Talking climate change, arctic crocodiles, tropical heat death, and climate whack-a-mole with Matthew Huber
It's still summer: the parks are filled with children, the skies are filled with lightning bugs; and the news cycle is filled with talk of oppressive heat. With the recent heat waves across many parts of the Earth, routine discussions center around climate impacts leading to increased heat stress, heat events, and mortality from heat. Matthew Huber, professor in Purdue Earth, Atmospheric, and Planetary Sciences (EAPS), is an expert on these topics and is often cited in publications ranging from The New York Times, Mother Jones, Reuters, Fox News, and many more. The New York Times recently labeled him “among the world’s leading authorities on heat stress and heat mortality.”
Huber studies the physics of climate change in the past, present, and future, including how it relates to extreme weather events and heat stress. Recently, he’s also been spending time working with faculty across Purdue's West Lafayette campus as the inaugural director of the newly launched Purdue Institute for a Sustainable Future, a research institute supported by the Office of the Executive Vice President for Research and Partnerships (EVPRP).
The institute draws on the work of hundreds of Purdue faculty who have worked to advance sustainability goals through centers such as the Center for the Environment and the Climate Change Research Center, which he directed in 2012-2013. The institute fosters and promotes research, partnerships, and engagement in areas including the environment, climate, food-energy-water security, and sustainability. Under Huber’s leadership, it will continue this tradition of supporting the research and development needed to provide viable solutions to grand challenges in these areas by connecting faculty and researchers with one another and by forging linkages between disciplines and communities within Purdue and beyond. With new levels of support, the institute will also be able to quickly respond to the growing number of opportunities to add value to state, national and international efforts to forward many of the goals outlined in the United Nations Sustainable Development Goals while also responding to immediate problems like those connected to climate change and the need for preparation, mitigation and resilience.
Huber has had a lifelong goal of resolving certain challenges, stemming back to his early days as an undergrad.
“I’ve been working my entire career, actually since I was an undergraduate at 19 years old,” says Huber, “to try and understand a very simple relationship, which is that as greenhouse gases increase and the world warms, how does the equator-to-pole temperature gradient change? It is widely understood that the poles warm more than the global average change, but how much more? Do storms more efficiently transport heat from the tropics toward the poles? Do clouds more efficiently retain heat or reflect sunlight? How much do the tropics warm? Can it get so hot that it becomes deadly?”
Climate scientists tend to look at certain time periods in intervals. These intervals reveal a vastly different world than humans are accustomed to today.
“When you look at climate change from the paleoclimate record of past ‘hothouse’ intervals, like the Eocene or Cretaceous” he says, “there were crocodiles and palm trees in Greenland. During those time periods, ice sheets at the poles generally didn’t exist. So, we know the poles can get really warm, but what about the tropics? Were they blisteringly hot? Answering that question has been Huber’s ambition for decades. What we’ve learned over decades of work studying these past hothouse climates is that the poles warm a lot when greenhouse gas concentrations, such as CO2, are increased, but the tropics warm too. In fact, at the extremes of greenhouse gas forcing from the geological record, the tropical oceans were hot tub hot (about 99°F).”
Why study these things? The fundamental reason, according to Huber, is to predict what the future may look like. In order to make these predictions, scientists rely on climate modeling. Because of the predictive nature of modeling, information is constantly being added to help pinpoint more accurate data points, reduce uncertainties, and provide a more robust view of the future.
Last winter, Huber and an international team of scientists, led by Yale graduate student Daniel Gaskell, published their most recent findings, which helped reduce the conflicts between climate models and empirical estimates of temperature covering 95 million years. These findings cleared up many inconsistencies in previous models and the team argued for a fundamental consistency in the dynamics of heat transport and radiative transfer across vastly different background states. Because the temperature difference between low and high latitude is a consistent and efficient measure of the global climate system, the team was able to test and correct models through time which revolutionizes our current modeling systems.
“This paper represented the culmination of many decades of me thinking about this issue and the working with the lead author, Daniel Gaskell, to compile the data, that we had for not just one brief period of time, but over most of the 100,000,000 years of Earth’s history,” says Huber. “We hammered down all of those inconsistencies as much as possible, like climate whack-a-mole. And we have established, to my mind for the first time within a tolerable degree of accuracy directly from past climate data, how the equator-to-pole temperature gradient changes as the globe warms.”
After gathering all this data and resolving data inconsistencies of current models, Huber said, something magnificent was revealed. What they found was that there is a simple linear regression between the planet’s globally averaged temperature and its temperature gradient.
“The data was all over the place and nobody had ever really looked at it all in one consistent way through 100 million years, but we were able to do that," he says. "This has important implications for climate modeling and climate theory. It gives us something to hang our hat on because the climate system is really complex and people are always talking about complexity and uncertainty and how little we understand, which is very reasonable. But if you can look at it along a high-quality data set and say, ‘when you change the temperature of the planet, the temperature gradient changes by this much. Wow. OK, let's see if theories and models can explain that.’ If they can, maybe they are more trustworthy and more accurate than models and theories that predict something else.”
Another key area of focus for Huber, which has led to many of his media interviews, is the concept of “wet bulb temperature.” This term refers to the theoretical maximum for how much a body’s temperature would reach if it was sweating as much as it possibly could. There is a threshold at which life is no longer sustainable. With recent heat waves like those along the west coast, as well as those that stretched across Europe and India this summer, it has become increasingly important to understand this relationship of heat to life. He explains these issues in a recent article he penned for the Bulletin of the Atomic Scientists. This tolerance for heat limitation is not something out of which human beings or other animals can rapidly evolve. Huber is cautious about using predictions for reasons other than scientific, but he concludes with a bit of hope for the animal kingdom.
“One may rely on either natural or man-made refugia (in other words, moving populations of 'warm-blooded animals' either uphill or away from hot humid regions, or building giant air-conditioned enclosures, in order to allow animals to continue to survive),” he says. “But, if humans are in the position of doing this in a big way, that already presumes the fight to preserve the major ecosystems that make our world beautiful has been lost. For the sake of all the animals, including us, I hope we choose a saner path.”
In this video by Pattrn, Huber describes the concept of wet bulb temperatures.
About the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University
The Department of Earth, Atmospheric, and Planetary Sciences (EAPS) combines four of Purdue’s most interdisciplinary programs: Geology & Geophysics, Environmental Sciences, Atmospheric Sciences, and Planetary Sciences. EAPS conducts world-class research, educates undergraduate and graduate students, and provides our college, university, state and country with the information necessary to understand the world and universe around us. Our research is globally recognized, our students are highly valued by graduate schools, employers, and our alumni continue to make significant contributions in academia, industry, and federal and state government.
Writer: Cheryl Pierce, Communications Specialist
Photo by Rebecca McElhoe, Purdue University.