It's a very big change, and it means that obviously, industrialized countries must cut their emissions, must become much more energy-efficient, and must move as quickly as possible to renewable energy. For developing countries and emerging economies, the problem and the challenge is to grow without emissions, because they must develop; they have very poor populations. So they must develop without emissions, and that is a different kind of problem. Indeed, no country in the world has actually grown without emissions. All the countries have developed with fossil fuels, and then may be moving to renewable energy. So it is a very big challenge, and it requires the total support of the international community, with the necessary finance and technology, and systems and support, because no country can make itself safe from the dangers of climate change. This is an issue that requires complete human solidarity. Human solidarity, if you like, based on self-interest -- because we are all in this together, and we have to work together to ensure that we reach zero carbon by 2050.