Understanding Earth's critical zone

ASU professor explains how the study of sustainability and the environment has changed over the years

April 20, 2021

The Earth’s near-surface environment, known as Earth’s critical zone, supports most life on the planet. This uppermost layer that extends from the tops of trees down to several feet below the surface is the area that humans most depend on.

“We grow our food in this zone. Most of our drinking water is filtered through this zone. The wild animals, forests, deserts, mountains, lakes and rivers — all the part of the Earth’s surface that we humans engage directly with in so many ways — are all part of this zone,” said Arjun Heimsath, professor in Arizona State University’s School of Earth and Space Exploration. Arjun Heimsath, professor in Arizona State University’s School of Earth and Space Exploration, teaches the course "Earth’s Critical Zone" where students explore how changes to the environment manifest themselves in landforms, water resources, soils, agriculture and ecosystems. Download Full Image

Heimsath believes that understanding the physical and chemical processes that operate in this zone, as well as the way that geology, climate and humans impact how these processes take place, is a critical step in addressing many of the challenges our planet faces.

In his course "Earth’s Critical Zone," students do exactly that by exploring how changes to the environment manifest themselves in landforms, water resources, soils, agriculture and ecosystems. 

“I enjoy watching students get excited about these topics that are so important for understanding how our planet works,” he said. “I just love watching their eyes light up when they ‘get’ a new science-based concept about how some aspect of the environment that they have always taken for granted actually works. It’s such a thrill to share in their excitement.”

For Earth Day, Heimsath gave insight on the importance of understanding Earth’s critical zone and how the study of sustainability and the environment has changed over the years.

Question: You were involved in the creation of the earth and environmental studies degree at The College of Liberal Arts and Sciences — tell us about that program. 

Answer: We began the earth and environmental studies degree about eight years ago, in response to the interest that a number of students in the School of Sustainability had articulated to me — to have more physical science in their degree. The hope with creating the degree was to attract students who have a fundamental interest in environmental studies along the lines of my own background — a deep commitment to understanding earth surface processes with the aim of helping to mitigate or prevent human impacts from harming the environment. … As humans continue to try to figure out how to better deal with overpopulation, climate change, biodiversity loss and habitat destruction to name a few key areas of concern, students coming out of The College with an earth and environmental studies degree will be in high demand across multiple sectors of the workforce. 

School of Earth and Space Exploration Professors Arjun Heimsath (left), Stephen Reynolds (middle) and Thomas Sharp (right) with two students at an outcrop near Durango, Colorado, while teaching in summer 2019. Photo by Nari Miller

Q: How did the "Earth’s Critical Zone" course come about?

A: I was quite active in a program at the National Science Foundation that was funding big projects focusing on the critical zone and realized that there was no single class that I had ever heard of that focused simply on Earth’s critical zone. No syllabus existed, no textbook — nothing. I thought, “How cool is this, I can make up this absolutely key class and call it ‘Earth’s Critical Zone.’” And that was that. I have subsequently gotten the class approved for science and society credit and also created a fully online, asynchronous version of it that I offer during the summer. 

Q: What are some of the biggest ways you’ve seen the study of sustainability and the environment change over the years?       

A: It’s become mainstream. I compare the level of awareness and education of the students that I teach in this major to those that I taught when I first started as a professor in 2000, and the difference is extraordinary. Students are coming into college as first-year students now with a level of understanding of sustainability and environmental change that seems comparable to what I emerged from my master’s degree with way back in the early 1990s. It’s encouraging and inspires hope. I’ve also noticed that college students these days seem to want to be way more proactive and engaged than my peers did 30 years ago. 

Q: This Earth Month, what issues do you feel are the most crucial to address and why?

A: The same issues that have been crucial to address for the last 50 years for all the same reasons that countless environmental scientists, activists and educated politicians have been articulating over and over and over again: climate change, biodiversity loss and habitat destruction. That’s probably the most difficult aspect of this field — change is slow, and humans don’t adapt unless there’s a very rapid and obvious crisis. 

The iconic sandstone landscape around Sedona, Arizona. Photo by Arjun Heimsath

Q: What can people do to effect change, and is there something that gives you hope for the future of these issues?

A: That trite expression that has maybe fallen out of the limelight is certainly applicable here: Think globally, act locally. This begins by voting in the right people to formulate science- and truth-based policies and continues by getting involved working on local issues at whatever level one is able to give. I feel hope because I’ve watched human behavior change to be more environmentally aware and also because I strongly believe the younger generations are way ahead of their elders in terms of changing behavior toward more environmentally friendly practices. There’s so much good that can be done, and I like seeing the younger generations getting into it. 

To learn more about Earth Month at ASU, visit earthmonth.asu.edu.

Emily Balli

Communications Specialist and Lead Writer, The College of Liberal Arts and Sciences

Attending ASU was a 'no-brainer' for Cronkite School convocation speaker

April 20, 2021

Editor's note: This story is part of a series of profiles of notable spring 2021 graduates.

After attending the Cronkite Sports Broadcast Boot Camp the summer before his senior year of high school, Harrison Zhang’s mind was made up. He was going to Arizona State University. Harrison Zhang will serve as the 2021 Cronkite Convocation speaker. Harrison Zhang. Download Full Image

“I fell in love with the facilities, campus and opportunities ASU offered," he said. It was a no-brainer after stepping on campus for the first time.”

Now four years later, the Irvine, California, native will receive his Bachelor of Arts in sports journalism and deliver the student convocation address May 3 for the Walter Cronkite School of Journalism and Mass Communication.

Zhang, who is Asian American, said he was not 100% sure he was going to fit in at ASU.

“I was skeptical on whether I would be judged or looked at differently because of my background, but I was surprised at the community built at Cronkite. I immediately felt welcomed and made so many amazing friends from all kinds of backgrounds.”

While the Cronkite School has a reputation for being a competitive program, Zhang soon realized that everyone has each other’s back and wants them to succeed. “One of my favorite parts about Cronkite is that I know I can turn to any one of my peers for advice in an area I’m not familiar with and they can do the same with me. The community is extremely supportive, and we’re all here to learn and grow together.”

Zhang was a recipient of the New American University President’s Award Scholarship each semester and joined The State Press student media outlet during his freshman year. He also completed several internships and worked with two organizations back home in Orange County: OC Sports Zone, a local online publication that focuses on high school sports, and Orange County SC, the professional soccer team that is part of the United Soccer League. Additionally, Zhang was involved with Sun Devil Athletics for most of his college career, assisting with social media strategy, graphics, video editing and photography and winning two NCAA Photo of the Week awards.

We recently caught up with Zhang and asked about his plans and his favorite memories at ASU.

Question: What was your “aha” moment when you realized you wanted to study the field you majored in?

Answer: My “aha” moment happened in seventh grade when my English teacher assigned us to do a “passion project” and explore something we want to learn more about and spend 20 minutes a day on it for a month. I chose to do a sports blog because I loved discussing sports. From there, I joined my high school newspaper and never looked back.

Q: Why did you choose ASU?

A: I love that ASU has a downtown campus that is smaller in size and more laid back, but it also has the Tempe campus for when I am looking for the big school feel. The class size at Cronkite is much smaller than people think, and I get to have amazing connections with my professors, many of whom are still working in the field. Also, the weather is not as hot as people think. After October, we mainly have 60-degree weather and sunny skies every day. As a California kid, I cannot handle the cold.

Q: Which professor taught you the most important lesson while at ASU?

A: Paola Boivin has been one of the most influential professors I have ever met. She exemplifies the values and dedication that I strive to carry into my professional career. She has taught me a lot about how far kindness can take you in this business. She always goes the extra mile to develop individual relationships and takes the time to get to know people as individuals. I think in this industry it is easy to get caught up in the hectic nature of what we do, but Paola has taught me a lot about slowing down and being personable with everyone. She would often bring up stories from when I first knew her at the Cronkite camp, and I’m amazed at how she remembers these things. It is because she takes the time to really care about and listen to her students and people she encounters, which is something I hope to take with me in my professional career.

Q: What’s the best piece of advice you’d give to those still in school?

A: Interestingly enough, when I got to ASU, I came in so headstrong knowing I wanted to be a sports writer and only that. I joined The State Press my first semester freshman year looking to be a sportswriter, but when they did not have spots open, I volunteered to join their photo desk hoping to just get any opportunity. When I started taking sports photos, I fell in love with capturing stories through a camera. This eventually led to an internship with Sun Devil Athletics in their digital media department. I am currently interested in photography, videography and content creation. I learned it is so critical to keep an open mind while in school because you never know what your true passion may be. It is 100% OK to try new things outside your initial comfort zone.

Q: What was your favorite spot on campus, whether for studying, meeting friends or just thinking about life?

A: My favorite spot on the downtown campus was the walkway between Tower 1 and Tower 2 at Taylor Place. The view overlooked the Cronkite building and the Phoenix skyline, which made it a great place to study or relax.

My favorite spot on the Tempe campus is the (Memorial Union). I spent a lot of time on the Tempe campus with all the sports games going on there. I could always rely on the MU for a good quick bite to eat after taking the downtown campus shuttle that dropped me off at Gammage.

My overall favorite spot on campus is Farrington Stadium. I spent a lot of my time there for my internship and often came early to games to do my homework there because the view is so nice. One of the hidden gems of campus for sure.

Q: What are your plans after graduation?

A: I plan on returning for my master’s degree in the 3+1 program at Cronkite. I am hoping to be a graduate assistant with the Sun Devil Athletics digital media department. God willing, I would like to pursue a job with a professional sports team after my master’s, managing their social media and developing digital content — photo, video, graphics. 

Q: If someone gave you $40 million to solve one problem on our planet, what would you tackle?

A: I would try and invest more in youth mental health. I think our youth education system struggles to address this issue effectively, which leads to a lot of mental health stigma and mental health issues in general for many students. Our youth is our future, and in the digital age, it is more important than ever to help normalize seeking help and educate students on the importance of mental health.

Written by Mario Baralta