Marty Strange
Senior Fellow
Center for Rural Affairs
Walthill, Nebraska
 

Before the
United States Senate
Committee on
Agriculture, Nutrition, and Forestry

March 5, 1998

My name is Marty Strange.  I am a Senior Fellow with the Center for Rural Affairs in Walthill, Nebraska.  I live and work in Randolph, Vermont. Thank you for the opportunity to share my views with the committee.

In 1992,  I led a Center for Rural Affairs staff study of agriculture’s contribution to greenhouse gas emissions and its potential role in reducing emissions and sequestering carbon in the soil. I’ve summarized this study in my written statement for the committee and appended a copy of it.  I respectfully request that this report be included in the hearing record.

With or without a Kyoto Treaty, with or without climate change due to greenhouse gas emissions, and with or without a commitment to do something about it, there are some measures that should be taken for the good of agriculture, soil, and society.  These are matters about which we have known a great deal for a long time, but have lacked sufficient will to really address.  If the mounting scientific evidence that human activity contributes to adverse climate change is powerful and persuasive enough to prompt action on these matters, we are all better off for it.  I hope that is the case.

In the long run, the element that matters most environmentally is probably carbon, the foundation of life itself.  Only a tiny proportion of the global carbon budget is involved in the flows that sustain life.  Ninety-nine percent of carbon is embedded in rock, in more or less stable form.  Of the remaining one percent that circulates through chemical and biological processes, most is also in relatively stable form deep in the ocean.  A much smaller proportion  (and falling fast) is stored in fossil fuels, and even tinier fragments are stored in the soil, mostly as organic matter. Even less is in the atmosphere, and less than that is in living plants and animals. But don’t let proportions mislead.  It is the balanced circulation among these last three pools – the soil, the air, and living things – totaling less than one-half of one percent of the earth’s carbon, that is critical to life. The largest environmental problem we face may well be the unbalancing reallocation of carbon from the soil, where it plays a crucial role in nutrient action, to the air, where at concentrated levels its critical role in the regulation of climate is altered.
 

 Farmers have a lot at stake in this issue.  They could be victims of the problem, or victims of the solution.  Either fate should be avoided, as a matter of policy.  But I want to focus especially on the brighter prospect that farmers can be big winners in a carefully crafted solution to the problem that has multiple benefits both for farmers and for the rest of society beyond that of mitigating climate change.
 
 
 

How Will Agriculture Be Affected?

  The climate changes now widely understood to be underway will seriously disrupt agriculture, and they will disrupt most severely those farms that are least flexible in their cropping patterns and uses of technology. Climate change may be the Achilles heel of many of  the industrialized farms that now characterize much of agriculture in the developed world.

 There is a contradictory viewpoint.  We have heard some argue that increased carbon dioxide in the atmosphere will feed plant growth and reduce moisture stress on plants, and will therefore be good for yields. This is based on simple plant growth theory and on research undertaken largely in laboratory conditions. Most scientists are skeptical.  They note that although carbon dioxide alone increases plant growth, the combined effect of carbon dioxide and other factors such as higher temperatures and rainfall variation and weed and insect adaptations may more than offset any increase due to carbon dioxide enrichment.  For example, if carbon dioxide increases the total leaf surface area of a plant, the plant may require more water even though its water loss per square inch of leaf area is smaller.  The more carbon dioxide in the air, the less tolerant plants seem to be to either high or low temperatures.  Also, plants will require more nitrogen fertilizer to make use of increased carbon dioxide in the air.  There is also reason to believe that plants may adapt to higher levels of carbon dioxide by reverting to lower rates of photosynthesis, and that plants raised in this condition will suffer reduced protein content, be less palatable, and store less well.  Moreover, weeds will do well, too, with higher carbon dioxide levels.  And insects will likely range farther, infest longer, and consume more under warmer temperatures.

However, the greatest climate change affecting agriculture will likely be the increase in extremes of hot, cold, wet, and dry, less predictability and more variability in patterns both day-to-day and year-to-year.  It is this variability, as much as or more than any shift in regional patterns or average climate conditions within a region that threaten the productivity of agriculture.

How Does U.S.  Agriculture Contribute to the Problem?

Agriculture’s contribution to the emission of greenhouse gases are reasonably well documented.  Methane emissions from both ruminant livestock and manure decomposition, nitrous oxide from fertilizer, and carbon dioxide from three major sources – energy use, soil erosion, and fertilizer manufacture – are the largest contributors.

Emissions from these major sources in U.S. agriculture probably reach about 644 million tons (measured in carbon dioxide radiant blocking equivalents), about two thirds of it in nearly equal proportion from each of the two sources of methane. Measured in total warming potential over the lifetime of the gasses in the atmosphere, the carbon dioxide emissions from energy use becomes much more important than the methane, because the carbon dioxide lasts so much longer.

Many of the modern technologies we use in American agriculture are particularly problematic.  I give two examples.

At the beginning of this decade, U.S. agriculture was consuming about one eighth of the world’s nitrogen fertilizer but accounted for between an estimated one third and one half of the nitrous oxide emissions.  Our share of emissions is disproportionate because we rely so heavily on anhydrous ammonia, which emits nitrous oxide at a much higher rate than other forms of fertilizer, especially the widely used urea.  This disproportional contribution to emissions may be lessening, however, as U.S. farmers under a variety of pressures have learned to manage fertilizer better while application rates in much of the rest of the world have grown substantially in recent years.  Still, anhydrous ammonia is a relatively inexpensive form of nitrogen that farmers prefer, and it emits nitrous oxide at a rate many times higher than other fertilizers.

A more complex problem growing steadily worse involves methane emission from the water-based livestock waste management systems that are now conventionally part of the “up-scale” pork industry. These manure handling systems are part of a cluster of technologies that integrate genetic programming, nutrition, building engineering, herd health management, and other technologies into large-scale production.  It is now possible to concentrate thousands of animals in closed buildings by flushing the manure into pits or lagoons.  In these water-based waste management systems, the task of decomposing the manure is accomplished by anaerobic bacteria.  This alters the composition and destination of manure constituents.  Notably, the production of methane is increased from about 10% (under drylot condition) to as much as 90% percent of theoretical potential.

In 1992, an estimated 28 percent of the U.S. hog herd was in facilities using anaerobic lagoons.  These systems produced about three fourths of the methane emissions for U.S. swine (1.28 mil. tons) and about one third of the manure methane emissions from beef, dairy, and swine operations combined.  This volume of methane was roughly equal in radiant blocking effect to all carbon dioxide emissions from all U.S. agriculture’s energy use, or to about 13 percent of all carbon-dioxide-equivalent greenhouse gas emissions from all major U.S. agricultural sources.  Since 1992, the number of hogs raised in facilities served with anaerobic lagoons has increased dramatically.

Good manure management is therefore far more than an issue of neighborhood nuisance or fertility management.  It is a climate change issue as well.  In fact, manure can be thought of as one of the delicate regulating materials through which carbon is allocated in ecologically balanced proportion between soil and atmosphere.  Placed in water, its capacity to do so is placed in jeopardy.  A manure management strategy that manages the flow of nutrients alone, without concerning the fate of carbon, is inadequate, even if it were to successfully avoid water pollution.

How Can Agriculture Win By Contributing to a Solution?

It is a reality that agriculture is a significant contributor to climate change. Fortunately, another reality burns brighter: Agriculture can contribute to efforts to mitigate climate change by controlling emissions, and it can be better off for doing so.  Most of the steps farmers can take should be taken for other good and sufficient reasons.  And if society recognizes the potential of farmers to contribute to the solution, it might make sound investments in the kind of strategies that will reward them for doing so.

In the mid 1970s, as energy prices were spiraling out of control, farmers began to adjust by conserving energy.  In the next fifteen years or so, they cut energy consumption by 15 to 20 percent, while increasing output by an even larger measure.  For some farmers, the response was both quick and effective.  As an example, a group of family farmers who participated in an alternative energy conservation project sponsored by the Center for Rural Affairs in the mid-to-late 1970s reduced energy consumption by 13 percent in only three years, reduced spending on energy by 19 percent over the same period, increased output nonetheless, and improved their net farm income by one-third.

In 1992, we outlined five strategies for reducing greenhouse gas emissions from U.S. agriculture by an estimated total of 116.4 million tons of carbon dioxide equivalent per year, and three strategies for storing carbon in soil at rates that would equate to a reduction in emissions of about 60.4 million tons of carbon dioxide per year.  At that time, such an achievement would have represented a 28 percent reduction in U.S. agriculture’s carbon-dioxide-equivalent emissions.   Most of these strategies are “cost-free” both to farmers and to society.  Most have multiple benefits other than climate change mitigation.  Most either increase productivity over the long run or improve net farm income, or both. These strategies are summarized in tables 9, 29, and 30 of the report appended to this statement.  I want to highlight four elements of these strategies here.
•
• Plant warm season native grass on previously cultivated soils that have been farmed for 100 years or more and depleted of roughly 40 to 50 percent of their original soil carbon.  This will store carbon in both the biomass of the grass and in the deep soil where it will be retained for a very long time.  Over a 20-year time span, a time period within reckoning for the Conservation Reserve Program, for example, this grass and the soils beneath it would store about 6.2 million tons of carbon, the equivalent of over 1.1 tons of carbon dioxide per acre per year. The current CRP program involving up to 36 million acres therefore offsets carbon dioxide emissions annually by nearly 40 million tons.  If we set a goal of planting even 20 million more acres to grass, we could offset emissions by another 22 million tons of carbon dioxide per year.
•
• Reduce soil erosion to the level that is naturally offset by soil formation. Excessive soil loss on all U.S. cropland totals about 1,600 million tons per year, with carbon loss representing an estimated 14-15 million tons per year.  According to a panel of scientists convened by the U.S. Environmental Protection Agency, about half that carbon ends up in the atmosphere as carbon dioxide.   Even a much more conservative estimate of half that rate of oxidation would mean an annual emission of carbon to the atmosphere of 3.6 million tons, or the equivalent of over 13 million tons of carbon dioxide per year.  If just the 120 million acres of highly erodible land still in cultivation were protected from excessive soil erosion, we could reduce atmospheric carbon emissions by 1.9 million tons per year, the equivalent of nearly 7 million tons of carbon dioxide per year.
•
• Reduce fertilizer use by 25 percent.  Despite some progress in recent years, the amount of nitrogen fertilizer wasted in U.S. agriculture remains alarmingly high.  Reduction of fertilizer use of the magnitude proposed could reduce both carbon dioxide emissions during manufacture (about 5.3 million tons) and nitrous oxide emissions during use of nitrogen fertilizer (with equivalent radiant blocking effect of  about 13.0 million tons of carbon dioxide annually).
•
• Reduce methane emissions from livestock manure in anaerobic lagoons.  If the methane emitted from these lagoons were held to the level that the same manure would produce in drylot conditions, the annual reduction in carbon dioxide equivalent emissions would be dramatic – conservatively estimated at 81.0 million tons of carbon dioxide.  Eliminating this emission alone would constitute an emission reduction that would be far greater than U.S. agriculture’s proportional share under the Kyoto Treaty.  Moreover, this is an “all-or-nothing” strategy, since if you are going to capture the methane, you are going to use it for heating or generating electricity, so it will be most efficient to capture all of it. This would, however, be a painful measure for the businesses that rely on lagoons for waste management.  These systems are the linchpin of their enterprise, and there is no cost-effective technology currently available for trapping and using the methane that now emits into the atmosphere.  Nonetheless, we know that there are commercially cost-effective alternative ways of producing pork and managing manure.  This potent source of atmospheric pollution should be curbed.
•
•  These four measures alone could reduce annual emissions from all major U.S. agricultural sources by nearly 20 percent.  They have the additional benefit of cutting operating costs without decreasing output, of preserving the underlying productivity of the soil, in which the farmer’s primary investment lies, of mitigating other forms of air and water pollution, and of conserving water and enhancing yield.

Public Policy Measures

The threat of global climate change is real and the promise of global community action in response to it is encouraging. The Kyoto Treaty is an inviting step, but one whose real effect cannot be completely evaluated except in the context of the actions taken to implement it. Fortunately, for agriculture, perhaps more than any other sector of the economy, most of the measures necessary to establish significant reductions in net emissions are either “no regret” policies that produce multiple economic and environmental benefits, or “good riddance” policies that curb practices that are otherwise bad anyway.  Whether the Kyoto Treaty is approved or not, many of the steps that agriculture might take to fulfill the goals of such a treaty should be taken independently  for good cause.

The policy measures taken to do so would generally be well within the experience of  farmers.  Direct payments to establish grass and to plant tress are customary in U.S. agriculture, but the public purpose in doing so has never been greater.  Both the landowner and the public are palpably benefited.  If Congress wishes to consider internal excess emission credits, where an emitting party pays for an offsetting sequestration of carbon by another party, many of these measures might be financed by electric utilities or other high emitters with a broad consumer base.

It is difficult to over emphasize the importance of grass as a target for such policies, because it is the fastest way to build soil carbon, and soil is the best place to store carbon for long term productive use in the widest range of ecological conditions.  Two features of grass are especially important.  First, when integrated into a whole farm plan, grass often not only builds soil carbon on  the land beneath it, but reduces soil erosion from water and wind on the cultivated land near it. The CRP’s provision for partial field enrollment encourages such an approach.  Second, allowing productive use of grass by grazing, including the current Conservation Reserve Program acres and the partial field enrollments, would also reduce the level of direct payment needed to induce farmer participation.

On a larger scale, it would also be attractive to consider a mechanism similar to a national trust to purchase tillage easements from farmers, assuring long term grass and tree plantings.

There has been considerable concern about the possibility of taxes as a means of curbing energy use and reducing emissions.  In general, a tax on fertilizer is unlikely to have much effect on consumption (it would have to be extremely high to do so), but a very small tax on fertilizer would handsomely fund a program of national research and extension on fertilizer and manure management.  Iowa’s successful experience with a fertilizer management program should be reviewed carefully by Congress toward this end.

Finally, if the essence of climate change in increased variability and more extremes, agriculture will need to become more locally diversified and more flexible than it now is.  Farmers will alter their management strategy to farm for optimum yields within more constrained and unpredictable weather conditions, where the extremes of hot, cold, dry, and wet are wider than they now are, occur more frequently, and vary more from year-to-year.  Our emphasis on an export-led farm economy will make us more vulnerable to climate change, but production for export tends toward large scale, specialized farms with relatively little tolerance for risk.  Congress cannot invent too many ways to encourage crop rotations and diversification as a mitigating strategy to cope with climate change.