Meet the researcher - Dr Lisa Goddard
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Dr Lisa Goddard
Climate researcher
Farmer Forecast relies heavily on multi-week, ENSO and seasonal forecasts from the International Research Institute (IRI) at Columbia University in the United States. This week, we chat with Dr. Lisa Goddard, the Director and Senior Research Scientist of the IRI. Lisa oversees research and product development aimed at providing climate information at the 10-20 year horizon and how that low-frequency variability and change interacts with the probabilistic risks and benefits of seasonal-to-interannual variability. Most of Lisa’s research focuses on diagnosing and extracting meaningful information from climate models and available observations. Lisa holds a Ph.D. in atmospheric and oceanic sciences from Princeton University and a B.A. in physics from the University of California at Berkeley.
Farmer Forecast caught up with Lisa to hear how a career in climate science evolved, along with seeking insights into seasonal forecasting more generally and which ENSO phase might be on the horizon in 2021.
What inspired you to become a climate researcher and at what age was this?
I decided to go into climate research when I was considering graduate school after getting my BA degree in physics. I loved physics, but did not really want to pursue the theoretical path. At that time, in the late 1980s, there was just starting to be stories in the news about the ozone hole and global warming. I thought, “This is an exciting way to apply my physics knowledge. This is something I want to learn more about, and maybe help people.”
Do you have any extended family or other connections with farming or agriculture, as much of your work involves helping farmers adapt to climate extremes?
No. My mother was a special education teacher, and my father worked for the State of California.
What are your favourite activities or interests away from research that helps recharge you for work mode?
My family and my dog, Chewy, are the most important source of joy in my life outside of work. I also enjoy hiking, reading, and gardening. I guess I do have a little connection to agriculture, but that’s fairly new.
Pacific Decadal Oscillation (PDO) is also a keen area of your research interests. This is also something that can offer farm managers some guidance for big-picture decision making. The rainfall charts produced by the longpaddock.com.au are fascinating, with clearly defined wet and dry phases that seem broadly aligned with the PDO. It seems more obvious in hindsight, but what are the issues with predicting the next move of decadal oscillation?
The Interdecadal Pacific Oscillation is a climate pattern in the Pacific that varies from decade to decade and affects global and regional climate on 10–40 year timescales. It is like El Niño and La Niña’s older, slower-moving, uncle or auntie, I suppose. We have lots of clues as to what drives these slow changes, and how they link to other ocean basins and the El Niño system, as well as how this pattern has behaved in the past, including the impacts on Australia. But our understanding of the underlying physics and potential avenues for predictability of these decade to decade changes remains a matter for ongoing research.
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Lisa with former Secretary of State Hillary Clinton.
Australian Farmers follow IRI ENSO predictions, seasonal and sub-seasonal forecasting regularly, as chart presentation in terciles is easy to understand. In your experience, what is one of the biggest challenges for users interpreting forecasts to translate into risk management and action?
I have seen that most decision-makers have a tough time using terciles. Part of the difficulty is that they may not know what constitutes above-normal or below-normal. Farmers are usually much more attuned to these things than the rest of the public. In addition to this categorical representation of the upcoming climate, terciles may not be the right decision point for all sectors. For example, in Southern Africa, the malaria community is interested in the wettest/driest 25% of the historical distribution. Disaster risk reduction efforts in the humanitarian sector are often more concerned with extremes. For this reason, the IRI started issuing what we call Flexible Format Forecasts about 10 years ago. In this way, someone coming into the forecast map rooms can ask to see the probability of being in say the driest 20% of the historical record or the probability of exceeding 10 cm in the coming season. This takes the decision away from the producer of the forecast and gives it back to those actually using the information.
In the most recent year with the late arrival of La Niña, GCMs tended to be over bullish on precipitation forecasts. Those predictions have certainly created scepticism about GCM outputs when rain hasn’t eventuated. How important is it to sense-check GCM outputs with climate fundamentals, such as SSTs distribution, statistics and other known research outputs for users to better manage risk?
This is the chronic frustration inherent in probabilistic information. The GCMs and the range of possibilities they produce are based on the response to current ocean, land, and atmosphere conditions. Models are not perfect, but they can be calibrated – both in strength and range of responses. It is important that this is considered and folded back into the forecasts. This is how IRI approach its seasonal forecasts. Even with all the care possible, though, nature may still deal the unexpected, low-probability outcome. If we had perfect models, Nature would be only one of many, many ensemble members, after all. One cannot easily get over feeling ‘burned’ by a forecast that seems wrong, but I would encourage users of forecasts to take a look at the longer-term performance of those forecast systems – like 10-20 years or more, before condemning them to the waste heap.
What do you see are the biggest challenges for climate scientists in the coming decade in terms of boosting seasonal model accuracy in a changing climate?
I think the challenge for seasonal forecasts will be to better capture the extremes, and extreme seasonal behaviour, of the climate system. Due to the changing climate and increased public awareness, there is a tendency to attribute all extreme events to climate change. Seasonal forecasts must include the drivers of climate change as well (most of them do), not because the greenhouse gasses change enough to make a difference from one season to the next, but their evolution will affect the trends in the model history, which is important for context. So, more accurate forecasts of extreme weather characteristics and seasonal means/totals a season or two ahead should provide considerable value for communication as well as for considerations of adaptive management.
The current ENSO forecasts are showing neutral-ish conditions for the second half of the year, although we are in the known predictability ‘gap’ at the moment. What do you think the chances of a La Niña forming are, as history shows quite of often one La Niña event will follow another?
According to some analysis done by one of my colleagues, about half of the La Niñas (not preceded by a La Niña) are followed by a second La Niña. We would typically look to the ocean for information on that possibility. The most robust condition for that is if the upper ocean heat content does not recover to normal or greater in the demise of the event. Currently, that is not the case; the heat content is almost back to normal. Other recent research has pointed to signals from the decaying La Niña reflecting off the coast of South America and influencing the air-sea coupling in the second half of the year. There are no obvious signals in the tropical Pacific right now. There are a few models that keep re-developing La Niña later this year, but the most bullish of those has been pathologically extreme throughout this event, another couple is related in their genealogy and also use the same analysis for their initial conditions. The spread of the models is just really all over the place. I think we need to wait a couple of months for more clarity.
A shot of Lisa as a calendar ‘çlimate model’ in standing at the edge of the Pulcaro Reservoir in Chile.
This is the April run of the IRI’s seasonal outlook (fresh off the press this morning) for the business end of the winter crop 2021.