RESEARCH shows that the world is undoubtedly warming. And, as the global average temperature keeps rising, heat waves are increasing in their frequency, duration and intensity for most of the world’s regions. Authors ADRIAAN VAN DER WALT, Senior Lecturer of Physical Geography and GIS, University of the Free State JENNIFER FITCHETT, Associate Professor of Physical Geography, University of the Witwatersrand SARAH ROFFE, Researcher, Agricultural Research Council But that doesn’t mean cold weather will disappear entirely. While annual extreme cold events are becoming less frequent and less intense, as you’d expect in a warming world, researchers suggest the climate systems that…