London's population has increased by more than three million people in the previous century, allowing the capital's metropolitan center to develop further than ever before. The capital's population grew steadily throughout the twentieth century, and it today numbers more over 10 million people, making it one of the world's 28 megacities. It is estimated that London will have a population of 12 million people by 2050. The city's growth is slowing, but it will not stop being a megacity even after 2020. Indeed, London is expected to continue to grow for the next 20 years until it reaches a population of about 18 million, which is when it will start declining again. In 2010, London had a population of 8 million people, so the number of megacities around the world has now reached 14. There are several other large cities in Europe and North America that are also expected to become megacities over the coming decades, including Paris, Berlin, Toronto, New York City, and Chicago. Megacities are defined as urban centers with populations of at least 10 million people. They account for 70 percent of global urban growth and nearly half of all carbon dioxide emissions from fuel combustion. Their size makes them efficient economic engines, but they suffer from many of the same problems as other large cities, such as crime and pollution. In conclusion, yes, London will be a megacity by 2020.