Climate change education is both important and challenging. Prior research suggests that many secondary school science teachers in the United States were conveying "mixed messages" to students that legitimized scientifically unwarranted explanations of recent global warming. In this paper, we focus on US climate education at the middle school level and assess whether teacher attention to recent global warming, and whether the messages conveyed to students, changed between 2014 and 2019. Pooling data from two nationally representative probability surveys of middle school science teachers, we show significant advances on several key criteria, but the prevalence of mixed messages remained high. Exploratory analysis suggests that improvements were spurred partly by the adoption of the Next Generation Science Standards by many states and by partly by shifts in the personal views of science educators.