* Any views expressed in this opinion piece are those of the author and not of Thomson Reuters Foundation.We may not be able to attribute migration directly to our changing climate, but we still need to act
Millions on the move, and many more millions likely to move - and our changing climate is the cause. This is not an unusual narrative, whether seen in news and views, or predictions of future movement from the advocacy community.
But the evidence of direct causality is not so clear, and in a report we have just released, we try unpick the facts of climate change and human mobility - asking what we do know and what we don’t. It is time to move beyond the rhetoric.
WHAT DO WE KNOW
We are a mobile species, of that there is no doubt - 244 million people live outside their birth country, and 740 million are displaced or have moved within their country. There are 157 million international migrants living in G20 countries, representing 3 percent of the population.
Evidence reveals that most cross-border migrants stay local, in their region. Beyond this we have insights into how movement is quite particular.
For example, Pakistani men are 11 times more likely to migrate during heatweaves than heavy rainfall because excessive heat has a heavier impact on income. And in India, increasingly erratic rains can push families to move, women doing so for up to three months, locally, and men for a year and more, and much further away.
We also know that sudden-onset climate hazards (storms, typhoons, extreme heat, flooding) displace millions - in 2016, 24 million, 32 times more than those displaced by earthquakes and tsunamis, and three times as many of those fleeing conflict.
And we know that between 2008 and 2016, sudden-onset events were responsible for 99 percent of internal displacement: an average of 21 million people annually. The events with the greatest impact are almost always flooding, such as in 2016, when all 10 of the largest disaster displacement events were from floods or storms.
So we know lots of people move, most often within their region as a matter of choice, while millions are forced to move, usually by flooding, and that patterns of movement can be discerned within particular geographies and hazards.
WHAT WE DON'T QUITE KNOW
It gets much more difficult from here.
Those hazards that creep up - drought, desertification, ocean acidification, salinisation, glacial retreat and sea-level rise - are much more difficult to track when it comes to their impact on human mobility. This is because with these - even with things you can visibly see over time, such as rising-sea levels - why people move may not actually be because of that sea-level rise, but attributable to many other factors.
These factors - political, social, economic, environmental, cultural - are part and parcel of people’s lives, and just as critical to why they may move or not.
Perhaps the education system is good enough to remain in an area where desertification is affecting your crops. Perhaps you take great stock in the cultural and familial connections of your home town, meaning you simply put up with seasonal flooding. Perhaps promised infrastructure, such as sea walls and other coastal protection, is year on year being postponed.
When people do move, they balance all these factors with the context of where they are going, and where they might go to. They consider issues of employment, healthcare, education, transportation, communication and much more.
The clear message is this: Independent of other context, our changing climate (arguably even for sudden-onset events) does not necessarily mean people will move.
WHAT SHOULD WE DO?
That we can’t attribute human mobility to the changing climate directly does not mean, however, that we should sit our hands. We certainly need better evidence on the complex inter-relationship between climate and movement, but we also need to take action, improved by ever-growing understanding.
Climate change and its interaction with human mobility is fundamentally about development. The flipside of not being able to link climate and movement directly is the realisation that it is precisely because movement is about every aspect of life and living.
That means an analysis of climate and human mobility must be built into development, into long-term planning and day-to-day delivery of services, particularly for the most vulnerable communities, those for whom movement is a critical consideration each and every day.
This is mirrored globally, where we see concepts and architecture around migration and displacement embedded within an international response machinery more than 70 years old and lagging far behind the complex decisions families and communities now make.
The Global Compacts on Migration and Refugees, due to be agreed in 2018, are key ways the system can catch up, ensuring climate change and climate risk are front and centre of frameworks to govern and support people who move, whether by choice or otherwise.
In addition, there are actions that can target climate impacts where it matters most. This includes investments in disaster risk reduction which can combat forced displacement head-on.
The longer-term picture requires investment in climate adaptation. Projects that tackle the slow-burn effects of sea-level rise, desertification, salinisation and more are critical to ensuring people can choose whether to move or stay.
Movement itself can be considered to be adaptation - and perhaps the best kind when it is based on a carefully considered decision by an individual and their family. This is a message we surely all understand.