A new report on climate change has painted a stark picture of New Zealand's contribution to global greenhouse gas emissions. It says climate change is already potentially irreversibly affecting the country's natural systems, and many aspects of climate change will continue for centuries. Global gross emissions of greenhouse gases rose 50 per cent from 1990 to 2013, mainly due to people burning more fossil fuels for electricity generation, heat, transport, manufacturing and construction. Despite New Zealand's contribution being quite small at 0.17 per cent, we have the fifth-highest level of emissions per person of the 35 countries in the OECD. Kathryn Ryan speaks with James Renwick, a professor at the School of Geography, Environment and Earth Sciences at Victoria University who contributed to the report.