When Arianna Varuolo-Clarke was growing up, her favorite evenings were spent watching the Weather Channel with her grandfather. She wanted to “chase thunderstorms” and understand where tornadoes came from, she said. She decided to become an atmospheric scientist. In 2014, she landed an internship at the National Center for Atmospheric Research as a college sophomore, and quickly realized that her path as a woman of color would not be easy.

“You’d walk through the halls and it’s a lot of old white men,” Ms. Varuolo-Clarke said. Still, she pushed forward and began her Ph.D. in atmospheric science at Columbia University last year.

The field’s lack of diversity gained new urgency in May when her graduate student cohort was targeted with a series of racist emails. The messages, sent to affiliates of the Lamont-Doherty Earth Observatory at Columbia by a person outside the community, said that black people were genetically inferior and did not belong in academia. It was “hurtful and invalidating” to be told that she didn’t belong in the world that had drawn her in since childhood, Ms. Varuolo-Clarke said. “It was an isolated incident. But it brought to the surface what still needs to be done in the field.”

In a commentary last week in Nature, Kuheli Dutt, Lamont-Doherty’s assistant director for academic affairs and diversity, wrote that “a lack of diversity and inclusion is the single largest cultural problem facing the geosciences today.”

The geosciences — which include the study of planet Earth, its oceans, its atmosphere and its interactions with human society — are among the least diverse across all fields of science. Nearly 90 percent of doctoral-degree recipients are white. In the country’s top 100 geoscience departments, people of color hold under 4 percent of tenured or tenure-track positions. A 2016 survey from the National Science Foundation showed that representation of people of color in geosciences has barely budged in the past four decades, although significant gains have been made in terms of gender balance.

The field’s lack of diversity begins with a pipeline problem, geoscientists say. National surveys have shown that black people are less likely than white people to participate in outdoor activities. One survey, conducted in 2009, queried 4,103 respondents and found that African-Americans accounted for just 7 percent of national park visitors, and another survey found that they were more likely to report receiving poor service by park employees. Robert Stanton, the first black director of the National Park Service, has said that the idea that “black folks don’t like parks” has become a “self-fulfilling prophecy.”

Lisa White, a micropaleontologist at University of California, Berkeley, said most public high schools, especially those in urban environments, did not have the resources to organize outdoor field trips introducing students to the earth sciences. As the assistant director of education and outreach at the U.C. Museum of Paleontology, Dr. White has noticed that students of color tend to be more familiar with medicine, engineering, computer science and other STEM fields that lead directly to job opportunities.

Compounding the pipeline problem is one of stereotypes. The typical earth scientist is often seen as a rugged white male.

“You think of a bearded guy on top of a mountain wearing flannel and hiking boots,” said Jonathan Nichols, an associate research professor at Lamont-Doherty. “We just had our big fall conference and there were 20,000-plus geologists, and you look around and it’s all old bearded guys.”

That stereotype, Dr. Nichols said, can make the field feel unwelcoming to people of color, who don’t see themselves represented at conferences and among faculty members. Dr. White concurred that the geosciences had an “image problem” that prevents young people of color from applying for research opportunities.

That lack of representation in turn affects the quality and focus of earth science research, especially on climate change.

“It’s not rich white people who will be impacted first and most by climate change,” Dr. Nichols said. “It’s the people in marginalized communities. And if you forget that this work isn’t just an academic pursuit, then why are you even doing it? You have to keep in mind the real impact.”

Lorelei Curtin, a fifth-year Ph.D. student at Columbia University, said her earth science classes could be enriched by a greater focus on nonwhite and Indigenous histories and voices, given that “Indigenous people have a unique connection to the land.”

Ms. Curtin helped start a book club at Lamont-Doherty called Race Talk, which brings together geoscientists for discussions on race and white privilege. The group has read “Race Talk and the Conspiracy of Silence,” by Derald Wing Sue, as well as “Home,” by Toni Morrison. Ms. Curtin said that scientists were not accustomed to conversations that center on individual stories and experiences rather than data, so sensitive discussion of racism presented a challenge.

Dr. Dutt, Lamont-Doherty’s diversity director, joined the Observatory 11 years ago as its only person of color in a leadership role. Since then she has led trainings for geoscientists on recognizing their implicit biases to foster a more racially inclusive environment.

Her article in Nature last week, titled “Race and Racism in the Geosciences,” was so popular that the journal’s editors removed its pay wall. The article called on geoscientists to take personal responsibility for ridding their field of prejudice.

“I wanted to write the piece to address the disconnect between the way white people and people of color view topics of racism,” Dr. Dutt said. “Most of the people I’ve worked with in my role as diversity officer are nice people and well-intentioned people. But privilege tends to be invisible to the person who has it.”

After the discriminatory email messages in May, Dr. Dutt organized a forum to discuss diversity, and the lack of it, in geoscience; the event was standing room only. Ms. Varuolo-Clarke was moved by how many of her classmates attended, realizing that the emails had brought to the surface racial challenges that the earth scientist community must confront.

“Sometimes it’s an elephant in the room that I’m a woman of color,” Ms. Varuolo-Clarke said. “I’d rather we talk about it versus tiptoeing around it.”