Addressing climate change with behavioral science: a global intervention tournament in 63 countries

Effectively reducing climate change requires marked, global behavior change. However, it is unclear which strategies are most likely to motivate people to change their climate beliefs and behaviors. Here, we tested 11 expert-crowdsourced interventions on four climate mitigation outcomes: beliefs, policy support, information sharing intention, and an effortful tree-planting behavioral task. Across 59,440 participants from 63 countries, the interventions’ effectiveness was small, largely limited to nonclimate skeptics, and differed across outcomes: Beliefs were strengthened mostly by decreasing psychological distance (by 2.3%), policy support by writing a letter to a future-generation member (2.6%), information sharing by negative emotion induction (12.1%), and no intervention increased the more effortful behavior—several interventions even reduced tree planting. Last, the effects of each intervention differed depending on people’s initial climate beliefs. These findings suggest that the impact of behavioral climate interventions varies across audiences and target behaviors

Rhizobium diversity in the light of evolution

International audienceRhizobia, nitrogen-fixing symbionts of legumes, are phylogenetically diverse soil bacteria. These bacteria do not share a unique genetic strategy to achieve symbiosis. Instead, they have evolved various mechanisms to induce and invade the root/stem organs where nitrogen fixation occurs. Most rhizobial lineages emerged from horizontal transfer of few essential symbiotic genes located on mobile genetic elements. Besides, rhizobia have extensively recruited their own native functions to optimize symbiosis and refine interaction with host plants. This has likely occurred following symbiotic gene transfer and via genomic adjustments under plant selection pressure. This two-step evolutionary scenario was recently validated by an evolution experiment that progressively turned a plant pathogen into legume symbionts. Acquisition and improvement of the first symbiotic stages, nodulation and infection, were most often gained via the rewiring of the virulence and/or metabolic regulatory network of the ancestral strain