Studying ancient tree leaf remains (fossils) found in New Zealand makes it possible to better understand the development and direction of climate change.

Scientists have studied tree leaves preserved from a forest that grew 23 million years ago. The study provides the first evidence of a link between high atmospheric carbon levels, increased plant development (growth), and relatively hot climatic conditions. The research has added to scientists' understanding of how the Earth warmed as CO2 levels in the atmosphere rose, and how plant life and development subsequently changed over the decades.