Several publications show how estimates of future climate change refugees vary substantially, from tens of millions to a billion. Let's look closely at the science.
A United Nations statement in 2005 garnered significant publicity that the world would see 50 million people moving due to environmental degradation by 2010. When 2010 arrived, it was not possible to calculate or verify that number.
Then, a group of scientists hit the headlines with their suggestion that the UN states the number of 'environmental refugees' (the term used by the media) would be 50 million by 2020. No citations were provided.
Scholars continually raise definitional questions meanwhile. A 'refugee' has a specific meaning under international law which cannot include environmental reasons for moving. Attributing long-term environmental changes, such as climate change, to specific choices to migrate is almost impossible.
With some exceptions.
Communities in the Arctic and tropical islands have been forced to relocate because the sea is destroying their homes. Climate change seems to be the only possible reason for the forced migration from Newtok and Shishmaref in Alaska along with Papua New Guinea's atolls of the Carteret Islands and Takuu.
Are these communities harbingers for much larger movements of people? Will the changing climate indeed force huge groups of people from farther south, whether that be Greece or Ghana, to seek solace in Scandinavia?
We do not know.
We do know that people have always moved, for combinations of environmental and non-environmental reasons. That will continue, with climate change being one influence amongst many.
We also know that climate change is causing the planet to change rapidly in alarming ways. Finally, we know that the human population has never been as large as today.
To understand the implications of this combination, we must research, plan and prepare, while fully assisting those who must move now due to climate change.
But we must never exaggerate.
Dr. Ilan Kelman is a Senior Research Fellow at the Center for International Climate and Environmental Research - Oslo (CICERO) and co-directs the Many Strong Voices programme.