Maritime transport carries over 80% of global trade by volume and remains the most energy-efficient mode for long-distance goods movement. However, the sector contributes approximately 3% of global Greenhouse Gas (GHG) emissions, a share that could rise to 17% by 2050 without effective regulation. In response, the International Maritime Organization (IMO) has introduced initial and short-term measures to enhance energy efficiency and reduce emissions. In 2023, IMO Strategy expanded on these efforts with medium-term measures, including Market-Based Mechanisms (MBMs) such as a GHG levy, a feebate system, and fuel intensity regulations combined with carbon pricing. This study evaluates the economic and environmental impacts of these measures using an integrated computational simulation model that combines Ocean Engineering and Economics. Our results indicate that all proposed measures support the IMO’s intermediate emission reduction targets through 2035, cutting absolute emissions by more than 50%. However, economic impacts vary significantly across regions, with most of Africa, Asia, and South America experiencing the greatest adverse effects on GDP and trade. Among the measures, the GHG levy exerts the strongest pressure on economic activity and food prices, while a revised fuel intensity mechanism imposes lower costs, particularly in the short term. Revenue redistribution mitigates GDP losses but does so unevenly across regions. By leveraging a general equilibrium model (GTAP) to capture indirect effects often overlooked in prior studies, this analysis provides a comprehensive comparison of policy impacts. The findings underscore the need for equitable and pragmatic decarbonization strategies in the maritime sector, contributing to ongoing IMO policy discussions.

This paper evaluates how the contribution of scientific publications on climate change from the University of São Paulo (USP) evolved between 1989 and 2022. The study conducted a bibliometric analysis of 2874 research articles collected from the Web of Science and Scopus databases to explore main trend topics and reveal influential journals and collaboration networks using the Bibliometrix software. The study shows an increasing and more significant temporal publication distribution from 2010 onwards. Based on the author’s affiliations, results indicate that the most important partnerships are national (67%), while the international co-authorships are predominantly with research collaborators of the Global North (North America and Europe). Several papers published in the period are in high-impact factor journals, evidence on climate change from USP. Environmental services, Atlantic Forest, Tropical Forest, Amazon, biodiversity, and Land use are the hotspot research topics to which USP researchers contribute. The evolution of three thematic groups was identified: (i) physical science, (ii) causes and effects, and (iii) strategies, discussed in themes such as organic matter, deforestation, and mitigation, respectively. This research is helpful to get insights into the current research development trends, to show the broadness of the scientific production, and the importance of the USP role in the climate change theme. Ultimately, it provides valuable information for further studies and suggests the possibility of advancing the research agenda on climate change with the Global South. Graphical Abstract

In 2009, the Brazilian School Feeding Program (PNAE) became the first national initiative worldwide to mandate that at least 30% of federal resources—previously spent on public tenders—be directed toward the direct procurement of food from family farmers. In Brazil, these producers are more likely to adopt environmentally sustainable agricultural practices and supply fresh foods. This policy, therefore, aimed to both improve students’ diet quality and strengthen local food systems through support for family farmers. Despite its ambition, the nationwide socioeconomic effects of this procurement reform remain overlooked. This paper aims to fill this gap by using an integrated economic modelling framework that combines a difference-in-differences model and an input‒output model. With the difference-in-differences model, we estimate the change in family and nonfamily farmer production value due to the modification in the PNAE procurement requirements. The input‒output model was used to assess the effects on employment and gross domestic product (GDP), with a representation of productive segments of family and nonfamily farming using information provided by the Brazilian Agricultural Census. Our findings indicate a positive socioeconomic effect of the program through improvements in employment and GDP. During the follow-up period, changes in PNAE food procurement policies generated a net increase of R$15 million (US$ 5 million) in GDP and approximately 24 thousand new jobs nationally. Most of the jobs and positive economic results were greater for family farmers, whose income increased by R$ 39 million (or approximately US$ 12 million). These gains can be attributed to the economic structure depicted in the estimated input‒output, which identified livestock family production as a labour-intensive economic segment. Economic modelling suggests that PNAE has the potential to promote more equitable economic development. Addressing the identified compliance problems in several municipalities could enhance the estimated effects. Improved monitoring and provision of technical support to both local school feeding programme managers and family farmers can increase compliance and contribute to the promotion of healthier, more equitable and sustainable food systems.