In 1884, 120-years ago, when Gilbert & Sullivan penned the lines of The Mikado, the world was 0.8^oC cooler than today, and the Royal Botanic Garden Edinburgh had accumulated over 30 years of phenological flowering data. Looking forwards 120-years into the future, spring temperatures are likely to increase by a further 4.5^oC as the enhanced greenhouse effect, driven by the burning of fossil-fuels, accelerates. But what will be the impact of the warming on flowering and plant development? The talk will explore three scenarios. One outcome suggested by the 'out-of-synch' hypothesis is that ecosystems will become dangerously desynchronised. Experiments in controlled laboratory conditions along with genetic profiling and plant physiology models have demonstrated the vast and complex array of plant responses to environmental cues. As the climate warms some plants will flower much earlier, some much later. Animals and insects will display even more irregular responses. The impacts on ecosystems will be dramatic and unpredictable. A second outcome is suggested by the 'perpetual summer' hypothesis. Global warming can be an opportunity for commerce and industry. Scottish agriculture and forestry will boom in the extended growing season. Spring will arrive earlier while autumn will be delayed. Figs will flourish in suburban Edinburgh gardens and palm-trees will adorn the promenade. The third hypothesis 'slipping seasons' purports that the botanical year will shift with respect to the climatic year. The botanical spring will arrive earlier but so will the autumn and winter.

An extreme view, contrary to current wisdom, but one based on statistical modelling of the RBGE phenological data, coupled with a simple climate change model, is that all temperature dependent taxa (about 2/3 of all species) will react to global warming in exactly the same manner. The model predicts that, in Edinburgh, 'The flowers that bloom in the spring' will shift their growing season forwards by exactly 50 days (11.1 days for every degree of warming) in line with hypothesis three.
 

Convenor:Aidan Sudbury