Drought Risk Atlas Uses Past to Predict Future: A Q&A with Climatologist Mark Svoboda

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A new tool called the Drought Risk Atlas promises to help decision-makers and the public better understand and prepare for future drought. The Atlas was developed and launched by the National Drought Mitigation Center at the University of Nebraska-Lincoln, which offers a variety of tools and data related to drought, including reports on precipitation, water supply, vegetation, climate, and drought indices. A climatologist with the Center, Mark Svoboda, explained how their latest innovation will help inform our understanding of drought.

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Can you explain the Drought Risk Atlas and what it’s going to be used for?

One of the questions we always get from the newspapers and radio and TV and people in general is, how does this drought compare to the Dust Bowl years or the ’70s or '88? Everyone seems to have a drought they remember. The Drought Risk Atlas was built with the idea that for the best climate stations out there that have really nice, long-term histories and not a lot of missing data, we can go back and look at the drought history. We’ve built a nice visual interface for that. People that want to download the raw data can get it, but it’s also a nice way to come in and look at the spatial behavior of drought, the intensity of drought. How large of an area, how long did it last, how often does that sort of drought come around? That was the motivation in building this tool, to help decision makers, citizens, and the media. 

For a citizen, what can they expect to see and draw from this?

You can search and hopefully find your station in the town you live in. If that doesn't exist or doesn't have a long history, there will be a station close to you. We've clumped these stations into clusters that have similar drought behavior. You can find your location, then look at drought and how it's behaved over time in your region with a variety of maps, time series, and all sorts of neat visualization tools on the interface. And that's all free and available to the public.

Why is this needed or useful?

It’s to give people a better sense of how they might need to adapt, preparing to get a different mindset about droughts, that they’re a normal part of our climate. We’ve seen [droughts] in the past and we’ll see them in the future with a changing climate. Are these droughts changing in their frequency? Are we seeing them become more intense but more short-lived, are they long-lived but of just a moderate intensity? Knowing how that impacts you and your operation, whether you’re a farmer or rancher or whoever it might be, may help us look to what we should expect from droughts in the future.

Do you think our ability to predict and prepare for drought is improving or has improved during the last few decades?

I think it's improved, but it has an awful long way to go. Especially in this part of the country, we're sort of landlocked. When you hear about El Niño and La Niña, things that are in the news quite often, they have a much stronger relationship to driving weather along the coastal areas of the country, or the Gulf Coast region, for example. In Nebraska it's not quite as strong, but there are indicators out there that if the ocean's in a certain state, whether abnormally warm or cold, you might expect to have a better chance of seeing drought. This can help folks better hedge their bets. Maybe what sort of operational decisions they'll make, depending on their business, could be driven by knowing something a few months to half a year in advance. But the forecast skill depends on a strong oceanic state, and the problem we've had the last two winters -- it's been neutral, not abnormally warm or cool in the ENSO (El Niño-Southern Oscillation) region of the equatorial Pacific. So the forecast hasn't been very skillful. So, in those times you want to always be prepared for drought as if it will occur any year, not just when there's a forecast to do so.

Will the Drought Risk Atlas help predict drought and prepare for drought in the future, knowing the historical record?

Where I think this tool will be useful is if you see a forecast for drought, or if you’re in a certain stage of drought, you can go back in the Atlas and look at other periods of drought that behaved the same way and maybe you’ll have a better anticipation of what impacts might be coming if this drought continues, if it gets more intense. If it covers a larger area, will this affect my water supply? Everyone will have a different question they want answered, but our goal was to provide some of the visualization tools that can answer several questions, and most questions we've anticipated. And if it doesn't, we've encouraged people to contact us and let us know what they'd like to see in the Atlas.

Some irrigators in Nebraska have talked about the “new normal” -- meaning they’re getting used to operating with less water year after year. Do you think the same concept applies to drought, in the sense that we’re in these longer phases of drought or maybe we’re entering a longer dry period?

That’s the kicker question. The million-dollar question is, is this an interlude? We may go back into wetter times. The models that the IPCC (Intergovernmental Panel on Climate Change) released in its report still show the continuing trend of a hotter atmosphere, which exacerbates drought, but also a moister atmosphere.

So it depends on the timing of these rains, how many days in between these rains. But in general, it’s not as easy as it was to look at the past and say the climate of the past is going to equal the climate of the future. The bars have changed. And if that shift continues long enough -- say, a couple decades -- that would mean more of a climate shift to the climate regime of a region. We would call that more arid, or aridity, which is a permanent feature of the climate, versus drought, which is a temporary departure from the normal of a region’s climate. So, droughts are going to then be the departure from that new, drier regime.

This interview has been condensed and edited.