The current report is focused on a technical screening and selecting exercise of climate/weather parameters and indices to be used in a bigger JRC Project on Climate Change Induced Migration (CLICIM). The main aim of the current exercise is to select among several tenths of variables and data sets, the ones that could be potentially influence directly or indirectly drivers of migration. Besides the mainstream climate change impact parameters such as temperature, wind, humidity, clouds and precipitation, we consider an extensive set of climate/weather extreme indices that could shed light on the possible relationships between environmental degradation parameters and induced migration.
In total we examine closely ninety five parameters and indices assessing their temporal and geographical coverage and relevance on the basis of the most recent climate change and migration literature before proceeding to the final selection of thirty seven meteorological parameters and extreme climate/weather indices.

The report describes the data availability for each parameter and index, limitations and capabilities in terms of coverage and spatial and temporal detail and provides references on the use of the variable mainly in the context of migration studies. Such empirical evidence has been considered as the primary criterion for selecting parameters and indices potentially influencing drivers of migration. Other criteria guiding our selection have been the technical suitability in respect of the main population and net migration data already assembled during the initial phase of the CLICIM Project.

This report will be followed by a similar screening exercise focusing on agriculture and water scarcity indices. In the final steps of CLICIM, the full set of the indices documented in these two screening reports will be put in relation with population and net migration data at high spatial resolution and utilised in statistical models exploring potential links between climate change impacts and induced migration.

According to the Intergovernmental Panel on Climate Change’s latest Report on Climate Change and Land (IPCC, 2019), climate change can lead to land degradation, even with the implementation of measures intended to avoid, reduce or reverse land degradation (high confidence). Such limits to adaptation are dynamic, site-specific and are determined through the interaction of biophysical changes with social and institutional conditions (very high confidence). In some situations, exceeding the limits of adaptation can trigger escalating losses or result in undesirable transformational changes (medium confidence) such as forced migration (low confidence), conflicts (low confidence) or poverty (medium confidence).

On the other hand, both the decrease (linked to drought events) or increase (linked to floods) of rainfall may enhance migration in an area of interest. Though precipitation also has a similar nonlinear effect on migration, the effect is smaller than that of temperature. It appears that sudden, serious catastrophes mainly driven by extreme precipitation events demonstrate lower permanent migration flows compared to the gradual effects of climate change mostly driven by temperature increase. Communities are uprooted due to a flood event, but they tend to return on permanent basis.