Potential of breadfruit cultivation to contribute to climate-resilient low latitude food systems

The number of people in food crisis around the world is increasing, exacerbated by the challenges of COVID-19 and a rapidly changing climate. Major crop yields are projected to decrease in low-latitude regions due to anthropogenic climate change, making tropical and sub-tropical food systems particularly vulnerable to climate shocks. Increased cultivation of breadfruit (Artocarpus altilis), often categorized as a neglected and underutilized species (NUS), has been suggested as an agricultural adaptation pathway for food insecure tropical and subtropical regions, due to its potential to enhance climate resilience and overall sustainability of low-latitude agricultural systems. To better understand breadfruit's cultivation suitability and geographic range in current and future climates, we employ a diverse set of observations and models to delineate the current climatically viable breadfruit range, and assess the climatically viable breadfruit range in the future (2061-2080) under stabilization and high emission scenarios. We find that the area of suitable breadfruit range within the tropics and subtropics is projected to decrease approximately 4.4% in the stabilization scenario and approximately 4.5% in the high emission scenario. In Southeast Asia and the Pacific Islands, yield quality and consistency show minimal decreases under the high emission scenario, with increases in total suitable area under both scenarios. In contrast, in Latin America and the Caribbean, the current range of breadfruit suitability is projected to contract approximately 10.1-11.5% (stabilization-high emission). Present and future model suitability outputs suggest that opportunities to successfully expand breadfruit cultivation over the next several decades exist in sub-Saharan Africa, where food insecurity is coincidentally high. However, in all regions, high emission scenario conditions reduce the overall consistency and quality of breadfruit yields compared to the stabilization scenario. Our results have the potential to inform global food security adaptation planning and highlight breadfruit as an ideal NUS to incorporate in food security adaptation strategies in a changing climate.

Changes in extremely hot days under stabilized 1.5 and 2.0 °C global warming scenarios as simulated by the HAPPI multi-model ensemble

The half a degree additional warming, prognosis and projected impacts (HAPPI) experimental protocol provides a multi-model database to compare the effects of stabilizing anthropogenic global warming of 1.5 ∘C over preindustrial levels to 2.0 ∘C over these levels. The HAPPI experiment is based upon large ensembles of global atmospheric models forced by sea surface temperature and sea ice concentrations plausible for these stabilization levels. This paper examines changes in extremes of high temperatures averaged over three consecutive days. Changes in this measure of extreme temperature are also compared to changes in hot season temperatures. We find that over land this measure of extreme high temperature increases from about 0.5 to 1.5 ∘C over present-day values in the 1.5 ∘C stabilization scenario, depending on location and model. We further find an additional 0.25 to 1.0 ∘C increase in extreme high temperatures over land in the 2.0 ∘C stabilization scenario. Results from the HAPPI models are consistent with similar results from the one available fully coupled climate model. However, a complicating factor in interpreting extreme temperature changes across the HAPPI models is their diversity of aerosol forcing changes.