The world is in a period of rapid change. Climate chaos is leading to floods and droughts and exacerbating inequality. A recent global survey indicated a majority of young people are 'very' or 'extremely' worried about climate change. This paper asks, in such a context, what is the role of mathematics education and, in particular, what can mathematics teacher educators (MTEs) do, in supporting teachers who want to engage in bringing global issues into their teaching? I report on work taking place in one university in the UK where, for the last 6 years, MTEs have been encouraging teachers to address global issues in their classroom. One role which has emerged for a MTE is in supporting the translation of scientific work on climate change into classroom tasks. In the UK, the spaces for such work are being squeezed in an increasingly politicized education system. The lens of critical mathematics education offers a mechanism for reflection on the role of the MTE.