Some of the more dire predictions on the world's population growth and its results have not come true. "Still, there's little doubt that the Earth's human carrying capacity has a limit. And growth can't continue indefinitely without more of the significant environmental health impacts we are already seeing," writes Richard Dahl in this seven-page article. Population is currently at 6.5 billion, and even though birth rates are declining everywhere in the world, population will not necessarily decline, and the UN predicts a population of 9.1 billion by 2050. Even though population growth has slowed in developed countries, poor countries will continue to have increased growth, most of it in cities and slums. "Whether one chooses to attribute impacts to human numbers or human behavior, the fact remains that the world's population – its numbers, its movement, its actions – is having a profound impact on human and environmental health," writes Dahl. All the same, he writes that population growth and its impact on health and the environment is often ignored, and he holds out some hope that the Millennium Ecosystem Assessment could bring more attention to the issue.