Continuando a publicacao das melhores redacoes do semestre, vamos ao nivel 6. Do mesmo jeito que no semestre passado, pedi um ensaio relacionado a qualquer assunto verde. De novo, o semestre rendeu criativamente e eu tive nao so um, mas dois ensaios excelentes sobre dois aspectos ambientais bem diversos. Parabens aos quatro DearStudents laureados! by Thais VenturaSustainable transportationGlobal warming brings significant challenges for cities and transportation is one of the sectors that most contributes with this. Therefore the need to plan for sustainable transportation is evident. Sustainability and sustainable development have been the main theme of many international conferences, but no strategy for sustainable transportation systems was established and approved in mutual agreement by all countries so far. However, across the globe each city is trying to implement their own sustainable policies.Planning for sustainable transportation systems is a complex task that involves multiple options, since prioritizing public transportation system until discouraging car use and promoting non-motorized modes such as cycling. With this range of alternatives, the planning for sustainable transportation systems is very uncertain. Governments should seek an optimal package of policies that is happily accepted by all affected groups and this solution could be very difficult to find.A successful example is the case of exclusive bus lanes. Analysis of the environmental impacts generated by exclusive bus lanes shows that these transportation systems lead to the reduction of greenhouse gas emissions responsible for global warming and provide other benefits such as better use of energy, reduction of fuel consumption and accidents. This system was implemented in the city of Curitiba, Brazil, and in the city of Bogota, Colombia, and both have the same achievements.Although there is not a common policy on sustainable transportation planning in all countries, individual efforts to move towards sustainable transportation can show significant results.by Rodrigo AcostaThe Renewable Energy AdvantagesOur world faces a lot of enviromental issues nowadays, and it seems that people started worrying more about it than they did in the past. There are a lot of Non-Governamental-Organizations today that care about helping animals and nature, and a lot of factories and industries that reduced the amount of non-renewable energy used in making their products. All of it is a reflect of the current situation of the Earth. Global warming is a scary thought that is becoming true and it could affect the lifestyle of a lot of people in the world.One of the biggest problems that have to be confronted is that the majority source of energy in the world is provided by fossil fuels. This kind of energy is not the best to be used, because it releases a lot of toxic gasses to the atmosphere that contribute with global warming. These fuels also have not appeared easily on Earth and it took a lot of years for them to be done. Some fossil fuels that are in our daily life are gasoline, mineral coal, diesel oil and natural gas.What should be done to confront that is the use of renewable energy. This kind of energy is called that way because it can be obtained