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How Will Climate Change Affect Agriculture?

A podcast with Chrissy Wozniak of North American Ag, featuring David Legates, Ph.D, C.C.M. at University of Delaware (July 9, 2024)


This podcast has been shared with permission. See the original podcast here.


Chrissy Wozniak is omnipresent in ag. She is the founder of North American Ag where she hosts Ag Spotlight and What Color is Your Tractor? podcasts. She also is VP of communications for American Agri-Women, secretary at Florida Agri-Women, and East Coast sales manager at Speedling Inc., which specialized in ornamental and vegetable transplants and other horticultural products. She and North American Ag and American Agri-Women also are Event Partners for this year’s Women in Agribusiness Summit. Wozniak definitely has the pulse on the sector.

Dr. Legates has been published more than 125 times in reference journals, conference proceedings, and monograph series and has made more than 250 professional presentations. His research has appeared in multiple publications such as the International Journal of Climatology, Journal of Geophysical Research, Journal of Environmental Hydrology, Journal of Climate, and the Journal of Geophysical Research. He also is a contributor to the Encyclopedia of Climate and Weather and Yearbook of Science and Technology.

Dr. Legates has argued for the necessity of technological progress in precipitation measurement used for validating climate change scenarios and for validation of existing data used for that purpose. He co-developed methods to correct bias in gauge-measured precipitation data for wind and temperature effects, with direct applicability in climate change, hydrology, and environmental impact studies.

Here are excerpts from Wozniak’s reporting on Dr. Legates’ presentation at the 2024 American Agri-Women Fly-In in Washington, D.C., in June. To hear the entire podcast, look here on the North American Ag website.

[Chrissy Wozniak]:

Among the many speakers we heard at the 2024 American Agri-Women Fly-In, there was one extraordinarily excellent presentation by University of Delaware Professor Emeritus David R. Legates, Ph.D., C.C.M. His content was thought-provoking and important as it flies against the grain of current ideology.


And with his presentation entitled “How Will Climate Change Affect Agriculture?”, he did a deep dive into real climate data and how environmental extremism is causing problems for the American farmer and overall global food security. Legates has testified three times as an expert witness before the U.S. Senate Committee on the Environment and Public Works, and before both Pennsylvania House and Senate committee meetings on climate change.


He participated in the historic joint USA USSR protocol for the Exchange of Climate Information in 1991 and received the 2002 Boeing Parametric Award for the best paper in image analysis and interpretation by the American Society of Photographer and Remote Sensing. He also won first place in the International Statistical Institute and Easy Paper Competition in Kuala Lumpur, Malaysia, and was awarded the Courage in Defense of Science Award in 2015.


[Dr. David Legates]:

It's a privilege and honor to be here. I must confess that I originally was very hesitant about speaking to this group because I thought she said this was a meeting of the American Angry Women Association. But I have a feeling by the time the talk is over, you probably should be angry women, particularly angry at how climate change is going to affect agriculture.

When we talk about climate change, one of the things we always focus on are what we call greenhouse gases. In particular, we're interested in carbon dioxide, methane, and nitrous oxide and how they're changing. We always forget the most important greenhouse gas – which is water vapor. And the reason we often forget it is because we can't regulate it.


And the question is always why do we worry about these trace gases when other gases, such as nitrogen, oxygen, and argon, together make up about 99 percent of the atmosphere and you never hear about them. The answer is because they can’t ‘dance’.



Climate change is not a hoax. Climate change has always happened, always will happen. The problem is we got into defining climate as average weather, and climate is something much more than average weather. If it were nothing more than average weather, then we'd be interested in the mean, the variation, the maximum, and the minimum and it should remain constant.


And if it doesn't remain constant, something's going horribly wrong. But in fact, we know the climate is all very dynamic. It's variable. It's ever-changing. Not every year looks like the other year. And some of that is driven by background changes in climate. We also recognize that humans can and do influence the climate.

The change in the last 150 years [in carbon dioxide] has been about 1/100 of 1 percent. That's equivalent of about one penny out of $100. There's not much change in carbon dioxide. The question is, is that change significant enough to change our climate? And that's what we want to investigate for globally. Satellite records show a warming since 1980 when we first had satellites to measure this kind of stuff – it went from about minus point three to about plus point three. So we've had a warming of about 6/10ths of a degree Celsius.


So the real climate change debate is to what extent are humans responsible for the recent climate change we see? What are the future consequences associated with climate change, both natural and human induced? And what should our response strategies be?



Based upon all this [and please listen to the entire presentation for details], I'm going to leave you with the following conclusion. Climate change will adversely affect agriculture. I think the following along almost everything I said was counter to that. So I need to change this one slightly. It's climate change policy that will adversely affect agriculture. It's not the change of climate, it's the change that we're attempting to do in the policy to try to protect the planet.


It's actually going to hurt agriculture. Much of that is related to this net zero concept, that zero emissions operations by 2050, including a 65 percent reduction by 2030.


We have got all sorts of concomitant legislation coming up to try to force this to happen, and much of it affects agriculture. Let's stop and think about it for a moment. If you've got to get a 65 percent reduction within the next seven years, you've got to go after the two biggest producers of trace gases, and that's transportation and agriculture.


And agriculture gets hit twice. Because how do you move the goods from food to table or from field to table? It is a transportation network. So both of those are going to be directly impacted.



See the presentation here for more details.


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About American Agri-Women

American Agri-Women (AAW) promotes the welfare of our national security through a safe and reliable food, fiber, and mineral supply. Since 1974, AAW members have worked together to educate consumers; advocate for agriculture; and offer networking and professional development opportunities. For more information, or to join, visit Find AAW on social media at: and


Learn more about David Legates at

North American Ag is devoted to highlighting the people and companies in agriculture who impact our industry and help feed the world. Subscribe here.

This episode of North American Ag is sponsored by NetGreen.


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