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Regional Impacts Among all the ramifications of climate change, perhaps none is more significant than the impact it has on agriculture. In the United States, agriculture, food, and related industries contribute almost a trillion dollars to the economy each year. Numerous studies have evaluated the adverse impacts of climate change on agriculture, but most of them only explored its impact on a single country or region without accounting for impacts on the rest of the world. Consequently, many studies produce biased results. A new study, however, explicitly quantifies the importance of accounting for global climate change when conducting regional assessments. The results show that indirect impacts of climate change from other regions of the world can be more important than the direct domestic impacts for markets connected by international trade. “In regions that are deeply integrated in global markets, the most important effects of climate change on the agricultural sector may come through international trade from outside the region rather than directly from within,” explains Petr Havlik, an IIASA researcher and coauthor of the new study. “As our study shows, regional assessments of climate change impacts that ignore international trade and climate change in the rest of the world may get even the sign of the domestic impacts wrong.” AMERICAS Overfishing of Atlantic cod around Newfoundland in eastern Canada led to a collapse in codfish stocks and the closing of cod fisheries in 1992. Researchers have observed that, before the collapse, the size at which cod matured and started to reproduce was gradually declining, and surmised that the phenomenon was likely an evolutionary response to heavy fishing. Since the 1990s, the Evolution and Ecology Program at IIASA has been at the forefront of research on how fish populations react to pressures from fishing. The program has been working with numerous international partners on various projects, including a collaboration with the Department of Fisheries and Oceans Canada to monitor how cod populations have been developing in Canadian waters since their collapse. The team’s most recent work shows, for the first time, that fishing has caused male cod to invest more energy into current reproduction, leaving them with less energy for their subsequent growth, reproduction, and survival. “One of the unanswered questions of our initial work was whether the life history of cod started to recover following the moratoria that were established around 1992. Despite initial signs of recovery, our more recent, and as yet unpublished research indicates that there has been none – only some minor fluctuations around a new mean. This underscores the importance of avoiding unwanted evolutionary changes,” says Mikko Heino, lead researcher for the project. The team’s research has informed many practical applications, including Evolutionary Impact Assessments – a collection of tools that allow fisheries managers to evaluate the impact of fishing regimes on evolution. Written by: Ansa Heyl Supporting the sustainable management of fisheries Further info: ar17.iiasa.ac.at/evolutionary-fisheries Mikko Heino: heino@iiasa.ac.at Further info: Baker JS, Havlik P, Beach R, Leclere D, Schmid E, Valin H, Cole J, Creason J, et al. (2018). Evaluating the effects of climate change on US agricultural systems: sensitivity to regional impact and trade expansion scenarios. Environmental Research Letters 13 (6): e064019 [pure.iiasa.ac.at/15342] Petr Havlik: havlikpt@iiasa.ac.at Written by: Jeremy Summers Analyzing the impacts of climate change on US agriculture 21www.iiasa.ac.at OptionsWinter 2018/19