat worldwide, and with them the meltwaters needed to irrigated crops. Countries such as Peru and Chile, which provide $5 billion worth of agricultural products for the United States each year, will likely not have these meltwaters in a few decades. The situation in the Himalaya Mountains is similar but on a vast scale—potentially affecting millions of people who depend on meltwaters to grow their food. To stay current on the melting of ice worldwide see the National Snow and Ice Data Center.
Air
Carbon dioxide levels in the atmosphere have increased over 40%, which should be a boon to agriculture because most plants benefit from this increase. However, experts believe that the intensifying extremes in weather will offset most benefits from higher carbon dioxide levels. Unfortunately, weeds, like other plants, also benefit from the increase and plant-feeding insects may eat more under higher levels of carbon dioxide in the future.
Soil
Soil deserves respect. A healthy soil functions as a vital living system that sustains plants, animals, and humans. It is the most biologically diverse part of the planet. The soil—the skin on the planet’s surface—is essential for life on earth.
Soil is a medium for plant growth, a source of nutrients, and a water purifier and reservoir. It also plays a huge role in modifying the earth’s atmosphere—80% of all the carbon in terrestrial systems is found in the soil. The organic matter in the soil, called humus, holds (sequesters) that carbon for a long time. Soils with higher organic matter absorb more rainwater and hold that moisture better between rains, which may be beneficial as droughts increase.
Globally, soil is changing as huge swaths of forest—more than half a million square miles between 1990 and 2016—are being cleared. When land is cleared or repeatedly cultivated without organic matter being returned, the soil loses carbon; an estimated 1.4 billion tons of carbon are lost each year. Experts agree that soil is a major source of carbon dioxide but if managed well, also has potential to sequester enough to help address climate change.
Plants Are Affected
Temperature
It’s getting warmer, but some changes in temperatures are surprising. Nighttime temperatures have increased faster than daytime temperatures, and this affects crops. For example, rice yields decline with higher nighttime temperatures.
Scientists expect heat waves to intensify, occur more often, and last longer in the coming decades. In fact, experts think high temperature stress will slash global corn, spring wheat, and soybean yields late in the century.
Because winters are warmer, farmers can now grow crops further north than previously. An additional shift of 13.3 miles is expected per decade, with huge implications for producing, transporting, and processing many major crops.
Another surprise: winter temperatures have increased twice as fast as summer temperatures, which means fruit and nut trees won’t experience enough winter chill. Without this chill, yields can drop dramatically. Warming winters do not bode well for California, and researchers predict it will become marginal for walnuts, peaches, and other important crops by the end of the century.
Water Dwelling Creatures
The oceans are also warming and becoming more stratified (layered), which prevents the upwelling of nutrients from the depths that are needed by tiny floating plants known as phytoplankton. These exquisite creatures produce over half the oxygen on which we depend, absorb carbon dioxide, and form the basis for the ocean’s food chain, from little fish to the larger fish that we eat. In some areas, phytoplankton have declined 20%.
Photo Credit:
Water
Warming conditions are causing glaciers to retreat worldwide, and with them the meltwaters needed to irrigated crops. Countries such as Peru and Chile, which provide $5 billion worth of agricultural products for the United States each year, will likely not have these meltwaters in a few decades. The situation in the Himalaya Mountains is similar but on a vast scale—potentially affecting millions of people who depend on meltwaters to grow their food. To stay current on the melting of ice worldwide see the
Photo Credits: Before & After National Snow and Ice Data Center
Air
Carbon dioxide levels in the atmosphere have increased over 40%, which should be a boon to agriculture because most plants benefit from this increase. However, experts believe that the intensifying extremes in weather will offset most benefits from higher carbon dioxide levels. Unfortunately, weeds, like other plants, also benefit from the increase and plant-feeding insects may eat more under higher levels of carbon dioxide in the future.
Soil
Soil deserves respect. A healthy soil functions as a vital living system that sustains plants, animals, and humans. It is the most biologically diverse part of the planet. The soil—the skin on the planet’s surface—is essential for life on earth.
Soil is a medium for plant growth, a source of nutrients, and a water purifier and reservoir. It also plays a huge role in modifying the earth’s atmosphere—80% of all the carbon in terrestrial systems is found in the soil. The organic matter in the soil, called humus, holds (sequesters) that carbon for a long time. Soils with higher organic matter absorb more rainwater and hold that moisture better between rains, which may be beneficial as droughts increase.
Globally, soil is changing as huge swaths of forest—more than half a million square miles between 1990 and 2016—are being cleared. When land is cleared or repeatedly cultivated without organic matter being returned, the soil loses carbon; an estimated 1.4 billion tons of carbon are lost each year. Experts agree that soil is a major source of carbon dioxide but if managed well, also has potential to sequester enough to help address climate change.