Making new homes out of wood instead of steel and concrete could avoid more than 100 billion tonnes of CO2 being emitted over the next 80 years, and help avoid climate catastrophe, scientists have said.    More timber plantations will be required for supplying construction wood, which could be a risk to biodiversity "if not carefully managed", the experts warned, but wood has a significantly lower carbon footprint than steel and concrete.    The emissions savings from a wide-scale adoption of wood as a construction material in cities would account for around 10 ...