Has spring already sprung?

Nature's Response To Climate Change....

Is Spring Getting Earlier?

This was the title of a talk given by Dr. Tim Sparks to the February 2003 Annual General Meeting of Woking Local Agenda 21, when he spoke about phenology, which is the timing of natural events, such as the first flowering of plants. He began by stating that the answer to the title's question is a definite `YES' as nature is already responding to a warming climate.

Historical records show fluctuations of the timing of spring events according to temperature. An outstanding series of records is that of the Marsham family in Norfolk, which began in 1736 and was continued by successive generations until 1958. They recorded 27 indicators of spring such as flowering dates, leafing dates, butterfly appearances etc. for a variety of species. Plotting of temperature against date of event shows a clear response to climatic conditions.

However not all species respond in the same way. The 176 years of Hawthorn flowering records (ranging from May 10 to June 19) demonstrated for 10C of warming, flowering occurred 10 days earlier but for Beech the difference was only four days. Early flowerings affect insect life. The Orange Tip Butterfly and Garlic Mustard need to remain synchronised so the caterpillars can feed on the Garlic Mustard.

The trend is the same for a variety of species including crops, for events to occur earlier in warmer years. Long term phenology records have provided an essential basis for comparison with changes in recent years. For example Jean Coomb's records in Ashtead of Oak leafing between 1950-2001 are a famous, immensely valuable series and form part of the Department of the Environment's Indicators of Climate Change. Natural events have been moving forward in this country for the last 60 years, and similar observations are being noted in other parts of the world.

What are the consequences of Climate Change? Already changes are affecting natural cycles. Problems in the synchronicity of the food chain are being experienced: birds like Great Tits hatch when the caterpillar peak has passed, etc. What is going to happen to the bluebell woods when canopy shading occurs earlier? What actions are we going to need to take to protect them? Associated threats of climate change include: more flooding, droughts, gales and outdoor fires, and sea level rise.

What actions can we take? Woking's 'Climate Change Strategy' is working towards ways to minimise emissions of gasses that contribute to global warming. Woking Local Agenda 21's Green Pages guide to environmentally friendly living presents a range of useful ideas.

You can contribute to understanding nature's response to climate change by joining in the UK Phenology Network's group of event recorders. There are in excess of 18,000 people across the country who are registered recorders with the Network. For information phone 01476 581111 or see www.phenology.org.uk.