In recent years the United Nations and other population agencies have projected that the global population will grow to just over 9 billion by 2050 before starting a gradual decline. Resource planning has often been based on this number.

Now an international group of scientists has analysed the latest data on population and has concluded that the gradual decline scenario is unlikely. Their analysis suggests that the global population could reach by 2100.

Some of the key findings of this new research include:

the world population can be expected to increase from the current 7.2 billion people to 9.6 billion in 2050 and 10.9 billion in 2100.

Asia will probably remain the most populous continent, although its population is likely to peak around the middle of the century and then decline.

the projected population of Africa, with a current population of about one billion, is projected to rise to between 3.1 and 5.7 billion with probability 95% by the end of the century, with a median projection of 4.2 billion.

rapid population growth in high-fertility countries can create a range of challenges: environmental (depletion of natural resources, pollution), economic (unemployment, low wages, poverty), health (high maternal and child mortality), governmental (lagging investments in health, education and infrastructure), and social (rising unrest and crime)

Projections of population data are important for both ecological and economic planners as well as for business. An abstract of the article, published in the journal Science, and a link to the full text (subscription or fee required) with more information on country data and probabilities can be found at http://www.sciencemag.org/content/early/2014/09/17/science.1257469.abstract