Gem Castillo is currently the President and Chairman of the Board of the Resources, Economics and Environment Center for Studies (REECS). He is also concurrently the President of the Resources and Environmental Economics Foundation of the Philippines (REAP) and the National Director of the Economy and Environment Group Philippines (EEG), the country institution partner of the Economy and Environment Partnership in Southeast Asia.
He is a local and international expert in natural resource and environmental economics. As an expert, he has been involved in a wide range of topics such as wealth accounting and valuation of ecosystem services, the economics of environmental governance, forest land use planning, the economics of coastal resources management, and payment for environmental services among others. He was involved, as the National Expert, in piloting the World Bank Program on Wealth Accounting and Valuation of Ecosystem Services (WAVES) in the Philippines and as Project Leader of a multi-disciplinary team that completed the Philippine Country Study on The Economics of Ecosystem and Biodiversity (TEEB) program of the UN Environment Program.
He received his BS Forestry and MS Forest Resources Management with a specialization in Forest Economics degrees both from the University of the Philippines Los Banos. He was accorded his doctorate degree in Forest Economics, and Certificate in Resource Economics from Michigan State University.