International negotiations on climate change, along with recent upsurges in migration across the Mediterranean Sea, have highlighted the need to better understand the possible effects of climate change on human migration-in particular, across national borders. Here we examine how, in the recent past (2000-2014), weather variations in 103 source countries translated into asylum applications to the European Union, which averaged 351,000 per year in our sample. We find that temperatures that deviated from the moderate optimum (~20°C) increased asylum applications in a nonlinear fashion, which implies an accelerated increase under continued future warming. Holding everything else constant, asylum applications by the end of the century are predicted to increase, on average, by 28% (98,000 additional asylum applications per year) under representative concentration pathway (RCP) scenario 4.5 and by 188% (660,000 additional applications per year) under RCP 8.5 for the 21 climate models in the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP).

We discuss an underutilized dataset to examine the causes of migration. The United Nations High Commissioner for Refugees publishes annual binational asylum applications and the resulting decisions. Asylum is granted to protect individuals from persecution. They are a small part of overall migration patterns: one-tenth of overall migration flows into OECD countries. The European Union receives the largest share of asylum applicants and has a low acceptance rate, but the rate increases when source countries have positive deviations from historic trends. Countries outside the EU and OECD receive almost all of the applications from neighbors with a contiguous land border.

The influence of temperature on diversity and ecosystem functioning is well studied; the converse however, that is, how biodiversity influences temperature, much less so. We manipulated freshwater algal species diversity in microbial microcosms to uncover how diversity influenced primary production, which is well documented in biodiversity research. We then also explored how visible‐spectrum absorbance and the local thermal environment responded to biodiversity change. Variations in the local thermal environment, that is, in the temperature of the immediate surroundings of a community, are known to matter not only for the rate of ecosystem processes, but also for persistence of species assemblages and the very relationship between biodiversity and ecosystem functioning. In our microcosm experiment, we found a significant positive association between algal species richness and primary production, a negative association between primary production and visible‐spectrum absorbance, and a positive association between visible‐spectrum absorbance and the response of the local thermal environment (i.e., change in thermal infrared emittance over a unit time). These findings support an indirect effect of algal diversity on the local thermal environment pointing to a hitherto unrecognized biodiversity effect in which diversity has a predictable influence on local thermal environments.

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Do bat gantries and underpasses help bats cross roads safely? PLoS One 7, e38775. 22. Cramer, P., and Center, U.T. (2012).Determining wildlife use of wildlife crossing structures under different scenarios (Utah