New Delhi : Union Railways Minister Suresh Prabhu has called for concerted efforts across the world to address the issue of climate change. Addressing a function in New Delhi yesterday, Prabhu said that people need to ensure their duties as a global citizen and tackle the problem of climate change as a top-most priority. He expressed concern over the growing population and stressed on the seriousness of climate change. Prabhu said the railways, which is trying to ensure its role in environment protection, has created an environment directorate at the ministry. Laying thrust on green power, he said that his ministry is trying to use as much solar power and installing solar panels on train-tops to generate enough power for internal purposes of a train.