Yale’s interdisciplinary major in environmental studies has doubled in size over the past few years, and the program is expanding and diversifying its course offerings to meet the increased interest.

While 15 seniors graduated with degrees in environmental studies in 2010, this year’s graduating class will have 30, and there are another 31 majors in the class of 2013, according to data from Environmental Studies Program Chair John Wargo. As total enrollment in environmental studies courses has also surged, gifts from anonymous donors have allowed the major to offer additional seminars, and new field courses are in the works for the 2012-’13 academic year.

Yale College has offered a major in environmental studies since 1985, when former Yale College Dean Howard Lamar encouraged the creation of a program in the subject. At the time, students could pursue environmental studies only as a second major. Faculty developed and approved a standalone version of the major in 2001, but only four students in the class of 2004 were in its first graduating class.

The major, which draws upon the natural sciences, social sciences and humanities, has prerequisites in chemistry, biology, and physics or math, and requires an application to make sure students are prepared for the “special challenges” posed by the mix of disciplines, Environmental Studies Director of Undergraduate Studies Paul Sabin said in a December email. Students typically apply to the major, which has no cap on how many students it can admit, in the spring of their sophomore year. This year the major offered sophomores an early application deadline in December for the first time, and Wargo said 15 students applied by the early deadline.

Though faculty and students interviewed said the major’s science prerequisites might deter some students, the program has grown significantly in recent years. Interest among non-majors is also strong: Nearly 1,000 Yale College students choose courses in the Environmental Studies Program or the School of Forestry and Environmental Studies each year, Wargo wrote in a Jan. 5 report on the state of the major.

Sabin said he attributes the increase in popularity to “growing interest in studying complex environmental problems” and a greater awareness of the major as more students take environmental studies courses.

Dean of Undergraduate Education Joseph Gordon said that increased summer opportunities for environmental studies majors and a strong partnership between the major and the environment school may also have made the major more attractive.

“There’s really collaboration [between the major and the environment school] now, not just two groups working in parallel,” Gordon said in a Thursday email.

Funding from several anonymous donors has enabled the major to offer 10 new seminars since 2009, Wargo wrote in the report. These include courses on how to use Geographic Information System (GIS) software, a popular research tool used to visualize data points on a map, as well as courses on energy policy, political ecology and science writing.

The major may also introduce a few new field courses in the coming academic year, which would take advantage of Yale’s proximity to thousands of acres of Connecticut forests and the Long Island Sound, Wargo said in a Tuesday email.

Seven environmental studies majors interviewed said they were drawn to the program because of its interdisciplinary and flexible nature. The major requires students to develop their own area of concentration but allows them to apply courses from numerous fields toward that concentration.

“What attracted me to [the major] was the possibility of combining conservation biology and policy into one major, and having the ability to focus on policy issues while simultaneously gaining a substantial background in the natural sciences,” Katherine Eshel ’13 said in a Wednesday email.

The major has also developed a more serious reputation since its creation, people involved with the program said.

Jeffrey Park, a professor of geology and geophysics who chaired the environmental studies program before Wargo, said the major was considered “soft” by some undergraduates and their parents when it was first offered as a standalone major, but that it has now become more popular.

Thomas Rokholt ’14 said that after taking the course “Global Problems of Population Growth” last spring, which is cross-listed in biology, history and the forestry school, he realized the environmental studies major was “not just for hippies.”

The spring application deadline to the major is Feb. 24.