Extreme weather has displaced around 26 million people from their homes every year since 2008. Yet climate migration has failed to make it on to the negotiating table at major climate change summits, and COP 21 could be no different.
The draft agreement gives short shrift to climate-induced migration: the word is used just twice in the 54-page document, and the only other mention relates to a “displacement coordination facility” to support those displaced. Campaigners and major migration agencies fear that even these will be axed from the final treaty. This matters because without momentum at global level, governments may fail to put in place policies and infrastructure to address links between climate and migration.
Extreme weather events and sea-level rise will displace people. But evidence shows this is unlikely to result in the ‘tides of people’ swamping Europe that scaremongers often speak of. 
Rather, cities in the global South are likely to bear the brunt of climate migration — or, to be more precise, their slums.
This is certainly the case in South Asia, which has some of the world’s fastest growing megacities. In Dhaka, capital of disaster-prone Bangladesh, roughly 350,000 migrants arrive every year, adding to the city’s 14 million inhabitants. Most are displaced from the delta region where storms and sea level rise have made farming less viable.
One way of viewing such migration is as a way to adapt to climate change. But government attitudes and policies around rural-to-urban migration are increasingly hostile.  Many governments refuse to provide services for fear of encouraging further migration, which they link to worsening crime, filth and disease. Research from Ghana and India shows the extent of government inaction.
This inaction keeps in place awful systems of waste disposal. Take the notorious ‘flying toilets’ of Accra and Nairobi, where waste is put into plastic bags and flung as far away as possible. Or open defecation, which plagues cities such as Delhi and Mumbai.
For cities to cope, local governments must recognise the inevitability of climate-induced migration, and take action to upgrade infrastructure and services.
This will be tough. The high density of informal settlements coupled with insecure tenancy can make it impossible to improve sanitation. Virtually every inch of land in informal settlements is in use, making it difficult to dig trenches for drainage. Many people live in tenements under constant threat of eviction, meaning landlords are reluctant to improve toilets.
Not only that, but many informal settlements develop in marginal areas of the city that are vulnerable to flooding and destruction due to severe weather.
There are more enlightened, imaginative approaches to improving urban settlements. In Mumbai, the NGO SPARC gathered feedback from local people and built community toilets that 20,000 people use every day. In Kibera, Nairobi’s largest slum, the Human Needs Project NGO developed a clever system of wastewater recycling for unplumbed neighbourhoods. Often these ideas come from local people themselves: the Global Initiative on Community-Based Adaptation is compiling and sharing information on what people are doing to adapt — and these ideas are likely to be more effective than top-down formulas.
But governments must also act. And cities shouldn’t only see newcomers as a risk or burden: often migrants are the most resourceful of their peers, providing cheap labour, trading and manufacturing goods for urban consumers. A more enlightened attitude to migrants will benefit cities and all who live in them.
Priya Deshingkar is Research Director of the Migrating out of Poverty research consortium. Her interests include precarious migrant occupations, exploitation in labour markets, informal settlements, gender and poverty.
This blog was originally published by Sci.Dev.Net on 3 December 2015 under their Focus on Migration series and is also available at:
 The Government Office for London Migration and global environmental change: future challenges and opportunities (UK government, 2011)
 UN Department of Economic and Social Affairs World population policies 2013 (UN, 2013)