An Interview with Nolan Doesken

Nolan grew up in rural Illinois. He studied Atmospheric Science at the University of Michigan and the University of Illinois. He moved to Colorado in 1977, where he’s been a climatologist for over 35 years.
 
The following interview has been edited for clarity and length.

Steve Rosenzweig: What made you want to be a climatologist?
 
Nolan Doesken: I got interested in climate through my dad, who loved to keep weather records in his journal. He let me look in his journal, and he kept track of things all the way back, well we just found one of his earliest journal entries from when he was a teenager back in the 1920s. But weather statistics to me were just fascinating, and so from a young age I loved keeping weather statistics, loved doing probability calculations for recreation on hot summer days as a teenager. But I also grew up in an agricultural area where the conversations that took place in the community were almost always weather and climate related, and that was the language that I loved to hear spoke, and I participated in that as soon as I could. 
 
SR: Has the conversation about weather and climate changed much in agricultural communities?
 
ND: Much about weather and climate conversation in rural conversation to me as I hear them today have not changed that much. People were always thinking that the climate was a little bit different than it had been in the past. They were thinking that it's becoming a little more variable and extreme than it has in the past. The main different thing is that now there's a lot of scientific evidence to show that climate on a global scale is in fact changing, at least in the temperature part – that is the most obvious one that we can see that we are warmer than we used to be. The weather records here on our campus weather station show that relatively clearly. But the natural variability in climate - the big storms that occur one year and not the next, the droughts that occur every few years - That still is the dominant part of conversation. And the question that comes up is are we getting more of those or are we getting less of those? And are the droughts worse? Do they come on more surprisingly? Are there cycles that are predictable? Do they relate to something or do they not? Now there's so much more science behind climate than there was when I was having those youthful conversations with the farmers of our community 50 years and even longer ago.
 
SR: What can you tell me about the climate in this region?
 
ND: The Western Great Plains have an amazing climate. It's the part of the country that has the largest year-to-year and day-to-day changes of almost any other part of the country. What's amazing about the Great Plains - the Western Great Plains in particular - is that temperature gradients vary. It gets cooler as you go north, gets warmer as you go south, quite dramatically. Precipitation has a perpendicular gradient. Precipitation gets greater as you go east, less as you go west. The rain shadow right in the immediately of the Rockies is the driest, then right as you hit really close to the foothills then you increase again. But the main character of the Great Plains is wild swings, big changes day-to-day month-to-month, large seasonal cycles. It's an area of natural extremes to begin with, and that's even before you add the next ingredient, which is climate change in action.
 
SR: What effect is climate change going to have in this region?
 
ND: Climate change is an interesting thing to try to track in the Great Plains, because there's already so much variation that it's hard to detect small trends. For example, precipitation. We've decided that based on what we've seen in the variability in our precipitation in the Great Plains, it would probably take another 50 years to have any hint at all whether there is an upward or a downward trend. Temperatures are a little more systematic, especially in the summertime when the variability is smaller. And there it doesn't take as long to be able to detect trends. And we have been detecting warming trends in most seasons of the year. Not yet hugely profound and dramatic, but measurable, i.e. a couple of degrees fahrenheit.
 
SR: So, we’ve already felt the warming effects of climate change, and they will continue to go up, but it’s harder to detect how climate change will affect precipitation. Is that right?
 
ND: In terms of precipitation, we're not exactly sure how that would play out in the next 50 to 100 years. It's just so naturally variable. The role of extremes, however, will probably play out. This is something that I wanted to say about the climate of the Great Plains to begin with. Semi-arid climates are ones where there are relatively few precipitation events – it's dry most of the time. You're total average precipitation is less than 20 inches per year. Much of Eastern Colorado is more in the 12-16 inch range. But, again, variability and extremes. Just a few storms will make the difference between a wet year and a dry year. And what the evidence related to climate change suggests is that we will probably have fewer storms in total, but possibly larger storms when they do occur, which makes for an interesting situation for managing water. It may end up as the same amount of precipitation, but distributed in fewer and larger events. Temperature is a little bit more predictable – and in fact a lot more predictable. All evidence says that the warming trend is going to be clearly detectable, indisputable, and on the warming direction for the next 50 years.
 
SR: What will climate change look like to a farmer in the Great Plains?
 
ND: If you're a farmer on the Great Plains, you will have trouble separating climate change from climate variability when it comes to precipitation. It's just masked. There's just so much variability already. But when it comes to temperature, we are warmer than we've been in the past and we are getting warmer. As we're seeing in this month's weather records, we haven't had a single day this month so far with below average temperatures. And most days have been considerably above. And that's the direction we seem to be going with temperatures. And that plays out in all other aspects of the climate because when it's warmer and dry, the water that you do have evaporates quicker, the growing season starts a little earlier in the spring, may last a little longer, that may mean more consumption of what little water you do have. But then it tells you that when you do get storms – and you will, and they may be really big when you get them – that you gotta work really hard with your management and your vegetation to try to capture and retain that moisture as much as you can. Anything that causes there to be warmer weather with possibly fewer precipitation events and possibly larger precip events and possibly quicker onset drought, will require some different approaches to how you manage your biological resources in your soil.
 
SR: You said the growing season is going to start earlier?
 
ND: What warmer temperatures mean when you're engaged in agriculture is that vegetation will begin to use more water earlier in the spring. Depending on what you plant and how you manage it, it may consume more water over the course of the growing season, and the soils will have the tendency during dry spells to dry out more quickly. Again, between the storms – and a few big storms will still dominate the annual precipitation accumulation – your ability to retain moisture from large and intense storms is critical in order to have the most water available in the soil when you need it. 
 
SR: A lot of people are very worried about climate change, but you seem like a pretty optimistic guy. Are you hopeful for the future?
 
ND: Of course. You can look at climate change as a doomsday scenario. You can look at it as an inconvenience, or you can look at it as an opportunity to see what we can do better. Agriculture is in a position where they can affect not only how they respond to the climate as it may be changing but also how the atmosphere's composition of carbon may in fact change over time as well. Agriculture can influence both sides of the climate system.
 
Steve Rosenzweig is a PhD Candidate at Colorado State University. This interview was conducted as part of a film project to document emerging innovations in dryland agriculture, which can be viewed here.

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