Tarhule grew up in Nigeria and earned a BS in geography (first class) and MS in environmental resources planning at the University of Jos before continuing to Canada, where he earned the MS and PhD in geography at McMaster University, Hamilton, Ontario. After completing his doctorate, Tarhule returned to the University of Jos as lecturer for one year and spent another year as a post-doctoral research fellow at Queens University, Kingston, Ontario, and from there accepted a position as assistant professor at the University of Oklahoma. There he rose through the ranks to become a professor, successful department chair and executive associate dean.
A productive scholar, Tarhule is a physical geographer who studies hydroclimatic variability, with a special emphasis on Africa. He has published almost 40 papers in refereed journals, served as principal advisor for more than a dozen graduate students, sponsored and supervised several postdoctoral fellows, and secured funding for his research from the National Science Foundation, the National Institute of Health, the U.S. Agency for International Development, and the Oklahoma Water Resources Research Institute.