Asa is a professor at the Department of Economics of the University of the Philippines (UP) Los Baños, where he has been teaching undergraduate and graduate courses in microeconomic theory and environmental economics since 2003. He is also part of the executive committee and a co-regional director for Luzon of the Economy and Environment Group – Philippines (EEG Philippines).
He has worked on a variety of environmental economic issues which include, among others, payment for ecosystem services, impact evaluation of community groundwater irrigation, climate change adaptation in coastal areas, and applications of different economic valuation methodologies on ecotourism, sanitation, agrobiodiversity, and forest conservation. He obtained his bachelor’s degree in economics from UP Los Baños and his master’s and doctoral degrees in agricultural and natural resource economics from UC Berkeley.