By Farooq Baloch
Climate change, often referred to today as global warming, will have a tremendous impact on the economy as well as the environment. It will affect agriculture and water resources in Nebraska as well, said University of Nebraska-Lincoln scientist Don Wilhite.
Nebraska farmers have learned to operate in a climate that is highly variable. However, research conducted at the university will enhance the understanding and adaptability of the state's agriculture while also enhancing economic opportunities.
Wilhite, UNL professor and director of the School of Natural
Resources (SNR), said SNR researchers are working on largescale climate modeling to get a better picture of how climate change is going to affect Nebraska.
He said the outcomes of their research will hopefully provide for better forecasts, especially seasonal
forecasts, to help water managers and agricultural producers in terms of what crops to plant, and when.
Wilhite- who specializes in drought monitoring and mitigation, drought preparedness and other
areas related to climate variability and change- said the research about climate change can translate into economic opportunities for the U.S.
For example, he said, by reducing greenhouse gas emissions- one of the main contributors to global warming- there are opportunities to develop green technologies that can be exported and the U.S. can be a leader in this new economy.
Wilhite said climate change is a natural feature of the earth's climate as noted by warm periods and ice ages in the past- increases and reductions in earth's temperature over time. These fluctuations in the earth's climate are closely tied to changes in atmospheric concentrations of carbon dioxide. Global warming, he said, has been used more recently as a synonym for climate change, since humans are most likely causing a change in climate through the emission of greenhouse gases into the atmosphere. These greenhouse gases are naturally occurring but make up less than one percent of the volume of earth's atmosphere.
Wilhite said greenhouse gases, such as carbon dioxide, methane, and nitrous oxide trap heat in the atmosphere. The emission of these gases increases their concentration in the atmosphere, which increases the ability of the atmosphere to hold more heat, thus, upsetting the natural heat balance for the earth. "So we're retaining more of that heat for longer periods of time," Wilhite said. "If it wasn't for these greenhouse gases, the surface temperature of the earth would be about 55 or 60 degrees cooler than it is today," he added.
Sources of GlobalWarming
According to the global mean temperature records of the last 100 years, Wilhite said the largest portion of global warming is due to the increase of carbon dioxide in the atmosphere. He added that methane and nitrous oxide are also contributors.
"The main source of greenhouse gases is the burning of fossil fuels such as coal,
petroleum, and natural gas," he added.
Consequences of Global Warming
Wilhite said the world has experienced about 1.5-degree F to 1.8-degree F warming over the last 60 to 100 years. "While a few areas have experienced some cooling, most areas have experienced significant warming, especially in the middle and higher latitudes," he said. In addition to increasing temperatures, the amount and seasonal distribution of precipitation will be affected for most regions. "The combination of these changes in climate will have a profound effect on water supplies for many locations and our ability to adapt to these changes," he added.
Wilhite said that one of the other areas of expected change in climate is that the severity, frequency, and the duration of extreme climatic events, such as drought, floods, and heat waves, will likely increase.
Wilhite said increasing atmospheric temperatures causes the oceans to warm as well, thus, oceans are
expanding, resulting in rising sea levels. Sea levels are also increasing due to the melting of glaciers around the world. This rise in sea level is going to have a tremendous impact upon land development and on the environment, especially in coastal areas, he added.
For example, Wilhite said, coastal cities may need to build sea walls, at enormous costs, to try and protect from waters as they rise.
He explained that flooding of coastal areas will also affect salt (sea) water intrusion into the aquifer system. In some areas, aquifer water may become more saline and even undrinkable.
Impact on Nebraska Agriculture
"The length of the growing season in Nebraska is increasing because of the warming that we have experienced," Wilhite said. Changes in precipitation amount and distribution are also likely to occur. He added that farmers will have to adapt to changes in precipitation, in terms of the amount or the seasonal distribution within a year. Farmers need to be aware of these changes, which may be outside of the range of what they have experienced in the past.
Wilhite said a rise in temperatures causes a substantial increase in the evaporation and transpiration rate- that is, how much water plants will use. "That may affect the types of crops that we can grow in Nebraska."
He explained that the increasing evaporation rate may mean that the aquifers will get less recharge.
"If aquifer levels decline, there is less water to pump for irrigation that might affect the viability of agriculture in the future," Wilhite said, adding that farmers will likely need to adapt to these changes by altering the crops grown or by switching to more drought-resistant varieties as they become available. Farmers might need to grow other crops that can thrive in a drier climate where there is less water available through irrigation. "So all of these things may have tremendous impacts on agriculture down the road," he added.
"Nebraska farmers have adapted quite well to the natural climate variability that exists in Nebraska," Wilhite said, and added if the climate becomes more variable in the future,
farmers' ability to adapt to a far different climate may be very difficult.
He said one of the other concerns is that the warmer winters that have been experienced in Nebraska over the last decade or more is the impact it is having on the overwintering of insects and diseases that affect plants. "Insects are overwintering and then creating more problems for agriculture." he said.
The Role of Research
The scientists at the University of Nebraska-Lincoln are working on climate modeling. They are trying to understand how these changes in global climate will affect the Great Plains area.
"Researchers in SNR and UNL are trying to understand how the climate of our region will change in response to these changes in the concentrations of greenhouse gas emissions," Wilhite said. "Increasing our understanding of these changes will allow us to provide better information to farmers and others in climate-sensitive businesses," he added.
He said a more accurate, advance forecast about a growing season will help farmers and agricultural producers to make better decisions about the types of crops they should plant and when they should plant them.
Wilhite said the climate of the future may be much different than today's so researchers at UNL are also working to develop new crop varieties that will be adapted to a changed climate.
While the research can help farmers adapt to this changing climate, there is also a need to reduce the amount of warming in the future.
"We have to agree on some limitations on the amount of fossil fuels that we're burning," Wilhite said, "and we have to reduce the emissions of carbon dioxide and some of these other trace gases."
He said there is concern that if the U.S. puts a ceiling on carbon dioxide emissions, it will have a substantial reduction in America's economy.
Wilhite said in the U.S., the issue of climate change has become politicized. He added he would like to see more science-based decisions associated with the issue of climate change in the future.
"What I think our politicians are not considering is that by not doing anything, it's costing us a lot in terms of impact on our environment and the sustainability of our planet for future generations. We are conducting a global experiment with potentially dire consequences," he said.
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