Climate change is part of nature. One question is how much human activity, including agriculture and food processing, affects that change.

KANSAS CITY — Climate change is part of nature. One question is how much human activity, including agriculture and food processing, affects that change. That debate won’t be settled here, but a look at the issue and how agriculture is being affected is worthwhile as more consumers and retailers demand food from sustainable sources that in one way or another relate to climate change, and as a forecast nine billion people on planet earth by 2050 must be fed.

One point is clear: the U.S. Environmental Protection Agency, especially, and all cabinet level departments from agriculture to transportation have been charged by the current administration to mitigate the projected effects of climate change and are adjusting (or already have adjusted) regulations, operations, programs and policies to that end. Thus, whether U.S. farmers, food processors and consumers realize it or not, they are being affected by climate change, either in the field, from the political front or through tax dollars.

President Barack Obama in June 2013 released his Climate Action Plan that included several executive actions aimed at reducing carbon and other greenhouse gas (GHG) emissions in the United States, preparing the United States for the impact of climate change and leading international efforts to combat global climate change and prepare for its impacts. That plan largely has dictated actions by government agencies, including the two that impact agriculture most — the U.S. Department of Agriculture and the E.P.A. The plan, among many other things, under the title Maintaining Agricultural Stability, directed the U.S.D.A. to create seven new Regional Climate Hubs “to deliver tailored, science-based knowledge to farmers, ranchers and forest landowners.”

Around the second anniversary of the release of Mr. Obama’s action plan, the E.P.A. on June 22 issued a major report titled “Climate Change in the United States: Benefits of Global Action,” as part of its ongoing Climate Change Impacts and Risk Analysis (CIRA) project. The U.S.D.A. also on June 22 announced additional steps to integrate climate change adaptation into its programs and operations.

It must be noted that any discussion on climate change inevitably will involve global warming, which pushes any number of “hot buttons” in the debate.

For definition sake, the National Oceanic and Atmospheric Administration (NOAA) on its web site offers the following explanation: “Global warming refers only to the earth’s rising surface temperature, while climate change includes warming and the ‘side effects’ of warming — like melting glaciers, heavier rainstorms or more frequent drought. Global warming is just one symptom of the much larger problem of climate change. Another distinction … is that when scientists or public leaders talk about global warming these days, they almost always mean human-caused warming — warming due to the rapid increase in carbon dioxide and other greenhouse gases from people burning coal, oil and gas. Climate change, on the other hand, can mean human-caused changes or natural ones, such as ice ages.”

The issue is even more complicated because resources that should be “neutral” in the debate can’t be assumed to be so, either pro or con. NOAA’s web site, for example, clearly leans toward global warming as a fact and human activity as a major cause, at least the current cycle. To be fair, NOAA notes the earth has experienced climate change before and temperatures have fluctuated throughout history “on 100,000-year cycles for at least the last million years.” The climate has warmed and cooled (ice age) during those cycles.

The U.S.D.A. in its June 22 updates on climate change adaptation, said it would:

• Integrate climate change adaptation planning, implementing actions and performance metrics into U.S.D.A. policies, programs and operations to minimize climate risks and exploit opportunities that climate change may bring;

• Analyze how climate change may affect its ability to achieve its mission, operations and policy and program objectives;

• Identify appropriate key performance measures to evaluate progress in climate change adaptation;

• Take part in adaptation implementation as part of a broader commitment to developing the next generation of regional climate solutions through its Regional Hubs;

• Incorporate climate-resilient decision making into international development programs and investments of relevant U.S.D.A. agencies; and

• Develop and maintain an adaptation plan for managing the challenges and consider potential climate change impacts when undertaking long-term exercise, setting priorities for scientific research and developing performance measures.

The U.S.D.A.’s seven Regional Climate Hubs were established in February 2014 and work in partnership with public and land grant universities, Cooperative Extension, U.S.D.A. researchers, NOAA, state and local governments, Department of Interior regional climate change experts, non-profits and the private sector.

“The Hubs translate climate change projections into potential impacts on the agricultural and forestry sectors,” the U.S.D.A. said, and “provide periodic regional assessments of risk and vulnerability … to help land managers better understand the potential direct and indirect impacts of a changing climate.”

But the key driver behind the administration’s climate change efforts appears to be the E.P.A.

The E.P.A.’s June 22 Benefits of Global Action report used a scenario that projected the global mean temperature to increase by more than 9°F by 2100 (85 years) with devastating effects, but that “significant GHG mitigation efforts” can limit that increase to less than 2°F above pre-industrial levels, with an increase of 3.6°F a “commonly regarded goal for avoiding dangerous climate change impacts.” The E.P.A. added, “Due to climate system inertia, benefits may not be apparent for several decades.” The report said global temperatures already had warmed 1.5°F since pre-industrial times.

“Without significant global GHG mitigation, climate change is projected to have a large negative impact on the U.S. agriculture sector,” the E.P.A. said.

Yield declines were projected for all major irrigated crops except hay by 2100, with substantial declines for all rainfed crops, although results varied depending on which forecast model was used.

“Global GHG mitigation is estimated to substantially benefit U.S. crop yields,” the E.P.A. said, with benefits increasing over the course of the century, except for rainfed hay and sorghum.

Conversely, “Global GHG mitigation is estimated to result in lower crop prices over the course of the 21st century compared to the reference,” the E.P.A. said.

U.S.D.A. Climate Hub Regions - the U.S.D.A. established seven Regional Climate Hubs in 2014 as part of President Obama's 2013 Climate Action Plan.

The E.P.A. estimates U.S. agriculture could avoid $1.5 billion to $3.8 billion in damages by 2050 and $6.6 billion to $11 billion in damages by 2100 through global GHG mitigation.

Others worried about climate change

There are individuals and groups involved in agriculture who embrace both climate change and global warming that are seeking to make changes.

“It’s easy to think of climate change as a problem far off into the future,” said the Montana Farmers Union (M.F.U.). “The reality, however, isn’t that convenient: Montana’s climate is already changing.

“For grains like wheat and barley, increasing temperatures will cause faster plant growth, which in turn reduces the time for plants to fully grow and mature, therefore reducing grain yield per plant. Researchers at Montana State University have demonstrated that the rise in temperature since 1950 has already reduced hard red spring wheat yields. Other studies have found that 1.8°F of temperature rise will reduce wheat yield by 6%. And the same temperature rise was found to reduce corn yields by 5% to 15%.”

On a broader scale, the National Farmers Union has in its policy, “N.F.U. is concerned about the effects of climate change and believes further research and analysis is necessary to determine its actual and potential impacts.”

The nation’s largest farm organization, the American Farm Bureau Federation, maintains, “Farm Bureau believes that adaptation strategies and tools can be utilized to face the challenges of more inclement weather and a changing climate. Appropriate funding and emphasis should be given to agricultural research. Having the technology, traits and production practices will be more beneficial than burdening the economy with additional regulations.”

The A.F.B.F. supports market-based solutions to reduce GHG emissions, rather than government limits, and opposes, among other things, “Climate change legislation that establishes mandatory cap-and-trade provisions; any climate change legislation that would make America less competitive in the global marketplace and put undue costs on American agriculture, business and consumers.”

Crop breeding for climate change

The Monsanto Co., often the prime target of activists because of its leadership in the development of bioengineered crops (G.M.O.s), is one of the companies leading the way in development of crops designed to perform better under more severe conditions, such as a drier climate.

“As a society, we’re just beginning to feel the impacts of climate change,” Monsanto said concerning its view on improving agriculture. “Some effects of agriculture — such as the greenhouse gases produced by farm machinery and the production of fertilizer — are contributing factors. And of course, agriculture itself can suffer from the effects of climate change. Agriculture needs to adapt to changing conditions and use farming techniques that reduce the impact of our changing climate.

“By some estimates, agriculture currently uses 60% of the arable land on planet earth. It also uses 70% of our fresh water.” Obviously, the stake of agriculture in climate change is enormous.

“The relationship between agriculture and climate change is complex,” Monsanto said. “Just as agriculture is searching for ways to dramatically increase food production, the effects of climate change are making production increases more difficult.”

Among the many products Monsanto is developing or had developed through plant breeding and biotechnology are its DroughtGuard Hybrids, including drought-tolerate corn, designed to require less water.

Pro and con debate goes on

At the same time, many in commercial agriculture, energy and other industrial markets tend to discount humans as the major cause of global warming and especially of climate change, and likely go too far the other way. They allege “scare” tactics used by some of those expressing alarm about global warming often are based more on emotion than on science, including relatively short-term findings presented as scientific proof while many projected results to mitigate climate change carry the caveat, “benefits may not be apparent for several decades,” as noted earlier.

Opponents also note that many, or even most, of the actions taken by the government have been the result of administrative orders or actions and have not come through the congressional process.

Many in commercial agriculture, energy and other industrial markets tend to discount humans as the major cause of global warming.

Those who take the stand that human activity is mainly responsible for global warming, and thus climate change, since 1900 far outnumber those who doubt the significance of the human contribution. Ninety-seven per cent of 11,000 peer-reviewed studies published from 1991-2011 endorsed the idea that humans were the major cause of global warming. Still, there are at least 1,000 scientists who disagree that human activity is the primary cause.

Those who cite human activity as the main cause of global warming also note unprecedented thawing of glaciers, the melting of the Arctic ice cap and rising sea levels as evidence. Those who doubt such major influence from human activity note that warming has not occurred over the past 17 years, that oceans have been rising since the end of the ice age and that models used to prove global warming fail to simulate exchanges of heat between surface layers and deeper parts of the oceans or climate conditions tens of thousands of years ago.

The high level of rising temperatures since 1900 also cited as the result of industrial activities’ influence on global warming fall within the bounds of natural temperature fluctuations over the past 3,000 years, according to opponents, who say the natural heating and cooling of the earth’s atmosphere is primarily caused by fluctuations in the sun’s heat, with sun spot activity as evidence.

The pro-con list could go on, but the point is that climate change and especially global warming are hotly debated subjects.

Meteorologist Drew Lerner, president of World Weather, Inc., sees climate change as a natural phenomenon and sides with those who believe human activity is not the primary cause of climate change.

“Global warming certainly cannot be disputed when one looks back and accepts the theory that the earth was once covered greatly in ice,” Mr. Lerner said. He cites sun spot activity as the primary cause of longer-term temperature changes, but also notes a key role played by ocean temperatures. He suggests the massive amount of data and information now available about weather events around the globe contribute to the idea that weather is much more active and severe than it once was. But that’s not the case, he contends, as the climate “is always in a state of flux.”

While the pro and con of global warming and climate change can be debated, there is no question that agriculture and other industries may make changes to better manage key resources.

As with any issue on a national and global scale, there are a myriad of factors involved. In the arena of climate change, it would seem that a combination of mitigation, as outlined in the June 22 E.P.A. document and as is being administered by the U.S.D.A., and adaptation, especially in the case of agriculture and as Monsanto and other plant breeders are doing with seed development, may be the best approach to a complicated and controversial subject.