The centripetal pull of climate: Evidence from European Parliament elections (1989-2019)
Marco Dueñas, Hector Galindo-Silva, Antoine Mandel
TL;DR
The paper addresses how short-run temperature shocks influence electoral competition in Europe by linking high-resolution regional climate data with European Parliament outcomes from 1989 to 2019. It employs a semi-non-parametric panel design with region and country-year fixed effects, using 12 temperature bins to capture non-linear effects on voting, while measuring vote concentration via the Herfindahl–Hirschman Index $HHI_i=\sum_j w_{ij}^2$ and polarisation via $Pol_i=\sqrt{\sum_j w_{ij}(\frac{p_j-\overline{p}_i}{5})^2}$, where $w_{ij}$ are vote shares and $p_j$ party positions. The main findings show that unusually warm days reduce polarisation and increase concentration around larger, centrist parties, with liberal and social democratic gains at the expense of right-wing and smaller parties; on the supply side, liberals and social democrats intensify climate-protection references in manifestos after warm periods. The results suggest climate shocks can restructure party systems by pushing voters toward the centre and by altering party strategies, highlighting climate change as a salient axis of electoral competition in Europe. Limitations include the focus on EP elections and the need to untangle climate-driven demand shifts from broader crisis responses, guiding future research beyond national contexts and across different climate phenomena.
Abstract
This paper examines the impact of temperature shocks on European Parliament elections. We combine high-resolution climate data with results from parliamentary elections between 1989 and 2019, aggregated at the NUTS-2 regional level. Exploiting exogenous variation in unusually warm and hot days during the months preceding elections, we identify the effect of short-run temperature shocks on voting behaviour. We find that temperature shocks reduce ideological polarisation and increase vote concentration, as voters consolidate around larger, more moderate parties. This aggregated pattern is explained by a gain in support of liberal and, to a lesser extent, social democratic parties, while right-wing parties lose vote share. Consistent with a salience mechanism, complementary analysis of party manifestos shows greater emphasis on climate-related issues in warmer pre-electoral contexts. Overall, our findings indicate that climate shocks can shift party systems toward the centre and weaken political extremes.