This article is part of a special report on Climate Solutions, which looks at efforts around the world to make a difference.CARCASTILLO, Spain — As wildfires ravaged the Cerro de Monserrate in Colombia in 2015, Juan Carlos Sesma, a Spanish retail consultant working in Bogotá, started thinking about reforesting the planet.With experience in improving systems for restaurant chains, supermarkets and for the department store El Corte Inglés, he imagined his know-how could be applied to the task of reversing deforestation.“I knew that if reforestation could be made efficient and profitable, the world would have a lot more trees,” he said.Taking time out from work, he bought a box of Empress tree seeds — a fast-growing species, capable of reaching 20 feet in one year — and flew back to his hometown in Spain determined to learn to plant trees and put his idea into practice.Mr. Sesma, 38, is among a growing group of world citizens who are not only concerned about the futu …
